diff options
Diffstat (limited to 'ANDROID_3.4.5/fs/btrfs/file.c')
| -rw-r--r-- | ANDROID_3.4.5/fs/btrfs/file.c | 1908 |
1 files changed, 1908 insertions, 0 deletions
diff --git a/ANDROID_3.4.5/fs/btrfs/file.c b/ANDROID_3.4.5/fs/btrfs/file.c new file mode 100644 index 00000000..53bf2d76 --- /dev/null +++ b/ANDROID_3.4.5/fs/btrfs/file.c @@ -0,0 +1,1908 @@ +/* + * Copyright (C) 2007 Oracle. All rights reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License v2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public + * License along with this program; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 021110-1307, USA. + */ + +#include <linux/fs.h> +#include <linux/pagemap.h> +#include <linux/highmem.h> +#include <linux/time.h> +#include <linux/init.h> +#include <linux/string.h> +#include <linux/backing-dev.h> +#include <linux/mpage.h> +#include <linux/falloc.h> +#include <linux/swap.h> +#include <linux/writeback.h> +#include <linux/statfs.h> +#include <linux/compat.h> +#include <linux/slab.h> +#include "ctree.h" +#include "disk-io.h" +#include "transaction.h" +#include "btrfs_inode.h" +#include "ioctl.h" +#include "print-tree.h" +#include "tree-log.h" +#include "locking.h" +#include "compat.h" + +/* + * when auto defrag is enabled we + * queue up these defrag structs to remember which + * inodes need defragging passes + */ +struct inode_defrag { + struct rb_node rb_node; + /* objectid */ + u64 ino; + /* + * transid where the defrag was added, we search for + * extents newer than this + */ + u64 transid; + + /* root objectid */ + u64 root; + + /* last offset we were able to defrag */ + u64 last_offset; + + /* if we've wrapped around back to zero once already */ + int cycled; +}; + +/* pop a record for an inode into the defrag tree. The lock + * must be held already + * + * If you're inserting a record for an older transid than an + * existing record, the transid already in the tree is lowered + * + * If an existing record is found the defrag item you + * pass in is freed + */ +static void __btrfs_add_inode_defrag(struct inode *inode, + struct inode_defrag *defrag) +{ + struct btrfs_root *root = BTRFS_I(inode)->root; + struct inode_defrag *entry; + struct rb_node **p; + struct rb_node *parent = NULL; + + p = &root->fs_info->defrag_inodes.rb_node; + while (*p) { + parent = *p; + entry = rb_entry(parent, struct inode_defrag, rb_node); + + if (defrag->ino < entry->ino) + p = &parent->rb_left; + else if (defrag->ino > entry->ino) + p = &parent->rb_right; + else { + /* if we're reinserting an entry for + * an old defrag run, make sure to + * lower the transid of our existing record + */ + if (defrag->transid < entry->transid) + entry->transid = defrag->transid; + if (defrag->last_offset > entry->last_offset) + entry->last_offset = defrag->last_offset; + goto exists; + } + } + BTRFS_I(inode)->in_defrag = 1; + rb_link_node(&defrag->rb_node, parent, p); + rb_insert_color(&defrag->rb_node, &root->fs_info->defrag_inodes); + return; + +exists: + kfree(defrag); + return; + +} + +/* + * insert a defrag record for this inode if auto defrag is + * enabled + */ +int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans, + struct inode *inode) +{ + struct btrfs_root *root = BTRFS_I(inode)->root; + struct inode_defrag *defrag; + u64 transid; + + if (!btrfs_test_opt(root, AUTO_DEFRAG)) + return 0; + + if (btrfs_fs_closing(root->fs_info)) + return 0; + + if (BTRFS_I(inode)->in_defrag) + return 0; + + if (trans) + transid = trans->transid; + else + transid = BTRFS_I(inode)->root->last_trans; + + defrag = kzalloc(sizeof(*defrag), GFP_NOFS); + if (!defrag) + return -ENOMEM; + + defrag->ino = btrfs_ino(inode); + defrag->transid = transid; + defrag->root = root->root_key.objectid; + + spin_lock(&root->fs_info->defrag_inodes_lock); + if (!BTRFS_I(inode)->in_defrag) + __btrfs_add_inode_defrag(inode, defrag); + else + kfree(defrag); + spin_unlock(&root->fs_info->defrag_inodes_lock); + return 0; +} + +/* + * must be called with the defrag_inodes lock held + */ +struct inode_defrag *btrfs_find_defrag_inode(struct btrfs_fs_info *info, u64 ino, + struct rb_node **next) +{ + struct inode_defrag *entry = NULL; + struct rb_node *p; + struct rb_node *parent = NULL; + + p = info->defrag_inodes.rb_node; + while (p) { + parent = p; + entry = rb_entry(parent, struct inode_defrag, rb_node); + + if (ino < entry->ino) + p = parent->rb_left; + else if (ino > entry->ino) + p = parent->rb_right; + else + return entry; + } + + if (next) { + while (parent && ino > entry->ino) { + parent = rb_next(parent); + entry = rb_entry(parent, struct inode_defrag, rb_node); + } + *next = parent; + } + return NULL; +} + +/* + * run through the list of inodes in the FS that need + * defragging + */ +int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info) +{ + struct inode_defrag *defrag; + struct btrfs_root *inode_root; + struct inode *inode; + struct rb_node *n; + struct btrfs_key key; + struct btrfs_ioctl_defrag_range_args range; + u64 first_ino = 0; + int num_defrag; + int defrag_batch = 1024; + + memset(&range, 0, sizeof(range)); + range.len = (u64)-1; + + atomic_inc(&fs_info->defrag_running); + spin_lock(&fs_info->defrag_inodes_lock); + while(1) { + n = NULL; + + /* find an inode to defrag */ + defrag = btrfs_find_defrag_inode(fs_info, first_ino, &n); + if (!defrag) { + if (n) + defrag = rb_entry(n, struct inode_defrag, rb_node); + else if (first_ino) { + first_ino = 0; + continue; + } else { + break; + } + } + + /* remove it from the rbtree */ + first_ino = defrag->ino + 1; + rb_erase(&defrag->rb_node, &fs_info->defrag_inodes); + + if (btrfs_fs_closing(fs_info)) + goto next_free; + + spin_unlock(&fs_info->defrag_inodes_lock); + + /* get the inode */ + key.objectid = defrag->root; + btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY); + key.offset = (u64)-1; + inode_root = btrfs_read_fs_root_no_name(fs_info, &key); + if (IS_ERR(inode_root)) + goto next; + + key.objectid = defrag->ino; + btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY); + key.offset = 0; + + inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL); + if (IS_ERR(inode)) + goto next; + + /* do a chunk of defrag */ + BTRFS_I(inode)->in_defrag = 0; + range.start = defrag->last_offset; + num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid, + defrag_batch); + /* + * if we filled the whole defrag batch, there + * must be more work to do. Queue this defrag + * again + */ + if (num_defrag == defrag_batch) { + defrag->last_offset = range.start; + __btrfs_add_inode_defrag(inode, defrag); + /* + * we don't want to kfree defrag, we added it back to + * the rbtree + */ + defrag = NULL; + } else if (defrag->last_offset && !defrag->cycled) { + /* + * we didn't fill our defrag batch, but + * we didn't start at zero. Make sure we loop + * around to the start of the file. + */ + defrag->last_offset = 0; + defrag->cycled = 1; + __btrfs_add_inode_defrag(inode, defrag); + defrag = NULL; + } + + iput(inode); +next: + spin_lock(&fs_info->defrag_inodes_lock); +next_free: + kfree(defrag); + } + spin_unlock(&fs_info->defrag_inodes_lock); + + atomic_dec(&fs_info->defrag_running); + + /* + * during unmount, we use the transaction_wait queue to + * wait for the defragger to stop + */ + wake_up(&fs_info->transaction_wait); + return 0; +} + +/* simple helper to fault in pages and copy. This should go away + * and be replaced with calls into generic code. + */ +static noinline int btrfs_copy_from_user(loff_t pos, int num_pages, + size_t write_bytes, + struct page **prepared_pages, + struct iov_iter *i) +{ + size_t copied = 0; + size_t total_copied = 0; + int pg = 0; + int offset = pos & (PAGE_CACHE_SIZE - 1); + + while (write_bytes > 0) { + size_t count = min_t(size_t, + PAGE_CACHE_SIZE - offset, write_bytes); + struct page *page = prepared_pages[pg]; + /* + * Copy data from userspace to the current page + * + * Disable pagefault to avoid recursive lock since + * the pages are already locked + */ + pagefault_disable(); + copied = iov_iter_copy_from_user_atomic(page, i, offset, count); + pagefault_enable(); + + /* Flush processor's dcache for this page */ + flush_dcache_page(page); + + /* + * if we get a partial write, we can end up with + * partially up to date pages. These add + * a lot of complexity, so make sure they don't + * happen by forcing this copy to be retried. + * + * The rest of the btrfs_file_write code will fall + * back to page at a time copies after we return 0. + */ + if (!PageUptodate(page) && copied < count) + copied = 0; + + iov_iter_advance(i, copied); + write_bytes -= copied; + total_copied += copied; + + /* Return to btrfs_file_aio_write to fault page */ + if (unlikely(copied == 0)) + break; + + if (unlikely(copied < PAGE_CACHE_SIZE - offset)) { + offset += copied; + } else { + pg++; + offset = 0; + } + } + return total_copied; +} + +/* + * unlocks pages after btrfs_file_write is done with them + */ +void btrfs_drop_pages(struct page **pages, size_t num_pages) +{ + size_t i; + for (i = 0; i < num_pages; i++) { + /* page checked is some magic around finding pages that + * have been modified without going through btrfs_set_page_dirty + * clear it here + */ + ClearPageChecked(pages[i]); + unlock_page(pages[i]); + mark_page_accessed(pages[i]); + page_cache_release(pages[i]); + } +} + +/* + * after copy_from_user, pages need to be dirtied and we need to make + * sure holes are created between the current EOF and the start of + * any next extents (if required). + * + * this also makes the decision about creating an inline extent vs + * doing real data extents, marking pages dirty and delalloc as required. + */ +int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode, + struct page **pages, size_t num_pages, + loff_t pos, size_t write_bytes, + struct extent_state **cached) +{ + int err = 0; + int i; + u64 num_bytes; + u64 start_pos; + u64 end_of_last_block; + u64 end_pos = pos + write_bytes; + loff_t isize = i_size_read(inode); + + start_pos = pos & ~((u64)root->sectorsize - 1); + num_bytes = (write_bytes + pos - start_pos + + root->sectorsize - 1) & ~((u64)root->sectorsize - 1); + + end_of_last_block = start_pos + num_bytes - 1; + err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block, + cached); + if (err) + return err; + + for (i = 0; i < num_pages; i++) { + struct page *p = pages[i]; + SetPageUptodate(p); + ClearPageChecked(p); + set_page_dirty(p); + } + + /* + * we've only changed i_size in ram, and we haven't updated + * the disk i_size. There is no need to log the inode + * at this time. + */ + if (end_pos > isize) + i_size_write(inode, end_pos); + return 0; +} + +/* + * this drops all the extents in the cache that intersect the range + * [start, end]. Existing extents are split as required. + */ +int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end, + int skip_pinned) +{ + struct extent_map *em; + struct extent_map *split = NULL; + struct extent_map *split2 = NULL; + struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree; + u64 len = end - start + 1; + int ret; + int testend = 1; + unsigned long flags; + int compressed = 0; + + WARN_ON(end < start); + if (end == (u64)-1) { + len = (u64)-1; + testend = 0; + } + while (1) { + if (!split) + split = alloc_extent_map(); + if (!split2) + split2 = alloc_extent_map(); + BUG_ON(!split || !split2); /* -ENOMEM */ + + write_lock(&em_tree->lock); + em = lookup_extent_mapping(em_tree, start, len); + if (!em) { + write_unlock(&em_tree->lock); + break; + } + flags = em->flags; + if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) { + if (testend && em->start + em->len >= start + len) { + free_extent_map(em); + write_unlock(&em_tree->lock); + break; + } + start = em->start + em->len; + if (testend) + len = start + len - (em->start + em->len); + free_extent_map(em); + write_unlock(&em_tree->lock); + continue; + } + compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags); + clear_bit(EXTENT_FLAG_PINNED, &em->flags); + remove_extent_mapping(em_tree, em); + + if (em->block_start < EXTENT_MAP_LAST_BYTE && + em->start < start) { + split->start = em->start; + split->len = start - em->start; + split->orig_start = em->orig_start; + split->block_start = em->block_start; + + if (compressed) + split->block_len = em->block_len; + else + split->block_len = split->len; + + split->bdev = em->bdev; + split->flags = flags; + split->compress_type = em->compress_type; + ret = add_extent_mapping(em_tree, split); + BUG_ON(ret); /* Logic error */ + free_extent_map(split); + split = split2; + split2 = NULL; + } + if (em->block_start < EXTENT_MAP_LAST_BYTE && + testend && em->start + em->len > start + len) { + u64 diff = start + len - em->start; + + split->start = start + len; + split->len = em->start + em->len - (start + len); + split->bdev = em->bdev; + split->flags = flags; + split->compress_type = em->compress_type; + + if (compressed) { + split->block_len = em->block_len; + split->block_start = em->block_start; + split->orig_start = em->orig_start; + } else { + split->block_len = split->len; + split->block_start = em->block_start + diff; + split->orig_start = split->start; + } + + ret = add_extent_mapping(em_tree, split); + BUG_ON(ret); /* Logic error */ + free_extent_map(split); + split = NULL; + } + write_unlock(&em_tree->lock); + + /* once for us */ + free_extent_map(em); + /* once for the tree*/ + free_extent_map(em); + } + if (split) + free_extent_map(split); + if (split2) + free_extent_map(split2); + return 0; +} + +/* + * this is very complex, but the basic idea is to drop all extents + * in the range start - end. hint_block is filled in with a block number + * that would be a good hint to the block allocator for this file. + * + * If an extent intersects the range but is not entirely inside the range + * it is either truncated or split. Anything entirely inside the range + * is deleted from the tree. + */ +int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode, + u64 start, u64 end, u64 *hint_byte, int drop_cache) +{ + struct btrfs_root *root = BTRFS_I(inode)->root; + struct extent_buffer *leaf; + struct btrfs_file_extent_item *fi; + struct btrfs_path *path; + struct btrfs_key key; + struct btrfs_key new_key; + u64 ino = btrfs_ino(inode); + u64 search_start = start; + u64 disk_bytenr = 0; + u64 num_bytes = 0; + u64 extent_offset = 0; + u64 extent_end = 0; + int del_nr = 0; + int del_slot = 0; + int extent_type; + int recow; + int ret; + int modify_tree = -1; + + if (drop_cache) + btrfs_drop_extent_cache(inode, start, end - 1, 0); + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + if (start >= BTRFS_I(inode)->disk_i_size) + modify_tree = 0; + + while (1) { + recow = 0; + ret = btrfs_lookup_file_extent(trans, root, path, ino, + search_start, modify_tree); + if (ret < 0) + break; + if (ret > 0 && path->slots[0] > 0 && search_start == start) { + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1); + if (key.objectid == ino && + key.type == BTRFS_EXTENT_DATA_KEY) + path->slots[0]--; + } + ret = 0; +next_slot: + leaf = path->nodes[0]; + if (path->slots[0] >= btrfs_header_nritems(leaf)) { + BUG_ON(del_nr > 0); + ret = btrfs_next_leaf(root, path); + if (ret < 0) + break; + if (ret > 0) { + ret = 0; + break; + } + leaf = path->nodes[0]; + recow = 1; + } + + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + if (key.objectid > ino || + key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end) + break; + + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + extent_type = btrfs_file_extent_type(leaf, fi); + + if (extent_type == BTRFS_FILE_EXTENT_REG || + extent_type == BTRFS_FILE_EXTENT_PREALLOC) { + disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi); + num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi); + extent_offset = btrfs_file_extent_offset(leaf, fi); + extent_end = key.offset + + btrfs_file_extent_num_bytes(leaf, fi); + } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) { + extent_end = key.offset + + btrfs_file_extent_inline_len(leaf, fi); + } else { + WARN_ON(1); + extent_end = search_start; + } + + if (extent_end <= search_start) { + path->slots[0]++; + goto next_slot; + } + + search_start = max(key.offset, start); + if (recow || !modify_tree) { + modify_tree = -1; + btrfs_release_path(path); + continue; + } + + /* + * | - range to drop - | + * | -------- extent -------- | + */ + if (start > key.offset && end < extent_end) { + BUG_ON(del_nr > 0); + BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE); + + memcpy(&new_key, &key, sizeof(new_key)); + new_key.offset = start; + ret = btrfs_duplicate_item(trans, root, path, + &new_key); + if (ret == -EAGAIN) { + btrfs_release_path(path); + continue; + } + if (ret < 0) + break; + + leaf = path->nodes[0]; + fi = btrfs_item_ptr(leaf, path->slots[0] - 1, + struct btrfs_file_extent_item); + btrfs_set_file_extent_num_bytes(leaf, fi, + start - key.offset); + + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + + extent_offset += start - key.offset; + btrfs_set_file_extent_offset(leaf, fi, extent_offset); + btrfs_set_file_extent_num_bytes(leaf, fi, + extent_end - start); + btrfs_mark_buffer_dirty(leaf); + + if (disk_bytenr > 0) { + ret = btrfs_inc_extent_ref(trans, root, + disk_bytenr, num_bytes, 0, + root->root_key.objectid, + new_key.objectid, + start - extent_offset, 0); + BUG_ON(ret); /* -ENOMEM */ + *hint_byte = disk_bytenr; + } + key.offset = start; + } + /* + * | ---- range to drop ----- | + * | -------- extent -------- | + */ + if (start <= key.offset && end < extent_end) { + BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE); + + memcpy(&new_key, &key, sizeof(new_key)); + new_key.offset = end; + btrfs_set_item_key_safe(trans, root, path, &new_key); + + extent_offset += end - key.offset; + btrfs_set_file_extent_offset(leaf, fi, extent_offset); + btrfs_set_file_extent_num_bytes(leaf, fi, + extent_end - end); + btrfs_mark_buffer_dirty(leaf); + if (disk_bytenr > 0) { + inode_sub_bytes(inode, end - key.offset); + *hint_byte = disk_bytenr; + } + break; + } + + search_start = extent_end; + /* + * | ---- range to drop ----- | + * | -------- extent -------- | + */ + if (start > key.offset && end >= extent_end) { + BUG_ON(del_nr > 0); + BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE); + + btrfs_set_file_extent_num_bytes(leaf, fi, + start - key.offset); + btrfs_mark_buffer_dirty(leaf); + if (disk_bytenr > 0) { + inode_sub_bytes(inode, extent_end - start); + *hint_byte = disk_bytenr; + } + if (end == extent_end) + break; + + path->slots[0]++; + goto next_slot; + } + + /* + * | ---- range to drop ----- | + * | ------ extent ------ | + */ + if (start <= key.offset && end >= extent_end) { + if (del_nr == 0) { + del_slot = path->slots[0]; + del_nr = 1; + } else { + BUG_ON(del_slot + del_nr != path->slots[0]); + del_nr++; + } + + if (extent_type == BTRFS_FILE_EXTENT_INLINE) { + inode_sub_bytes(inode, + extent_end - key.offset); + extent_end = ALIGN(extent_end, + root->sectorsize); + } else if (disk_bytenr > 0) { + ret = btrfs_free_extent(trans, root, + disk_bytenr, num_bytes, 0, + root->root_key.objectid, + key.objectid, key.offset - + extent_offset, 0); + BUG_ON(ret); /* -ENOMEM */ + inode_sub_bytes(inode, + extent_end - key.offset); + *hint_byte = disk_bytenr; + } + + if (end == extent_end) + break; + + if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) { + path->slots[0]++; + goto next_slot; + } + + ret = btrfs_del_items(trans, root, path, del_slot, + del_nr); + if (ret) { + btrfs_abort_transaction(trans, root, ret); + goto out; + } + + del_nr = 0; + del_slot = 0; + + btrfs_release_path(path); + continue; + } + + BUG_ON(1); + } + + if (!ret && del_nr > 0) { + ret = btrfs_del_items(trans, root, path, del_slot, del_nr); + if (ret) + btrfs_abort_transaction(trans, root, ret); + } + +out: + btrfs_free_path(path); + return ret; +} + +static int extent_mergeable(struct extent_buffer *leaf, int slot, + u64 objectid, u64 bytenr, u64 orig_offset, + u64 *start, u64 *end) +{ + struct btrfs_file_extent_item *fi; + struct btrfs_key key; + u64 extent_end; + + if (slot < 0 || slot >= btrfs_header_nritems(leaf)) + return 0; + + btrfs_item_key_to_cpu(leaf, &key, slot); + if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY) + return 0; + + fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); + if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG || + btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr || + btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset || + btrfs_file_extent_compression(leaf, fi) || + btrfs_file_extent_encryption(leaf, fi) || + btrfs_file_extent_other_encoding(leaf, fi)) + return 0; + + extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi); + if ((*start && *start != key.offset) || (*end && *end != extent_end)) + return 0; + + *start = key.offset; + *end = extent_end; + return 1; +} + +/* + * Mark extent in the range start - end as written. + * + * This changes extent type from 'pre-allocated' to 'regular'. If only + * part of extent is marked as written, the extent will be split into + * two or three. + */ +int btrfs_mark_extent_written(struct btrfs_trans_handle *trans, + struct inode *inode, u64 start, u64 end) +{ + struct btrfs_root *root = BTRFS_I(inode)->root; + struct extent_buffer *leaf; + struct btrfs_path *path; + struct btrfs_file_extent_item *fi; + struct btrfs_key key; + struct btrfs_key new_key; + u64 bytenr; + u64 num_bytes; + u64 extent_end; + u64 orig_offset; + u64 other_start; + u64 other_end; + u64 split; + int del_nr = 0; + int del_slot = 0; + int recow; + int ret; + u64 ino = btrfs_ino(inode); + + btrfs_drop_extent_cache(inode, start, end - 1, 0); + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; +again: + recow = 0; + split = start; + key.objectid = ino; + key.type = BTRFS_EXTENT_DATA_KEY; + key.offset = split; + + ret = btrfs_search_slot(trans, root, &key, path, -1, 1); + if (ret < 0) + goto out; + if (ret > 0 && path->slots[0] > 0) + path->slots[0]--; + + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + BUG_ON(key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY); + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + BUG_ON(btrfs_file_extent_type(leaf, fi) != + BTRFS_FILE_EXTENT_PREALLOC); + extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi); + BUG_ON(key.offset > start || extent_end < end); + + bytenr = btrfs_file_extent_disk_bytenr(leaf, fi); + num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi); + orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi); + memcpy(&new_key, &key, sizeof(new_key)); + + if (start == key.offset && end < extent_end) { + other_start = 0; + other_end = start; + if (extent_mergeable(leaf, path->slots[0] - 1, + ino, bytenr, orig_offset, + &other_start, &other_end)) { + new_key.offset = end; + btrfs_set_item_key_safe(trans, root, path, &new_key); + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + btrfs_set_file_extent_num_bytes(leaf, fi, + extent_end - end); + btrfs_set_file_extent_offset(leaf, fi, + end - orig_offset); + fi = btrfs_item_ptr(leaf, path->slots[0] - 1, + struct btrfs_file_extent_item); + btrfs_set_file_extent_num_bytes(leaf, fi, + end - other_start); + btrfs_mark_buffer_dirty(leaf); + goto out; + } + } + + if (start > key.offset && end == extent_end) { + other_start = end; + other_end = 0; + if (extent_mergeable(leaf, path->slots[0] + 1, + ino, bytenr, orig_offset, + &other_start, &other_end)) { + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + btrfs_set_file_extent_num_bytes(leaf, fi, + start - key.offset); + path->slots[0]++; + new_key.offset = start; + btrfs_set_item_key_safe(trans, root, path, &new_key); + + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + btrfs_set_file_extent_num_bytes(leaf, fi, + other_end - start); + btrfs_set_file_extent_offset(leaf, fi, + start - orig_offset); + btrfs_mark_buffer_dirty(leaf); + goto out; + } + } + + while (start > key.offset || end < extent_end) { + if (key.offset == start) + split = end; + + new_key.offset = split; + ret = btrfs_duplicate_item(trans, root, path, &new_key); + if (ret == -EAGAIN) { + btrfs_release_path(path); + goto again; + } + if (ret < 0) { + btrfs_abort_transaction(trans, root, ret); + goto out; + } + + leaf = path->nodes[0]; + fi = btrfs_item_ptr(leaf, path->slots[0] - 1, + struct btrfs_file_extent_item); + btrfs_set_file_extent_num_bytes(leaf, fi, + split - key.offset); + + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + + btrfs_set_file_extent_offset(leaf, fi, split - orig_offset); + btrfs_set_file_extent_num_bytes(leaf, fi, + extent_end - split); + btrfs_mark_buffer_dirty(leaf); + + ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0, + root->root_key.objectid, + ino, orig_offset, 0); + BUG_ON(ret); /* -ENOMEM */ + + if (split == start) { + key.offset = start; + } else { + BUG_ON(start != key.offset); + path->slots[0]--; + extent_end = end; + } + recow = 1; + } + + other_start = end; + other_end = 0; + if (extent_mergeable(leaf, path->slots[0] + 1, + ino, bytenr, orig_offset, + &other_start, &other_end)) { + if (recow) { + btrfs_release_path(path); + goto again; + } + extent_end = other_end; + del_slot = path->slots[0] + 1; + del_nr++; + ret = btrfs_free_extent(trans, root, bytenr, num_bytes, + 0, root->root_key.objectid, + ino, orig_offset, 0); + BUG_ON(ret); /* -ENOMEM */ + } + other_start = 0; + other_end = start; + if (extent_mergeable(leaf, path->slots[0] - 1, + ino, bytenr, orig_offset, + &other_start, &other_end)) { + if (recow) { + btrfs_release_path(path); + goto again; + } + key.offset = other_start; + del_slot = path->slots[0]; + del_nr++; + ret = btrfs_free_extent(trans, root, bytenr, num_bytes, + 0, root->root_key.objectid, + ino, orig_offset, 0); + BUG_ON(ret); /* -ENOMEM */ + } + if (del_nr == 0) { + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + btrfs_set_file_extent_type(leaf, fi, + BTRFS_FILE_EXTENT_REG); + btrfs_mark_buffer_dirty(leaf); + } else { + fi = btrfs_item_ptr(leaf, del_slot - 1, + struct btrfs_file_extent_item); + btrfs_set_file_extent_type(leaf, fi, + BTRFS_FILE_EXTENT_REG); + btrfs_set_file_extent_num_bytes(leaf, fi, + extent_end - key.offset); + btrfs_mark_buffer_dirty(leaf); + + ret = btrfs_del_items(trans, root, path, del_slot, del_nr); + if (ret < 0) { + btrfs_abort_transaction(trans, root, ret); + goto out; + } + } +out: + btrfs_free_path(path); + return 0; +} + +/* + * on error we return an unlocked page and the error value + * on success we return a locked page and 0 + */ +static int prepare_uptodate_page(struct page *page, u64 pos, + bool force_uptodate) +{ + int ret = 0; + + if (((pos & (PAGE_CACHE_SIZE - 1)) || force_uptodate) && + !PageUptodate(page)) { + ret = btrfs_readpage(NULL, page); + if (ret) + return ret; + lock_page(page); + if (!PageUptodate(page)) { + unlock_page(page); + return -EIO; + } + } + return 0; +} + +/* + * this gets pages into the page cache and locks them down, it also properly + * waits for data=ordered extents to finish before allowing the pages to be + * modified. + */ +static noinline int prepare_pages(struct btrfs_root *root, struct file *file, + struct page **pages, size_t num_pages, + loff_t pos, unsigned long first_index, + size_t write_bytes, bool force_uptodate) +{ + struct extent_state *cached_state = NULL; + int i; + unsigned long index = pos >> PAGE_CACHE_SHIFT; + struct inode *inode = fdentry(file)->d_inode; + gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping); + int err = 0; + int faili = 0; + u64 start_pos; + u64 last_pos; + + start_pos = pos & ~((u64)root->sectorsize - 1); + last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT; + +again: + for (i = 0; i < num_pages; i++) { + pages[i] = find_or_create_page(inode->i_mapping, index + i, + mask | __GFP_WRITE); + if (!pages[i]) { + faili = i - 1; + err = -ENOMEM; + goto fail; + } + + if (i == 0) + err = prepare_uptodate_page(pages[i], pos, + force_uptodate); + if (i == num_pages - 1) + err = prepare_uptodate_page(pages[i], + pos + write_bytes, false); + if (err) { + page_cache_release(pages[i]); + faili = i - 1; + goto fail; + } + wait_on_page_writeback(pages[i]); + } + err = 0; + if (start_pos < inode->i_size) { + struct btrfs_ordered_extent *ordered; + lock_extent_bits(&BTRFS_I(inode)->io_tree, + start_pos, last_pos - 1, 0, &cached_state); + ordered = btrfs_lookup_first_ordered_extent(inode, + last_pos - 1); + if (ordered && + ordered->file_offset + ordered->len > start_pos && + ordered->file_offset < last_pos) { + btrfs_put_ordered_extent(ordered); + unlock_extent_cached(&BTRFS_I(inode)->io_tree, + start_pos, last_pos - 1, + &cached_state, GFP_NOFS); + for (i = 0; i < num_pages; i++) { + unlock_page(pages[i]); + page_cache_release(pages[i]); + } + btrfs_wait_ordered_range(inode, start_pos, + last_pos - start_pos); + goto again; + } + if (ordered) + btrfs_put_ordered_extent(ordered); + + clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos, + last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC | + EXTENT_DO_ACCOUNTING, 0, 0, &cached_state, + GFP_NOFS); + unlock_extent_cached(&BTRFS_I(inode)->io_tree, + start_pos, last_pos - 1, &cached_state, + GFP_NOFS); + } + for (i = 0; i < num_pages; i++) { + if (clear_page_dirty_for_io(pages[i])) + account_page_redirty(pages[i]); + set_page_extent_mapped(pages[i]); + WARN_ON(!PageLocked(pages[i])); + } + return 0; +fail: + while (faili >= 0) { + unlock_page(pages[faili]); + page_cache_release(pages[faili]); + faili--; + } + return err; + +} + +static noinline ssize_t __btrfs_buffered_write(struct file *file, + struct iov_iter *i, + loff_t pos) +{ + struct inode *inode = fdentry(file)->d_inode; + struct btrfs_root *root = BTRFS_I(inode)->root; + struct page **pages = NULL; + unsigned long first_index; + size_t num_written = 0; + int nrptrs; + int ret = 0; + bool force_page_uptodate = false; + + nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) / + PAGE_CACHE_SIZE, PAGE_CACHE_SIZE / + (sizeof(struct page *))); + nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied); + nrptrs = max(nrptrs, 8); + pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL); + if (!pages) + return -ENOMEM; + + first_index = pos >> PAGE_CACHE_SHIFT; + + while (iov_iter_count(i) > 0) { + size_t offset = pos & (PAGE_CACHE_SIZE - 1); + size_t write_bytes = min(iov_iter_count(i), + nrptrs * (size_t)PAGE_CACHE_SIZE - + offset); + size_t num_pages = (write_bytes + offset + + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; + size_t dirty_pages; + size_t copied; + + WARN_ON(num_pages > nrptrs); + + /* + * Fault pages before locking them in prepare_pages + * to avoid recursive lock + */ + if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) { + ret = -EFAULT; + break; + } + + ret = btrfs_delalloc_reserve_space(inode, + num_pages << PAGE_CACHE_SHIFT); + if (ret) + break; + + /* + * This is going to setup the pages array with the number of + * pages we want, so we don't really need to worry about the + * contents of pages from loop to loop + */ + ret = prepare_pages(root, file, pages, num_pages, + pos, first_index, write_bytes, + force_page_uptodate); + if (ret) { + btrfs_delalloc_release_space(inode, + num_pages << PAGE_CACHE_SHIFT); + break; + } + + copied = btrfs_copy_from_user(pos, num_pages, + write_bytes, pages, i); + + /* + * if we have trouble faulting in the pages, fall + * back to one page at a time + */ + if (copied < write_bytes) + nrptrs = 1; + + if (copied == 0) { + force_page_uptodate = true; + dirty_pages = 0; + } else { + force_page_uptodate = false; + dirty_pages = (copied + offset + + PAGE_CACHE_SIZE - 1) >> + PAGE_CACHE_SHIFT; + } + + /* + * If we had a short copy we need to release the excess delaloc + * bytes we reserved. We need to increment outstanding_extents + * because btrfs_delalloc_release_space will decrement it, but + * we still have an outstanding extent for the chunk we actually + * managed to copy. + */ + if (num_pages > dirty_pages) { + if (copied > 0) { + spin_lock(&BTRFS_I(inode)->lock); + BTRFS_I(inode)->outstanding_extents++; + spin_unlock(&BTRFS_I(inode)->lock); + } + btrfs_delalloc_release_space(inode, + (num_pages - dirty_pages) << + PAGE_CACHE_SHIFT); + } + + if (copied > 0) { + ret = btrfs_dirty_pages(root, inode, pages, + dirty_pages, pos, copied, + NULL); + if (ret) { + btrfs_delalloc_release_space(inode, + dirty_pages << PAGE_CACHE_SHIFT); + btrfs_drop_pages(pages, num_pages); + break; + } + } + + btrfs_drop_pages(pages, num_pages); + + cond_resched(); + + balance_dirty_pages_ratelimited_nr(inode->i_mapping, + dirty_pages); + if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1) + btrfs_btree_balance_dirty(root, 1); + + pos += copied; + num_written += copied; + } + + kfree(pages); + + return num_written ? num_written : ret; +} + +static ssize_t __btrfs_direct_write(struct kiocb *iocb, + const struct iovec *iov, + unsigned long nr_segs, loff_t pos, + loff_t *ppos, size_t count, size_t ocount) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = fdentry(file)->d_inode; + struct iov_iter i; + ssize_t written; + ssize_t written_buffered; + loff_t endbyte; + int err; + + written = generic_file_direct_write(iocb, iov, &nr_segs, pos, ppos, + count, ocount); + + /* + * the generic O_DIRECT will update in-memory i_size after the + * DIOs are done. But our endio handlers that update the on + * disk i_size never update past the in memory i_size. So we + * need one more update here to catch any additions to the + * file + */ + if (inode->i_size != BTRFS_I(inode)->disk_i_size) { + btrfs_ordered_update_i_size(inode, inode->i_size, NULL); + mark_inode_dirty(inode); + } + + if (written < 0 || written == count) + return written; + + pos += written; + count -= written; + iov_iter_init(&i, iov, nr_segs, count, written); + written_buffered = __btrfs_buffered_write(file, &i, pos); + if (written_buffered < 0) { + err = written_buffered; + goto out; + } + endbyte = pos + written_buffered - 1; + err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte); + if (err) + goto out; + written += written_buffered; + *ppos = pos + written_buffered; + invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT, + endbyte >> PAGE_CACHE_SHIFT); +out: + return written ? written : err; +} + +static ssize_t btrfs_file_aio_write(struct kiocb *iocb, + const struct iovec *iov, + unsigned long nr_segs, loff_t pos) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = fdentry(file)->d_inode; + struct btrfs_root *root = BTRFS_I(inode)->root; + loff_t *ppos = &iocb->ki_pos; + u64 start_pos; + ssize_t num_written = 0; + ssize_t err = 0; + size_t count, ocount; + + vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE); + + mutex_lock(&inode->i_mutex); + + err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ); + if (err) { + mutex_unlock(&inode->i_mutex); + goto out; + } + count = ocount; + + current->backing_dev_info = inode->i_mapping->backing_dev_info; + err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode)); + if (err) { + mutex_unlock(&inode->i_mutex); + goto out; + } + + if (count == 0) { + mutex_unlock(&inode->i_mutex); + goto out; + } + + err = file_remove_suid(file); + if (err) { + mutex_unlock(&inode->i_mutex); + goto out; + } + + /* + * If BTRFS flips readonly due to some impossible error + * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR), + * although we have opened a file as writable, we have + * to stop this write operation to ensure FS consistency. + */ + if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) { + mutex_unlock(&inode->i_mutex); + err = -EROFS; + goto out; + } + + err = btrfs_update_time(file); + if (err) { + mutex_unlock(&inode->i_mutex); + goto out; + } + BTRFS_I(inode)->sequence++; + + start_pos = round_down(pos, root->sectorsize); + if (start_pos > i_size_read(inode)) { + err = btrfs_cont_expand(inode, i_size_read(inode), start_pos); + if (err) { + mutex_unlock(&inode->i_mutex); + goto out; + } + } + + if (unlikely(file->f_flags & O_DIRECT)) { + num_written = __btrfs_direct_write(iocb, iov, nr_segs, + pos, ppos, count, ocount); + } else { + struct iov_iter i; + + iov_iter_init(&i, iov, nr_segs, count, num_written); + + num_written = __btrfs_buffered_write(file, &i, pos); + if (num_written > 0) + *ppos = pos + num_written; + } + + mutex_unlock(&inode->i_mutex); + + /* + * we want to make sure fsync finds this change + * but we haven't joined a transaction running right now. + * + * Later on, someone is sure to update the inode and get the + * real transid recorded. + * + * We set last_trans now to the fs_info generation + 1, + * this will either be one more than the running transaction + * or the generation used for the next transaction if there isn't + * one running right now. + */ + BTRFS_I(inode)->last_trans = root->fs_info->generation + 1; + if (num_written > 0 || num_written == -EIOCBQUEUED) { + err = generic_write_sync(file, pos, num_written); + if (err < 0 && num_written > 0) + num_written = err; + } +out: + current->backing_dev_info = NULL; + return num_written ? num_written : err; +} + +int btrfs_release_file(struct inode *inode, struct file *filp) +{ + /* + * ordered_data_close is set by settattr when we are about to truncate + * a file from a non-zero size to a zero size. This tries to + * flush down new bytes that may have been written if the + * application were using truncate to replace a file in place. + */ + if (BTRFS_I(inode)->ordered_data_close) { + BTRFS_I(inode)->ordered_data_close = 0; + btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode); + if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT) + filemap_flush(inode->i_mapping); + } + if (filp->private_data) + btrfs_ioctl_trans_end(filp); + return 0; +} + +/* + * fsync call for both files and directories. This logs the inode into + * the tree log instead of forcing full commits whenever possible. + * + * It needs to call filemap_fdatawait so that all ordered extent updates are + * in the metadata btree are up to date for copying to the log. + * + * It drops the inode mutex before doing the tree log commit. This is an + * important optimization for directories because holding the mutex prevents + * new operations on the dir while we write to disk. + */ +int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync) +{ + struct dentry *dentry = file->f_path.dentry; + struct inode *inode = dentry->d_inode; + struct btrfs_root *root = BTRFS_I(inode)->root; + int ret = 0; + struct btrfs_trans_handle *trans; + + trace_btrfs_sync_file(file, datasync); + + ret = filemap_write_and_wait_range(inode->i_mapping, start, end); + if (ret) + return ret; + mutex_lock(&inode->i_mutex); + + /* we wait first, since the writeback may change the inode */ + root->log_batch++; + btrfs_wait_ordered_range(inode, 0, (u64)-1); + root->log_batch++; + + /* + * check the transaction that last modified this inode + * and see if its already been committed + */ + if (!BTRFS_I(inode)->last_trans) { + mutex_unlock(&inode->i_mutex); + goto out; + } + + /* + * if the last transaction that changed this file was before + * the current transaction, we can bail out now without any + * syncing + */ + smp_mb(); + if (BTRFS_I(inode)->last_trans <= + root->fs_info->last_trans_committed) { + BTRFS_I(inode)->last_trans = 0; + mutex_unlock(&inode->i_mutex); + goto out; + } + + /* + * ok we haven't committed the transaction yet, lets do a commit + */ + if (file->private_data) + btrfs_ioctl_trans_end(file); + + trans = btrfs_start_transaction(root, 0); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + mutex_unlock(&inode->i_mutex); + goto out; + } + + ret = btrfs_log_dentry_safe(trans, root, dentry); + if (ret < 0) { + mutex_unlock(&inode->i_mutex); + goto out; + } + + /* we've logged all the items and now have a consistent + * version of the file in the log. It is possible that + * someone will come in and modify the file, but that's + * fine because the log is consistent on disk, and we + * have references to all of the file's extents + * + * It is possible that someone will come in and log the + * file again, but that will end up using the synchronization + * inside btrfs_sync_log to keep things safe. + */ + mutex_unlock(&inode->i_mutex); + + if (ret != BTRFS_NO_LOG_SYNC) { + if (ret > 0) { + ret = btrfs_commit_transaction(trans, root); + } else { + ret = btrfs_sync_log(trans, root); + if (ret == 0) + ret = btrfs_end_transaction(trans, root); + else + ret = btrfs_commit_transaction(trans, root); + } + } else { + ret = btrfs_end_transaction(trans, root); + } +out: + return ret > 0 ? -EIO : ret; +} + +static const struct vm_operations_struct btrfs_file_vm_ops = { + .fault = filemap_fault, + .page_mkwrite = btrfs_page_mkwrite, +}; + +static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma) +{ + struct address_space *mapping = filp->f_mapping; + + if (!mapping->a_ops->readpage) + return -ENOEXEC; + + file_accessed(filp); + vma->vm_ops = &btrfs_file_vm_ops; + vma->vm_flags |= VM_CAN_NONLINEAR; + + return 0; +} + +static long btrfs_fallocate(struct file *file, int mode, + loff_t offset, loff_t len) +{ + struct inode *inode = file->f_path.dentry->d_inode; + struct extent_state *cached_state = NULL; + u64 cur_offset; + u64 last_byte; + u64 alloc_start; + u64 alloc_end; + u64 alloc_hint = 0; + u64 locked_end; + u64 mask = BTRFS_I(inode)->root->sectorsize - 1; + struct extent_map *em; + int ret; + + alloc_start = offset & ~mask; + alloc_end = (offset + len + mask) & ~mask; + + /* We only support the FALLOC_FL_KEEP_SIZE mode */ + if (mode & ~FALLOC_FL_KEEP_SIZE) + return -EOPNOTSUPP; + + /* + * Make sure we have enough space before we do the + * allocation. + */ + ret = btrfs_check_data_free_space(inode, len); + if (ret) + return ret; + + /* + * wait for ordered IO before we have any locks. We'll loop again + * below with the locks held. + */ + btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start); + + mutex_lock(&inode->i_mutex); + ret = inode_newsize_ok(inode, alloc_end); + if (ret) + goto out; + + if (alloc_start > inode->i_size) { + ret = btrfs_cont_expand(inode, i_size_read(inode), + alloc_start); + if (ret) + goto out; + } + + locked_end = alloc_end - 1; + while (1) { + struct btrfs_ordered_extent *ordered; + + /* the extent lock is ordered inside the running + * transaction + */ + lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start, + locked_end, 0, &cached_state); + ordered = btrfs_lookup_first_ordered_extent(inode, + alloc_end - 1); + if (ordered && + ordered->file_offset + ordered->len > alloc_start && + ordered->file_offset < alloc_end) { + btrfs_put_ordered_extent(ordered); + unlock_extent_cached(&BTRFS_I(inode)->io_tree, + alloc_start, locked_end, + &cached_state, GFP_NOFS); + /* + * we can't wait on the range with the transaction + * running or with the extent lock held + */ + btrfs_wait_ordered_range(inode, alloc_start, + alloc_end - alloc_start); + } else { + if (ordered) + btrfs_put_ordered_extent(ordered); + break; + } + } + + cur_offset = alloc_start; + while (1) { + u64 actual_end; + + em = btrfs_get_extent(inode, NULL, 0, cur_offset, + alloc_end - cur_offset, 0); + if (IS_ERR_OR_NULL(em)) { + if (!em) + ret = -ENOMEM; + else + ret = PTR_ERR(em); + break; + } + last_byte = min(extent_map_end(em), alloc_end); + actual_end = min_t(u64, extent_map_end(em), offset + len); + last_byte = (last_byte + mask) & ~mask; + + if (em->block_start == EXTENT_MAP_HOLE || + (cur_offset >= inode->i_size && + !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) { + ret = btrfs_prealloc_file_range(inode, mode, cur_offset, + last_byte - cur_offset, + 1 << inode->i_blkbits, + offset + len, + &alloc_hint); + + if (ret < 0) { + free_extent_map(em); + break; + } + } else if (actual_end > inode->i_size && + !(mode & FALLOC_FL_KEEP_SIZE)) { + /* + * We didn't need to allocate any more space, but we + * still extended the size of the file so we need to + * update i_size. + */ + inode->i_ctime = CURRENT_TIME; + i_size_write(inode, actual_end); + btrfs_ordered_update_i_size(inode, actual_end, NULL); + } + free_extent_map(em); + + cur_offset = last_byte; + if (cur_offset >= alloc_end) { + ret = 0; + break; + } + } + unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end, + &cached_state, GFP_NOFS); +out: + mutex_unlock(&inode->i_mutex); + /* Let go of our reservation. */ + btrfs_free_reserved_data_space(inode, len); + return ret; +} + +static int find_desired_extent(struct inode *inode, loff_t *offset, int origin) +{ + struct btrfs_root *root = BTRFS_I(inode)->root; + struct extent_map *em; + struct extent_state *cached_state = NULL; + u64 lockstart = *offset; + u64 lockend = i_size_read(inode); + u64 start = *offset; + u64 orig_start = *offset; + u64 len = i_size_read(inode); + u64 last_end = 0; + int ret = 0; + + lockend = max_t(u64, root->sectorsize, lockend); + if (lockend <= lockstart) + lockend = lockstart + root->sectorsize; + + len = lockend - lockstart + 1; + + len = max_t(u64, len, root->sectorsize); + if (inode->i_size == 0) + return -ENXIO; + + lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend, 0, + &cached_state); + + /* + * Delalloc is such a pain. If we have a hole and we have pending + * delalloc for a portion of the hole we will get back a hole that + * exists for the entire range since it hasn't been actually written + * yet. So to take care of this case we need to look for an extent just + * before the position we want in case there is outstanding delalloc + * going on here. + */ + if (origin == SEEK_HOLE && start != 0) { + if (start <= root->sectorsize) + em = btrfs_get_extent_fiemap(inode, NULL, 0, 0, + root->sectorsize, 0); + else + em = btrfs_get_extent_fiemap(inode, NULL, 0, + start - root->sectorsize, + root->sectorsize, 0); + if (IS_ERR(em)) { + ret = PTR_ERR(em); + goto out; + } + last_end = em->start + em->len; + if (em->block_start == EXTENT_MAP_DELALLOC) + last_end = min_t(u64, last_end, inode->i_size); + free_extent_map(em); + } + + while (1) { + em = btrfs_get_extent_fiemap(inode, NULL, 0, start, len, 0); + if (IS_ERR(em)) { + ret = PTR_ERR(em); + break; + } + + if (em->block_start == EXTENT_MAP_HOLE) { + if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) { + if (last_end <= orig_start) { + free_extent_map(em); + ret = -ENXIO; + break; + } + } + + if (origin == SEEK_HOLE) { + *offset = start; + free_extent_map(em); + break; + } + } else { + if (origin == SEEK_DATA) { + if (em->block_start == EXTENT_MAP_DELALLOC) { + if (start >= inode->i_size) { + free_extent_map(em); + ret = -ENXIO; + break; + } + } + + *offset = start; + free_extent_map(em); + break; + } + } + + start = em->start + em->len; + last_end = em->start + em->len; + + if (em->block_start == EXTENT_MAP_DELALLOC) + last_end = min_t(u64, last_end, inode->i_size); + + if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) { + free_extent_map(em); + ret = -ENXIO; + break; + } + free_extent_map(em); + cond_resched(); + } + if (!ret) + *offset = min(*offset, inode->i_size); +out: + unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend, + &cached_state, GFP_NOFS); + return ret; +} + +static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int origin) +{ + struct inode *inode = file->f_mapping->host; + int ret; + + mutex_lock(&inode->i_mutex); + switch (origin) { + case SEEK_END: + case SEEK_CUR: + offset = generic_file_llseek(file, offset, origin); + goto out; + case SEEK_DATA: + case SEEK_HOLE: + if (offset >= i_size_read(inode)) { + mutex_unlock(&inode->i_mutex); + return -ENXIO; + } + + ret = find_desired_extent(inode, &offset, origin); + if (ret) { + mutex_unlock(&inode->i_mutex); + return ret; + } + } + + if (offset < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET)) { + offset = -EINVAL; + goto out; + } + if (offset > inode->i_sb->s_maxbytes) { + offset = -EINVAL; + goto out; + } + + /* Special lock needed here? */ + if (offset != file->f_pos) { + file->f_pos = offset; + file->f_version = 0; + } +out: + mutex_unlock(&inode->i_mutex); + return offset; +} + +const struct file_operations btrfs_file_operations = { + .llseek = btrfs_file_llseek, + .read = do_sync_read, + .write = do_sync_write, + .aio_read = generic_file_aio_read, + .splice_read = generic_file_splice_read, + .aio_write = btrfs_file_aio_write, + .mmap = btrfs_file_mmap, + .open = generic_file_open, + .release = btrfs_release_file, + .fsync = btrfs_sync_file, + .fallocate = btrfs_fallocate, + .unlocked_ioctl = btrfs_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = btrfs_ioctl, +#endif +}; |