diff options
Diffstat (limited to 'fs/ext4/inode.c')
| -rw-r--r-- | fs/ext4/inode.c | 4676 |
1 files changed, 4676 insertions, 0 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c new file mode 100644 index 00000000..c77b0bd2 --- /dev/null +++ b/fs/ext4/inode.c @@ -0,0 +1,4676 @@ +/* + * linux/fs/ext4/inode.c + * + * Copyright (C) 1992, 1993, 1994, 1995 + * Remy Card (card@masi.ibp.fr) + * Laboratoire MASI - Institut Blaise Pascal + * Universite Pierre et Marie Curie (Paris VI) + * + * from + * + * linux/fs/minix/inode.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + * + * 64-bit file support on 64-bit platforms by Jakub Jelinek + * (jj@sunsite.ms.mff.cuni.cz) + * + * Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000 + */ + +#include <linux/fs.h> +#include <linux/time.h> +#include <linux/jbd2.h> +#include <linux/highuid.h> +#include <linux/pagemap.h> +#include <linux/quotaops.h> +#include <linux/string.h> +#include <linux/buffer_head.h> +#include <linux/writeback.h> +#include <linux/pagevec.h> +#include <linux/mpage.h> +#include <linux/namei.h> +#include <linux/uio.h> +#include <linux/bio.h> +#include <linux/workqueue.h> +#include <linux/kernel.h> +#include <linux/printk.h> +#include <linux/slab.h> +#include <linux/ratelimit.h> + +#include "ext4_jbd2.h" +#include "xattr.h" +#include "acl.h" +#include "truncate.h" + +#include <trace/events/ext4.h> + +#define MPAGE_DA_EXTENT_TAIL 0x01 + +static inline int ext4_begin_ordered_truncate(struct inode *inode, + loff_t new_size) +{ + trace_ext4_begin_ordered_truncate(inode, new_size); + /* + * If jinode is zero, then we never opened the file for + * writing, so there's no need to call + * jbd2_journal_begin_ordered_truncate() since there's no + * outstanding writes we need to flush. + */ + if (!EXT4_I(inode)->jinode) + return 0; + return jbd2_journal_begin_ordered_truncate(EXT4_JOURNAL(inode), + EXT4_I(inode)->jinode, + new_size); +} + +static void ext4_invalidatepage(struct page *page, unsigned long offset); +static int noalloc_get_block_write(struct inode *inode, sector_t iblock, + struct buffer_head *bh_result, int create); +static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode); +static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate); +static int __ext4_journalled_writepage(struct page *page, unsigned int len); +static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh); +static int ext4_discard_partial_page_buffers_no_lock(handle_t *handle, + struct inode *inode, struct page *page, loff_t from, + loff_t length, int flags); + +/* + * Test whether an inode is a fast symlink. + */ +static int ext4_inode_is_fast_symlink(struct inode *inode) +{ + int ea_blocks = EXT4_I(inode)->i_file_acl ? + (inode->i_sb->s_blocksize >> 9) : 0; + + return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0); +} + +/* + * Restart the transaction associated with *handle. This does a commit, + * so before we call here everything must be consistently dirtied against + * this transaction. + */ +int ext4_truncate_restart_trans(handle_t *handle, struct inode *inode, + int nblocks) +{ + int ret; + + /* + * Drop i_data_sem to avoid deadlock with ext4_map_blocks. At this + * moment, get_block can be called only for blocks inside i_size since + * page cache has been already dropped and writes are blocked by + * i_mutex. So we can safely drop the i_data_sem here. + */ + BUG_ON(EXT4_JOURNAL(inode) == NULL); + jbd_debug(2, "restarting handle %p\n", handle); + up_write(&EXT4_I(inode)->i_data_sem); + ret = ext4_journal_restart(handle, nblocks); + down_write(&EXT4_I(inode)->i_data_sem); + ext4_discard_preallocations(inode); + + return ret; +} + +/* + * Called at the last iput() if i_nlink is zero. + */ +void ext4_evict_inode(struct inode *inode) +{ + handle_t *handle; + int err; + + trace_ext4_evict_inode(inode); + + ext4_ioend_wait(inode); + + if (inode->i_nlink) { + /* + * When journalling data dirty buffers are tracked only in the + * journal. So although mm thinks everything is clean and + * ready for reaping the inode might still have some pages to + * write in the running transaction or waiting to be + * checkpointed. Thus calling jbd2_journal_invalidatepage() + * (via truncate_inode_pages()) to discard these buffers can + * cause data loss. Also even if we did not discard these + * buffers, we would have no way to find them after the inode + * is reaped and thus user could see stale data if he tries to + * read them before the transaction is checkpointed. So be + * careful and force everything to disk here... We use + * ei->i_datasync_tid to store the newest transaction + * containing inode's data. + * + * Note that directories do not have this problem because they + * don't use page cache. + */ + if (ext4_should_journal_data(inode) && + (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode))) { + journal_t *journal = EXT4_SB(inode->i_sb)->s_journal; + tid_t commit_tid = EXT4_I(inode)->i_datasync_tid; + + jbd2_log_start_commit(journal, commit_tid); + jbd2_log_wait_commit(journal, commit_tid); + filemap_write_and_wait(&inode->i_data); + } + truncate_inode_pages(&inode->i_data, 0); + goto no_delete; + } + + if (!is_bad_inode(inode)) + dquot_initialize(inode); + + if (ext4_should_order_data(inode)) + ext4_begin_ordered_truncate(inode, 0); + truncate_inode_pages(&inode->i_data, 0); + + if (is_bad_inode(inode)) + goto no_delete; + + handle = ext4_journal_start(inode, ext4_blocks_for_truncate(inode)+3); + if (IS_ERR(handle)) { + ext4_std_error(inode->i_sb, PTR_ERR(handle)); + /* + * If we're going to skip the normal cleanup, we still need to + * make sure that the in-core orphan linked list is properly + * cleaned up. + */ + ext4_orphan_del(NULL, inode); + goto no_delete; + } + + if (IS_SYNC(inode)) + ext4_handle_sync(handle); + inode->i_size = 0; + err = ext4_mark_inode_dirty(handle, inode); + if (err) { + ext4_warning(inode->i_sb, + "couldn't mark inode dirty (err %d)", err); + goto stop_handle; + } + if (inode->i_blocks) + ext4_truncate(inode); + + /* + * ext4_ext_truncate() doesn't reserve any slop when it + * restarts journal transactions; therefore there may not be + * enough credits left in the handle to remove the inode from + * the orphan list and set the dtime field. + */ + if (!ext4_handle_has_enough_credits(handle, 3)) { + err = ext4_journal_extend(handle, 3); + if (err > 0) + err = ext4_journal_restart(handle, 3); + if (err != 0) { + ext4_warning(inode->i_sb, + "couldn't extend journal (err %d)", err); + stop_handle: + ext4_journal_stop(handle); + ext4_orphan_del(NULL, inode); + goto no_delete; + } + } + + /* + * Kill off the orphan record which ext4_truncate created. + * AKPM: I think this can be inside the above `if'. + * Note that ext4_orphan_del() has to be able to cope with the + * deletion of a non-existent orphan - this is because we don't + * know if ext4_truncate() actually created an orphan record. + * (Well, we could do this if we need to, but heck - it works) + */ + ext4_orphan_del(handle, inode); + EXT4_I(inode)->i_dtime = get_seconds(); + + /* + * One subtle ordering requirement: if anything has gone wrong + * (transaction abort, IO errors, whatever), then we can still + * do these next steps (the fs will already have been marked as + * having errors), but we can't free the inode if the mark_dirty + * fails. + */ + if (ext4_mark_inode_dirty(handle, inode)) + /* If that failed, just do the required in-core inode clear. */ + ext4_clear_inode(inode); + else + ext4_free_inode(handle, inode); + ext4_journal_stop(handle); + return; +no_delete: + ext4_clear_inode(inode); /* We must guarantee clearing of inode... */ +} + +#ifdef CONFIG_QUOTA +qsize_t *ext4_get_reserved_space(struct inode *inode) +{ + return &EXT4_I(inode)->i_reserved_quota; +} +#endif + +/* + * Calculate the number of metadata blocks need to reserve + * to allocate a block located at @lblock + */ +static int ext4_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock) +{ + if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) + return ext4_ext_calc_metadata_amount(inode, lblock); + + return ext4_ind_calc_metadata_amount(inode, lblock); +} + +/* + * Called with i_data_sem down, which is important since we can call + * ext4_discard_preallocations() from here. + */ +void ext4_da_update_reserve_space(struct inode *inode, + int used, int quota_claim) +{ + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + struct ext4_inode_info *ei = EXT4_I(inode); + + spin_lock(&ei->i_block_reservation_lock); + trace_ext4_da_update_reserve_space(inode, used, quota_claim); + if (unlikely(used > ei->i_reserved_data_blocks)) { + ext4_msg(inode->i_sb, KERN_NOTICE, "%s: ino %lu, used %d " + "with only %d reserved data blocks", + __func__, inode->i_ino, used, + ei->i_reserved_data_blocks); + WARN_ON(1); + used = ei->i_reserved_data_blocks; + } + + /* Update per-inode reservations */ + ei->i_reserved_data_blocks -= used; + ei->i_reserved_meta_blocks -= ei->i_allocated_meta_blocks; + percpu_counter_sub(&sbi->s_dirtyclusters_counter, + used + ei->i_allocated_meta_blocks); + ei->i_allocated_meta_blocks = 0; + + if (ei->i_reserved_data_blocks == 0) { + /* + * We can release all of the reserved metadata blocks + * only when we have written all of the delayed + * allocation blocks. + */ + percpu_counter_sub(&sbi->s_dirtyclusters_counter, + ei->i_reserved_meta_blocks); + ei->i_reserved_meta_blocks = 0; + ei->i_da_metadata_calc_len = 0; + } + spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); + + /* Update quota subsystem for data blocks */ + if (quota_claim) + dquot_claim_block(inode, EXT4_C2B(sbi, used)); + else { + /* + * We did fallocate with an offset that is already delayed + * allocated. So on delayed allocated writeback we should + * not re-claim the quota for fallocated blocks. + */ + dquot_release_reservation_block(inode, EXT4_C2B(sbi, used)); + } + + /* + * If we have done all the pending block allocations and if + * there aren't any writers on the inode, we can discard the + * inode's preallocations. + */ + if ((ei->i_reserved_data_blocks == 0) && + (atomic_read(&inode->i_writecount) == 0)) + ext4_discard_preallocations(inode); +} + +static int __check_block_validity(struct inode *inode, const char *func, + unsigned int line, + struct ext4_map_blocks *map) +{ + if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), map->m_pblk, + map->m_len)) { + ext4_error_inode(inode, func, line, map->m_pblk, + "lblock %lu mapped to illegal pblock " + "(length %d)", (unsigned long) map->m_lblk, + map->m_len); + return -EIO; + } + return 0; +} + +#define check_block_validity(inode, map) \ + __check_block_validity((inode), __func__, __LINE__, (map)) + +/* + * Return the number of contiguous dirty pages in a given inode + * starting at page frame idx. + */ +static pgoff_t ext4_num_dirty_pages(struct inode *inode, pgoff_t idx, + unsigned int max_pages) +{ + struct address_space *mapping = inode->i_mapping; + pgoff_t index; + struct pagevec pvec; + pgoff_t num = 0; + int i, nr_pages, done = 0; + + if (max_pages == 0) + return 0; + pagevec_init(&pvec, 0); + while (!done) { + index = idx; + nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, + PAGECACHE_TAG_DIRTY, + (pgoff_t)PAGEVEC_SIZE); + if (nr_pages == 0) + break; + for (i = 0; i < nr_pages; i++) { + struct page *page = pvec.pages[i]; + struct buffer_head *bh, *head; + + lock_page(page); + if (unlikely(page->mapping != mapping) || + !PageDirty(page) || + PageWriteback(page) || + page->index != idx) { + done = 1; + unlock_page(page); + break; + } + if (page_has_buffers(page)) { + bh = head = page_buffers(page); + do { + if (!buffer_delay(bh) && + !buffer_unwritten(bh)) + done = 1; + bh = bh->b_this_page; + } while (!done && (bh != head)); + } + unlock_page(page); + if (done) + break; + idx++; + num++; + if (num >= max_pages) { + done = 1; + break; + } + } + pagevec_release(&pvec); + } + return num; +} + +/* + * Sets the BH_Da_Mapped bit on the buffer heads corresponding to the given map. + */ +static void set_buffers_da_mapped(struct inode *inode, + struct ext4_map_blocks *map) +{ + struct address_space *mapping = inode->i_mapping; + struct pagevec pvec; + int i, nr_pages; + pgoff_t index, end; + + index = map->m_lblk >> (PAGE_CACHE_SHIFT - inode->i_blkbits); + end = (map->m_lblk + map->m_len - 1) >> + (PAGE_CACHE_SHIFT - inode->i_blkbits); + + pagevec_init(&pvec, 0); + while (index <= end) { + nr_pages = pagevec_lookup(&pvec, mapping, index, + min(end - index + 1, + (pgoff_t)PAGEVEC_SIZE)); + if (nr_pages == 0) + break; + for (i = 0; i < nr_pages; i++) { + struct page *page = pvec.pages[i]; + struct buffer_head *bh, *head; + + if (unlikely(page->mapping != mapping) || + !PageDirty(page)) + break; + + if (page_has_buffers(page)) { + bh = head = page_buffers(page); + do { + set_buffer_da_mapped(bh); + bh = bh->b_this_page; + } while (bh != head); + } + index++; + } + pagevec_release(&pvec); + } +} + +/* + * The ext4_map_blocks() function tries to look up the requested blocks, + * and returns if the blocks are already mapped. + * + * Otherwise it takes the write lock of the i_data_sem and allocate blocks + * and store the allocated blocks in the result buffer head and mark it + * mapped. + * + * If file type is extents based, it will call ext4_ext_map_blocks(), + * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping + * based files + * + * On success, it returns the number of blocks being mapped or allocate. + * if create==0 and the blocks are pre-allocated and uninitialized block, + * the result buffer head is unmapped. If the create ==1, it will make sure + * the buffer head is mapped. + * + * It returns 0 if plain look up failed (blocks have not been allocated), in + * that case, buffer head is unmapped + * + * It returns the error in case of allocation failure. + */ +int ext4_map_blocks(handle_t *handle, struct inode *inode, + struct ext4_map_blocks *map, int flags) +{ + int retval; + + map->m_flags = 0; + ext_debug("ext4_map_blocks(): inode %lu, flag %d, max_blocks %u," + "logical block %lu\n", inode->i_ino, flags, map->m_len, + (unsigned long) map->m_lblk); + /* + * Try to see if we can get the block without requesting a new + * file system block. + */ + down_read((&EXT4_I(inode)->i_data_sem)); + if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { + retval = ext4_ext_map_blocks(handle, inode, map, flags & + EXT4_GET_BLOCKS_KEEP_SIZE); + } else { + retval = ext4_ind_map_blocks(handle, inode, map, flags & + EXT4_GET_BLOCKS_KEEP_SIZE); + } + up_read((&EXT4_I(inode)->i_data_sem)); + + if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) { + int ret = check_block_validity(inode, map); + if (ret != 0) + return ret; + } + + /* If it is only a block(s) look up */ + if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) + return retval; + + /* + * Returns if the blocks have already allocated + * + * Note that if blocks have been preallocated + * ext4_ext_get_block() returns the create = 0 + * with buffer head unmapped. + */ + if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) + return retval; + + /* + * When we call get_blocks without the create flag, the + * BH_Unwritten flag could have gotten set if the blocks + * requested were part of a uninitialized extent. We need to + * clear this flag now that we are committed to convert all or + * part of the uninitialized extent to be an initialized + * extent. This is because we need to avoid the combination + * of BH_Unwritten and BH_Mapped flags being simultaneously + * set on the buffer_head. + */ + map->m_flags &= ~EXT4_MAP_UNWRITTEN; + + /* + * New blocks allocate and/or writing to uninitialized extent + * will possibly result in updating i_data, so we take + * the write lock of i_data_sem, and call get_blocks() + * with create == 1 flag. + */ + down_write((&EXT4_I(inode)->i_data_sem)); + + /* + * if the caller is from delayed allocation writeout path + * we have already reserved fs blocks for allocation + * let the underlying get_block() function know to + * avoid double accounting + */ + if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) + ext4_set_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED); + /* + * We need to check for EXT4 here because migrate + * could have changed the inode type in between + */ + if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { + retval = ext4_ext_map_blocks(handle, inode, map, flags); + } else { + retval = ext4_ind_map_blocks(handle, inode, map, flags); + + if (retval > 0 && map->m_flags & EXT4_MAP_NEW) { + /* + * We allocated new blocks which will result in + * i_data's format changing. Force the migrate + * to fail by clearing migrate flags + */ + ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE); + } + + /* + * Update reserved blocks/metadata blocks after successful + * block allocation which had been deferred till now. We don't + * support fallocate for non extent files. So we can update + * reserve space here. + */ + if ((retval > 0) && + (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)) + ext4_da_update_reserve_space(inode, retval, 1); + } + if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) { + ext4_clear_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED); + + /* If we have successfully mapped the delayed allocated blocks, + * set the BH_Da_Mapped bit on them. Its important to do this + * under the protection of i_data_sem. + */ + if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) + set_buffers_da_mapped(inode, map); + } + + up_write((&EXT4_I(inode)->i_data_sem)); + if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) { + int ret = check_block_validity(inode, map); + if (ret != 0) + return ret; + } + return retval; +} + +/* Maximum number of blocks we map for direct IO at once. */ +#define DIO_MAX_BLOCKS 4096 + +static int _ext4_get_block(struct inode *inode, sector_t iblock, + struct buffer_head *bh, int flags) +{ + handle_t *handle = ext4_journal_current_handle(); + struct ext4_map_blocks map; + int ret = 0, started = 0; + int dio_credits; + + map.m_lblk = iblock; + map.m_len = bh->b_size >> inode->i_blkbits; + + if (flags && !handle) { + /* Direct IO write... */ + if (map.m_len > DIO_MAX_BLOCKS) + map.m_len = DIO_MAX_BLOCKS; + dio_credits = ext4_chunk_trans_blocks(inode, map.m_len); + handle = ext4_journal_start(inode, dio_credits); + if (IS_ERR(handle)) { + ret = PTR_ERR(handle); + return ret; + } + started = 1; + } + + ret = ext4_map_blocks(handle, inode, &map, flags); + if (ret > 0) { + map_bh(bh, inode->i_sb, map.m_pblk); + bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags; + bh->b_size = inode->i_sb->s_blocksize * map.m_len; + ret = 0; + } + if (started) + ext4_journal_stop(handle); + return ret; +} + +int ext4_get_block(struct inode *inode, sector_t iblock, + struct buffer_head *bh, int create) +{ + return _ext4_get_block(inode, iblock, bh, + create ? EXT4_GET_BLOCKS_CREATE : 0); +} + +/* + * `handle' can be NULL if create is zero + */ +struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode, + ext4_lblk_t block, int create, int *errp) +{ + struct ext4_map_blocks map; + struct buffer_head *bh; + int fatal = 0, err; + + J_ASSERT(handle != NULL || create == 0); + + map.m_lblk = block; + map.m_len = 1; + err = ext4_map_blocks(handle, inode, &map, + create ? EXT4_GET_BLOCKS_CREATE : 0); + + if (err < 0) + *errp = err; + if (err <= 0) + return NULL; + *errp = 0; + + bh = sb_getblk(inode->i_sb, map.m_pblk); + if (!bh) { + *errp = -EIO; + return NULL; + } + if (map.m_flags & EXT4_MAP_NEW) { + J_ASSERT(create != 0); + J_ASSERT(handle != NULL); + + /* + * Now that we do not always journal data, we should + * keep in mind whether this should always journal the + * new buffer as metadata. For now, regular file + * writes use ext4_get_block instead, so it's not a + * problem. + */ + lock_buffer(bh); + BUFFER_TRACE(bh, "call get_create_access"); + fatal = ext4_journal_get_create_access(handle, bh); + if (!fatal && !buffer_uptodate(bh)) { + memset(bh->b_data, 0, inode->i_sb->s_blocksize); + set_buffer_uptodate(bh); + } + unlock_buffer(bh); + BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata"); + err = ext4_handle_dirty_metadata(handle, inode, bh); + if (!fatal) + fatal = err; + } else { + BUFFER_TRACE(bh, "not a new buffer"); + } + if (fatal) { + *errp = fatal; + brelse(bh); + bh = NULL; + } + return bh; +} + +struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode, + ext4_lblk_t block, int create, int *err) +{ + struct buffer_head *bh; + + bh = ext4_getblk(handle, inode, block, create, err); + if (!bh) + return bh; + if (buffer_uptodate(bh)) + return bh; + ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh); + wait_on_buffer(bh); + if (buffer_uptodate(bh)) + return bh; + put_bh(bh); + *err = -EIO; + return NULL; +} + +static int walk_page_buffers(handle_t *handle, + struct buffer_head *head, + unsigned from, + unsigned to, + int *partial, + int (*fn)(handle_t *handle, + struct buffer_head *bh)) +{ + struct buffer_head *bh; + unsigned block_start, block_end; + unsigned blocksize = head->b_size; + int err, ret = 0; + struct buffer_head *next; + + for (bh = head, block_start = 0; + ret == 0 && (bh != head || !block_start); + block_start = block_end, bh = next) { + next = bh->b_this_page; + block_end = block_start + blocksize; + if (block_end <= from || block_start >= to) { + if (partial && !buffer_uptodate(bh)) + *partial = 1; + continue; + } + err = (*fn)(handle, bh); + if (!ret) + ret = err; + } + return ret; +} + +/* + * To preserve ordering, it is essential that the hole instantiation and + * the data write be encapsulated in a single transaction. We cannot + * close off a transaction and start a new one between the ext4_get_block() + * and the commit_write(). So doing the jbd2_journal_start at the start of + * prepare_write() is the right place. + * + * Also, this function can nest inside ext4_writepage() -> + * block_write_full_page(). In that case, we *know* that ext4_writepage() + * has generated enough buffer credits to do the whole page. So we won't + * block on the journal in that case, which is good, because the caller may + * be PF_MEMALLOC. + * + * By accident, ext4 can be reentered when a transaction is open via + * quota file writes. If we were to commit the transaction while thus + * reentered, there can be a deadlock - we would be holding a quota + * lock, and the commit would never complete if another thread had a + * transaction open and was blocking on the quota lock - a ranking + * violation. + * + * So what we do is to rely on the fact that jbd2_journal_stop/journal_start + * will _not_ run commit under these circumstances because handle->h_ref + * is elevated. We'll still have enough credits for the tiny quotafile + * write. + */ +static int do_journal_get_write_access(handle_t *handle, + struct buffer_head *bh) +{ + int dirty = buffer_dirty(bh); + int ret; + + if (!buffer_mapped(bh) || buffer_freed(bh)) + return 0; + /* + * __block_write_begin() could have dirtied some buffers. Clean + * the dirty bit as jbd2_journal_get_write_access() could complain + * otherwise about fs integrity issues. Setting of the dirty bit + * by __block_write_begin() isn't a real problem here as we clear + * the bit before releasing a page lock and thus writeback cannot + * ever write the buffer. + */ + if (dirty) + clear_buffer_dirty(bh); + ret = ext4_journal_get_write_access(handle, bh); + if (!ret && dirty) + ret = ext4_handle_dirty_metadata(handle, NULL, bh); + return ret; +} + +static int ext4_get_block_write(struct inode *inode, sector_t iblock, + struct buffer_head *bh_result, int create); +static int ext4_write_begin(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned flags, + struct page **pagep, void **fsdata) +{ + struct inode *inode = mapping->host; + int ret, needed_blocks; + handle_t *handle; + int retries = 0; + struct page *page; + pgoff_t index; + unsigned from, to; + + trace_ext4_write_begin(inode, pos, len, flags); + /* + * Reserve one block more for addition to orphan list in case + * we allocate blocks but write fails for some reason + */ + needed_blocks = ext4_writepage_trans_blocks(inode) + 1; + index = pos >> PAGE_CACHE_SHIFT; + from = pos & (PAGE_CACHE_SIZE - 1); + to = from + len; + +retry: + handle = ext4_journal_start(inode, needed_blocks); + if (IS_ERR(handle)) { + ret = PTR_ERR(handle); + goto out; + } + + /* We cannot recurse into the filesystem as the transaction is already + * started */ + flags |= AOP_FLAG_NOFS; + + page = grab_cache_page_write_begin(mapping, index, flags); + if (!page) { + ext4_journal_stop(handle); + ret = -ENOMEM; + goto out; + } + *pagep = page; + + if (ext4_should_dioread_nolock(inode)) + ret = __block_write_begin(page, pos, len, ext4_get_block_write); + else + ret = __block_write_begin(page, pos, len, ext4_get_block); + + if (!ret && ext4_should_journal_data(inode)) { + ret = walk_page_buffers(handle, page_buffers(page), + from, to, NULL, do_journal_get_write_access); + } + + if (ret) { + unlock_page(page); + page_cache_release(page); + /* + * __block_write_begin may have instantiated a few blocks + * outside i_size. Trim these off again. Don't need + * i_size_read because we hold i_mutex. + * + * Add inode to orphan list in case we crash before + * truncate finishes + */ + if (pos + len > inode->i_size && ext4_can_truncate(inode)) + ext4_orphan_add(handle, inode); + + ext4_journal_stop(handle); + if (pos + len > inode->i_size) { + ext4_truncate_failed_write(inode); + /* + * If truncate failed early the inode might + * still be on the orphan list; we need to + * make sure the inode is removed from the + * orphan list in that case. + */ + if (inode->i_nlink) + ext4_orphan_del(NULL, inode); + } + } + + if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) + goto retry; +out: + return ret; +} + +/* For write_end() in data=journal mode */ +static int write_end_fn(handle_t *handle, struct buffer_head *bh) +{ + if (!buffer_mapped(bh) || buffer_freed(bh)) + return 0; + set_buffer_uptodate(bh); + return ext4_handle_dirty_metadata(handle, NULL, bh); +} + +static int ext4_generic_write_end(struct file *file, + struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *page, void *fsdata) +{ + int i_size_changed = 0; + struct inode *inode = mapping->host; + handle_t *handle = ext4_journal_current_handle(); + + copied = block_write_end(file, mapping, pos, len, copied, page, fsdata); + + /* + * No need to use i_size_read() here, the i_size + * cannot change under us because we hold i_mutex. + * + * But it's important to update i_size while still holding page lock: + * page writeout could otherwise come in and zero beyond i_size. + */ + if (pos + copied > inode->i_size) { + i_size_write(inode, pos + copied); + i_size_changed = 1; + } + + if (pos + copied > EXT4_I(inode)->i_disksize) { + /* We need to mark inode dirty even if + * new_i_size is less that inode->i_size + * bu greater than i_disksize.(hint delalloc) + */ + ext4_update_i_disksize(inode, (pos + copied)); + i_size_changed = 1; + } + unlock_page(page); + page_cache_release(page); + + /* + * Don't mark the inode dirty under page lock. First, it unnecessarily + * makes the holding time of page lock longer. Second, it forces lock + * ordering of page lock and transaction start for journaling + * filesystems. + */ + if (i_size_changed) + ext4_mark_inode_dirty(handle, inode); + + return copied; +} + +/* + * We need to pick up the new inode size which generic_commit_write gave us + * `file' can be NULL - eg, when called from page_symlink(). + * + * ext4 never places buffers on inode->i_mapping->private_list. metadata + * buffers are managed internally. + */ +static int ext4_ordered_write_end(struct file *file, + struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *page, void *fsdata) +{ + handle_t *handle = ext4_journal_current_handle(); + struct inode *inode = mapping->host; + int ret = 0, ret2; + + trace_ext4_ordered_write_end(inode, pos, len, copied); + ret = ext4_jbd2_file_inode(handle, inode); + + if (ret == 0) { + ret2 = ext4_generic_write_end(file, mapping, pos, len, copied, + page, fsdata); + copied = ret2; + if (pos + len > inode->i_size && ext4_can_truncate(inode)) + /* if we have allocated more blocks and copied + * less. We will have blocks allocated outside + * inode->i_size. So truncate them + */ + ext4_orphan_add(handle, inode); + if (ret2 < 0) + ret = ret2; + } else { + unlock_page(page); + page_cache_release(page); + } + + ret2 = ext4_journal_stop(handle); + if (!ret) + ret = ret2; + + if (pos + len > inode->i_size) { + ext4_truncate_failed_write(inode); + /* + * If truncate failed early the inode might still be + * on the orphan list; we need to make sure the inode + * is removed from the orphan list in that case. + */ + if (inode->i_nlink) + ext4_orphan_del(NULL, inode); + } + + + return ret ? ret : copied; +} + +static int ext4_writeback_write_end(struct file *file, + struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *page, void *fsdata) +{ + handle_t *handle = ext4_journal_current_handle(); + struct inode *inode = mapping->host; + int ret = 0, ret2; + + trace_ext4_writeback_write_end(inode, pos, len, copied); + ret2 = ext4_generic_write_end(file, mapping, pos, len, copied, + page, fsdata); + copied = ret2; + if (pos + len > inode->i_size && ext4_can_truncate(inode)) + /* if we have allocated more blocks and copied + * less. We will have blocks allocated outside + * inode->i_size. So truncate them + */ + ext4_orphan_add(handle, inode); + + if (ret2 < 0) + ret = ret2; + + ret2 = ext4_journal_stop(handle); + if (!ret) + ret = ret2; + + if (pos + len > inode->i_size) { + ext4_truncate_failed_write(inode); + /* + * If truncate failed early the inode might still be + * on the orphan list; we need to make sure the inode + * is removed from the orphan list in that case. + */ + if (inode->i_nlink) + ext4_orphan_del(NULL, inode); + } + + return ret ? ret : copied; +} + +static int ext4_journalled_write_end(struct file *file, + struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *page, void *fsdata) +{ + handle_t *handle = ext4_journal_current_handle(); + struct inode *inode = mapping->host; + int ret = 0, ret2; + int partial = 0; + unsigned from, to; + loff_t new_i_size; + + trace_ext4_journalled_write_end(inode, pos, len, copied); + from = pos & (PAGE_CACHE_SIZE - 1); + to = from + len; + + BUG_ON(!ext4_handle_valid(handle)); + + if (copied < len) { + if (!PageUptodate(page)) + copied = 0; + page_zero_new_buffers(page, from+copied, to); + } + + ret = walk_page_buffers(handle, page_buffers(page), from, + to, &partial, write_end_fn); + if (!partial) + SetPageUptodate(page); + new_i_size = pos + copied; + if (new_i_size > inode->i_size) + i_size_write(inode, pos+copied); + ext4_set_inode_state(inode, EXT4_STATE_JDATA); + EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid; + if (new_i_size > EXT4_I(inode)->i_disksize) { + ext4_update_i_disksize(inode, new_i_size); + ret2 = ext4_mark_inode_dirty(handle, inode); + if (!ret) + ret = ret2; + } + + unlock_page(page); + page_cache_release(page); + if (pos + len > inode->i_size && ext4_can_truncate(inode)) + /* if we have allocated more blocks and copied + * less. We will have blocks allocated outside + * inode->i_size. So truncate them + */ + ext4_orphan_add(handle, inode); + + ret2 = ext4_journal_stop(handle); + if (!ret) + ret = ret2; + if (pos + len > inode->i_size) { + ext4_truncate_failed_write(inode); + /* + * If truncate failed early the inode might still be + * on the orphan list; we need to make sure the inode + * is removed from the orphan list in that case. + */ + if (inode->i_nlink) + ext4_orphan_del(NULL, inode); + } + + return ret ? ret : copied; +} + +/* + * Reserve a single cluster located at lblock + */ +static int ext4_da_reserve_space(struct inode *inode, ext4_lblk_t lblock) +{ + int retries = 0; + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + struct ext4_inode_info *ei = EXT4_I(inode); + unsigned int md_needed; + int ret; + + /* + * recalculate the amount of metadata blocks to reserve + * in order to allocate nrblocks + * worse case is one extent per block + */ +repeat: + spin_lock(&ei->i_block_reservation_lock); + md_needed = EXT4_NUM_B2C(sbi, + ext4_calc_metadata_amount(inode, lblock)); + trace_ext4_da_reserve_space(inode, md_needed); + spin_unlock(&ei->i_block_reservation_lock); + + /* + * We will charge metadata quota at writeout time; this saves + * us from metadata over-estimation, though we may go over by + * a small amount in the end. Here we just reserve for data. + */ + ret = dquot_reserve_block(inode, EXT4_C2B(sbi, 1)); + if (ret) + return ret; + /* + * We do still charge estimated metadata to the sb though; + * we cannot afford to run out of free blocks. + */ + if (ext4_claim_free_clusters(sbi, md_needed + 1, 0)) { + dquot_release_reservation_block(inode, EXT4_C2B(sbi, 1)); + if (ext4_should_retry_alloc(inode->i_sb, &retries)) { + yield(); + goto repeat; + } + return -ENOSPC; + } + spin_lock(&ei->i_block_reservation_lock); + ei->i_reserved_data_blocks++; + ei->i_reserved_meta_blocks += md_needed; + spin_unlock(&ei->i_block_reservation_lock); + + return 0; /* success */ +} + +static void ext4_da_release_space(struct inode *inode, int to_free) +{ + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + struct ext4_inode_info *ei = EXT4_I(inode); + + if (!to_free) + return; /* Nothing to release, exit */ + + spin_lock(&EXT4_I(inode)->i_block_reservation_lock); + + trace_ext4_da_release_space(inode, to_free); + if (unlikely(to_free > ei->i_reserved_data_blocks)) { + /* + * if there aren't enough reserved blocks, then the + * counter is messed up somewhere. Since this + * function is called from invalidate page, it's + * harmless to return without any action. + */ + ext4_msg(inode->i_sb, KERN_NOTICE, "ext4_da_release_space: " + "ino %lu, to_free %d with only %d reserved " + "data blocks", inode->i_ino, to_free, + ei->i_reserved_data_blocks); + WARN_ON(1); + to_free = ei->i_reserved_data_blocks; + } + ei->i_reserved_data_blocks -= to_free; + + if (ei->i_reserved_data_blocks == 0) { + /* + * We can release all of the reserved metadata blocks + * only when we have written all of the delayed + * allocation blocks. + * Note that in case of bigalloc, i_reserved_meta_blocks, + * i_reserved_data_blocks, etc. refer to number of clusters. + */ + percpu_counter_sub(&sbi->s_dirtyclusters_counter, + ei->i_reserved_meta_blocks); + ei->i_reserved_meta_blocks = 0; + ei->i_da_metadata_calc_len = 0; + } + + /* update fs dirty data blocks counter */ + percpu_counter_sub(&sbi->s_dirtyclusters_counter, to_free); + + spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); + + dquot_release_reservation_block(inode, EXT4_C2B(sbi, to_free)); +} + +static void ext4_da_page_release_reservation(struct page *page, + unsigned long offset) +{ + int to_release = 0; + struct buffer_head *head, *bh; + unsigned int curr_off = 0; + struct inode *inode = page->mapping->host; + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + int num_clusters; + + head = page_buffers(page); + bh = head; + do { + unsigned int next_off = curr_off + bh->b_size; + + if ((offset <= curr_off) && (buffer_delay(bh))) { + to_release++; + clear_buffer_delay(bh); + clear_buffer_da_mapped(bh); + } + curr_off = next_off; + } while ((bh = bh->b_this_page) != head); + + /* If we have released all the blocks belonging to a cluster, then we + * need to release the reserved space for that cluster. */ + num_clusters = EXT4_NUM_B2C(sbi, to_release); + while (num_clusters > 0) { + ext4_fsblk_t lblk; + lblk = (page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits)) + + ((num_clusters - 1) << sbi->s_cluster_bits); + if (sbi->s_cluster_ratio == 1 || + !ext4_find_delalloc_cluster(inode, lblk, 1)) + ext4_da_release_space(inode, 1); + + num_clusters--; + } +} + +/* + * Delayed allocation stuff + */ + +/* + * mpage_da_submit_io - walks through extent of pages and try to write + * them with writepage() call back + * + * @mpd->inode: inode + * @mpd->first_page: first page of the extent + * @mpd->next_page: page after the last page of the extent + * + * By the time mpage_da_submit_io() is called we expect all blocks + * to be allocated. this may be wrong if allocation failed. + * + * As pages are already locked by write_cache_pages(), we can't use it + */ +static int mpage_da_submit_io(struct mpage_da_data *mpd, + struct ext4_map_blocks *map) +{ + struct pagevec pvec; + unsigned long index, end; + int ret = 0, err, nr_pages, i; + struct inode *inode = mpd->inode; + struct address_space *mapping = inode->i_mapping; + loff_t size = i_size_read(inode); + unsigned int len, block_start; + struct buffer_head *bh, *page_bufs = NULL; + int journal_data = ext4_should_journal_data(inode); + sector_t pblock = 0, cur_logical = 0; + struct ext4_io_submit io_submit; + + BUG_ON(mpd->next_page <= mpd->first_page); + memset(&io_submit, 0, sizeof(io_submit)); + /* + * We need to start from the first_page to the next_page - 1 + * to make sure we also write the mapped dirty buffer_heads. + * If we look at mpd->b_blocknr we would only be looking + * at the currently mapped buffer_heads. + */ + index = mpd->first_page; + end = mpd->next_page - 1; + + pagevec_init(&pvec, 0); + while (index <= end) { + nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE); + if (nr_pages == 0) + break; + for (i = 0; i < nr_pages; i++) { + int commit_write = 0, skip_page = 0; + struct page *page = pvec.pages[i]; + + index = page->index; + if (index > end) + break; + + if (index == size >> PAGE_CACHE_SHIFT) + len = size & ~PAGE_CACHE_MASK; + else + len = PAGE_CACHE_SIZE; + if (map) { + cur_logical = index << (PAGE_CACHE_SHIFT - + inode->i_blkbits); + pblock = map->m_pblk + (cur_logical - + map->m_lblk); + } + index++; + + BUG_ON(!PageLocked(page)); + BUG_ON(PageWriteback(page)); + + /* + * If the page does not have buffers (for + * whatever reason), try to create them using + * __block_write_begin. If this fails, + * skip the page and move on. + */ + if (!page_has_buffers(page)) { + if (__block_write_begin(page, 0, len, + noalloc_get_block_write)) { + skip_page: + unlock_page(page); + continue; + } + commit_write = 1; + } + + bh = page_bufs = page_buffers(page); + block_start = 0; + do { + if (!bh) + goto skip_page; + if (map && (cur_logical >= map->m_lblk) && + (cur_logical <= (map->m_lblk + + (map->m_len - 1)))) { + if (buffer_delay(bh)) { + clear_buffer_delay(bh); + bh->b_blocknr = pblock; + } + if (buffer_da_mapped(bh)) + clear_buffer_da_mapped(bh); + if (buffer_unwritten(bh) || + buffer_mapped(bh)) + BUG_ON(bh->b_blocknr != pblock); + if (map->m_flags & EXT4_MAP_UNINIT) + set_buffer_uninit(bh); + clear_buffer_unwritten(bh); + } + + /* + * skip page if block allocation undone and + * block is dirty + */ + if (ext4_bh_delay_or_unwritten(NULL, bh)) + skip_page = 1; + bh = bh->b_this_page; + block_start += bh->b_size; + cur_logical++; + pblock++; + } while (bh != page_bufs); + + if (skip_page) + goto skip_page; + + if (commit_write) + /* mark the buffer_heads as dirty & uptodate */ + block_commit_write(page, 0, len); + + clear_page_dirty_for_io(page); + /* + * Delalloc doesn't support data journalling, + * but eventually maybe we'll lift this + * restriction. + */ + if (unlikely(journal_data && PageChecked(page))) + err = __ext4_journalled_writepage(page, len); + else if (test_opt(inode->i_sb, MBLK_IO_SUBMIT)) + err = ext4_bio_write_page(&io_submit, page, + len, mpd->wbc); + else if (buffer_uninit(page_bufs)) { + ext4_set_bh_endio(page_bufs, inode); + err = block_write_full_page_endio(page, + noalloc_get_block_write, + mpd->wbc, ext4_end_io_buffer_write); + } else + err = block_write_full_page(page, + noalloc_get_block_write, mpd->wbc); + + if (!err) + mpd->pages_written++; + /* + * In error case, we have to continue because + * remaining pages are still locked + */ + if (ret == 0) + ret = err; + } + pagevec_release(&pvec); + } + ext4_io_submit(&io_submit); + return ret; +} + +static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd) +{ + int nr_pages, i; + pgoff_t index, end; + struct pagevec pvec; + struct inode *inode = mpd->inode; + struct address_space *mapping = inode->i_mapping; + + index = mpd->first_page; + end = mpd->next_page - 1; + while (index <= end) { + nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE); + if (nr_pages == 0) + break; + for (i = 0; i < nr_pages; i++) { + struct page *page = pvec.pages[i]; + if (page->index > end) + break; + BUG_ON(!PageLocked(page)); + BUG_ON(PageWriteback(page)); + block_invalidatepage(page, 0); + ClearPageUptodate(page); + unlock_page(page); + } + index = pvec.pages[nr_pages - 1]->index + 1; + pagevec_release(&pvec); + } + return; +} + +static void ext4_print_free_blocks(struct inode *inode) +{ + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + struct super_block *sb = inode->i_sb; + + ext4_msg(sb, KERN_CRIT, "Total free blocks count %lld", + EXT4_C2B(EXT4_SB(inode->i_sb), + ext4_count_free_clusters(inode->i_sb))); + ext4_msg(sb, KERN_CRIT, "Free/Dirty block details"); + ext4_msg(sb, KERN_CRIT, "free_blocks=%lld", + (long long) EXT4_C2B(EXT4_SB(inode->i_sb), + percpu_counter_sum(&sbi->s_freeclusters_counter))); + ext4_msg(sb, KERN_CRIT, "dirty_blocks=%lld", + (long long) EXT4_C2B(EXT4_SB(inode->i_sb), + percpu_counter_sum(&sbi->s_dirtyclusters_counter))); + ext4_msg(sb, KERN_CRIT, "Block reservation details"); + ext4_msg(sb, KERN_CRIT, "i_reserved_data_blocks=%u", + EXT4_I(inode)->i_reserved_data_blocks); + ext4_msg(sb, KERN_CRIT, "i_reserved_meta_blocks=%u", + EXT4_I(inode)->i_reserved_meta_blocks); + return; +} + +/* + * mpage_da_map_and_submit - go through given space, map them + * if necessary, and then submit them for I/O + * + * @mpd - bh describing space + * + * The function skips space we know is already mapped to disk blocks. + * + */ +static void mpage_da_map_and_submit(struct mpage_da_data *mpd) +{ + int err, blks, get_blocks_flags; + struct ext4_map_blocks map, *mapp = NULL; + sector_t next = mpd->b_blocknr; + unsigned max_blocks = mpd->b_size >> mpd->inode->i_blkbits; + loff_t disksize = EXT4_I(mpd->inode)->i_disksize; + handle_t *handle = NULL; + + /* + * If the blocks are mapped already, or we couldn't accumulate + * any blocks, then proceed immediately to the submission stage. + */ + if ((mpd->b_size == 0) || + ((mpd->b_state & (1 << BH_Mapped)) && + !(mpd->b_state & (1 << BH_Delay)) && + !(mpd->b_state & (1 << BH_Unwritten)))) + goto submit_io; + + handle = ext4_journal_current_handle(); + BUG_ON(!handle); + + /* + * Call ext4_map_blocks() to allocate any delayed allocation + * blocks, or to convert an uninitialized extent to be + * initialized (in the case where we have written into + * one or more preallocated blocks). + * + * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE to + * indicate that we are on the delayed allocation path. This + * affects functions in many different parts of the allocation + * call path. This flag exists primarily because we don't + * want to change *many* call functions, so ext4_map_blocks() + * will set the EXT4_STATE_DELALLOC_RESERVED flag once the + * inode's allocation semaphore is taken. + * + * If the blocks in questions were delalloc blocks, set + * EXT4_GET_BLOCKS_DELALLOC_RESERVE so the delalloc accounting + * variables are updated after the blocks have been allocated. + */ + map.m_lblk = next; + map.m_len = max_blocks; + get_blocks_flags = EXT4_GET_BLOCKS_CREATE; + if (ext4_should_dioread_nolock(mpd->inode)) + get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT; + if (mpd->b_state & (1 << BH_Delay)) + get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE; + + blks = ext4_map_blocks(handle, mpd->inode, &map, get_blocks_flags); + if (blks < 0) { + struct super_block *sb = mpd->inode->i_sb; + + err = blks; + /* + * If get block returns EAGAIN or ENOSPC and there + * appears to be free blocks we will just let + * mpage_da_submit_io() unlock all of the pages. + */ + if (err == -EAGAIN) + goto submit_io; + + if (err == -ENOSPC && ext4_count_free_clusters(sb)) { + mpd->retval = err; + goto submit_io; + } + + /* + * get block failure will cause us to loop in + * writepages, because a_ops->writepage won't be able + * to make progress. The page will be redirtied by + * writepage and writepages will again try to write + * the same. + */ + if (!(EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED)) { + ext4_msg(sb, KERN_CRIT, + "delayed block allocation failed for inode %lu " + "at logical offset %llu with max blocks %zd " + "with error %d", mpd->inode->i_ino, + (unsigned long long) next, + mpd->b_size >> mpd->inode->i_blkbits, err); + ext4_msg(sb, KERN_CRIT, + "This should not happen!! Data will be lost\n"); + if (err == -ENOSPC) + ext4_print_free_blocks(mpd->inode); + } + /* invalidate all the pages */ + ext4_da_block_invalidatepages(mpd); + + /* Mark this page range as having been completed */ + mpd->io_done = 1; + return; + } + BUG_ON(blks == 0); + + mapp = ↦ + if (map.m_flags & EXT4_MAP_NEW) { + struct block_device *bdev = mpd->inode->i_sb->s_bdev; + int i; + + for (i = 0; i < map.m_len; i++) + unmap_underlying_metadata(bdev, map.m_pblk + i); + + if (ext4_should_order_data(mpd->inode)) { + err = ext4_jbd2_file_inode(handle, mpd->inode); + if (err) { + /* Only if the journal is aborted */ + mpd->retval = err; + goto submit_io; + } + } + } + + /* + * Update on-disk size along with block allocation. + */ + disksize = ((loff_t) next + blks) << mpd->inode->i_blkbits; + if (disksize > i_size_read(mpd->inode)) + disksize = i_size_read(mpd->inode); + if (disksize > EXT4_I(mpd->inode)->i_disksize) { + ext4_update_i_disksize(mpd->inode, disksize); + err = ext4_mark_inode_dirty(handle, mpd->inode); + if (err) + ext4_error(mpd->inode->i_sb, + "Failed to mark inode %lu dirty", + mpd->inode->i_ino); + } + +submit_io: + mpage_da_submit_io(mpd, mapp); + mpd->io_done = 1; +} + +#define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \ + (1 << BH_Delay) | (1 << BH_Unwritten)) + +/* + * mpage_add_bh_to_extent - try to add one more block to extent of blocks + * + * @mpd->lbh - extent of blocks + * @logical - logical number of the block in the file + * @bh - bh of the block (used to access block's state) + * + * the function is used to collect contig. blocks in same state + */ +static void mpage_add_bh_to_extent(struct mpage_da_data *mpd, + sector_t logical, size_t b_size, + unsigned long b_state) +{ + sector_t next; + int nrblocks = mpd->b_size >> mpd->inode->i_blkbits; + + /* + * XXX Don't go larger than mballoc is willing to allocate + * This is a stopgap solution. We eventually need to fold + * mpage_da_submit_io() into this function and then call + * ext4_map_blocks() multiple times in a loop + */ + if (nrblocks >= 8*1024*1024/mpd->inode->i_sb->s_blocksize) + goto flush_it; + + /* check if thereserved journal credits might overflow */ + if (!(ext4_test_inode_flag(mpd->inode, EXT4_INODE_EXTENTS))) { + if (nrblocks >= EXT4_MAX_TRANS_DATA) { + /* + * With non-extent format we are limited by the journal + * credit available. Total credit needed to insert + * nrblocks contiguous blocks is dependent on the + * nrblocks. So limit nrblocks. + */ + goto flush_it; + } else if ((nrblocks + (b_size >> mpd->inode->i_blkbits)) > + EXT4_MAX_TRANS_DATA) { + /* + * Adding the new buffer_head would make it cross the + * allowed limit for which we have journal credit + * reserved. So limit the new bh->b_size + */ + b_size = (EXT4_MAX_TRANS_DATA - nrblocks) << + mpd->inode->i_blkbits; + /* we will do mpage_da_submit_io in the next loop */ + } + } + /* + * First block in the extent + */ + if (mpd->b_size == 0) { + mpd->b_blocknr = logical; + mpd->b_size = b_size; + mpd->b_state = b_state & BH_FLAGS; + return; + } + + next = mpd->b_blocknr + nrblocks; + /* + * Can we merge the block to our big extent? + */ + if (logical == next && (b_state & BH_FLAGS) == mpd->b_state) { + mpd->b_size += b_size; + return; + } + +flush_it: + /* + * We couldn't merge the block to our extent, so we + * need to flush current extent and start new one + */ + mpage_da_map_and_submit(mpd); + return; +} + +static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh) +{ + return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh); +} + +/* + * This function is grabs code from the very beginning of + * ext4_map_blocks, but assumes that the caller is from delayed write + * time. This function looks up the requested blocks and sets the + * buffer delay bit under the protection of i_data_sem. + */ +static int ext4_da_map_blocks(struct inode *inode, sector_t iblock, + struct ext4_map_blocks *map, + struct buffer_head *bh) +{ + int retval; + sector_t invalid_block = ~((sector_t) 0xffff); + + if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es)) + invalid_block = ~0; + + map->m_flags = 0; + ext_debug("ext4_da_map_blocks(): inode %lu, max_blocks %u," + "logical block %lu\n", inode->i_ino, map->m_len, + (unsigned long) map->m_lblk); + /* + * Try to see if we can get the block without requesting a new + * file system block. + */ + down_read((&EXT4_I(inode)->i_data_sem)); + if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) + retval = ext4_ext_map_blocks(NULL, inode, map, 0); + else + retval = ext4_ind_map_blocks(NULL, inode, map, 0); + + if (retval == 0) { + /* + * XXX: __block_prepare_write() unmaps passed block, + * is it OK? + */ + /* If the block was allocated from previously allocated cluster, + * then we dont need to reserve it again. */ + if (!(map->m_flags & EXT4_MAP_FROM_CLUSTER)) { + retval = ext4_da_reserve_space(inode, iblock); + if (retval) + /* not enough space to reserve */ + goto out_unlock; + } + + /* Clear EXT4_MAP_FROM_CLUSTER flag since its purpose is served + * and it should not appear on the bh->b_state. + */ + map->m_flags &= ~EXT4_MAP_FROM_CLUSTER; + + map_bh(bh, inode->i_sb, invalid_block); + set_buffer_new(bh); + set_buffer_delay(bh); + } + +out_unlock: + up_read((&EXT4_I(inode)->i_data_sem)); + + return retval; +} + +/* + * This is a special get_blocks_t callback which is used by + * ext4_da_write_begin(). It will either return mapped block or + * reserve space for a single block. + * + * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set. + * We also have b_blocknr = -1 and b_bdev initialized properly + * + * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set. + * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev + * initialized properly. + */ +static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock, + struct buffer_head *bh, int create) +{ + struct ext4_map_blocks map; + int ret = 0; + + BUG_ON(create == 0); + BUG_ON(bh->b_size != inode->i_sb->s_blocksize); + + map.m_lblk = iblock; + map.m_len = 1; + + /* + * first, we need to know whether the block is allocated already + * preallocated blocks are unmapped but should treated + * the same as allocated blocks. + */ + ret = ext4_da_map_blocks(inode, iblock, &map, bh); + if (ret <= 0) + return ret; + + map_bh(bh, inode->i_sb, map.m_pblk); + bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags; + + if (buffer_unwritten(bh)) { + /* A delayed write to unwritten bh should be marked + * new and mapped. Mapped ensures that we don't do + * get_block multiple times when we write to the same + * offset and new ensures that we do proper zero out + * for partial write. + */ + set_buffer_new(bh); + set_buffer_mapped(bh); + } + return 0; +} + +/* + * This function is used as a standard get_block_t calback function + * when there is no desire to allocate any blocks. It is used as a + * callback function for block_write_begin() and block_write_full_page(). + * These functions should only try to map a single block at a time. + * + * Since this function doesn't do block allocations even if the caller + * requests it by passing in create=1, it is critically important that + * any caller checks to make sure that any buffer heads are returned + * by this function are either all already mapped or marked for + * delayed allocation before calling block_write_full_page(). Otherwise, + * b_blocknr could be left unitialized, and the page write functions will + * be taken by surprise. + */ +static int noalloc_get_block_write(struct inode *inode, sector_t iblock, + struct buffer_head *bh_result, int create) +{ + BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize); + return _ext4_get_block(inode, iblock, bh_result, 0); +} + +static int bget_one(handle_t *handle, struct buffer_head *bh) +{ + get_bh(bh); + return 0; +} + +static int bput_one(handle_t *handle, struct buffer_head *bh) +{ + put_bh(bh); + return 0; +} + +static int __ext4_journalled_writepage(struct page *page, + unsigned int len) +{ + struct address_space *mapping = page->mapping; + struct inode *inode = mapping->host; + struct buffer_head *page_bufs; + handle_t *handle = NULL; + int ret = 0; + int err; + + ClearPageChecked(page); + page_bufs = page_buffers(page); + BUG_ON(!page_bufs); + walk_page_buffers(handle, page_bufs, 0, len, NULL, bget_one); + /* As soon as we unlock the page, it can go away, but we have + * references to buffers so we are safe */ + unlock_page(page); + + handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode)); + if (IS_ERR(handle)) { + ret = PTR_ERR(handle); + goto out; + } + + BUG_ON(!ext4_handle_valid(handle)); + + ret = walk_page_buffers(handle, page_bufs, 0, len, NULL, + do_journal_get_write_access); + + err = walk_page_buffers(handle, page_bufs, 0, len, NULL, + write_end_fn); + if (ret == 0) + ret = err; + EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid; + err = ext4_journal_stop(handle); + if (!ret) + ret = err; + + walk_page_buffers(handle, page_bufs, 0, len, NULL, bput_one); + ext4_set_inode_state(inode, EXT4_STATE_JDATA); +out: + return ret; +} + +static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode); +static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate); + +/* + * Note that we don't need to start a transaction unless we're journaling data + * because we should have holes filled from ext4_page_mkwrite(). We even don't + * need to file the inode to the transaction's list in ordered mode because if + * we are writing back data added by write(), the inode is already there and if + * we are writing back data modified via mmap(), no one guarantees in which + * transaction the data will hit the disk. In case we are journaling data, we + * cannot start transaction directly because transaction start ranks above page + * lock so we have to do some magic. + * + * This function can get called via... + * - ext4_da_writepages after taking page lock (have journal handle) + * - journal_submit_inode_data_buffers (no journal handle) + * - shrink_page_list via pdflush (no journal handle) + * - grab_page_cache when doing write_begin (have journal handle) + * + * We don't do any block allocation in this function. If we have page with + * multiple blocks we need to write those buffer_heads that are mapped. This + * is important for mmaped based write. So if we do with blocksize 1K + * truncate(f, 1024); + * a = mmap(f, 0, 4096); + * a[0] = 'a'; + * truncate(f, 4096); + * we have in the page first buffer_head mapped via page_mkwrite call back + * but other buffer_heads would be unmapped but dirty (dirty done via the + * do_wp_page). So writepage should write the first block. If we modify + * the mmap area beyond 1024 we will again get a page_fault and the + * page_mkwrite callback will do the block allocation and mark the + * buffer_heads mapped. + * + * We redirty the page if we have any buffer_heads that is either delay or + * unwritten in the page. + * + * We can get recursively called as show below. + * + * ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() -> + * ext4_writepage() + * + * But since we don't do any block allocation we should not deadlock. + * Page also have the dirty flag cleared so we don't get recurive page_lock. + */ +static int ext4_writepage(struct page *page, + struct writeback_control *wbc) +{ + int ret = 0, commit_write = 0; + loff_t size; + unsigned int len; + struct buffer_head *page_bufs = NULL; + struct inode *inode = page->mapping->host; + + trace_ext4_writepage(page); + size = i_size_read(inode); + if (page->index == size >> PAGE_CACHE_SHIFT) + len = size & ~PAGE_CACHE_MASK; + else + len = PAGE_CACHE_SIZE; + + /* + * If the page does not have buffers (for whatever reason), + * try to create them using __block_write_begin. If this + * fails, redirty the page and move on. + */ + if (!page_has_buffers(page)) { + if (__block_write_begin(page, 0, len, + noalloc_get_block_write)) { + redirty_page: + redirty_page_for_writepage(wbc, page); + unlock_page(page); + return 0; + } + commit_write = 1; + } + page_bufs = page_buffers(page); + if (walk_page_buffers(NULL, page_bufs, 0, len, NULL, + ext4_bh_delay_or_unwritten)) { + /* + * We don't want to do block allocation, so redirty + * the page and return. We may reach here when we do + * a journal commit via journal_submit_inode_data_buffers. + * We can also reach here via shrink_page_list but it + * should never be for direct reclaim so warn if that + * happens + */ + WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == + PF_MEMALLOC); + goto redirty_page; + } + if (commit_write) + /* now mark the buffer_heads as dirty and uptodate */ + block_commit_write(page, 0, len); + + if (PageChecked(page) && ext4_should_journal_data(inode)) + /* + * It's mmapped pagecache. Add buffers and journal it. There + * doesn't seem much point in redirtying the page here. + */ + return __ext4_journalled_writepage(page, len); + + if (buffer_uninit(page_bufs)) { + ext4_set_bh_endio(page_bufs, inode); + ret = block_write_full_page_endio(page, noalloc_get_block_write, + wbc, ext4_end_io_buffer_write); + } else + ret = block_write_full_page(page, noalloc_get_block_write, + wbc); + + return ret; +} + +/* + * This is called via ext4_da_writepages() to + * calculate the total number of credits to reserve to fit + * a single extent allocation into a single transaction, + * ext4_da_writpeages() will loop calling this before + * the block allocation. + */ + +static int ext4_da_writepages_trans_blocks(struct inode *inode) +{ + int max_blocks = EXT4_I(inode)->i_reserved_data_blocks; + + /* + * With non-extent format the journal credit needed to + * insert nrblocks contiguous block is dependent on + * number of contiguous block. So we will limit + * number of contiguous block to a sane value + */ + if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) && + (max_blocks > EXT4_MAX_TRANS_DATA)) + max_blocks = EXT4_MAX_TRANS_DATA; + + return ext4_chunk_trans_blocks(inode, max_blocks); +} + +/* + * write_cache_pages_da - walk the list of dirty pages of the given + * address space and accumulate pages that need writing, and call + * mpage_da_map_and_submit to map a single contiguous memory region + * and then write them. + */ +static int write_cache_pages_da(struct address_space *mapping, + struct writeback_control *wbc, + struct mpage_da_data *mpd, + pgoff_t *done_index) +{ + struct buffer_head *bh, *head; + struct inode *inode = mapping->host; + struct pagevec pvec; + unsigned int nr_pages; + sector_t logical; + pgoff_t index, end; + long nr_to_write = wbc->nr_to_write; + int i, tag, ret = 0; + + memset(mpd, 0, sizeof(struct mpage_da_data)); + mpd->wbc = wbc; + mpd->inode = inode; + pagevec_init(&pvec, 0); + index = wbc->range_start >> PAGE_CACHE_SHIFT; + end = wbc->range_end >> PAGE_CACHE_SHIFT; + + if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages) + tag = PAGECACHE_TAG_TOWRITE; + else + tag = PAGECACHE_TAG_DIRTY; + + *done_index = index; + while (index <= end) { + nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag, + min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1); + if (nr_pages == 0) + return 0; + + for (i = 0; i < nr_pages; i++) { + struct page *page = pvec.pages[i]; + + /* + * At this point, the page may be truncated or + * invalidated (changing page->mapping to NULL), or + * even swizzled back from swapper_space to tmpfs file + * mapping. However, page->index will not change + * because we have a reference on the page. + */ + if (page->index > end) + goto out; + + *done_index = page->index + 1; + + /* + * If we can't merge this page, and we have + * accumulated an contiguous region, write it + */ + if ((mpd->next_page != page->index) && + (mpd->next_page != mpd->first_page)) { + mpage_da_map_and_submit(mpd); + goto ret_extent_tail; + } + + lock_page(page); + + /* + * If the page is no longer dirty, or its + * mapping no longer corresponds to inode we + * are writing (which means it has been + * truncated or invalidated), or the page is + * already under writeback and we are not + * doing a data integrity writeback, skip the page + */ + if (!PageDirty(page) || + (PageWriteback(page) && + (wbc->sync_mode == WB_SYNC_NONE)) || + unlikely(page->mapping != mapping)) { + unlock_page(page); + continue; + } + + wait_on_page_writeback(page); + BUG_ON(PageWriteback(page)); + + if (mpd->next_page != page->index) + mpd->first_page = page->index; + mpd->next_page = page->index + 1; + logical = (sector_t) page->index << + (PAGE_CACHE_SHIFT - inode->i_blkbits); + + if (!page_has_buffers(page)) { + mpage_add_bh_to_extent(mpd, logical, + PAGE_CACHE_SIZE, + (1 << BH_Dirty) | (1 << BH_Uptodate)); + if (mpd->io_done) + goto ret_extent_tail; + } else { + /* + * Page with regular buffer heads, + * just add all dirty ones + */ + head = page_buffers(page); + bh = head; + do { + BUG_ON(buffer_locked(bh)); + /* + * We need to try to allocate + * unmapped blocks in the same page. + * Otherwise we won't make progress + * with the page in ext4_writepage + */ + if (ext4_bh_delay_or_unwritten(NULL, bh)) { + mpage_add_bh_to_extent(mpd, logical, + bh->b_size, + bh->b_state); + if (mpd->io_done) + goto ret_extent_tail; + } else if (buffer_dirty(bh) && (buffer_mapped(bh))) { + /* + * mapped dirty buffer. We need + * to update the b_state + * because we look at b_state + * in mpage_da_map_blocks. We + * don't update b_size because + * if we find an unmapped + * buffer_head later we need to + * use the b_state flag of that + * buffer_head. + */ + if (mpd->b_size == 0) + mpd->b_state = bh->b_state & BH_FLAGS; + } + logical++; + } while ((bh = bh->b_this_page) != head); + } + + if (nr_to_write > 0) { + nr_to_write--; + if (nr_to_write == 0 && + wbc->sync_mode == WB_SYNC_NONE) + /* + * We stop writing back only if we are + * not doing integrity sync. In case of + * integrity sync we have to keep going + * because someone may be concurrently + * dirtying pages, and we might have + * synced a lot of newly appeared dirty + * pages, but have not synced all of the + * old dirty pages. + */ + goto out; + } + } + pagevec_release(&pvec); + cond_resched(); + } + return 0; +ret_extent_tail: + ret = MPAGE_DA_EXTENT_TAIL; +out: + pagevec_release(&pvec); + cond_resched(); + return ret; +} + + +static int ext4_da_writepages(struct address_space *mapping, + struct writeback_control *wbc) +{ + pgoff_t index; + int range_whole = 0; + handle_t *handle = NULL; + struct mpage_da_data mpd; + struct inode *inode = mapping->host; + int pages_written = 0; + unsigned int max_pages; + int range_cyclic, cycled = 1, io_done = 0; + int needed_blocks, ret = 0; + long desired_nr_to_write, nr_to_writebump = 0; + loff_t range_start = wbc->range_start; + struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb); + pgoff_t done_index = 0; + pgoff_t end; + struct blk_plug plug; + + trace_ext4_da_writepages(inode, wbc); + + /* + * No pages to write? This is mainly a kludge to avoid starting + * a transaction for special inodes like journal inode on last iput() + * because that could violate lock ordering on umount + */ + if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) + return 0; + + /* + * If the filesystem has aborted, it is read-only, so return + * right away instead of dumping stack traces later on that + * will obscure the real source of the problem. We test + * EXT4_MF_FS_ABORTED instead of sb->s_flag's MS_RDONLY because + * the latter could be true if the filesystem is mounted + * read-only, and in that case, ext4_da_writepages should + * *never* be called, so if that ever happens, we would want + * the stack trace. + */ + if (unlikely(sbi->s_mount_flags & EXT4_MF_FS_ABORTED)) + return -EROFS; + + if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) + range_whole = 1; + + range_cyclic = wbc->range_cyclic; + if (wbc->range_cyclic) { + index = mapping->writeback_index; + if (index) + cycled = 0; + wbc->range_start = index << PAGE_CACHE_SHIFT; + wbc->range_end = LLONG_MAX; + wbc->range_cyclic = 0; + end = -1; + } else { + index = wbc->range_start >> PAGE_CACHE_SHIFT; + end = wbc->range_end >> PAGE_CACHE_SHIFT; + } + + /* + * This works around two forms of stupidity. The first is in + * the writeback code, which caps the maximum number of pages + * written to be 1024 pages. This is wrong on multiple + * levels; different architectues have a different page size, + * which changes the maximum amount of data which gets + * written. Secondly, 4 megabytes is way too small. XFS + * forces this value to be 16 megabytes by multiplying + * nr_to_write parameter by four, and then relies on its + * allocator to allocate larger extents to make them + * contiguous. Unfortunately this brings us to the second + * stupidity, which is that ext4's mballoc code only allocates + * at most 2048 blocks. So we force contiguous writes up to + * the number of dirty blocks in the inode, or + * sbi->max_writeback_mb_bump whichever is smaller. + */ + max_pages = sbi->s_max_writeback_mb_bump << (20 - PAGE_CACHE_SHIFT); + if (!range_cyclic && range_whole) { + if (wbc->nr_to_write == LONG_MAX) + desired_nr_to_write = wbc->nr_to_write; + else + desired_nr_to_write = wbc->nr_to_write * 8; + } else + desired_nr_to_write = ext4_num_dirty_pages(inode, index, + max_pages); + if (desired_nr_to_write > max_pages) + desired_nr_to_write = max_pages; + + if (wbc->nr_to_write < desired_nr_to_write) { + nr_to_writebump = desired_nr_to_write - wbc->nr_to_write; + wbc->nr_to_write = desired_nr_to_write; + } + +retry: + if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages) + tag_pages_for_writeback(mapping, index, end); + + blk_start_plug(&plug); + while (!ret && wbc->nr_to_write > 0) { + + /* + * we insert one extent at a time. So we need + * credit needed for single extent allocation. + * journalled mode is currently not supported + * by delalloc + */ + BUG_ON(ext4_should_journal_data(inode)); + needed_blocks = ext4_da_writepages_trans_blocks(inode); + + /* start a new transaction*/ + handle = ext4_journal_start(inode, needed_blocks); + if (IS_ERR(handle)) { + ret = PTR_ERR(handle); + ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: " + "%ld pages, ino %lu; err %d", __func__, + wbc->nr_to_write, inode->i_ino, ret); + blk_finish_plug(&plug); + goto out_writepages; + } + + /* + * Now call write_cache_pages_da() to find the next + * contiguous region of logical blocks that need + * blocks to be allocated by ext4 and submit them. + */ + ret = write_cache_pages_da(mapping, wbc, &mpd, &done_index); + /* + * If we have a contiguous extent of pages and we + * haven't done the I/O yet, map the blocks and submit + * them for I/O. + */ + if (!mpd.io_done && mpd.next_page != mpd.first_page) { + mpage_da_map_and_submit(&mpd); + ret = MPAGE_DA_EXTENT_TAIL; + } + trace_ext4_da_write_pages(inode, &mpd); + wbc->nr_to_write -= mpd.pages_written; + + ext4_journal_stop(handle); + + if ((mpd.retval == -ENOSPC) && sbi->s_journal) { + /* commit the transaction which would + * free blocks released in the transaction + * and try again + */ + jbd2_journal_force_commit_nested(sbi->s_journal); + ret = 0; + } else if (ret == MPAGE_DA_EXTENT_TAIL) { + /* + * Got one extent now try with rest of the pages. + * If mpd.retval is set -EIO, journal is aborted. + * So we don't need to write any more. + */ + pages_written += mpd.pages_written; + ret = mpd.retval; + io_done = 1; + } else if (wbc->nr_to_write) + /* + * There is no more writeout needed + * or we requested for a noblocking writeout + * and we found the device congested + */ + break; + } + blk_finish_plug(&plug); + if (!io_done && !cycled) { + cycled = 1; + index = 0; + wbc->range_start = index << PAGE_CACHE_SHIFT; + wbc->range_end = mapping->writeback_index - 1; + goto retry; + } + + /* Update index */ + wbc->range_cyclic = range_cyclic; + if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) + /* + * set the writeback_index so that range_cyclic + * mode will write it back later + */ + mapping->writeback_index = done_index; + +out_writepages: + wbc->nr_to_write -= nr_to_writebump; + wbc->range_start = range_start; + trace_ext4_da_writepages_result(inode, wbc, ret, pages_written); + return ret; +} + +#define FALL_BACK_TO_NONDELALLOC 1 +static int ext4_nonda_switch(struct super_block *sb) +{ + s64 free_blocks, dirty_blocks; + struct ext4_sb_info *sbi = EXT4_SB(sb); + + /* + * switch to non delalloc mode if we are running low + * on free block. The free block accounting via percpu + * counters can get slightly wrong with percpu_counter_batch getting + * accumulated on each CPU without updating global counters + * Delalloc need an accurate free block accounting. So switch + * to non delalloc when we are near to error range. + */ + free_blocks = EXT4_C2B(sbi, + percpu_counter_read_positive(&sbi->s_freeclusters_counter)); + dirty_blocks = percpu_counter_read_positive(&sbi->s_dirtyclusters_counter); + if (2 * free_blocks < 3 * dirty_blocks || + free_blocks < (dirty_blocks + EXT4_FREECLUSTERS_WATERMARK)) { + /* + * free block count is less than 150% of dirty blocks + * or free blocks is less than watermark + */ + return 1; + } + /* + * Even if we don't switch but are nearing capacity, + * start pushing delalloc when 1/2 of free blocks are dirty. + */ + if (free_blocks < 2 * dirty_blocks) + writeback_inodes_sb_if_idle(sb, WB_REASON_FS_FREE_SPACE); + + return 0; +} + +static int ext4_da_write_begin(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned flags, + struct page **pagep, void **fsdata) +{ + int ret, retries = 0; + struct page *page; + pgoff_t index; + struct inode *inode = mapping->host; + handle_t *handle; + + index = pos >> PAGE_CACHE_SHIFT; + + if (ext4_nonda_switch(inode->i_sb)) { + *fsdata = (void *)FALL_BACK_TO_NONDELALLOC; + return ext4_write_begin(file, mapping, pos, + len, flags, pagep, fsdata); + } + *fsdata = (void *)0; + trace_ext4_da_write_begin(inode, pos, len, flags); +retry: + /* + * With delayed allocation, we don't log the i_disksize update + * if there is delayed block allocation. But we still need + * to journalling the i_disksize update if writes to the end + * of file which has an already mapped buffer. + */ + handle = ext4_journal_start(inode, 1); + if (IS_ERR(handle)) { + ret = PTR_ERR(handle); + goto out; + } + /* We cannot recurse into the filesystem as the transaction is already + * started */ + flags |= AOP_FLAG_NOFS; + + page = grab_cache_page_write_begin(mapping, index, flags); + if (!page) { + ext4_journal_stop(handle); + ret = -ENOMEM; + goto out; + } + *pagep = page; + + ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep); + if (ret < 0) { + unlock_page(page); + ext4_journal_stop(handle); + page_cache_release(page); + /* + * block_write_begin may have instantiated a few blocks + * outside i_size. Trim these off again. Don't need + * i_size_read because we hold i_mutex. + */ + if (pos + len > inode->i_size) + ext4_truncate_failed_write(inode); + } + + if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) + goto retry; +out: + return ret; +} + +/* + * Check if we should update i_disksize + * when write to the end of file but not require block allocation + */ +static int ext4_da_should_update_i_disksize(struct page *page, + unsigned long offset) +{ + struct buffer_head *bh; + struct inode *inode = page->mapping->host; + unsigned int idx; + int i; + + bh = page_buffers(page); + idx = offset >> inode->i_blkbits; + + for (i = 0; i < idx; i++) + bh = bh->b_this_page; + + if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh)) + return 0; + return 1; +} + +static int ext4_da_write_end(struct file *file, + struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *page, void *fsdata) +{ + struct inode *inode = mapping->host; + int ret = 0, ret2; + handle_t *handle = ext4_journal_current_handle(); + loff_t new_i_size; + unsigned long start, end; + int write_mode = (int)(unsigned long)fsdata; + + if (write_mode == FALL_BACK_TO_NONDELALLOC) { + switch (ext4_inode_journal_mode(inode)) { + case EXT4_INODE_ORDERED_DATA_MODE: + return ext4_ordered_write_end(file, mapping, pos, + len, copied, page, fsdata); + case EXT4_INODE_WRITEBACK_DATA_MODE: + return ext4_writeback_write_end(file, mapping, pos, + len, copied, page, fsdata); + default: + BUG(); + } + } + + trace_ext4_da_write_end(inode, pos, len, copied); + start = pos & (PAGE_CACHE_SIZE - 1); + end = start + copied - 1; + + /* + * generic_write_end() will run mark_inode_dirty() if i_size + * changes. So let's piggyback the i_disksize mark_inode_dirty + * into that. + */ + + new_i_size = pos + copied; + if (copied && new_i_size > EXT4_I(inode)->i_disksize) { + if (ext4_da_should_update_i_disksize(page, end)) { + down_write(&EXT4_I(inode)->i_data_sem); + if (new_i_size > EXT4_I(inode)->i_disksize) { + /* + * Updating i_disksize when extending file + * without needing block allocation + */ + if (ext4_should_order_data(inode)) + ret = ext4_jbd2_file_inode(handle, + inode); + + EXT4_I(inode)->i_disksize = new_i_size; + } + up_write(&EXT4_I(inode)->i_data_sem); + /* We need to mark inode dirty even if + * new_i_size is less that inode->i_size + * bu greater than i_disksize.(hint delalloc) + */ + ext4_mark_inode_dirty(handle, inode); + } + } + ret2 = generic_write_end(file, mapping, pos, len, copied, + page, fsdata); + copied = ret2; + if (ret2 < 0) + ret = ret2; + ret2 = ext4_journal_stop(handle); + if (!ret) + ret = ret2; + + return ret ? ret : copied; +} + +static void ext4_da_invalidatepage(struct page *page, unsigned long offset) +{ + /* + * Drop reserved blocks + */ + BUG_ON(!PageLocked(page)); + if (!page_has_buffers(page)) + goto out; + + ext4_da_page_release_reservation(page, offset); + +out: + ext4_invalidatepage(page, offset); + + return; +} + +/* + * Force all delayed allocation blocks to be allocated for a given inode. + */ +int ext4_alloc_da_blocks(struct inode *inode) +{ + trace_ext4_alloc_da_blocks(inode); + + if (!EXT4_I(inode)->i_reserved_data_blocks && + !EXT4_I(inode)->i_reserved_meta_blocks) + return 0; + + /* + * We do something simple for now. The filemap_flush() will + * also start triggering a write of the data blocks, which is + * not strictly speaking necessary (and for users of + * laptop_mode, not even desirable). However, to do otherwise + * would require replicating code paths in: + * + * ext4_da_writepages() -> + * write_cache_pages() ---> (via passed in callback function) + * __mpage_da_writepage() --> + * mpage_add_bh_to_extent() + * mpage_da_map_blocks() + * + * The problem is that write_cache_pages(), located in + * mm/page-writeback.c, marks pages clean in preparation for + * doing I/O, which is not desirable if we're not planning on + * doing I/O at all. + * + * We could call write_cache_pages(), and then redirty all of + * the pages by calling redirty_page_for_writepage() but that + * would be ugly in the extreme. So instead we would need to + * replicate parts of the code in the above functions, + * simplifying them because we wouldn't actually intend to + * write out the pages, but rather only collect contiguous + * logical block extents, call the multi-block allocator, and + * then update the buffer heads with the block allocations. + * + * For now, though, we'll cheat by calling filemap_flush(), + * which will map the blocks, and start the I/O, but not + * actually wait for the I/O to complete. + */ + return filemap_flush(inode->i_mapping); +} + +/* + * bmap() is special. It gets used by applications such as lilo and by + * the swapper to find the on-disk block of a specific piece of data. + * + * Naturally, this is dangerous if the block concerned is still in the + * journal. If somebody makes a swapfile on an ext4 data-journaling + * filesystem and enables swap, then they may get a nasty shock when the + * data getting swapped to that swapfile suddenly gets overwritten by + * the original zero's written out previously to the journal and + * awaiting writeback in the kernel's buffer cache. + * + * So, if we see any bmap calls here on a modified, data-journaled file, + * take extra steps to flush any blocks which might be in the cache. + */ +static sector_t ext4_bmap(struct address_space *mapping, sector_t block) +{ + struct inode *inode = mapping->host; + journal_t *journal; + int err; + + if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) && + test_opt(inode->i_sb, DELALLOC)) { + /* + * With delalloc we want to sync the file + * so that we can make sure we allocate + * blocks for file + */ + filemap_write_and_wait(mapping); + } + + if (EXT4_JOURNAL(inode) && + ext4_test_inode_state(inode, EXT4_STATE_JDATA)) { + /* + * This is a REALLY heavyweight approach, but the use of + * bmap on dirty files is expected to be extremely rare: + * only if we run lilo or swapon on a freshly made file + * do we expect this to happen. + * + * (bmap requires CAP_SYS_RAWIO so this does not + * represent an unprivileged user DOS attack --- we'd be + * in trouble if mortal users could trigger this path at + * will.) + * + * NB. EXT4_STATE_JDATA is not set on files other than + * regular files. If somebody wants to bmap a directory + * or symlink and gets confused because the buffer + * hasn't yet been flushed to disk, they deserve + * everything they get. + */ + + ext4_clear_inode_state(inode, EXT4_STATE_JDATA); + journal = EXT4_JOURNAL(inode); + jbd2_journal_lock_updates(journal); + err = jbd2_journal_flush(journal); + jbd2_journal_unlock_updates(journal); + + if (err) + return 0; + } + + return generic_block_bmap(mapping, block, ext4_get_block); +} + +static int ext4_readpage(struct file *file, struct page *page) +{ + trace_ext4_readpage(page); + return mpage_readpage(page, ext4_get_block); +} + +static int +ext4_readpages(struct file *file, struct address_space *mapping, + struct list_head *pages, unsigned nr_pages) +{ + return mpage_readpages(mapping, pages, nr_pages, ext4_get_block); +} + +static void ext4_invalidatepage_free_endio(struct page *page, unsigned long offset) +{ + struct buffer_head *head, *bh; + unsigned int curr_off = 0; + + if (!page_has_buffers(page)) + return; + head = bh = page_buffers(page); + do { + if (offset <= curr_off && test_clear_buffer_uninit(bh) + && bh->b_private) { + ext4_free_io_end(bh->b_private); + bh->b_private = NULL; + bh->b_end_io = NULL; + } + curr_off = curr_off + bh->b_size; + bh = bh->b_this_page; + } while (bh != head); +} + +static void ext4_invalidatepage(struct page *page, unsigned long offset) +{ + journal_t *journal = EXT4_JOURNAL(page->mapping->host); + + trace_ext4_invalidatepage(page, offset); + + /* + * free any io_end structure allocated for buffers to be discarded + */ + if (ext4_should_dioread_nolock(page->mapping->host)) + ext4_invalidatepage_free_endio(page, offset); + /* + * If it's a full truncate we just forget about the pending dirtying + */ + if (offset == 0) + ClearPageChecked(page); + + if (journal) + jbd2_journal_invalidatepage(journal, page, offset); + else + block_invalidatepage(page, offset); +} + +static int ext4_releasepage(struct page *page, gfp_t wait) +{ + journal_t *journal = EXT4_JOURNAL(page->mapping->host); + + trace_ext4_releasepage(page); + + WARN_ON(PageChecked(page)); + if (!page_has_buffers(page)) + return 0; + if (journal) + return jbd2_journal_try_to_free_buffers(journal, page, wait); + else + return try_to_free_buffers(page); +} + +/* + * ext4_get_block used when preparing for a DIO write or buffer write. + * We allocate an uinitialized extent if blocks haven't been allocated. + * The extent will be converted to initialized after the IO is complete. + */ +static int ext4_get_block_write(struct inode *inode, sector_t iblock, + struct buffer_head *bh_result, int create) +{ + ext4_debug("ext4_get_block_write: inode %lu, create flag %d\n", + inode->i_ino, create); + return _ext4_get_block(inode, iblock, bh_result, + EXT4_GET_BLOCKS_IO_CREATE_EXT); +} + +static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset, + ssize_t size, void *private, int ret, + bool is_async) +{ + struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode; + ext4_io_end_t *io_end = iocb->private; + struct workqueue_struct *wq; + unsigned long flags; + struct ext4_inode_info *ei; + + /* if not async direct IO or dio with 0 bytes write, just return */ + if (!io_end || !size) + goto out; + + ext_debug("ext4_end_io_dio(): io_end 0x%p " + "for inode %lu, iocb 0x%p, offset %llu, size %zd\n", + iocb->private, io_end->inode->i_ino, iocb, offset, + size); + + iocb->private = NULL; + + /* if not aio dio with unwritten extents, just free io and return */ + if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) { + ext4_free_io_end(io_end); +out: + if (is_async) + aio_complete(iocb, ret, 0); + inode_dio_done(inode); + return; + } + + io_end->offset = offset; + io_end->size = size; + if (is_async) { + io_end->iocb = iocb; + io_end->result = ret; + } + wq = EXT4_SB(io_end->inode->i_sb)->dio_unwritten_wq; + + /* Add the io_end to per-inode completed aio dio list*/ + ei = EXT4_I(io_end->inode); + spin_lock_irqsave(&ei->i_completed_io_lock, flags); + list_add_tail(&io_end->list, &ei->i_completed_io_list); + spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); + + /* queue the work to convert unwritten extents to written */ + queue_work(wq, &io_end->work); +} + +static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate) +{ + ext4_io_end_t *io_end = bh->b_private; + struct workqueue_struct *wq; + struct inode *inode; + unsigned long flags; + + if (!test_clear_buffer_uninit(bh) || !io_end) + goto out; + + if (!(io_end->inode->i_sb->s_flags & MS_ACTIVE)) { + ext4_msg(io_end->inode->i_sb, KERN_INFO, + "sb umounted, discard end_io request for inode %lu", + io_end->inode->i_ino); + ext4_free_io_end(io_end); + goto out; + } + + /* + * It may be over-defensive here to check EXT4_IO_END_UNWRITTEN now, + * but being more careful is always safe for the future change. + */ + inode = io_end->inode; + ext4_set_io_unwritten_flag(inode, io_end); + + /* Add the io_end to per-inode completed io list*/ + spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags); + list_add_tail(&io_end->list, &EXT4_I(inode)->i_completed_io_list); + spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags); + + wq = EXT4_SB(inode->i_sb)->dio_unwritten_wq; + /* queue the work to convert unwritten extents to written */ + queue_work(wq, &io_end->work); +out: + bh->b_private = NULL; + bh->b_end_io = NULL; + clear_buffer_uninit(bh); + end_buffer_async_write(bh, uptodate); +} + +static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode) +{ + ext4_io_end_t *io_end; + struct page *page = bh->b_page; + loff_t offset = (sector_t)page->index << PAGE_CACHE_SHIFT; + size_t size = bh->b_size; + +retry: + io_end = ext4_init_io_end(inode, GFP_ATOMIC); + if (!io_end) { + pr_warn_ratelimited("%s: allocation fail\n", __func__); + schedule(); + goto retry; + } + io_end->offset = offset; + io_end->size = size; + /* + * We need to hold a reference to the page to make sure it + * doesn't get evicted before ext4_end_io_work() has a chance + * to convert the extent from written to unwritten. + */ + io_end->page = page; + get_page(io_end->page); + + bh->b_private = io_end; + bh->b_end_io = ext4_end_io_buffer_write; + return 0; +} + +/* + * For ext4 extent files, ext4 will do direct-io write to holes, + * preallocated extents, and those write extend the file, no need to + * fall back to buffered IO. + * + * For holes, we fallocate those blocks, mark them as uninitialized + * If those blocks were preallocated, we mark sure they are splited, but + * still keep the range to write as uninitialized. + * + * The unwrritten extents will be converted to written when DIO is completed. + * For async direct IO, since the IO may still pending when return, we + * set up an end_io call back function, which will do the conversion + * when async direct IO completed. + * + * If the O_DIRECT write will extend the file then add this inode to the + * orphan list. So recovery will truncate it back to the original size + * if the machine crashes during the write. + * + */ +static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb, + const struct iovec *iov, loff_t offset, + unsigned long nr_segs) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file->f_mapping->host; + ssize_t ret; + size_t count = iov_length(iov, nr_segs); + + loff_t final_size = offset + count; + if (rw == WRITE && final_size <= inode->i_size) { + /* + * We could direct write to holes and fallocate. + * + * Allocated blocks to fill the hole are marked as uninitialized + * to prevent parallel buffered read to expose the stale data + * before DIO complete the data IO. + * + * As to previously fallocated extents, ext4 get_block + * will just simply mark the buffer mapped but still + * keep the extents uninitialized. + * + * for non AIO case, we will convert those unwritten extents + * to written after return back from blockdev_direct_IO. + * + * for async DIO, the conversion needs to be defered when + * the IO is completed. The ext4 end_io callback function + * will be called to take care of the conversion work. + * Here for async case, we allocate an io_end structure to + * hook to the iocb. + */ + iocb->private = NULL; + EXT4_I(inode)->cur_aio_dio = NULL; + if (!is_sync_kiocb(iocb)) { + ext4_io_end_t *io_end = + ext4_init_io_end(inode, GFP_NOFS); + if (!io_end) + return -ENOMEM; + io_end->flag |= EXT4_IO_END_DIRECT; + iocb->private = io_end; + /* + * we save the io structure for current async + * direct IO, so that later ext4_map_blocks() + * could flag the io structure whether there + * is a unwritten extents needs to be converted + * when IO is completed. + */ + EXT4_I(inode)->cur_aio_dio = iocb->private; + } + + ret = __blockdev_direct_IO(rw, iocb, inode, + inode->i_sb->s_bdev, iov, + offset, nr_segs, + ext4_get_block_write, + ext4_end_io_dio, + NULL, + DIO_LOCKING); + if (iocb->private) + EXT4_I(inode)->cur_aio_dio = NULL; + /* + * The io_end structure takes a reference to the inode, + * that structure needs to be destroyed and the + * reference to the inode need to be dropped, when IO is + * complete, even with 0 byte write, or failed. + * + * In the successful AIO DIO case, the io_end structure will be + * desctroyed and the reference to the inode will be dropped + * after the end_io call back function is called. + * + * In the case there is 0 byte write, or error case, since + * VFS direct IO won't invoke the end_io call back function, + * we need to free the end_io structure here. + */ + if (ret != -EIOCBQUEUED && ret <= 0 && iocb->private) { + ext4_free_io_end(iocb->private); + iocb->private = NULL; + } else if (ret > 0 && ext4_test_inode_state(inode, + EXT4_STATE_DIO_UNWRITTEN)) { + int err; + /* + * for non AIO case, since the IO is already + * completed, we could do the conversion right here + */ + err = ext4_convert_unwritten_extents(inode, + offset, ret); + if (err < 0) + ret = err; + ext4_clear_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN); + } + return ret; + } + + /* for write the the end of file case, we fall back to old way */ + return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs); +} + +static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb, + const struct iovec *iov, loff_t offset, + unsigned long nr_segs) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file->f_mapping->host; + ssize_t ret; + + /* + * If we are doing data journalling we don't support O_DIRECT + */ + if (ext4_should_journal_data(inode)) + return 0; + + trace_ext4_direct_IO_enter(inode, offset, iov_length(iov, nr_segs), rw); + if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) + ret = ext4_ext_direct_IO(rw, iocb, iov, offset, nr_segs); + else + ret = ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs); + trace_ext4_direct_IO_exit(inode, offset, + iov_length(iov, nr_segs), rw, ret); + return ret; +} + +/* + * Pages can be marked dirty completely asynchronously from ext4's journalling + * activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do + * much here because ->set_page_dirty is called under VFS locks. The page is + * not necessarily locked. + * + * We cannot just dirty the page and leave attached buffers clean, because the + * buffers' dirty state is "definitive". We cannot just set the buffers dirty + * or jbddirty because all the journalling code will explode. + * + * So what we do is to mark the page "pending dirty" and next time writepage + * is called, propagate that into the buffers appropriately. + */ +static int ext4_journalled_set_page_dirty(struct page *page) +{ + SetPageChecked(page); + return __set_page_dirty_nobuffers(page); +} + +static const struct address_space_operations ext4_ordered_aops = { + .readpage = ext4_readpage, + .readpages = ext4_readpages, + .writepage = ext4_writepage, + .write_begin = ext4_write_begin, + .write_end = ext4_ordered_write_end, + .bmap = ext4_bmap, + .invalidatepage = ext4_invalidatepage, + .releasepage = ext4_releasepage, + .direct_IO = ext4_direct_IO, + .migratepage = buffer_migrate_page, + .is_partially_uptodate = block_is_partially_uptodate, + .error_remove_page = generic_error_remove_page, +}; + +static const struct address_space_operations ext4_writeback_aops = { + .readpage = ext4_readpage, + .readpages = ext4_readpages, + .writepage = ext4_writepage, + .write_begin = ext4_write_begin, + .write_end = ext4_writeback_write_end, + .bmap = ext4_bmap, + .invalidatepage = ext4_invalidatepage, + .releasepage = ext4_releasepage, + .direct_IO = ext4_direct_IO, + .migratepage = buffer_migrate_page, + .is_partially_uptodate = block_is_partially_uptodate, + .error_remove_page = generic_error_remove_page, +}; + +static const struct address_space_operations ext4_journalled_aops = { + .readpage = ext4_readpage, + .readpages = ext4_readpages, + .writepage = ext4_writepage, + .write_begin = ext4_write_begin, + .write_end = ext4_journalled_write_end, + .set_page_dirty = ext4_journalled_set_page_dirty, + .bmap = ext4_bmap, + .invalidatepage = ext4_invalidatepage, + .releasepage = ext4_releasepage, + .direct_IO = ext4_direct_IO, + .is_partially_uptodate = block_is_partially_uptodate, + .error_remove_page = generic_error_remove_page, +}; + +static const struct address_space_operations ext4_da_aops = { + .readpage = ext4_readpage, + .readpages = ext4_readpages, + .writepage = ext4_writepage, + .writepages = ext4_da_writepages, + .write_begin = ext4_da_write_begin, + .write_end = ext4_da_write_end, + .bmap = ext4_bmap, + .invalidatepage = ext4_da_invalidatepage, + .releasepage = ext4_releasepage, + .direct_IO = ext4_direct_IO, + .migratepage = buffer_migrate_page, + .is_partially_uptodate = block_is_partially_uptodate, + .error_remove_page = generic_error_remove_page, +}; + +void ext4_set_aops(struct inode *inode) +{ + switch (ext4_inode_journal_mode(inode)) { + case EXT4_INODE_ORDERED_DATA_MODE: + if (test_opt(inode->i_sb, DELALLOC)) + inode->i_mapping->a_ops = &ext4_da_aops; + else + inode->i_mapping->a_ops = &ext4_ordered_aops; + break; + case EXT4_INODE_WRITEBACK_DATA_MODE: + if (test_opt(inode->i_sb, DELALLOC)) + inode->i_mapping->a_ops = &ext4_da_aops; + else + inode->i_mapping->a_ops = &ext4_writeback_aops; + break; + case EXT4_INODE_JOURNAL_DATA_MODE: + inode->i_mapping->a_ops = &ext4_journalled_aops; + break; + default: + BUG(); + } +} + + +/* + * ext4_discard_partial_page_buffers() + * Wrapper function for ext4_discard_partial_page_buffers_no_lock. + * This function finds and locks the page containing the offset + * "from" and passes it to ext4_discard_partial_page_buffers_no_lock. + * Calling functions that already have the page locked should call + * ext4_discard_partial_page_buffers_no_lock directly. + */ +int ext4_discard_partial_page_buffers(handle_t *handle, + struct address_space *mapping, loff_t from, + loff_t length, int flags) +{ + struct inode *inode = mapping->host; + struct page *page; + int err = 0; + + page = find_or_create_page(mapping, from >> PAGE_CACHE_SHIFT, + mapping_gfp_mask(mapping) & ~__GFP_FS); + if (!page) + return -ENOMEM; + + err = ext4_discard_partial_page_buffers_no_lock(handle, inode, page, + from, length, flags); + + unlock_page(page); + page_cache_release(page); + return err; +} + +/* + * ext4_discard_partial_page_buffers_no_lock() + * Zeros a page range of length 'length' starting from offset 'from'. + * Buffer heads that correspond to the block aligned regions of the + * zeroed range will be unmapped. Unblock aligned regions + * will have the corresponding buffer head mapped if needed so that + * that region of the page can be updated with the partial zero out. + * + * This function assumes that the page has already been locked. The + * The range to be discarded must be contained with in the given page. + * If the specified range exceeds the end of the page it will be shortened + * to the end of the page that corresponds to 'from'. This function is + * appropriate for updating a page and it buffer heads to be unmapped and + * zeroed for blocks that have been either released, or are going to be + * released. + * + * handle: The journal handle + * inode: The files inode + * page: A locked page that contains the offset "from" + * from: The starting byte offset (from the begining of the file) + * to begin discarding + * len: The length of bytes to discard + * flags: Optional flags that may be used: + * + * EXT4_DISCARD_PARTIAL_PG_ZERO_UNMAPPED + * Only zero the regions of the page whose buffer heads + * have already been unmapped. This flag is appropriate + * for updateing the contents of a page whose blocks may + * have already been released, and we only want to zero + * out the regions that correspond to those released blocks. + * + * Returns zero on sucess or negative on failure. + */ +static int ext4_discard_partial_page_buffers_no_lock(handle_t *handle, + struct inode *inode, struct page *page, loff_t from, + loff_t length, int flags) +{ + ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT; + unsigned int offset = from & (PAGE_CACHE_SIZE-1); + unsigned int blocksize, max, pos; + ext4_lblk_t iblock; + struct buffer_head *bh; + int err = 0; + + blocksize = inode->i_sb->s_blocksize; + max = PAGE_CACHE_SIZE - offset; + + if (index != page->index) + return -EINVAL; + + /* + * correct length if it does not fall between + * 'from' and the end of the page + */ + if (length > max || length < 0) + length = max; + + iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits); + + if (!page_has_buffers(page)) + create_empty_buffers(page, blocksize, 0); + + /* Find the buffer that contains "offset" */ + bh = page_buffers(page); + pos = blocksize; + while (offset >= pos) { + bh = bh->b_this_page; + iblock++; + pos += blocksize; + } + + pos = offset; + while (pos < offset + length) { + unsigned int end_of_block, range_to_discard; + + err = 0; + + /* The length of space left to zero and unmap */ + range_to_discard = offset + length - pos; + + /* The length of space until the end of the block */ + end_of_block = blocksize - (pos & (blocksize-1)); + + /* + * Do not unmap or zero past end of block + * for this buffer head + */ + if (range_to_discard > end_of_block) + range_to_discard = end_of_block; + + + /* + * Skip this buffer head if we are only zeroing unampped + * regions of the page + */ + if (flags & EXT4_DISCARD_PARTIAL_PG_ZERO_UNMAPPED && + buffer_mapped(bh)) + goto next; + + /* If the range is block aligned, unmap */ + if (range_to_discard == blocksize) { + clear_buffer_dirty(bh); + bh->b_bdev = NULL; + clear_buffer_mapped(bh); + clear_buffer_req(bh); + clear_buffer_new(bh); + clear_buffer_delay(bh); + clear_buffer_unwritten(bh); + clear_buffer_uptodate(bh); + zero_user(page, pos, range_to_discard); + BUFFER_TRACE(bh, "Buffer discarded"); + goto next; + } + + /* + * If this block is not completely contained in the range + * to be discarded, then it is not going to be released. Because + * we need to keep this block, we need to make sure this part + * of the page is uptodate before we modify it by writeing + * partial zeros on it. + */ + if (!buffer_mapped(bh)) { + /* + * Buffer head must be mapped before we can read + * from the block + */ + BUFFER_TRACE(bh, "unmapped"); + ext4_get_block(inode, iblock, bh, 0); + /* unmapped? It's a hole - nothing to do */ + if (!buffer_mapped(bh)) { + BUFFER_TRACE(bh, "still unmapped"); + goto next; + } + } + + /* Ok, it's mapped. Make sure it's up-to-date */ + if (PageUptodate(page)) + set_buffer_uptodate(bh); + + if (!buffer_uptodate(bh)) { + err = -EIO; + ll_rw_block(READ, 1, &bh); + wait_on_buffer(bh); + /* Uhhuh. Read error. Complain and punt.*/ + if (!buffer_uptodate(bh)) + goto next; + } + + if (ext4_should_journal_data(inode)) { + BUFFER_TRACE(bh, "get write access"); + err = ext4_journal_get_write_access(handle, bh); + if (err) + goto next; + } + + zero_user(page, pos, range_to_discard); + + err = 0; + if (ext4_should_journal_data(inode)) { + err = ext4_handle_dirty_metadata(handle, inode, bh); + } else + mark_buffer_dirty(bh); + + BUFFER_TRACE(bh, "Partial buffer zeroed"); +next: + bh = bh->b_this_page; + iblock++; + pos += range_to_discard; + } + + return err; +} + +int ext4_can_truncate(struct inode *inode) +{ + if (S_ISREG(inode->i_mode)) + return 1; + if (S_ISDIR(inode->i_mode)) + return 1; + if (S_ISLNK(inode->i_mode)) + return !ext4_inode_is_fast_symlink(inode); + return 0; +} + +/* + * ext4_punch_hole: punches a hole in a file by releaseing the blocks + * associated with the given offset and length + * + * @inode: File inode + * @offset: The offset where the hole will begin + * @len: The length of the hole + * + * Returns: 0 on sucess or negative on failure + */ + +int ext4_punch_hole(struct file *file, loff_t offset, loff_t length) +{ + struct inode *inode = file->f_path.dentry->d_inode; + if (!S_ISREG(inode->i_mode)) + return -EOPNOTSUPP; + + if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { + /* TODO: Add support for non extent hole punching */ + return -EOPNOTSUPP; + } + + if (EXT4_SB(inode->i_sb)->s_cluster_ratio > 1) { + /* TODO: Add support for bigalloc file systems */ + return -EOPNOTSUPP; + } + + return ext4_ext_punch_hole(file, offset, length); +} + +/* + * ext4_truncate() + * + * We block out ext4_get_block() block instantiations across the entire + * transaction, and VFS/VM ensures that ext4_truncate() cannot run + * simultaneously on behalf of the same inode. + * + * As we work through the truncate and commit bits of it to the journal there + * is one core, guiding principle: the file's tree must always be consistent on + * disk. We must be able to restart the truncate after a crash. + * + * The file's tree may be transiently inconsistent in memory (although it + * probably isn't), but whenever we close off and commit a journal transaction, + * the contents of (the filesystem + the journal) must be consistent and + * restartable. It's pretty simple, really: bottom up, right to left (although + * left-to-right works OK too). + * + * Note that at recovery time, journal replay occurs *before* the restart of + * truncate against the orphan inode list. + * + * The committed inode has the new, desired i_size (which is the same as + * i_disksize in this case). After a crash, ext4_orphan_cleanup() will see + * that this inode's truncate did not complete and it will again call + * ext4_truncate() to have another go. So there will be instantiated blocks + * to the right of the truncation point in a crashed ext4 filesystem. But + * that's fine - as long as they are linked from the inode, the post-crash + * ext4_truncate() run will find them and release them. + */ +void ext4_truncate(struct inode *inode) +{ + trace_ext4_truncate_enter(inode); + + if (!ext4_can_truncate(inode)) + return; + + ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS); + + if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC)) + ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE); + + if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) + ext4_ext_truncate(inode); + else + ext4_ind_truncate(inode); + + trace_ext4_truncate_exit(inode); +} + +/* + * ext4_get_inode_loc returns with an extra refcount against the inode's + * underlying buffer_head on success. If 'in_mem' is true, we have all + * data in memory that is needed to recreate the on-disk version of this + * inode. + */ +static int __ext4_get_inode_loc(struct inode *inode, + struct ext4_iloc *iloc, int in_mem) +{ + struct ext4_group_desc *gdp; + struct buffer_head *bh; + struct super_block *sb = inode->i_sb; + ext4_fsblk_t block; + int inodes_per_block, inode_offset; + + iloc->bh = NULL; + if (!ext4_valid_inum(sb, inode->i_ino)) + return -EIO; + + iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb); + gdp = ext4_get_group_desc(sb, iloc->block_group, NULL); + if (!gdp) + return -EIO; + + /* + * Figure out the offset within the block group inode table + */ + inodes_per_block = EXT4_SB(sb)->s_inodes_per_block; + inode_offset = ((inode->i_ino - 1) % + EXT4_INODES_PER_GROUP(sb)); + block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block); + iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb); + + bh = sb_getblk(sb, block); + if (!bh) { + EXT4_ERROR_INODE_BLOCK(inode, block, + "unable to read itable block"); + return -EIO; + } + if (!buffer_uptodate(bh)) { + lock_buffer(bh); + + /* + * If the buffer has the write error flag, we have failed + * to write out another inode in the same block. In this + * case, we don't have to read the block because we may + * read the old inode data successfully. + */ + if (buffer_write_io_error(bh) && !buffer_uptodate(bh)) + set_buffer_uptodate(bh); + + if (buffer_uptodate(bh)) { + /* someone brought it uptodate while we waited */ + unlock_buffer(bh); + goto has_buffer; + } + + /* + * If we have all information of the inode in memory and this + * is the only valid inode in the block, we need not read the + * block. + */ + if (in_mem) { + struct buffer_head *bitmap_bh; + int i, start; + + start = inode_offset & ~(inodes_per_block - 1); + + /* Is the inode bitmap in cache? */ + bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp)); + if (!bitmap_bh) + goto make_io; + + /* + * If the inode bitmap isn't in cache then the + * optimisation may end up performing two reads instead + * of one, so skip it. + */ + if (!buffer_uptodate(bitmap_bh)) { + brelse(bitmap_bh); + goto make_io; + } + for (i = start; i < start + inodes_per_block; i++) { + if (i == inode_offset) + continue; + if (ext4_test_bit(i, bitmap_bh->b_data)) + break; + } + brelse(bitmap_bh); + if (i == start + inodes_per_block) { + /* all other inodes are free, so skip I/O */ + memset(bh->b_data, 0, bh->b_size); + set_buffer_uptodate(bh); + unlock_buffer(bh); + goto has_buffer; + } + } + +make_io: + /* + * If we need to do any I/O, try to pre-readahead extra + * blocks from the inode table. + */ + if (EXT4_SB(sb)->s_inode_readahead_blks) { + ext4_fsblk_t b, end, table; + unsigned num; + + table = ext4_inode_table(sb, gdp); + /* s_inode_readahead_blks is always a power of 2 */ + b = block & ~(EXT4_SB(sb)->s_inode_readahead_blks-1); + if (table > b) + b = table; + end = b + EXT4_SB(sb)->s_inode_readahead_blks; + num = EXT4_INODES_PER_GROUP(sb); + if (EXT4_HAS_RO_COMPAT_FEATURE(sb, + EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) + num -= ext4_itable_unused_count(sb, gdp); + table += num / inodes_per_block; + if (end > table) + end = table; + while (b <= end) + sb_breadahead(sb, b++); + } + + /* + * There are other valid inodes in the buffer, this inode + * has in-inode xattrs, or we don't have this inode in memory. + * Read the block from disk. + */ + trace_ext4_load_inode(inode); + get_bh(bh); + bh->b_end_io = end_buffer_read_sync; + submit_bh(READ | REQ_META | REQ_PRIO, bh); + wait_on_buffer(bh); + if (!buffer_uptodate(bh)) { + EXT4_ERROR_INODE_BLOCK(inode, block, + "unable to read itable block"); + brelse(bh); + return -EIO; + } + } +has_buffer: + iloc->bh = bh; + return 0; +} + +int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc) +{ + /* We have all inode data except xattrs in memory here. */ + return __ext4_get_inode_loc(inode, iloc, + !ext4_test_inode_state(inode, EXT4_STATE_XATTR)); +} + +void ext4_set_inode_flags(struct inode *inode) +{ + unsigned int flags = EXT4_I(inode)->i_flags; + + inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC); + if (flags & EXT4_SYNC_FL) + inode->i_flags |= S_SYNC; + if (flags & EXT4_APPEND_FL) + inode->i_flags |= S_APPEND; + if (flags & EXT4_IMMUTABLE_FL) + inode->i_flags |= S_IMMUTABLE; + if (flags & EXT4_NOATIME_FL) + inode->i_flags |= S_NOATIME; + if (flags & EXT4_DIRSYNC_FL) + inode->i_flags |= S_DIRSYNC; +} + +/* Propagate flags from i_flags to EXT4_I(inode)->i_flags */ +void ext4_get_inode_flags(struct ext4_inode_info *ei) +{ + unsigned int vfs_fl; + unsigned long old_fl, new_fl; + + do { + vfs_fl = ei->vfs_inode.i_flags; + old_fl = ei->i_flags; + new_fl = old_fl & ~(EXT4_SYNC_FL|EXT4_APPEND_FL| + EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL| + EXT4_DIRSYNC_FL); + if (vfs_fl & S_SYNC) + new_fl |= EXT4_SYNC_FL; + if (vfs_fl & S_APPEND) + new_fl |= EXT4_APPEND_FL; + if (vfs_fl & S_IMMUTABLE) + new_fl |= EXT4_IMMUTABLE_FL; + if (vfs_fl & S_NOATIME) + new_fl |= EXT4_NOATIME_FL; + if (vfs_fl & S_DIRSYNC) + new_fl |= EXT4_DIRSYNC_FL; + } while (cmpxchg(&ei->i_flags, old_fl, new_fl) != old_fl); +} + +static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode, + struct ext4_inode_info *ei) +{ + blkcnt_t i_blocks ; + struct inode *inode = &(ei->vfs_inode); + struct super_block *sb = inode->i_sb; + + if (EXT4_HAS_RO_COMPAT_FEATURE(sb, + EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) { + /* we are using combined 48 bit field */ + i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 | + le32_to_cpu(raw_inode->i_blocks_lo); + if (ext4_test_inode_flag(inode, EXT4_INODE_HUGE_FILE)) { + /* i_blocks represent file system block size */ + return i_blocks << (inode->i_blkbits - 9); + } else { + return i_blocks; + } + } else { + return le32_to_cpu(raw_inode->i_blocks_lo); + } +} + +struct inode *ext4_iget(struct super_block *sb, unsigned long ino) +{ + struct ext4_iloc iloc; + struct ext4_inode *raw_inode; + struct ext4_inode_info *ei; + struct inode *inode; + journal_t *journal = EXT4_SB(sb)->s_journal; + long ret; + int block; + + inode = iget_locked(sb, ino); + if (!inode) + return ERR_PTR(-ENOMEM); + if (!(inode->i_state & I_NEW)) + return inode; + + ei = EXT4_I(inode); + iloc.bh = NULL; + + ret = __ext4_get_inode_loc(inode, &iloc, 0); + if (ret < 0) + goto bad_inode; + raw_inode = ext4_raw_inode(&iloc); + inode->i_mode = le16_to_cpu(raw_inode->i_mode); + inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low); + inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low); + if (!(test_opt(inode->i_sb, NO_UID32))) { + inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16; + inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16; + } + set_nlink(inode, le16_to_cpu(raw_inode->i_links_count)); + + ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */ + ei->i_dir_start_lookup = 0; + ei->i_dtime = le32_to_cpu(raw_inode->i_dtime); + /* We now have enough fields to check if the inode was active or not. + * This is needed because nfsd might try to access dead inodes + * the test is that same one that e2fsck uses + * NeilBrown 1999oct15 + */ + if (inode->i_nlink == 0) { + if (inode->i_mode == 0 || + !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) { + /* this inode is deleted */ + ret = -ESTALE; + goto bad_inode; + } + /* The only unlinked inodes we let through here have + * valid i_mode and are being read by the orphan + * recovery code: that's fine, we're about to complete + * the process of deleting those. */ + } + ei->i_flags = le32_to_cpu(raw_inode->i_flags); + inode->i_blocks = ext4_inode_blocks(raw_inode, ei); + ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo); + if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT)) + ei->i_file_acl |= + ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32; + inode->i_size = ext4_isize(raw_inode); + ei->i_disksize = inode->i_size; +#ifdef CONFIG_QUOTA + ei->i_reserved_quota = 0; +#endif + inode->i_generation = le32_to_cpu(raw_inode->i_generation); + ei->i_block_group = iloc.block_group; + ei->i_last_alloc_group = ~0; + /* + * NOTE! The in-memory inode i_data array is in little-endian order + * even on big-endian machines: we do NOT byteswap the block numbers! + */ + for (block = 0; block < EXT4_N_BLOCKS; block++) + ei->i_data[block] = raw_inode->i_block[block]; + INIT_LIST_HEAD(&ei->i_orphan); + + /* + * Set transaction id's of transactions that have to be committed + * to finish f[data]sync. We set them to currently running transaction + * as we cannot be sure that the inode or some of its metadata isn't + * part of the transaction - the inode could have been reclaimed and + * now it is reread from disk. + */ + if (journal) { + transaction_t *transaction; + tid_t tid; + + read_lock(&journal->j_state_lock); + if (journal->j_running_transaction) + transaction = journal->j_running_transaction; + else + transaction = journal->j_committing_transaction; + if (transaction) + tid = transaction->t_tid; + else + tid = journal->j_commit_sequence; + read_unlock(&journal->j_state_lock); + ei->i_sync_tid = tid; + ei->i_datasync_tid = tid; + } + + if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) { + ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize); + if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > + EXT4_INODE_SIZE(inode->i_sb)) { + ret = -EIO; + goto bad_inode; + } + if (ei->i_extra_isize == 0) { + /* The extra space is currently unused. Use it. */ + ei->i_extra_isize = sizeof(struct ext4_inode) - + EXT4_GOOD_OLD_INODE_SIZE; + } else { + __le32 *magic = (void *)raw_inode + + EXT4_GOOD_OLD_INODE_SIZE + + ei->i_extra_isize; + if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC)) + ext4_set_inode_state(inode, EXT4_STATE_XATTR); + } + } else + ei->i_extra_isize = 0; + + EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode); + EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode); + EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode); + EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode); + + inode->i_version = le32_to_cpu(raw_inode->i_disk_version); + if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) { + if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi)) + inode->i_version |= + (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32; + } + + ret = 0; + if (ei->i_file_acl && + !ext4_data_block_valid(EXT4_SB(sb), ei->i_file_acl, 1)) { + EXT4_ERROR_INODE(inode, "bad extended attribute block %llu", + ei->i_file_acl); + ret = -EIO; + goto bad_inode; + } else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { + if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || + (S_ISLNK(inode->i_mode) && + !ext4_inode_is_fast_symlink(inode))) + /* Validate extent which is part of inode */ + ret = ext4_ext_check_inode(inode); + } else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || + (S_ISLNK(inode->i_mode) && + !ext4_inode_is_fast_symlink(inode))) { + /* Validate block references which are part of inode */ + ret = ext4_ind_check_inode(inode); + } + if (ret) + goto bad_inode; + + if (S_ISREG(inode->i_mode)) { + inode->i_op = &ext4_file_inode_operations; + inode->i_fop = &ext4_file_operations; + ext4_set_aops(inode); + } else if (S_ISDIR(inode->i_mode)) { + inode->i_op = &ext4_dir_inode_operations; + inode->i_fop = &ext4_dir_operations; + } else if (S_ISLNK(inode->i_mode)) { + if (ext4_inode_is_fast_symlink(inode)) { + inode->i_op = &ext4_fast_symlink_inode_operations; + nd_terminate_link(ei->i_data, inode->i_size, + sizeof(ei->i_data) - 1); + } else { + inode->i_op = &ext4_symlink_inode_operations; + ext4_set_aops(inode); + } + } else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) || + S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { + inode->i_op = &ext4_special_inode_operations; + if (raw_inode->i_block[0]) + init_special_inode(inode, inode->i_mode, + old_decode_dev(le32_to_cpu(raw_inode->i_block[0]))); + else + init_special_inode(inode, inode->i_mode, + new_decode_dev(le32_to_cpu(raw_inode->i_block[1]))); + } else { + ret = -EIO; + EXT4_ERROR_INODE(inode, "bogus i_mode (%o)", inode->i_mode); + goto bad_inode; + } + brelse(iloc.bh); + ext4_set_inode_flags(inode); + unlock_new_inode(inode); + return inode; + +bad_inode: + brelse(iloc.bh); + iget_failed(inode); + return ERR_PTR(ret); +} + +static int ext4_inode_blocks_set(handle_t *handle, + struct ext4_inode *raw_inode, + struct ext4_inode_info *ei) +{ + struct inode *inode = &(ei->vfs_inode); + u64 i_blocks = inode->i_blocks; + struct super_block *sb = inode->i_sb; + + if (i_blocks <= ~0U) { + /* + * i_blocks can be represnted in a 32 bit variable + * as multiple of 512 bytes + */ + raw_inode->i_blocks_lo = cpu_to_le32(i_blocks); + raw_inode->i_blocks_high = 0; + ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE); + return 0; + } + if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) + return -EFBIG; + + if (i_blocks <= 0xffffffffffffULL) { + /* + * i_blocks can be represented in a 48 bit variable + * as multiple of 512 bytes + */ + raw_inode->i_blocks_lo = cpu_to_le32(i_blocks); + raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32); + ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE); + } else { + ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE); + /* i_block is stored in file system block size */ + i_blocks = i_blocks >> (inode->i_blkbits - 9); + raw_inode->i_blocks_lo = cpu_to_le32(i_blocks); + raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32); + } + return 0; +} + +/* + * Post the struct inode info into an on-disk inode location in the + * buffer-cache. This gobbles the caller's reference to the + * buffer_head in the inode location struct. + * + * The caller must have write access to iloc->bh. + */ +static int ext4_do_update_inode(handle_t *handle, + struct inode *inode, + struct ext4_iloc *iloc) +{ + struct ext4_inode *raw_inode = ext4_raw_inode(iloc); + struct ext4_inode_info *ei = EXT4_I(inode); + struct buffer_head *bh = iloc->bh; + int err = 0, rc, block; + + /* For fields not not tracking in the in-memory inode, + * initialise them to zero for new inodes. */ + if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) + memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size); + + ext4_get_inode_flags(ei); + raw_inode->i_mode = cpu_to_le16(inode->i_mode); + if (!(test_opt(inode->i_sb, NO_UID32))) { + raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid)); + raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid)); +/* + * Fix up interoperability with old kernels. Otherwise, old inodes get + * re-used with the upper 16 bits of the uid/gid intact + */ + if (!ei->i_dtime) { + raw_inode->i_uid_high = + cpu_to_le16(high_16_bits(inode->i_uid)); + raw_inode->i_gid_high = + cpu_to_le16(high_16_bits(inode->i_gid)); + } else { + raw_inode->i_uid_high = 0; + raw_inode->i_gid_high = 0; + } + } else { + raw_inode->i_uid_low = + cpu_to_le16(fs_high2lowuid(inode->i_uid)); + raw_inode->i_gid_low = + cpu_to_le16(fs_high2lowgid(inode->i_gid)); + raw_inode->i_uid_high = 0; + raw_inode->i_gid_high = 0; + } + raw_inode->i_links_count = cpu_to_le16(inode->i_nlink); + + EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode); + EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode); + EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode); + EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode); + + if (ext4_inode_blocks_set(handle, raw_inode, ei)) + goto out_brelse; + raw_inode->i_dtime = cpu_to_le32(ei->i_dtime); + raw_inode->i_flags = cpu_to_le32(ei->i_flags & 0xFFFFFFFF); + if (EXT4_SB(inode->i_sb)->s_es->s_creator_os != + cpu_to_le32(EXT4_OS_HURD)) + raw_inode->i_file_acl_high = + cpu_to_le16(ei->i_file_acl >> 32); + raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl); + ext4_isize_set(raw_inode, ei->i_disksize); + if (ei->i_disksize > 0x7fffffffULL) { + struct super_block *sb = inode->i_sb; + if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, + EXT4_FEATURE_RO_COMPAT_LARGE_FILE) || + EXT4_SB(sb)->s_es->s_rev_level == + cpu_to_le32(EXT4_GOOD_OLD_REV)) { + /* If this is the first large file + * created, add a flag to the superblock. + */ + err = ext4_journal_get_write_access(handle, + EXT4_SB(sb)->s_sbh); + if (err) + goto out_brelse; + ext4_update_dynamic_rev(sb); + EXT4_SET_RO_COMPAT_FEATURE(sb, + EXT4_FEATURE_RO_COMPAT_LARGE_FILE); + ext4_handle_sync(handle); + err = ext4_handle_dirty_super(handle, sb); + } + } + raw_inode->i_generation = cpu_to_le32(inode->i_generation); + if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) { + if (old_valid_dev(inode->i_rdev)) { + raw_inode->i_block[0] = + cpu_to_le32(old_encode_dev(inode->i_rdev)); + raw_inode->i_block[1] = 0; + } else { + raw_inode->i_block[0] = 0; + raw_inode->i_block[1] = + cpu_to_le32(new_encode_dev(inode->i_rdev)); + raw_inode->i_block[2] = 0; + } + } else + for (block = 0; block < EXT4_N_BLOCKS; block++) + raw_inode->i_block[block] = ei->i_data[block]; + + raw_inode->i_disk_version = cpu_to_le32(inode->i_version); + if (ei->i_extra_isize) { + if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi)) + raw_inode->i_version_hi = + cpu_to_le32(inode->i_version >> 32); + raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize); + } + + BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata"); + rc = ext4_handle_dirty_metadata(handle, NULL, bh); + if (!err) + err = rc; + ext4_clear_inode_state(inode, EXT4_STATE_NEW); + + ext4_update_inode_fsync_trans(handle, inode, 0); +out_brelse: + brelse(bh); + ext4_std_error(inode->i_sb, err); + return err; +} + +/* + * ext4_write_inode() + * + * We are called from a few places: + * + * - Within generic_file_write() for O_SYNC files. + * Here, there will be no transaction running. We wait for any running + * trasnaction to commit. + * + * - Within sys_sync(), kupdate and such. + * We wait on commit, if tol to. + * + * - Within prune_icache() (PF_MEMALLOC == true) + * Here we simply return. We can't afford to block kswapd on the + * journal commit. + * + * In all cases it is actually safe for us to return without doing anything, + * because the inode has been copied into a raw inode buffer in + * ext4_mark_inode_dirty(). This is a correctness thing for O_SYNC and for + * knfsd. + * + * Note that we are absolutely dependent upon all inode dirtiers doing the + * right thing: they *must* call mark_inode_dirty() after dirtying info in + * which we are interested. + * + * It would be a bug for them to not do this. The code: + * + * mark_inode_dirty(inode) + * stuff(); + * inode->i_size = expr; + * + * is in error because a kswapd-driven write_inode() could occur while + * `stuff()' is running, and the new i_size will be lost. Plus the inode + * will no longer be on the superblock's dirty inode list. + */ +int ext4_write_inode(struct inode *inode, struct writeback_control *wbc) +{ + int err; + + if (current->flags & PF_MEMALLOC) + return 0; + + if (EXT4_SB(inode->i_sb)->s_journal) { + if (ext4_journal_current_handle()) { + jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n"); + dump_stack(); + return -EIO; + } + + if (wbc->sync_mode != WB_SYNC_ALL) + return 0; + + err = ext4_force_commit(inode->i_sb); + } else { + struct ext4_iloc iloc; + + err = __ext4_get_inode_loc(inode, &iloc, 0); + if (err) + return err; + if (wbc->sync_mode == WB_SYNC_ALL) + sync_dirty_buffer(iloc.bh); + if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) { + EXT4_ERROR_INODE_BLOCK(inode, iloc.bh->b_blocknr, + "IO error syncing inode"); + err = -EIO; + } + brelse(iloc.bh); + } + return err; +} + +/* + * ext4_setattr() + * + * Called from notify_change. + * + * We want to trap VFS attempts to truncate the file as soon as + * possible. In particular, we want to make sure that when the VFS + * shrinks i_size, we put the inode on the orphan list and modify + * i_disksize immediately, so that during the subsequent flushing of + * dirty pages and freeing of disk blocks, we can guarantee that any + * commit will leave the blocks being flushed in an unused state on + * disk. (On recovery, the inode will get truncated and the blocks will + * be freed, so we have a strong guarantee that no future commit will + * leave these blocks visible to the user.) + * + * Another thing we have to assure is that if we are in ordered mode + * and inode is still attached to the committing transaction, we must + * we start writeout of all the dirty pages which are being truncated. + * This way we are sure that all the data written in the previous + * transaction are already on disk (truncate waits for pages under + * writeback). + * + * Called with inode->i_mutex down. + */ +int ext4_setattr(struct dentry *dentry, struct iattr *attr) +{ + struct inode *inode = dentry->d_inode; + int error, rc = 0; + int orphan = 0; + const unsigned int ia_valid = attr->ia_valid; + + error = inode_change_ok(inode, attr); + if (error) + return error; + + if (is_quota_modification(inode, attr)) + dquot_initialize(inode); + if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) || + (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) { + handle_t *handle; + + /* (user+group)*(old+new) structure, inode write (sb, + * inode block, ? - but truncate inode update has it) */ + handle = ext4_journal_start(inode, (EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb)+ + EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb))+3); + if (IS_ERR(handle)) { + error = PTR_ERR(handle); + goto err_out; + } + error = dquot_transfer(inode, attr); + if (error) { + ext4_journal_stop(handle); + return error; + } + /* Update corresponding info in inode so that everything is in + * one transaction */ + if (attr->ia_valid & ATTR_UID) + inode->i_uid = attr->ia_uid; + if (attr->ia_valid & ATTR_GID) + inode->i_gid = attr->ia_gid; + error = ext4_mark_inode_dirty(handle, inode); + ext4_journal_stop(handle); + } + + if (attr->ia_valid & ATTR_SIZE) { + inode_dio_wait(inode); + + if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) { + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + + if (attr->ia_size > sbi->s_bitmap_maxbytes) + return -EFBIG; + } + } + + if (S_ISREG(inode->i_mode) && + attr->ia_valid & ATTR_SIZE && + (attr->ia_size < inode->i_size)) { + handle_t *handle; + + handle = ext4_journal_start(inode, 3); + if (IS_ERR(handle)) { + error = PTR_ERR(handle); + goto err_out; + } + if (ext4_handle_valid(handle)) { + error = ext4_orphan_add(handle, inode); + orphan = 1; + } + EXT4_I(inode)->i_disksize = attr->ia_size; + rc = ext4_mark_inode_dirty(handle, inode); + if (!error) + error = rc; + ext4_journal_stop(handle); + + if (ext4_should_order_data(inode)) { + error = ext4_begin_ordered_truncate(inode, + attr->ia_size); + if (error) { + /* Do as much error cleanup as possible */ + handle = ext4_journal_start(inode, 3); + if (IS_ERR(handle)) { + ext4_orphan_del(NULL, inode); + goto err_out; + } + ext4_orphan_del(handle, inode); + orphan = 0; + ext4_journal_stop(handle); + goto err_out; + } + } + } + + if (attr->ia_valid & ATTR_SIZE) { + if (attr->ia_size != i_size_read(inode)) + truncate_setsize(inode, attr->ia_size); + ext4_truncate(inode); + } + + if (!rc) { + setattr_copy(inode, attr); + mark_inode_dirty(inode); + } + + /* + * If the call to ext4_truncate failed to get a transaction handle at + * all, we need to clean up the in-core orphan list manually. + */ + if (orphan && inode->i_nlink) + ext4_orphan_del(NULL, inode); + + if (!rc && (ia_valid & ATTR_MODE)) + rc = ext4_acl_chmod(inode); + +err_out: + ext4_std_error(inode->i_sb, error); + if (!error) + error = rc; + return error; +} + +int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry, + struct kstat *stat) +{ + struct inode *inode; + unsigned long delalloc_blocks; + + inode = dentry->d_inode; + generic_fillattr(inode, stat); + + /* + * We can't update i_blocks if the block allocation is delayed + * otherwise in the case of system crash before the real block + * allocation is done, we will have i_blocks inconsistent with + * on-disk file blocks. + * We always keep i_blocks updated together with real + * allocation. But to not confuse with user, stat + * will return the blocks that include the delayed allocation + * blocks for this file. + */ + delalloc_blocks = EXT4_I(inode)->i_reserved_data_blocks; + + stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9; + return 0; +} + +static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk) +{ + if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) + return ext4_ind_trans_blocks(inode, nrblocks, chunk); + return ext4_ext_index_trans_blocks(inode, nrblocks, chunk); +} + +/* + * Account for index blocks, block groups bitmaps and block group + * descriptor blocks if modify datablocks and index blocks + * worse case, the indexs blocks spread over different block groups + * + * If datablocks are discontiguous, they are possible to spread over + * different block groups too. If they are contiuguous, with flexbg, + * they could still across block group boundary. + * + * Also account for superblock, inode, quota and xattr blocks + */ +static int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk) +{ + ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb); + int gdpblocks; + int idxblocks; + int ret = 0; + + /* + * How many index blocks need to touch to modify nrblocks? + * The "Chunk" flag indicating whether the nrblocks is + * physically contiguous on disk + * + * For Direct IO and fallocate, they calls get_block to allocate + * one single extent at a time, so they could set the "Chunk" flag + */ + idxblocks = ext4_index_trans_blocks(inode, nrblocks, chunk); + + ret = idxblocks; + + /* + * Now let's see how many group bitmaps and group descriptors need + * to account + */ + groups = idxblocks; + if (chunk) + groups += 1; + else + groups += nrblocks; + + gdpblocks = groups; + if (groups > ngroups) + groups = ngroups; + if (groups > EXT4_SB(inode->i_sb)->s_gdb_count) + gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count; + + /* bitmaps and block group descriptor blocks */ + ret += groups + gdpblocks; + + /* Blocks for super block, inode, quota and xattr blocks */ + ret += EXT4_META_TRANS_BLOCKS(inode->i_sb); + + return ret; +} + +/* + * Calculate the total number of credits to reserve to fit + * the modification of a single pages into a single transaction, + * which may include multiple chunks of block allocations. + * + * This could be called via ext4_write_begin() + * + * We need to consider the worse case, when + * one new block per extent. + */ +int ext4_writepage_trans_blocks(struct inode *inode) +{ + int bpp = ext4_journal_blocks_per_page(inode); + int ret; + + ret = ext4_meta_trans_blocks(inode, bpp, 0); + + /* Account for data blocks for journalled mode */ + if (ext4_should_journal_data(inode)) + ret += bpp; + return ret; +} + +/* + * Calculate the journal credits for a chunk of data modification. + * + * This is called from DIO, fallocate or whoever calling + * ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks. + * + * journal buffers for data blocks are not included here, as DIO + * and fallocate do no need to journal data buffers. + */ +int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks) +{ + return ext4_meta_trans_blocks(inode, nrblocks, 1); +} + +/* + * The caller must have previously called ext4_reserve_inode_write(). + * Give this, we know that the caller already has write access to iloc->bh. + */ +int ext4_mark_iloc_dirty(handle_t *handle, + struct inode *inode, struct ext4_iloc *iloc) +{ + int err = 0; + + if (IS_I_VERSION(inode)) + inode_inc_iversion(inode); + + /* the do_update_inode consumes one bh->b_count */ + get_bh(iloc->bh); + + /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */ + err = ext4_do_update_inode(handle, inode, iloc); + put_bh(iloc->bh); + return err; +} + +/* + * On success, We end up with an outstanding reference count against + * iloc->bh. This _must_ be cleaned up later. + */ + +int +ext4_reserve_inode_write(handle_t *handle, struct inode *inode, + struct ext4_iloc *iloc) +{ + int err; + + err = ext4_get_inode_loc(inode, iloc); + if (!err) { + BUFFER_TRACE(iloc->bh, "get_write_access"); + err = ext4_journal_get_write_access(handle, iloc->bh); + if (err) { + brelse(iloc->bh); + iloc->bh = NULL; + } + } + ext4_std_error(inode->i_sb, err); + return err; +} + +/* + * Expand an inode by new_extra_isize bytes. + * Returns 0 on success or negative error number on failure. + */ +static int ext4_expand_extra_isize(struct inode *inode, + unsigned int new_extra_isize, + struct ext4_iloc iloc, + handle_t *handle) +{ + struct ext4_inode *raw_inode; + struct ext4_xattr_ibody_header *header; + + if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) + return 0; + + raw_inode = ext4_raw_inode(&iloc); + + header = IHDR(inode, raw_inode); + + /* No extended attributes present */ + if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) || + header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) { + memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0, + new_extra_isize); + EXT4_I(inode)->i_extra_isize = new_extra_isize; + return 0; + } + + /* try to expand with EAs present */ + return ext4_expand_extra_isize_ea(inode, new_extra_isize, + raw_inode, handle); +} + +/* + * What we do here is to mark the in-core inode as clean with respect to inode + * dirtiness (it may still be data-dirty). + * This means that the in-core inode may be reaped by prune_icache + * without having to perform any I/O. This is a very good thing, + * because *any* task may call prune_icache - even ones which + * have a transaction open against a different journal. + * + * Is this cheating? Not really. Sure, we haven't written the + * inode out, but prune_icache isn't a user-visible syncing function. + * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync) + * we start and wait on commits. + * + * Is this efficient/effective? Well, we're being nice to the system + * by cleaning up our inodes proactively so they can be reaped + * without I/O. But we are potentially leaving up to five seconds' + * worth of inodes floating about which prune_icache wants us to + * write out. One way to fix that would be to get prune_icache() + * to do a write_super() to free up some memory. It has the desired + * effect. + */ +int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode) +{ + struct ext4_iloc iloc; + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + static unsigned int mnt_count; + int err, ret; + + might_sleep(); + trace_ext4_mark_inode_dirty(inode, _RET_IP_); + err = ext4_reserve_inode_write(handle, inode, &iloc); + if (ext4_handle_valid(handle) && + EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize && + !ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) { + /* + * We need extra buffer credits since we may write into EA block + * with this same handle. If journal_extend fails, then it will + * only result in a minor loss of functionality for that inode. + * If this is felt to be critical, then e2fsck should be run to + * force a large enough s_min_extra_isize. + */ + if ((jbd2_journal_extend(handle, + EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) { + ret = ext4_expand_extra_isize(inode, + sbi->s_want_extra_isize, + iloc, handle); + if (ret) { + ext4_set_inode_state(inode, + EXT4_STATE_NO_EXPAND); + if (mnt_count != + le16_to_cpu(sbi->s_es->s_mnt_count)) { + ext4_warning(inode->i_sb, + "Unable to expand inode %lu. Delete" + " some EAs or run e2fsck.", + inode->i_ino); + mnt_count = + le16_to_cpu(sbi->s_es->s_mnt_count); + } + } + } + } + if (!err) + err = ext4_mark_iloc_dirty(handle, inode, &iloc); + return err; +} + +/* + * ext4_dirty_inode() is called from __mark_inode_dirty() + * + * We're really interested in the case where a file is being extended. + * i_size has been changed by generic_commit_write() and we thus need + * to include the updated inode in the current transaction. + * + * Also, dquot_alloc_block() will always dirty the inode when blocks + * are allocated to the file. + * + * If the inode is marked synchronous, we don't honour that here - doing + * so would cause a commit on atime updates, which we don't bother doing. + * We handle synchronous inodes at the highest possible level. + */ +void ext4_dirty_inode(struct inode *inode, int flags) +{ + handle_t *handle; + + handle = ext4_journal_start(inode, 2); + if (IS_ERR(handle)) + goto out; + + ext4_mark_inode_dirty(handle, inode); + + ext4_journal_stop(handle); +out: + return; +} + +#if 0 +/* + * Bind an inode's backing buffer_head into this transaction, to prevent + * it from being flushed to disk early. Unlike + * ext4_reserve_inode_write, this leaves behind no bh reference and + * returns no iloc structure, so the caller needs to repeat the iloc + * lookup to mark the inode dirty later. + */ +static int ext4_pin_inode(handle_t *handle, struct inode *inode) +{ + struct ext4_iloc iloc; + + int err = 0; + if (handle) { + err = ext4_get_inode_loc(inode, &iloc); + if (!err) { + BUFFER_TRACE(iloc.bh, "get_write_access"); + err = jbd2_journal_get_write_access(handle, iloc.bh); + if (!err) + err = ext4_handle_dirty_metadata(handle, + NULL, + iloc.bh); + brelse(iloc.bh); + } + } + ext4_std_error(inode->i_sb, err); + return err; +} +#endif + +int ext4_change_inode_journal_flag(struct inode *inode, int val) +{ + journal_t *journal; + handle_t *handle; + int err; + + /* + * We have to be very careful here: changing a data block's + * journaling status dynamically is dangerous. If we write a + * data block to the journal, change the status and then delete + * that block, we risk forgetting to revoke the old log record + * from the journal and so a subsequent replay can corrupt data. + * So, first we make sure that the journal is empty and that + * nobody is changing anything. + */ + + journal = EXT4_JOURNAL(inode); + if (!journal) + return 0; + if (is_journal_aborted(journal)) + return -EROFS; + /* We have to allocate physical blocks for delalloc blocks + * before flushing journal. otherwise delalloc blocks can not + * be allocated any more. even more truncate on delalloc blocks + * could trigger BUG by flushing delalloc blocks in journal. + * There is no delalloc block in non-journal data mode. + */ + if (val && test_opt(inode->i_sb, DELALLOC)) { + err = ext4_alloc_da_blocks(inode); + if (err < 0) + return err; + } + + jbd2_journal_lock_updates(journal); + + /* + * OK, there are no updates running now, and all cached data is + * synced to disk. We are now in a completely consistent state + * which doesn't have anything in the journal, and we know that + * no filesystem updates are running, so it is safe to modify + * the inode's in-core data-journaling state flag now. + */ + + if (val) + ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA); + else { + jbd2_journal_flush(journal); + ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA); + } + ext4_set_aops(inode); + + jbd2_journal_unlock_updates(journal); + + /* Finally we can mark the inode as dirty. */ + + handle = ext4_journal_start(inode, 1); + if (IS_ERR(handle)) + return PTR_ERR(handle); + + err = ext4_mark_inode_dirty(handle, inode); + ext4_handle_sync(handle); + ext4_journal_stop(handle); + ext4_std_error(inode->i_sb, err); + + return err; +} + +static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh) +{ + return !buffer_mapped(bh); +} + +int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + struct page *page = vmf->page; + loff_t size; + unsigned long len; + int ret; + struct file *file = vma->vm_file; + struct inode *inode = file->f_path.dentry->d_inode; + struct address_space *mapping = inode->i_mapping; + handle_t *handle; + get_block_t *get_block; + int retries = 0; + + /* + * This check is racy but catches the common case. We rely on + * __block_page_mkwrite() to do a reliable check. + */ + vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE); + /* Delalloc case is easy... */ + if (test_opt(inode->i_sb, DELALLOC) && + !ext4_should_journal_data(inode) && + !ext4_nonda_switch(inode->i_sb)) { + do { + ret = __block_page_mkwrite(vma, vmf, + ext4_da_get_block_prep); + } while (ret == -ENOSPC && + ext4_should_retry_alloc(inode->i_sb, &retries)); + goto out_ret; + } + + lock_page(page); + size = i_size_read(inode); + /* Page got truncated from under us? */ + if (page->mapping != mapping || page_offset(page) > size) { + unlock_page(page); + ret = VM_FAULT_NOPAGE; + goto out; + } + + if (page->index == size >> PAGE_CACHE_SHIFT) + len = size & ~PAGE_CACHE_MASK; + else + len = PAGE_CACHE_SIZE; + /* + * Return if we have all the buffers mapped. This avoids the need to do + * journal_start/journal_stop which can block and take a long time + */ + if (page_has_buffers(page)) { + if (!walk_page_buffers(NULL, page_buffers(page), 0, len, NULL, + ext4_bh_unmapped)) { + /* Wait so that we don't change page under IO */ + wait_on_page_writeback(page); + ret = VM_FAULT_LOCKED; + goto out; + } + } + unlock_page(page); + /* OK, we need to fill the hole... */ + if (ext4_should_dioread_nolock(inode)) + get_block = ext4_get_block_write; + else + get_block = ext4_get_block; +retry_alloc: + handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode)); + if (IS_ERR(handle)) { + ret = VM_FAULT_SIGBUS; + goto out; + } + ret = __block_page_mkwrite(vma, vmf, get_block); + if (!ret && ext4_should_journal_data(inode)) { + if (walk_page_buffers(handle, page_buffers(page), 0, + PAGE_CACHE_SIZE, NULL, do_journal_get_write_access)) { + unlock_page(page); + ret = VM_FAULT_SIGBUS; + ext4_journal_stop(handle); + goto out; + } + ext4_set_inode_state(inode, EXT4_STATE_JDATA); + } + ext4_journal_stop(handle); + if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) + goto retry_alloc; +out_ret: + ret = block_page_mkwrite_return(ret); +out: + return ret; +} |