diff options
Diffstat (limited to 'ANDROID_3.4.5/fs/ext2/balloc.c')
| -rw-r--r-- | ANDROID_3.4.5/fs/ext2/balloc.c | 1555 |
1 files changed, 0 insertions, 1555 deletions
diff --git a/ANDROID_3.4.5/fs/ext2/balloc.c b/ANDROID_3.4.5/fs/ext2/balloc.c deleted file mode 100644 index a8cbe1bc..00000000 --- a/ANDROID_3.4.5/fs/ext2/balloc.c +++ /dev/null @@ -1,1555 +0,0 @@ -/* - * linux/fs/ext2/balloc.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) - * - * Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993 - * Big-endian to little-endian byte-swapping/bitmaps by - * David S. Miller (davem@caip.rutgers.edu), 1995 - */ - -#include "ext2.h" -#include <linux/quotaops.h> -#include <linux/slab.h> -#include <linux/sched.h> -#include <linux/buffer_head.h> -#include <linux/capability.h> - -/* - * balloc.c contains the blocks allocation and deallocation routines - */ - -/* - * The free blocks are managed by bitmaps. A file system contains several - * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap - * block for inodes, N blocks for the inode table and data blocks. - * - * The file system contains group descriptors which are located after the - * super block. Each descriptor contains the number of the bitmap block and - * the free blocks count in the block. The descriptors are loaded in memory - * when a file system is mounted (see ext2_fill_super). - */ - - -#define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) - -struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb, - unsigned int block_group, - struct buffer_head ** bh) -{ - unsigned long group_desc; - unsigned long offset; - struct ext2_group_desc * desc; - struct ext2_sb_info *sbi = EXT2_SB(sb); - - if (block_group >= sbi->s_groups_count) { - ext2_error (sb, "ext2_get_group_desc", - "block_group >= groups_count - " - "block_group = %d, groups_count = %lu", - block_group, sbi->s_groups_count); - - return NULL; - } - - group_desc = block_group >> EXT2_DESC_PER_BLOCK_BITS(sb); - offset = block_group & (EXT2_DESC_PER_BLOCK(sb) - 1); - if (!sbi->s_group_desc[group_desc]) { - ext2_error (sb, "ext2_get_group_desc", - "Group descriptor not loaded - " - "block_group = %d, group_desc = %lu, desc = %lu", - block_group, group_desc, offset); - return NULL; - } - - desc = (struct ext2_group_desc *) sbi->s_group_desc[group_desc]->b_data; - if (bh) - *bh = sbi->s_group_desc[group_desc]; - return desc + offset; -} - -static int ext2_valid_block_bitmap(struct super_block *sb, - struct ext2_group_desc *desc, - unsigned int block_group, - struct buffer_head *bh) -{ - ext2_grpblk_t offset; - ext2_grpblk_t next_zero_bit; - ext2_fsblk_t bitmap_blk; - ext2_fsblk_t group_first_block; - - group_first_block = ext2_group_first_block_no(sb, block_group); - - /* check whether block bitmap block number is set */ - bitmap_blk = le32_to_cpu(desc->bg_block_bitmap); - offset = bitmap_blk - group_first_block; - if (!ext2_test_bit(offset, bh->b_data)) - /* bad block bitmap */ - goto err_out; - - /* check whether the inode bitmap block number is set */ - bitmap_blk = le32_to_cpu(desc->bg_inode_bitmap); - offset = bitmap_blk - group_first_block; - if (!ext2_test_bit(offset, bh->b_data)) - /* bad block bitmap */ - goto err_out; - - /* check whether the inode table block number is set */ - bitmap_blk = le32_to_cpu(desc->bg_inode_table); - offset = bitmap_blk - group_first_block; - next_zero_bit = ext2_find_next_zero_bit(bh->b_data, - offset + EXT2_SB(sb)->s_itb_per_group, - offset); - if (next_zero_bit >= offset + EXT2_SB(sb)->s_itb_per_group) - /* good bitmap for inode tables */ - return 1; - -err_out: - ext2_error(sb, __func__, - "Invalid block bitmap - " - "block_group = %d, block = %lu", - block_group, bitmap_blk); - return 0; -} - -/* - * Read the bitmap for a given block_group,and validate the - * bits for block/inode/inode tables are set in the bitmaps - * - * Return buffer_head on success or NULL in case of failure. - */ -static struct buffer_head * -read_block_bitmap(struct super_block *sb, unsigned int block_group) -{ - struct ext2_group_desc * desc; - struct buffer_head * bh = NULL; - ext2_fsblk_t bitmap_blk; - - desc = ext2_get_group_desc(sb, block_group, NULL); - if (!desc) - return NULL; - bitmap_blk = le32_to_cpu(desc->bg_block_bitmap); - bh = sb_getblk(sb, bitmap_blk); - if (unlikely(!bh)) { - ext2_error(sb, __func__, - "Cannot read block bitmap - " - "block_group = %d, block_bitmap = %u", - block_group, le32_to_cpu(desc->bg_block_bitmap)); - return NULL; - } - if (likely(bh_uptodate_or_lock(bh))) - return bh; - - if (bh_submit_read(bh) < 0) { - brelse(bh); - ext2_error(sb, __func__, - "Cannot read block bitmap - " - "block_group = %d, block_bitmap = %u", - block_group, le32_to_cpu(desc->bg_block_bitmap)); - return NULL; - } - - ext2_valid_block_bitmap(sb, desc, block_group, bh); - /* - * file system mounted not to panic on error, continue with corrupt - * bitmap - */ - return bh; -} - -static void release_blocks(struct super_block *sb, int count) -{ - if (count) { - struct ext2_sb_info *sbi = EXT2_SB(sb); - - percpu_counter_add(&sbi->s_freeblocks_counter, count); - sb->s_dirt = 1; - } -} - -static void group_adjust_blocks(struct super_block *sb, int group_no, - struct ext2_group_desc *desc, struct buffer_head *bh, int count) -{ - if (count) { - struct ext2_sb_info *sbi = EXT2_SB(sb); - unsigned free_blocks; - - spin_lock(sb_bgl_lock(sbi, group_no)); - free_blocks = le16_to_cpu(desc->bg_free_blocks_count); - desc->bg_free_blocks_count = cpu_to_le16(free_blocks + count); - spin_unlock(sb_bgl_lock(sbi, group_no)); - sb->s_dirt = 1; - mark_buffer_dirty(bh); - } -} - -/* - * The reservation window structure operations - * -------------------------------------------- - * Operations include: - * dump, find, add, remove, is_empty, find_next_reservable_window, etc. - * - * We use a red-black tree to represent per-filesystem reservation - * windows. - * - */ - -/** - * __rsv_window_dump() -- Dump the filesystem block allocation reservation map - * @rb_root: root of per-filesystem reservation rb tree - * @verbose: verbose mode - * @fn: function which wishes to dump the reservation map - * - * If verbose is turned on, it will print the whole block reservation - * windows(start, end). Otherwise, it will only print out the "bad" windows, - * those windows that overlap with their immediate neighbors. - */ -#if 1 -static void __rsv_window_dump(struct rb_root *root, int verbose, - const char *fn) -{ - struct rb_node *n; - struct ext2_reserve_window_node *rsv, *prev; - int bad; - -restart: - n = rb_first(root); - bad = 0; - prev = NULL; - - printk("Block Allocation Reservation Windows Map (%s):\n", fn); - while (n) { - rsv = rb_entry(n, struct ext2_reserve_window_node, rsv_node); - if (verbose) - printk("reservation window 0x%p " - "start: %lu, end: %lu\n", - rsv, rsv->rsv_start, rsv->rsv_end); - if (rsv->rsv_start && rsv->rsv_start >= rsv->rsv_end) { - printk("Bad reservation %p (start >= end)\n", - rsv); - bad = 1; - } - if (prev && prev->rsv_end >= rsv->rsv_start) { - printk("Bad reservation %p (prev->end >= start)\n", - rsv); - bad = 1; - } - if (bad) { - if (!verbose) { - printk("Restarting reservation walk in verbose mode\n"); - verbose = 1; - goto restart; - } - } - n = rb_next(n); - prev = rsv; - } - printk("Window map complete.\n"); - BUG_ON(bad); -} -#define rsv_window_dump(root, verbose) \ - __rsv_window_dump((root), (verbose), __func__) -#else -#define rsv_window_dump(root, verbose) do {} while (0) -#endif - -/** - * goal_in_my_reservation() - * @rsv: inode's reservation window - * @grp_goal: given goal block relative to the allocation block group - * @group: the current allocation block group - * @sb: filesystem super block - * - * Test if the given goal block (group relative) is within the file's - * own block reservation window range. - * - * If the reservation window is outside the goal allocation group, return 0; - * grp_goal (given goal block) could be -1, which means no specific - * goal block. In this case, always return 1. - * If the goal block is within the reservation window, return 1; - * otherwise, return 0; - */ -static int -goal_in_my_reservation(struct ext2_reserve_window *rsv, ext2_grpblk_t grp_goal, - unsigned int group, struct super_block * sb) -{ - ext2_fsblk_t group_first_block, group_last_block; - - group_first_block = ext2_group_first_block_no(sb, group); - group_last_block = group_first_block + EXT2_BLOCKS_PER_GROUP(sb) - 1; - - if ((rsv->_rsv_start > group_last_block) || - (rsv->_rsv_end < group_first_block)) - return 0; - if ((grp_goal >= 0) && ((grp_goal + group_first_block < rsv->_rsv_start) - || (grp_goal + group_first_block > rsv->_rsv_end))) - return 0; - return 1; -} - -/** - * search_reserve_window() - * @rb_root: root of reservation tree - * @goal: target allocation block - * - * Find the reserved window which includes the goal, or the previous one - * if the goal is not in any window. - * Returns NULL if there are no windows or if all windows start after the goal. - */ -static struct ext2_reserve_window_node * -search_reserve_window(struct rb_root *root, ext2_fsblk_t goal) -{ - struct rb_node *n = root->rb_node; - struct ext2_reserve_window_node *rsv; - - if (!n) - return NULL; - - do { - rsv = rb_entry(n, struct ext2_reserve_window_node, rsv_node); - - if (goal < rsv->rsv_start) - n = n->rb_left; - else if (goal > rsv->rsv_end) - n = n->rb_right; - else - return rsv; - } while (n); - /* - * We've fallen off the end of the tree: the goal wasn't inside - * any particular node. OK, the previous node must be to one - * side of the interval containing the goal. If it's the RHS, - * we need to back up one. - */ - if (rsv->rsv_start > goal) { - n = rb_prev(&rsv->rsv_node); - rsv = rb_entry(n, struct ext2_reserve_window_node, rsv_node); - } - return rsv; -} - -/* - * ext2_rsv_window_add() -- Insert a window to the block reservation rb tree. - * @sb: super block - * @rsv: reservation window to add - * - * Must be called with rsv_lock held. - */ -void ext2_rsv_window_add(struct super_block *sb, - struct ext2_reserve_window_node *rsv) -{ - struct rb_root *root = &EXT2_SB(sb)->s_rsv_window_root; - struct rb_node *node = &rsv->rsv_node; - ext2_fsblk_t start = rsv->rsv_start; - - struct rb_node ** p = &root->rb_node; - struct rb_node * parent = NULL; - struct ext2_reserve_window_node *this; - - while (*p) - { - parent = *p; - this = rb_entry(parent, struct ext2_reserve_window_node, rsv_node); - - if (start < this->rsv_start) - p = &(*p)->rb_left; - else if (start > this->rsv_end) - p = &(*p)->rb_right; - else { - rsv_window_dump(root, 1); - BUG(); - } - } - - rb_link_node(node, parent, p); - rb_insert_color(node, root); -} - -/** - * rsv_window_remove() -- unlink a window from the reservation rb tree - * @sb: super block - * @rsv: reservation window to remove - * - * Mark the block reservation window as not allocated, and unlink it - * from the filesystem reservation window rb tree. Must be called with - * rsv_lock held. - */ -static void rsv_window_remove(struct super_block *sb, - struct ext2_reserve_window_node *rsv) -{ - rsv->rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED; - rsv->rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED; - rsv->rsv_alloc_hit = 0; - rb_erase(&rsv->rsv_node, &EXT2_SB(sb)->s_rsv_window_root); -} - -/* - * rsv_is_empty() -- Check if the reservation window is allocated. - * @rsv: given reservation window to check - * - * returns 1 if the end block is EXT2_RESERVE_WINDOW_NOT_ALLOCATED. - */ -static inline int rsv_is_empty(struct ext2_reserve_window *rsv) -{ - /* a valid reservation end block could not be 0 */ - return (rsv->_rsv_end == EXT2_RESERVE_WINDOW_NOT_ALLOCATED); -} - -/** - * ext2_init_block_alloc_info() - * @inode: file inode structure - * - * Allocate and initialize the reservation window structure, and - * link the window to the ext2 inode structure at last - * - * The reservation window structure is only dynamically allocated - * and linked to ext2 inode the first time the open file - * needs a new block. So, before every ext2_new_block(s) call, for - * regular files, we should check whether the reservation window - * structure exists or not. In the latter case, this function is called. - * Fail to do so will result in block reservation being turned off for that - * open file. - * - * This function is called from ext2_get_blocks_handle(), also called - * when setting the reservation window size through ioctl before the file - * is open for write (needs block allocation). - * - * Needs truncate_mutex protection prior to calling this function. - */ -void ext2_init_block_alloc_info(struct inode *inode) -{ - struct ext2_inode_info *ei = EXT2_I(inode); - struct ext2_block_alloc_info *block_i; - struct super_block *sb = inode->i_sb; - - block_i = kmalloc(sizeof(*block_i), GFP_NOFS); - if (block_i) { - struct ext2_reserve_window_node *rsv = &block_i->rsv_window_node; - - rsv->rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED; - rsv->rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED; - - /* - * if filesystem is mounted with NORESERVATION, the goal - * reservation window size is set to zero to indicate - * block reservation is off - */ - if (!test_opt(sb, RESERVATION)) - rsv->rsv_goal_size = 0; - else - rsv->rsv_goal_size = EXT2_DEFAULT_RESERVE_BLOCKS; - rsv->rsv_alloc_hit = 0; - block_i->last_alloc_logical_block = 0; - block_i->last_alloc_physical_block = 0; - } - ei->i_block_alloc_info = block_i; -} - -/** - * ext2_discard_reservation() - * @inode: inode - * - * Discard(free) block reservation window on last file close, or truncate - * or at last iput(). - * - * It is being called in three cases: - * ext2_release_file(): last writer closes the file - * ext2_clear_inode(): last iput(), when nobody links to this file. - * ext2_truncate(): when the block indirect map is about to change. - */ -void ext2_discard_reservation(struct inode *inode) -{ - struct ext2_inode_info *ei = EXT2_I(inode); - struct ext2_block_alloc_info *block_i = ei->i_block_alloc_info; - struct ext2_reserve_window_node *rsv; - spinlock_t *rsv_lock = &EXT2_SB(inode->i_sb)->s_rsv_window_lock; - - if (!block_i) - return; - - rsv = &block_i->rsv_window_node; - if (!rsv_is_empty(&rsv->rsv_window)) { - spin_lock(rsv_lock); - if (!rsv_is_empty(&rsv->rsv_window)) - rsv_window_remove(inode->i_sb, rsv); - spin_unlock(rsv_lock); - } -} - -/** - * ext2_free_blocks_sb() -- Free given blocks and update quota and i_blocks - * @inode: inode - * @block: start physcial block to free - * @count: number of blocks to free - */ -void ext2_free_blocks (struct inode * inode, unsigned long block, - unsigned long count) -{ - struct buffer_head *bitmap_bh = NULL; - struct buffer_head * bh2; - unsigned long block_group; - unsigned long bit; - unsigned long i; - unsigned long overflow; - struct super_block * sb = inode->i_sb; - struct ext2_sb_info * sbi = EXT2_SB(sb); - struct ext2_group_desc * desc; - struct ext2_super_block * es = sbi->s_es; - unsigned freed = 0, group_freed; - - if (block < le32_to_cpu(es->s_first_data_block) || - block + count < block || - block + count > le32_to_cpu(es->s_blocks_count)) { - ext2_error (sb, "ext2_free_blocks", - "Freeing blocks not in datazone - " - "block = %lu, count = %lu", block, count); - goto error_return; - } - - ext2_debug ("freeing block(s) %lu-%lu\n", block, block + count - 1); - -do_more: - overflow = 0; - block_group = (block - le32_to_cpu(es->s_first_data_block)) / - EXT2_BLOCKS_PER_GROUP(sb); - bit = (block - le32_to_cpu(es->s_first_data_block)) % - EXT2_BLOCKS_PER_GROUP(sb); - /* - * Check to see if we are freeing blocks across a group - * boundary. - */ - if (bit + count > EXT2_BLOCKS_PER_GROUP(sb)) { - overflow = bit + count - EXT2_BLOCKS_PER_GROUP(sb); - count -= overflow; - } - brelse(bitmap_bh); - bitmap_bh = read_block_bitmap(sb, block_group); - if (!bitmap_bh) - goto error_return; - - desc = ext2_get_group_desc (sb, block_group, &bh2); - if (!desc) - goto error_return; - - if (in_range (le32_to_cpu(desc->bg_block_bitmap), block, count) || - in_range (le32_to_cpu(desc->bg_inode_bitmap), block, count) || - in_range (block, le32_to_cpu(desc->bg_inode_table), - sbi->s_itb_per_group) || - in_range (block + count - 1, le32_to_cpu(desc->bg_inode_table), - sbi->s_itb_per_group)) { - ext2_error (sb, "ext2_free_blocks", - "Freeing blocks in system zones - " - "Block = %lu, count = %lu", - block, count); - goto error_return; - } - - for (i = 0, group_freed = 0; i < count; i++) { - if (!ext2_clear_bit_atomic(sb_bgl_lock(sbi, block_group), - bit + i, bitmap_bh->b_data)) { - ext2_error(sb, __func__, - "bit already cleared for block %lu", block + i); - } else { - group_freed++; - } - } - - mark_buffer_dirty(bitmap_bh); - if (sb->s_flags & MS_SYNCHRONOUS) - sync_dirty_buffer(bitmap_bh); - - group_adjust_blocks(sb, block_group, desc, bh2, group_freed); - freed += group_freed; - - if (overflow) { - block += count; - count = overflow; - goto do_more; - } -error_return: - brelse(bitmap_bh); - release_blocks(sb, freed); - dquot_free_block_nodirty(inode, freed); -} - -/** - * bitmap_search_next_usable_block() - * @start: the starting block (group relative) of the search - * @bh: bufferhead contains the block group bitmap - * @maxblocks: the ending block (group relative) of the reservation - * - * The bitmap search --- search forward through the actual bitmap on disk until - * we find a bit free. - */ -static ext2_grpblk_t -bitmap_search_next_usable_block(ext2_grpblk_t start, struct buffer_head *bh, - ext2_grpblk_t maxblocks) -{ - ext2_grpblk_t next; - - next = ext2_find_next_zero_bit(bh->b_data, maxblocks, start); - if (next >= maxblocks) - return -1; - return next; -} - -/** - * find_next_usable_block() - * @start: the starting block (group relative) to find next - * allocatable block in bitmap. - * @bh: bufferhead contains the block group bitmap - * @maxblocks: the ending block (group relative) for the search - * - * Find an allocatable block in a bitmap. We perform the "most - * appropriate allocation" algorithm of looking for a free block near - * the initial goal; then for a free byte somewhere in the bitmap; - * then for any free bit in the bitmap. - */ -static ext2_grpblk_t -find_next_usable_block(int start, struct buffer_head *bh, int maxblocks) -{ - ext2_grpblk_t here, next; - char *p, *r; - - if (start > 0) { - /* - * The goal was occupied; search forward for a free - * block within the next XX blocks. - * - * end_goal is more or less random, but it has to be - * less than EXT2_BLOCKS_PER_GROUP. Aligning up to the - * next 64-bit boundary is simple.. - */ - ext2_grpblk_t end_goal = (start + 63) & ~63; - if (end_goal > maxblocks) - end_goal = maxblocks; - here = ext2_find_next_zero_bit(bh->b_data, end_goal, start); - if (here < end_goal) - return here; - ext2_debug("Bit not found near goal\n"); - } - - here = start; - if (here < 0) - here = 0; - - p = ((char *)bh->b_data) + (here >> 3); - r = memscan(p, 0, ((maxblocks + 7) >> 3) - (here >> 3)); - next = (r - ((char *)bh->b_data)) << 3; - - if (next < maxblocks && next >= here) - return next; - - here = bitmap_search_next_usable_block(here, bh, maxblocks); - return here; -} - -/** - * ext2_try_to_allocate() - * @sb: superblock - * @group: given allocation block group - * @bitmap_bh: bufferhead holds the block bitmap - * @grp_goal: given target block within the group - * @count: target number of blocks to allocate - * @my_rsv: reservation window - * - * Attempt to allocate blocks within a give range. Set the range of allocation - * first, then find the first free bit(s) from the bitmap (within the range), - * and at last, allocate the blocks by claiming the found free bit as allocated. - * - * To set the range of this allocation: - * if there is a reservation window, only try to allocate block(s) - * from the file's own reservation window; - * Otherwise, the allocation range starts from the give goal block, - * ends at the block group's last block. - * - * If we failed to allocate the desired block then we may end up crossing to a - * new bitmap. - */ -static int -ext2_try_to_allocate(struct super_block *sb, int group, - struct buffer_head *bitmap_bh, ext2_grpblk_t grp_goal, - unsigned long *count, - struct ext2_reserve_window *my_rsv) -{ - ext2_fsblk_t group_first_block; - ext2_grpblk_t start, end; - unsigned long num = 0; - - /* we do allocation within the reservation window if we have a window */ - if (my_rsv) { - group_first_block = ext2_group_first_block_no(sb, group); - if (my_rsv->_rsv_start >= group_first_block) - start = my_rsv->_rsv_start - group_first_block; - else - /* reservation window cross group boundary */ - start = 0; - end = my_rsv->_rsv_end - group_first_block + 1; - if (end > EXT2_BLOCKS_PER_GROUP(sb)) - /* reservation window crosses group boundary */ - end = EXT2_BLOCKS_PER_GROUP(sb); - if ((start <= grp_goal) && (grp_goal < end)) - start = grp_goal; - else - grp_goal = -1; - } else { - if (grp_goal > 0) - start = grp_goal; - else - start = 0; - end = EXT2_BLOCKS_PER_GROUP(sb); - } - - BUG_ON(start > EXT2_BLOCKS_PER_GROUP(sb)); - -repeat: - if (grp_goal < 0) { - grp_goal = find_next_usable_block(start, bitmap_bh, end); - if (grp_goal < 0) - goto fail_access; - if (!my_rsv) { - int i; - - for (i = 0; i < 7 && grp_goal > start && - !ext2_test_bit(grp_goal - 1, - bitmap_bh->b_data); - i++, grp_goal--) - ; - } - } - start = grp_goal; - - if (ext2_set_bit_atomic(sb_bgl_lock(EXT2_SB(sb), group), grp_goal, - bitmap_bh->b_data)) { - /* - * The block was allocated by another thread, or it was - * allocated and then freed by another thread - */ - start++; - grp_goal++; - if (start >= end) - goto fail_access; - goto repeat; - } - num++; - grp_goal++; - while (num < *count && grp_goal < end - && !ext2_set_bit_atomic(sb_bgl_lock(EXT2_SB(sb), group), - grp_goal, bitmap_bh->b_data)) { - num++; - grp_goal++; - } - *count = num; - return grp_goal - num; -fail_access: - *count = num; - return -1; -} - -/** - * find_next_reservable_window(): - * find a reservable space within the given range. - * It does not allocate the reservation window for now: - * alloc_new_reservation() will do the work later. - * - * @search_head: the head of the searching list; - * This is not necessarily the list head of the whole filesystem - * - * We have both head and start_block to assist the search - * for the reservable space. The list starts from head, - * but we will shift to the place where start_block is, - * then start from there, when looking for a reservable space. - * - * @size: the target new reservation window size - * - * @group_first_block: the first block we consider to start - * the real search from - * - * @last_block: - * the maximum block number that our goal reservable space - * could start from. This is normally the last block in this - * group. The search will end when we found the start of next - * possible reservable space is out of this boundary. - * This could handle the cross boundary reservation window - * request. - * - * basically we search from the given range, rather than the whole - * reservation double linked list, (start_block, last_block) - * to find a free region that is of my size and has not - * been reserved. - * - */ -static int find_next_reservable_window( - struct ext2_reserve_window_node *search_head, - struct ext2_reserve_window_node *my_rsv, - struct super_block * sb, - ext2_fsblk_t start_block, - ext2_fsblk_t last_block) -{ - struct rb_node *next; - struct ext2_reserve_window_node *rsv, *prev; - ext2_fsblk_t cur; - int size = my_rsv->rsv_goal_size; - - /* TODO: make the start of the reservation window byte-aligned */ - /* cur = *start_block & ~7;*/ - cur = start_block; - rsv = search_head; - if (!rsv) - return -1; - - while (1) { - if (cur <= rsv->rsv_end) - cur = rsv->rsv_end + 1; - - /* TODO? - * in the case we could not find a reservable space - * that is what is expected, during the re-search, we could - * remember what's the largest reservable space we could have - * and return that one. - * - * For now it will fail if we could not find the reservable - * space with expected-size (or more)... - */ - if (cur > last_block) - return -1; /* fail */ - - prev = rsv; - next = rb_next(&rsv->rsv_node); - rsv = rb_entry(next,struct ext2_reserve_window_node,rsv_node); - - /* - * Reached the last reservation, we can just append to the - * previous one. - */ - if (!next) - break; - - if (cur + size <= rsv->rsv_start) { - /* - * Found a reserveable space big enough. We could - * have a reservation across the group boundary here - */ - break; - } - } - /* - * we come here either : - * when we reach the end of the whole list, - * and there is empty reservable space after last entry in the list. - * append it to the end of the list. - * - * or we found one reservable space in the middle of the list, - * return the reservation window that we could append to. - * succeed. - */ - - if ((prev != my_rsv) && (!rsv_is_empty(&my_rsv->rsv_window))) - rsv_window_remove(sb, my_rsv); - - /* - * Let's book the whole available window for now. We will check the - * disk bitmap later and then, if there are free blocks then we adjust - * the window size if it's larger than requested. - * Otherwise, we will remove this node from the tree next time - * call find_next_reservable_window. - */ - my_rsv->rsv_start = cur; - my_rsv->rsv_end = cur + size - 1; - my_rsv->rsv_alloc_hit = 0; - - if (prev != my_rsv) - ext2_rsv_window_add(sb, my_rsv); - - return 0; -} - -/** - * alloc_new_reservation()--allocate a new reservation window - * - * To make a new reservation, we search part of the filesystem - * reservation list (the list that inside the group). We try to - * allocate a new reservation window near the allocation goal, - * or the beginning of the group, if there is no goal. - * - * We first find a reservable space after the goal, then from - * there, we check the bitmap for the first free block after - * it. If there is no free block until the end of group, then the - * whole group is full, we failed. Otherwise, check if the free - * block is inside the expected reservable space, if so, we - * succeed. - * If the first free block is outside the reservable space, then - * start from the first free block, we search for next available - * space, and go on. - * - * on succeed, a new reservation will be found and inserted into the list - * It contains at least one free block, and it does not overlap with other - * reservation windows. - * - * failed: we failed to find a reservation window in this group - * - * @rsv: the reservation - * - * @grp_goal: The goal (group-relative). It is where the search for a - * free reservable space should start from. - * if we have a goal(goal >0 ), then start from there, - * no goal(goal = -1), we start from the first block - * of the group. - * - * @sb: the super block - * @group: the group we are trying to allocate in - * @bitmap_bh: the block group block bitmap - * - */ -static int alloc_new_reservation(struct ext2_reserve_window_node *my_rsv, - ext2_grpblk_t grp_goal, struct super_block *sb, - unsigned int group, struct buffer_head *bitmap_bh) -{ - struct ext2_reserve_window_node *search_head; - ext2_fsblk_t group_first_block, group_end_block, start_block; - ext2_grpblk_t first_free_block; - struct rb_root *fs_rsv_root = &EXT2_SB(sb)->s_rsv_window_root; - unsigned long size; - int ret; - spinlock_t *rsv_lock = &EXT2_SB(sb)->s_rsv_window_lock; - - group_first_block = ext2_group_first_block_no(sb, group); - group_end_block = group_first_block + (EXT2_BLOCKS_PER_GROUP(sb) - 1); - - if (grp_goal < 0) - start_block = group_first_block; - else - start_block = grp_goal + group_first_block; - - size = my_rsv->rsv_goal_size; - - if (!rsv_is_empty(&my_rsv->rsv_window)) { - /* - * if the old reservation is cross group boundary - * and if the goal is inside the old reservation window, - * we will come here when we just failed to allocate from - * the first part of the window. We still have another part - * that belongs to the next group. In this case, there is no - * point to discard our window and try to allocate a new one - * in this group(which will fail). we should - * keep the reservation window, just simply move on. - * - * Maybe we could shift the start block of the reservation - * window to the first block of next group. - */ - - if ((my_rsv->rsv_start <= group_end_block) && - (my_rsv->rsv_end > group_end_block) && - (start_block >= my_rsv->rsv_start)) - return -1; - - if ((my_rsv->rsv_alloc_hit > - (my_rsv->rsv_end - my_rsv->rsv_start + 1) / 2)) { - /* - * if the previously allocation hit ratio is - * greater than 1/2, then we double the size of - * the reservation window the next time, - * otherwise we keep the same size window - */ - size = size * 2; - if (size > EXT2_MAX_RESERVE_BLOCKS) - size = EXT2_MAX_RESERVE_BLOCKS; - my_rsv->rsv_goal_size= size; - } - } - - spin_lock(rsv_lock); - /* - * shift the search start to the window near the goal block - */ - search_head = search_reserve_window(fs_rsv_root, start_block); - - /* - * find_next_reservable_window() simply finds a reservable window - * inside the given range(start_block, group_end_block). - * - * To make sure the reservation window has a free bit inside it, we - * need to check the bitmap after we found a reservable window. - */ -retry: - ret = find_next_reservable_window(search_head, my_rsv, sb, - start_block, group_end_block); - - if (ret == -1) { - if (!rsv_is_empty(&my_rsv->rsv_window)) - rsv_window_remove(sb, my_rsv); - spin_unlock(rsv_lock); - return -1; - } - - /* - * On success, find_next_reservable_window() returns the - * reservation window where there is a reservable space after it. - * Before we reserve this reservable space, we need - * to make sure there is at least a free block inside this region. - * - * Search the first free bit on the block bitmap. Search starts from - * the start block of the reservable space we just found. - */ - spin_unlock(rsv_lock); - first_free_block = bitmap_search_next_usable_block( - my_rsv->rsv_start - group_first_block, - bitmap_bh, group_end_block - group_first_block + 1); - - if (first_free_block < 0) { - /* - * no free block left on the bitmap, no point - * to reserve the space. return failed. - */ - spin_lock(rsv_lock); - if (!rsv_is_empty(&my_rsv->rsv_window)) - rsv_window_remove(sb, my_rsv); - spin_unlock(rsv_lock); - return -1; /* failed */ - } - - start_block = first_free_block + group_first_block; - /* - * check if the first free block is within the - * free space we just reserved - */ - if (start_block >= my_rsv->rsv_start && start_block <= my_rsv->rsv_end) - return 0; /* success */ - /* - * if the first free bit we found is out of the reservable space - * continue search for next reservable space, - * start from where the free block is, - * we also shift the list head to where we stopped last time - */ - search_head = my_rsv; - spin_lock(rsv_lock); - goto retry; -} - -/** - * try_to_extend_reservation() - * @my_rsv: given reservation window - * @sb: super block - * @size: the delta to extend - * - * Attempt to expand the reservation window large enough to have - * required number of free blocks - * - * Since ext2_try_to_allocate() will always allocate blocks within - * the reservation window range, if the window size is too small, - * multiple blocks allocation has to stop at the end of the reservation - * window. To make this more efficient, given the total number of - * blocks needed and the current size of the window, we try to - * expand the reservation window size if necessary on a best-effort - * basis before ext2_new_blocks() tries to allocate blocks. - */ -static void try_to_extend_reservation(struct ext2_reserve_window_node *my_rsv, - struct super_block *sb, int size) -{ - struct ext2_reserve_window_node *next_rsv; - struct rb_node *next; - spinlock_t *rsv_lock = &EXT2_SB(sb)->s_rsv_window_lock; - - if (!spin_trylock(rsv_lock)) - return; - - next = rb_next(&my_rsv->rsv_node); - - if (!next) - my_rsv->rsv_end += size; - else { - next_rsv = rb_entry(next, struct ext2_reserve_window_node, rsv_node); - - if ((next_rsv->rsv_start - my_rsv->rsv_end - 1) >= size) - my_rsv->rsv_end += size; - else - my_rsv->rsv_end = next_rsv->rsv_start - 1; - } - spin_unlock(rsv_lock); -} - -/** - * ext2_try_to_allocate_with_rsv() - * @sb: superblock - * @group: given allocation block group - * @bitmap_bh: bufferhead holds the block bitmap - * @grp_goal: given target block within the group - * @count: target number of blocks to allocate - * @my_rsv: reservation window - * - * This is the main function used to allocate a new block and its reservation - * window. - * - * Each time when a new block allocation is need, first try to allocate from - * its own reservation. If it does not have a reservation window, instead of - * looking for a free bit on bitmap first, then look up the reservation list to - * see if it is inside somebody else's reservation window, we try to allocate a - * reservation window for it starting from the goal first. Then do the block - * allocation within the reservation window. - * - * This will avoid keeping on searching the reservation list again and - * again when somebody is looking for a free block (without - * reservation), and there are lots of free blocks, but they are all - * being reserved. - * - * We use a red-black tree for the per-filesystem reservation list. - */ -static ext2_grpblk_t -ext2_try_to_allocate_with_rsv(struct super_block *sb, unsigned int group, - struct buffer_head *bitmap_bh, ext2_grpblk_t grp_goal, - struct ext2_reserve_window_node * my_rsv, - unsigned long *count) -{ - ext2_fsblk_t group_first_block, group_last_block; - ext2_grpblk_t ret = 0; - unsigned long num = *count; - - /* - * we don't deal with reservation when - * filesystem is mounted without reservation - * or the file is not a regular file - * or last attempt to allocate a block with reservation turned on failed - */ - if (my_rsv == NULL) { - return ext2_try_to_allocate(sb, group, bitmap_bh, - grp_goal, count, NULL); - } - /* - * grp_goal is a group relative block number (if there is a goal) - * 0 <= grp_goal < EXT2_BLOCKS_PER_GROUP(sb) - * first block is a filesystem wide block number - * first block is the block number of the first block in this group - */ - group_first_block = ext2_group_first_block_no(sb, group); - group_last_block = group_first_block + (EXT2_BLOCKS_PER_GROUP(sb) - 1); - - /* - * Basically we will allocate a new block from inode's reservation - * window. - * - * We need to allocate a new reservation window, if: - * a) inode does not have a reservation window; or - * b) last attempt to allocate a block from existing reservation - * failed; or - * c) we come here with a goal and with a reservation window - * - * We do not need to allocate a new reservation window if we come here - * at the beginning with a goal and the goal is inside the window, or - * we don't have a goal but already have a reservation window. - * then we could go to allocate from the reservation window directly. - */ - while (1) { - if (rsv_is_empty(&my_rsv->rsv_window) || (ret < 0) || - !goal_in_my_reservation(&my_rsv->rsv_window, - grp_goal, group, sb)) { - if (my_rsv->rsv_goal_size < *count) - my_rsv->rsv_goal_size = *count; - ret = alloc_new_reservation(my_rsv, grp_goal, sb, - group, bitmap_bh); - if (ret < 0) - break; /* failed */ - - if (!goal_in_my_reservation(&my_rsv->rsv_window, - grp_goal, group, sb)) - grp_goal = -1; - } else if (grp_goal >= 0) { - int curr = my_rsv->rsv_end - - (grp_goal + group_first_block) + 1; - - if (curr < *count) - try_to_extend_reservation(my_rsv, sb, - *count - curr); - } - - if ((my_rsv->rsv_start > group_last_block) || - (my_rsv->rsv_end < group_first_block)) { - rsv_window_dump(&EXT2_SB(sb)->s_rsv_window_root, 1); - BUG(); - } - ret = ext2_try_to_allocate(sb, group, bitmap_bh, grp_goal, - &num, &my_rsv->rsv_window); - if (ret >= 0) { - my_rsv->rsv_alloc_hit += num; - *count = num; - break; /* succeed */ - } - num = *count; - } - return ret; -} - -/** - * ext2_has_free_blocks() - * @sbi: in-core super block structure. - * - * Check if filesystem has at least 1 free block available for allocation. - */ -static int ext2_has_free_blocks(struct ext2_sb_info *sbi) -{ - ext2_fsblk_t free_blocks, root_blocks; - - free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter); - root_blocks = le32_to_cpu(sbi->s_es->s_r_blocks_count); - if (free_blocks < root_blocks + 1 && !capable(CAP_SYS_RESOURCE) && - sbi->s_resuid != current_fsuid() && - (sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) { - return 0; - } - return 1; -} - -/* - * ext2_new_blocks() -- core block(s) allocation function - * @inode: file inode - * @goal: given target block(filesystem wide) - * @count: target number of blocks to allocate - * @errp: error code - * - * ext2_new_blocks uses a goal block to assist allocation. If the goal is - * free, or there is a free block within 32 blocks of the goal, that block - * is allocated. Otherwise a forward search is made for a free block; within - * each block group the search first looks for an entire free byte in the block - * bitmap, and then for any free bit if that fails. - * This function also updates quota and i_blocks field. - */ -ext2_fsblk_t ext2_new_blocks(struct inode *inode, ext2_fsblk_t goal, - unsigned long *count, int *errp) -{ - struct buffer_head *bitmap_bh = NULL; - struct buffer_head *gdp_bh; - int group_no; - int goal_group; - ext2_grpblk_t grp_target_blk; /* blockgroup relative goal block */ - ext2_grpblk_t grp_alloc_blk; /* blockgroup-relative allocated block*/ - ext2_fsblk_t ret_block; /* filesyetem-wide allocated block */ - int bgi; /* blockgroup iteration index */ - int performed_allocation = 0; - ext2_grpblk_t free_blocks; /* number of free blocks in a group */ - struct super_block *sb; - struct ext2_group_desc *gdp; - struct ext2_super_block *es; - struct ext2_sb_info *sbi; - struct ext2_reserve_window_node *my_rsv = NULL; - struct ext2_block_alloc_info *block_i; - unsigned short windowsz = 0; - unsigned long ngroups; - unsigned long num = *count; - int ret; - - *errp = -ENOSPC; - sb = inode->i_sb; - if (!sb) { - printk("ext2_new_blocks: nonexistent device"); - return 0; - } - - /* - * Check quota for allocation of this block. - */ - ret = dquot_alloc_block(inode, num); - if (ret) { - *errp = ret; - return 0; - } - - sbi = EXT2_SB(sb); - es = EXT2_SB(sb)->s_es; - ext2_debug("goal=%lu.\n", goal); - /* - * Allocate a block from reservation only when - * filesystem is mounted with reservation(default,-o reservation), and - * it's a regular file, and - * the desired window size is greater than 0 (One could use ioctl - * command EXT2_IOC_SETRSVSZ to set the window size to 0 to turn off - * reservation on that particular file) - */ - block_i = EXT2_I(inode)->i_block_alloc_info; - if (block_i) { - windowsz = block_i->rsv_window_node.rsv_goal_size; - if (windowsz > 0) - my_rsv = &block_i->rsv_window_node; - } - - if (!ext2_has_free_blocks(sbi)) { - *errp = -ENOSPC; - goto out; - } - - /* - * First, test whether the goal block is free. - */ - if (goal < le32_to_cpu(es->s_first_data_block) || - goal >= le32_to_cpu(es->s_blocks_count)) - goal = le32_to_cpu(es->s_first_data_block); - group_no = (goal - le32_to_cpu(es->s_first_data_block)) / - EXT2_BLOCKS_PER_GROUP(sb); - goal_group = group_no; -retry_alloc: - gdp = ext2_get_group_desc(sb, group_no, &gdp_bh); - if (!gdp) - goto io_error; - - free_blocks = le16_to_cpu(gdp->bg_free_blocks_count); - /* - * if there is not enough free blocks to make a new resevation - * turn off reservation for this allocation - */ - if (my_rsv && (free_blocks < windowsz) - && (free_blocks > 0) - && (rsv_is_empty(&my_rsv->rsv_window))) - my_rsv = NULL; - - if (free_blocks > 0) { - grp_target_blk = ((goal - le32_to_cpu(es->s_first_data_block)) % - EXT2_BLOCKS_PER_GROUP(sb)); - bitmap_bh = read_block_bitmap(sb, group_no); - if (!bitmap_bh) - goto io_error; - grp_alloc_blk = ext2_try_to_allocate_with_rsv(sb, group_no, - bitmap_bh, grp_target_blk, - my_rsv, &num); - if (grp_alloc_blk >= 0) - goto allocated; - } - - ngroups = EXT2_SB(sb)->s_groups_count; - smp_rmb(); - - /* - * Now search the rest of the groups. We assume that - * group_no and gdp correctly point to the last group visited. - */ - for (bgi = 0; bgi < ngroups; bgi++) { - group_no++; - if (group_no >= ngroups) - group_no = 0; - gdp = ext2_get_group_desc(sb, group_no, &gdp_bh); - if (!gdp) - goto io_error; - - free_blocks = le16_to_cpu(gdp->bg_free_blocks_count); - /* - * skip this group (and avoid loading bitmap) if there - * are no free blocks - */ - if (!free_blocks) - continue; - /* - * skip this group if the number of - * free blocks is less than half of the reservation - * window size. - */ - if (my_rsv && (free_blocks <= (windowsz/2))) - continue; - - brelse(bitmap_bh); - bitmap_bh = read_block_bitmap(sb, group_no); - if (!bitmap_bh) - goto io_error; - /* - * try to allocate block(s) from this group, without a goal(-1). - */ - grp_alloc_blk = ext2_try_to_allocate_with_rsv(sb, group_no, - bitmap_bh, -1, my_rsv, &num); - if (grp_alloc_blk >= 0) - goto allocated; - } - /* - * We may end up a bogus earlier ENOSPC error due to - * filesystem is "full" of reservations, but - * there maybe indeed free blocks available on disk - * In this case, we just forget about the reservations - * just do block allocation as without reservations. - */ - if (my_rsv) { - my_rsv = NULL; - windowsz = 0; - group_no = goal_group; - goto retry_alloc; - } - /* No space left on the device */ - *errp = -ENOSPC; - goto out; - -allocated: - - ext2_debug("using block group %d(%d)\n", - group_no, gdp->bg_free_blocks_count); - - ret_block = grp_alloc_blk + ext2_group_first_block_no(sb, group_no); - - if (in_range(le32_to_cpu(gdp->bg_block_bitmap), ret_block, num) || - in_range(le32_to_cpu(gdp->bg_inode_bitmap), ret_block, num) || - in_range(ret_block, le32_to_cpu(gdp->bg_inode_table), - EXT2_SB(sb)->s_itb_per_group) || - in_range(ret_block + num - 1, le32_to_cpu(gdp->bg_inode_table), - EXT2_SB(sb)->s_itb_per_group)) { - ext2_error(sb, "ext2_new_blocks", - "Allocating block in system zone - " - "blocks from "E2FSBLK", length %lu", - ret_block, num); - /* - * ext2_try_to_allocate marked the blocks we allocated as in - * use. So we may want to selectively mark some of the blocks - * as free - */ - goto retry_alloc; - } - - performed_allocation = 1; - - if (ret_block + num - 1 >= le32_to_cpu(es->s_blocks_count)) { - ext2_error(sb, "ext2_new_blocks", - "block("E2FSBLK") >= blocks count(%d) - " - "block_group = %d, es == %p ", ret_block, - le32_to_cpu(es->s_blocks_count), group_no, es); - goto out; - } - - group_adjust_blocks(sb, group_no, gdp, gdp_bh, -num); - percpu_counter_sub(&sbi->s_freeblocks_counter, num); - - mark_buffer_dirty(bitmap_bh); - if (sb->s_flags & MS_SYNCHRONOUS) - sync_dirty_buffer(bitmap_bh); - - *errp = 0; - brelse(bitmap_bh); - dquot_free_block_nodirty(inode, *count-num); - mark_inode_dirty(inode); - *count = num; - return ret_block; - -io_error: - *errp = -EIO; -out: - /* - * Undo the block allocation - */ - if (!performed_allocation) { - dquot_free_block_nodirty(inode, *count); - mark_inode_dirty(inode); - } - brelse(bitmap_bh); - return 0; -} - -ext2_fsblk_t ext2_new_block(struct inode *inode, unsigned long goal, int *errp) -{ - unsigned long count = 1; - - return ext2_new_blocks(inode, goal, &count, errp); -} - -#ifdef EXT2FS_DEBUG - -static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0}; - -unsigned long ext2_count_free (struct buffer_head * map, unsigned int numchars) -{ - unsigned int i; - unsigned long sum = 0; - - if (!map) - return (0); - for (i = 0; i < numchars; i++) - sum += nibblemap[map->b_data[i] & 0xf] + - nibblemap[(map->b_data[i] >> 4) & 0xf]; - return (sum); -} - -#endif /* EXT2FS_DEBUG */ - -unsigned long ext2_count_free_blocks (struct super_block * sb) -{ - struct ext2_group_desc * desc; - unsigned long desc_count = 0; - int i; -#ifdef EXT2FS_DEBUG - unsigned long bitmap_count, x; - struct ext2_super_block *es; - - es = EXT2_SB(sb)->s_es; - desc_count = 0; - bitmap_count = 0; - desc = NULL; - for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) { - struct buffer_head *bitmap_bh; - desc = ext2_get_group_desc (sb, i, NULL); - if (!desc) - continue; - desc_count += le16_to_cpu(desc->bg_free_blocks_count); - bitmap_bh = read_block_bitmap(sb, i); - if (!bitmap_bh) - continue; - - x = ext2_count_free(bitmap_bh, sb->s_blocksize); - printk ("group %d: stored = %d, counted = %lu\n", - i, le16_to_cpu(desc->bg_free_blocks_count), x); - bitmap_count += x; - brelse(bitmap_bh); - } - printk("ext2_count_free_blocks: stored = %lu, computed = %lu, %lu\n", - (long)le32_to_cpu(es->s_free_blocks_count), - desc_count, bitmap_count); - return bitmap_count; -#else - for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) { - desc = ext2_get_group_desc (sb, i, NULL); - if (!desc) - continue; - desc_count += le16_to_cpu(desc->bg_free_blocks_count); - } - return desc_count; -#endif -} - -static inline int test_root(int a, int b) -{ - int num = b; - - while (a > num) - num *= b; - return num == a; -} - -static int ext2_group_sparse(int group) -{ - if (group <= 1) - return 1; - return (test_root(group, 3) || test_root(group, 5) || - test_root(group, 7)); -} - -/** - * ext2_bg_has_super - number of blocks used by the superblock in group - * @sb: superblock for filesystem - * @group: group number to check - * - * Return the number of blocks used by the superblock (primary or backup) - * in this group. Currently this will be only 0 or 1. - */ -int ext2_bg_has_super(struct super_block *sb, int group) -{ - if (EXT2_HAS_RO_COMPAT_FEATURE(sb,EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)&& - !ext2_group_sparse(group)) - return 0; - return 1; -} - -/** - * ext2_bg_num_gdb - number of blocks used by the group table in group - * @sb: superblock for filesystem - * @group: group number to check - * - * Return the number of blocks used by the group descriptor table - * (primary or backup) in this group. In the future there may be a - * different number of descriptor blocks in each group. - */ -unsigned long ext2_bg_num_gdb(struct super_block *sb, int group) -{ - return ext2_bg_has_super(sb, group) ? EXT2_SB(sb)->s_gdb_count : 0; -} - |