diff options
Diffstat (limited to 'fs/ext4/balloc.c')
| -rw-r--r-- | fs/ext4/balloc.c | 345 |
1 files changed, 207 insertions, 138 deletions
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c index f8224ad..f6dba45 100644 --- a/fs/ext4/balloc.c +++ b/fs/ext4/balloc.c @@ -28,7 +28,8 @@ */ /* - * Calculate the block group number and offset, given a block number + * Calculate the block group number and offset into the block/cluster + * allocation bitmap, given a block number */ void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr, ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp) @@ -37,7 +38,8 @@ void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr, ext4_grpblk_t offset; blocknr = blocknr - le32_to_cpu(es->s_first_data_block); - offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)); + offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >> + EXT4_SB(sb)->s_cluster_bits; if (offsetp) *offsetp = offset; if (blockgrpp) @@ -55,130 +57,169 @@ static int ext4_block_in_group(struct super_block *sb, ext4_fsblk_t block, return 0; } -static int ext4_group_used_meta_blocks(struct super_block *sb, - ext4_group_t block_group, - struct ext4_group_desc *gdp) +/* Return the number of clusters used for file system metadata; this + * represents the overhead needed by the file system. + */ +unsigned ext4_num_overhead_clusters(struct super_block *sb, + ext4_group_t block_group, + struct ext4_group_desc *gdp) { - ext4_fsblk_t tmp; + unsigned num_clusters; + int block_cluster = -1, inode_cluster = -1, itbl_cluster = -1, i, c; + ext4_fsblk_t start = ext4_group_first_block_no(sb, block_group); + ext4_fsblk_t itbl_blk; struct ext4_sb_info *sbi = EXT4_SB(sb); - /* block bitmap, inode bitmap, and inode table blocks */ - int used_blocks = sbi->s_itb_per_group + 2; - if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) { - if (!ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), - block_group)) - used_blocks--; - - if (!ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), - block_group)) - used_blocks--; - - tmp = ext4_inode_table(sb, gdp); - for (; tmp < ext4_inode_table(sb, gdp) + - sbi->s_itb_per_group; tmp++) { - if (!ext4_block_in_group(sb, tmp, block_group)) - used_blocks -= 1; + /* This is the number of clusters used by the superblock, + * block group descriptors, and reserved block group + * descriptor blocks */ + num_clusters = ext4_num_base_meta_clusters(sb, block_group); + + /* + * For the allocation bitmaps and inode table, we first need + * to check to see if the block is in the block group. If it + * is, then check to see if the cluster is already accounted + * for in the clusters used for the base metadata cluster, or + * if we can increment the base metadata cluster to include + * that block. Otherwise, we will have to track the cluster + * used for the allocation bitmap or inode table explicitly. + * Normally all of these blocks are contiguous, so the special + * case handling shouldn't be necessary except for *very* + * unusual file system layouts. + */ + if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) { + block_cluster = EXT4_B2C(sbi, (start - + ext4_block_bitmap(sb, gdp))); + if (block_cluster < num_clusters) + block_cluster = -1; + else if (block_cluster == num_clusters) { + num_clusters++; + block_cluster = -1; } } - return used_blocks; -} -/* Initializes an uninitialized block bitmap if given, and returns the - * number of blocks free in the group. */ -unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh, - ext4_group_t block_group, struct ext4_group_desc *gdp) -{ - int bit, bit_max; - ext4_group_t ngroups = ext4_get_groups_count(sb); - unsigned free_blocks, group_blocks; - struct ext4_sb_info *sbi = EXT4_SB(sb); - - if (bh) { - J_ASSERT_BH(bh, buffer_locked(bh)); - - /* If checksum is bad mark all blocks used to prevent allocation - * essentially implementing a per-group read-only flag. */ - if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) { - ext4_error(sb, "Checksum bad for group %u", - block_group); - ext4_free_blks_set(sb, gdp, 0); - ext4_free_inodes_set(sb, gdp, 0); - ext4_itable_unused_set(sb, gdp, 0); - memset(bh->b_data, 0xff, sb->s_blocksize); - return 0; + if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) { + inode_cluster = EXT4_B2C(sbi, + start - ext4_inode_bitmap(sb, gdp)); + if (inode_cluster < num_clusters) + inode_cluster = -1; + else if (inode_cluster == num_clusters) { + num_clusters++; + inode_cluster = -1; } - memset(bh->b_data, 0, sb->s_blocksize); } - /* Check for superblock and gdt backups in this group */ - bit_max = ext4_bg_has_super(sb, block_group); - - if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) || - block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * - sbi->s_desc_per_block) { - if (bit_max) { - bit_max += ext4_bg_num_gdb(sb, block_group); - bit_max += - le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); + itbl_blk = ext4_inode_table(sb, gdp); + for (i = 0; i < sbi->s_itb_per_group; i++) { + if (ext4_block_in_group(sb, itbl_blk + i, block_group)) { + c = EXT4_B2C(sbi, start - itbl_blk + i); + if ((c < num_clusters) || (c == inode_cluster) || + (c == block_cluster) || (c == itbl_cluster)) + continue; + if (c == num_clusters) { + num_clusters++; + continue; + } + num_clusters++; + itbl_cluster = c; } - } else { /* For META_BG_BLOCK_GROUPS */ - bit_max += ext4_bg_num_gdb(sb, block_group); } - if (block_group == ngroups - 1) { + if (block_cluster != -1) + num_clusters++; + if (inode_cluster != -1) + num_clusters++; + + return num_clusters; +} + +static unsigned int num_clusters_in_group(struct super_block *sb, + ext4_group_t block_group) +{ + unsigned int blocks; + + if (block_group == ext4_get_groups_count(sb) - 1) { /* - * Even though mke2fs always initialize first and last group - * if some other tool enabled the EXT4_BG_BLOCK_UNINIT we need - * to make sure we calculate the right free blocks + * Even though mke2fs always initializes the first and + * last group, just in case some other tool was used, + * we need to make sure we calculate the right free + * blocks. */ - group_blocks = ext4_blocks_count(sbi->s_es) - - ext4_group_first_block_no(sb, ngroups - 1); - } else { - group_blocks = EXT4_BLOCKS_PER_GROUP(sb); - } + blocks = ext4_blocks_count(EXT4_SB(sb)->s_es) - + ext4_group_first_block_no(sb, block_group); + } else + blocks = EXT4_BLOCKS_PER_GROUP(sb); + return EXT4_NUM_B2C(EXT4_SB(sb), blocks); +} - free_blocks = group_blocks - bit_max; +/* Initializes an uninitialized block bitmap */ +void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh, + ext4_group_t block_group, + struct ext4_group_desc *gdp) +{ + unsigned int bit, bit_max; + struct ext4_sb_info *sbi = EXT4_SB(sb); + ext4_fsblk_t start, tmp; + int flex_bg = 0; + + J_ASSERT_BH(bh, buffer_locked(bh)); + + /* If checksum is bad mark all blocks used to prevent allocation + * essentially implementing a per-group read-only flag. */ + if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) { + ext4_error(sb, "Checksum bad for group %u", block_group); + ext4_free_group_clusters_set(sb, gdp, 0); + ext4_free_inodes_set(sb, gdp, 0); + ext4_itable_unused_set(sb, gdp, 0); + memset(bh->b_data, 0xff, sb->s_blocksize); + return; + } + memset(bh->b_data, 0, sb->s_blocksize); - if (bh) { - ext4_fsblk_t start, tmp; - int flex_bg = 0; + bit_max = ext4_num_base_meta_clusters(sb, block_group); + for (bit = 0; bit < bit_max; bit++) + ext4_set_bit(bit, bh->b_data); - for (bit = 0; bit < bit_max; bit++) - ext4_set_bit(bit, bh->b_data); + start = ext4_group_first_block_no(sb, block_group); - start = ext4_group_first_block_no(sb, block_group); + if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) + flex_bg = 1; - if (EXT4_HAS_INCOMPAT_FEATURE(sb, - EXT4_FEATURE_INCOMPAT_FLEX_BG)) - flex_bg = 1; + /* Set bits for block and inode bitmaps, and inode table */ + tmp = ext4_block_bitmap(sb, gdp); + if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) + ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); - /* Set bits for block and inode bitmaps, and inode table */ - tmp = ext4_block_bitmap(sb, gdp); - if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) - ext4_set_bit(tmp - start, bh->b_data); + tmp = ext4_inode_bitmap(sb, gdp); + if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) + ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); - tmp = ext4_inode_bitmap(sb, gdp); + tmp = ext4_inode_table(sb, gdp); + for (; tmp < ext4_inode_table(sb, gdp) + + sbi->s_itb_per_group; tmp++) { if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) - ext4_set_bit(tmp - start, bh->b_data); - - tmp = ext4_inode_table(sb, gdp); - for (; tmp < ext4_inode_table(sb, gdp) + - sbi->s_itb_per_group; tmp++) { - if (!flex_bg || - ext4_block_in_group(sb, tmp, block_group)) - ext4_set_bit(tmp - start, bh->b_data); - } - /* - * Also if the number of blocks within the group is - * less than the blocksize * 8 ( which is the size - * of bitmap ), set rest of the block bitmap to 1 - */ - ext4_mark_bitmap_end(group_blocks, sb->s_blocksize * 8, - bh->b_data); + ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); } - return free_blocks - ext4_group_used_meta_blocks(sb, block_group, gdp); + + /* + * Also if the number of blocks within the group is less than + * the blocksize * 8 ( which is the size of bitmap ), set rest + * of the block bitmap to 1 + */ + ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group), + sb->s_blocksize * 8, bh->b_data); } +/* Return the number of free blocks in a block group. It is used when + * the block bitmap is uninitialized, so we can't just count the bits + * in the bitmap. */ +unsigned ext4_free_clusters_after_init(struct super_block *sb, + ext4_group_t block_group, + struct ext4_group_desc *gdp) +{ + return num_clusters_in_group(sb, block_group) - + ext4_num_overhead_clusters(sb, block_group, gdp); +} /* * The free blocks are managed by bitmaps. A file system contains several @@ -362,53 +403,54 @@ ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) } /** - * ext4_has_free_blocks() + * ext4_has_free_clusters() * @sbi: in-core super block structure. - * @nblocks: number of needed blocks + * @nclusters: number of needed blocks + * @flags: flags from ext4_mb_new_blocks() * - * Check if filesystem has nblocks free & available for allocation. + * Check if filesystem has nclusters free & available for allocation. * On success return 1, return 0 on failure. */ -static int ext4_has_free_blocks(struct ext4_sb_info *sbi, - s64 nblocks, unsigned int flags) +static int ext4_has_free_clusters(struct ext4_sb_info *sbi, + s64 nclusters, unsigned int flags) { - s64 free_blocks, dirty_blocks, root_blocks; - struct percpu_counter *fbc = &sbi->s_freeblocks_counter; - struct percpu_counter *dbc = &sbi->s_dirtyblocks_counter; - - free_blocks = percpu_counter_read_positive(fbc); - dirty_blocks = percpu_counter_read_positive(dbc); - root_blocks = ext4_r_blocks_count(sbi->s_es); - - if (free_blocks - (nblocks + root_blocks + dirty_blocks) < - EXT4_FREEBLOCKS_WATERMARK) { - free_blocks = percpu_counter_sum_positive(fbc); - dirty_blocks = percpu_counter_sum_positive(dbc); + s64 free_clusters, dirty_clusters, root_clusters; + struct percpu_counter *fcc = &sbi->s_freeclusters_counter; + struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter; + + free_clusters = percpu_counter_read_positive(fcc); + dirty_clusters = percpu_counter_read_positive(dcc); + root_clusters = EXT4_B2C(sbi, ext4_r_blocks_count(sbi->s_es)); + + if (free_clusters - (nclusters + root_clusters + dirty_clusters) < + EXT4_FREECLUSTERS_WATERMARK) { + free_clusters = EXT4_C2B(sbi, percpu_counter_sum_positive(fcc)); + dirty_clusters = percpu_counter_sum_positive(dcc); } - /* Check whether we have space after - * accounting for current dirty blocks & root reserved blocks. + /* Check whether we have space after accounting for current + * dirty clusters & root reserved clusters. */ - if (free_blocks >= ((root_blocks + nblocks) + dirty_blocks)) + if (free_clusters >= ((root_clusters + nclusters) + dirty_clusters)) return 1; - /* Hm, nope. Are (enough) root reserved blocks available? */ + /* Hm, nope. Are (enough) root reserved clusters available? */ if (sbi->s_resuid == current_fsuid() || ((sbi->s_resgid != 0) && in_group_p(sbi->s_resgid)) || capable(CAP_SYS_RESOURCE) || (flags & EXT4_MB_USE_ROOT_BLOCKS)) { - if (free_blocks >= (nblocks + dirty_blocks)) + if (free_clusters >= (nclusters + dirty_clusters)) return 1; } return 0; } -int ext4_claim_free_blocks(struct ext4_sb_info *sbi, - s64 nblocks, unsigned int flags) +int ext4_claim_free_clusters(struct ext4_sb_info *sbi, + s64 nclusters, unsigned int flags) { - if (ext4_has_free_blocks(sbi, nblocks, flags)) { - percpu_counter_add(&sbi->s_dirtyblocks_counter, nblocks); + if (ext4_has_free_clusters(sbi, nclusters, flags)) { + percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters); return 0; } else return -ENOSPC; @@ -428,7 +470,7 @@ int ext4_claim_free_blocks(struct ext4_sb_info *sbi, */ int ext4_should_retry_alloc(struct super_block *sb, int *retries) { - if (!ext4_has_free_blocks(EXT4_SB(sb), 1, 0) || + if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) || (*retries)++ > 3 || !EXT4_SB(sb)->s_journal) return 0; @@ -444,7 +486,7 @@ int ext4_should_retry_alloc(struct super_block *sb, int *retries) * @handle: handle to this transaction * @inode: file inode * @goal: given target block(filesystem wide) - * @count: pointer to total number of blocks needed + * @count: pointer to total number of clusters needed * @errp: error code * * Return 1st allocated block number on success, *count stores total account @@ -476,18 +518,19 @@ ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode, spin_lock(&EXT4_I(inode)->i_block_reservation_lock); EXT4_I(inode)->i_allocated_meta_blocks += ar.len; spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); - dquot_alloc_block_nofail(inode, ar.len); + dquot_alloc_block_nofail(inode, + EXT4_C2B(EXT4_SB(inode->i_sb), ar.len)); } return ret; } /** - * ext4_count_free_blocks() -- count filesystem free blocks + * ext4_count_free_clusters() -- count filesystem free clusters * @sb: superblock * - * Adds up the number of free blocks from each block group. + * Adds up the number of free clusters from each block group. */ -ext4_fsblk_t ext4_count_free_blocks(struct super_block *sb) +ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb) { ext4_fsblk_t desc_count; struct ext4_group_desc *gdp; @@ -508,7 +551,7 @@ ext4_fsblk_t ext4_count_free_blocks(struct super_block *sb) gdp = ext4_get_group_desc(sb, i, NULL); if (!gdp) continue; - desc_count += ext4_free_blks_count(sb, gdp); + desc_count += ext4_free_group_clusters(sb, gdp); brelse(bitmap_bh); bitmap_bh = ext4_read_block_bitmap(sb, i); if (bitmap_bh == NULL) @@ -516,12 +559,13 @@ ext4_fsblk_t ext4_count_free_blocks(struct super_block *sb) x = ext4_count_free(bitmap_bh, sb->s_blocksize); printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n", - i, ext4_free_blks_count(sb, gdp), x); + i, ext4_free_group_clusters(sb, gdp), x); bitmap_count += x; } brelse(bitmap_bh); - printk(KERN_DEBUG "ext4_count_free_blocks: stored = %llu" - ", computed = %llu, %llu\n", ext4_free_blocks_count(es), + printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu" + ", computed = %llu, %llu\n", + EXT4_B2C(sbi, ext4_free_blocks_count(es)), desc_count, bitmap_count); return bitmap_count; #else @@ -530,7 +574,7 @@ ext4_fsblk_t ext4_count_free_blocks(struct super_block *sb) gdp = ext4_get_group_desc(sb, i, NULL); if (!gdp) continue; - desc_count += ext4_free_blks_count(sb, gdp); + desc_count += ext4_free_group_clusters(sb, gdp); } return desc_count; @@ -620,6 +664,31 @@ unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) } +/* + * This function returns the number of file system metadata clusters at + * the beginning of a block group, including the reserved gdt blocks. + */ +unsigned ext4_num_base_meta_clusters(struct super_block *sb, + ext4_group_t block_group) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + unsigned num; + + /* Check for superblock and gdt backups in this group */ + num = ext4_bg_has_super(sb, block_group); + + if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) || + block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * + sbi->s_desc_per_block) { + if (num) { + num += ext4_bg_num_gdb(sb, block_group); + num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); + } + } else { /* For META_BG_BLOCK_GROUPS */ + num += ext4_bg_num_gdb(sb, block_group); + } + return EXT4_NUM_B2C(sbi, num); +} /** * ext4_inode_to_goal_block - return a hint for block allocation * @inode: inode for block allocation |
