diff options
Diffstat (limited to 'fs/ext4/balloc.c')
| -rw-r--r-- | fs/ext4/balloc.c | 910 |
1 files changed, 910 insertions, 0 deletions
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c new file mode 100644 index 000000000..f9645de9d --- /dev/null +++ b/fs/ext4/balloc.c @@ -0,0 +1,910 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/fs/ext4/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 <linux/time.h> +#include <linux/capability.h> +#include <linux/fs.h> +#include <linux/quotaops.h> +#include <linux/buffer_head.h> +#include "ext4.h" +#include "ext4_jbd2.h" +#include "mballoc.h" + +#include <trace/events/ext4.h> + +static unsigned ext4_num_base_meta_clusters(struct super_block *sb, + ext4_group_t block_group); +/* + * balloc.c contains the blocks allocation and deallocation routines + */ + +/* + * Calculate block group number for a given block number + */ +ext4_group_t ext4_get_group_number(struct super_block *sb, + ext4_fsblk_t block) +{ + ext4_group_t group; + + if (test_opt2(sb, STD_GROUP_SIZE)) + group = (block - + le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) >> + (EXT4_BLOCK_SIZE_BITS(sb) + EXT4_CLUSTER_BITS(sb) + 3); + else + ext4_get_group_no_and_offset(sb, block, &group, NULL); + return group; +} + +/* + * 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) +{ + struct ext4_super_block *es = EXT4_SB(sb)->s_es; + ext4_grpblk_t offset; + + blocknr = blocknr - le32_to_cpu(es->s_first_data_block); + offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >> + EXT4_SB(sb)->s_cluster_bits; + if (offsetp) + *offsetp = offset; + if (blockgrpp) + *blockgrpp = blocknr; + +} + +/* + * Check whether the 'block' lives within the 'block_group'. Returns 1 if so + * and 0 otherwise. + */ +static inline int ext4_block_in_group(struct super_block *sb, + ext4_fsblk_t block, + ext4_group_t block_group) +{ + ext4_group_t actual_group; + + actual_group = ext4_get_group_number(sb, block); + return (actual_group == block_group) ? 1 : 0; +} + +/* Return the number of clusters used for file system metadata; this + * represents the overhead needed by the file system. + */ +static unsigned ext4_num_overhead_clusters(struct super_block *sb, + ext4_group_t block_group, + struct ext4_group_desc *gdp) +{ + 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); + + /* 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, + ext4_block_bitmap(sb, gdp) - start); + if (block_cluster < num_clusters) + block_cluster = -1; + else if (block_cluster == num_clusters) { + num_clusters++; + block_cluster = -1; + } + } + + if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) { + inode_cluster = EXT4_B2C(sbi, + ext4_inode_bitmap(sb, gdp) - start); + if (inode_cluster < num_clusters) + inode_cluster = -1; + else if (inode_cluster == num_clusters) { + num_clusters++; + inode_cluster = -1; + } + } + + 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, itbl_blk + i - start); + 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; + } + } + + 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 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. + */ + 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); +} + +/* Initializes an uninitialized block bitmap */ +static int 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; + + 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(sb, block_group, gdp)) { + ext4_mark_group_bitmap_corrupted(sb, block_group, + EXT4_GROUP_INFO_BBITMAP_CORRUPT | + EXT4_GROUP_INFO_IBITMAP_CORRUPT); + return -EFSBADCRC; + } + memset(bh->b_data, 0, sb->s_blocksize); + + bit_max = ext4_num_base_meta_clusters(sb, block_group); + if ((bit_max >> 3) >= bh->b_size) + return -EFSCORRUPTED; + + for (bit = 0; bit < bit_max; bit++) + ext4_set_bit(bit, bh->b_data); + + start = ext4_group_first_block_no(sb, block_group); + + /* Set bits for block and inode bitmaps, and inode table */ + tmp = ext4_block_bitmap(sb, gdp); + if (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); + if (ext4_block_in_group(sb, tmp, block_group)) + ext4_set_bit(EXT4_B2C(sbi, 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 (ext4_block_in_group(sb, tmp, block_group)) + ext4_set_bit(EXT4_B2C(sbi, 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(num_clusters_in_group(sb, block_group), + sb->s_blocksize * 8, bh->b_data); + return 0; +} + +/* 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 + * 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 ext4_fill_super). + */ + +/** + * ext4_get_group_desc() -- load group descriptor from disk + * @sb: super block + * @block_group: given block group + * @bh: pointer to the buffer head to store the block + * group descriptor + */ +struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb, + ext4_group_t block_group, + struct buffer_head **bh) +{ + unsigned int group_desc; + unsigned int offset; + ext4_group_t ngroups = ext4_get_groups_count(sb); + struct ext4_group_desc *desc; + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct buffer_head *bh_p; + + if (block_group >= ngroups) { + ext4_error(sb, "block_group >= groups_count - block_group = %u," + " groups_count = %u", block_group, ngroups); + + return NULL; + } + + group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); + offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); + bh_p = sbi_array_rcu_deref(sbi, s_group_desc, group_desc); + /* + * sbi_array_rcu_deref returns with rcu unlocked, this is ok since + * the pointer being dereferenced won't be dereferenced again. By + * looking at the usage in add_new_gdb() the value isn't modified, + * just the pointer, and so it remains valid. + */ + if (!bh_p) { + ext4_error(sb, "Group descriptor not loaded - " + "block_group = %u, group_desc = %u, desc = %u", + block_group, group_desc, offset); + return NULL; + } + + desc = (struct ext4_group_desc *)( + (__u8 *)bh_p->b_data + + offset * EXT4_DESC_SIZE(sb)); + if (bh) + *bh = bh_p; + return desc; +} + +/* + * Return the block number which was discovered to be invalid, or 0 if + * the block bitmap is valid. + */ +static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb, + struct ext4_group_desc *desc, + ext4_group_t block_group, + struct buffer_head *bh) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + ext4_grpblk_t offset; + ext4_grpblk_t next_zero_bit; + ext4_grpblk_t max_bit = EXT4_CLUSTERS_PER_GROUP(sb); + ext4_fsblk_t blk; + ext4_fsblk_t group_first_block; + + if (ext4_has_feature_flex_bg(sb)) { + /* with FLEX_BG, the inode/block bitmaps and itable + * blocks may not be in the group at all + * so the bitmap validation will be skipped for those groups + * or it has to also read the block group where the bitmaps + * are located to verify they are set. + */ + return 0; + } + group_first_block = ext4_group_first_block_no(sb, block_group); + + /* check whether block bitmap block number is set */ + blk = ext4_block_bitmap(sb, desc); + offset = blk - group_first_block; + if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || + !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) + /* bad block bitmap */ + return blk; + + /* check whether the inode bitmap block number is set */ + blk = ext4_inode_bitmap(sb, desc); + offset = blk - group_first_block; + if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || + !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) + /* bad block bitmap */ + return blk; + + /* check whether the inode table block number is set */ + blk = ext4_inode_table(sb, desc); + offset = blk - group_first_block; + if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || + EXT4_B2C(sbi, offset + sbi->s_itb_per_group) >= max_bit) + return blk; + next_zero_bit = ext4_find_next_zero_bit(bh->b_data, + EXT4_B2C(sbi, offset + sbi->s_itb_per_group), + EXT4_B2C(sbi, offset)); + if (next_zero_bit < + EXT4_B2C(sbi, offset + sbi->s_itb_per_group)) + /* bad bitmap for inode tables */ + return blk; + return 0; +} + +static int ext4_validate_block_bitmap(struct super_block *sb, + struct ext4_group_desc *desc, + ext4_group_t block_group, + struct buffer_head *bh) +{ + ext4_fsblk_t blk; + struct ext4_group_info *grp = ext4_get_group_info(sb, block_group); + + if (buffer_verified(bh)) + return 0; + if (EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) + return -EFSCORRUPTED; + + ext4_lock_group(sb, block_group); + if (buffer_verified(bh)) + goto verified; + if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group, + desc, bh))) { + ext4_unlock_group(sb, block_group); + ext4_error(sb, "bg %u: bad block bitmap checksum", block_group); + ext4_mark_group_bitmap_corrupted(sb, block_group, + EXT4_GROUP_INFO_BBITMAP_CORRUPT); + return -EFSBADCRC; + } + blk = ext4_valid_block_bitmap(sb, desc, block_group, bh); + if (unlikely(blk != 0)) { + ext4_unlock_group(sb, block_group); + ext4_error(sb, "bg %u: block %llu: invalid block bitmap", + block_group, blk); + ext4_mark_group_bitmap_corrupted(sb, block_group, + EXT4_GROUP_INFO_BBITMAP_CORRUPT); + return -EFSCORRUPTED; + } + set_buffer_verified(bh); +verified: + ext4_unlock_group(sb, block_group); + return 0; +} + +/** + * ext4_read_block_bitmap_nowait() + * @sb: super block + * @block_group: given block group + * + * 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. + */ +struct buffer_head * +ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group) +{ + struct ext4_group_desc *desc; + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct buffer_head *bh; + ext4_fsblk_t bitmap_blk; + int err; + + desc = ext4_get_group_desc(sb, block_group, NULL); + if (!desc) + return ERR_PTR(-EFSCORRUPTED); + bitmap_blk = ext4_block_bitmap(sb, desc); + if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) || + (bitmap_blk >= ext4_blocks_count(sbi->s_es))) { + ext4_error(sb, "Invalid block bitmap block %llu in " + "block_group %u", bitmap_blk, block_group); + ext4_mark_group_bitmap_corrupted(sb, block_group, + EXT4_GROUP_INFO_BBITMAP_CORRUPT); + return ERR_PTR(-EFSCORRUPTED); + } + bh = sb_getblk(sb, bitmap_blk); + if (unlikely(!bh)) { + ext4_warning(sb, "Cannot get buffer for block bitmap - " + "block_group = %u, block_bitmap = %llu", + block_group, bitmap_blk); + return ERR_PTR(-ENOMEM); + } + + if (bitmap_uptodate(bh)) + goto verify; + + lock_buffer(bh); + if (bitmap_uptodate(bh)) { + unlock_buffer(bh); + goto verify; + } + ext4_lock_group(sb, block_group); + if (ext4_has_group_desc_csum(sb) && + (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) { + if (block_group == 0) { + ext4_unlock_group(sb, block_group); + unlock_buffer(bh); + ext4_error(sb, "Block bitmap for bg 0 marked " + "uninitialized"); + err = -EFSCORRUPTED; + goto out; + } + err = ext4_init_block_bitmap(sb, bh, block_group, desc); + set_bitmap_uptodate(bh); + set_buffer_uptodate(bh); + set_buffer_verified(bh); + ext4_unlock_group(sb, block_group); + unlock_buffer(bh); + if (err) { + ext4_error(sb, "Failed to init block bitmap for group " + "%u: %d", block_group, err); + goto out; + } + goto verify; + } + ext4_unlock_group(sb, block_group); + if (buffer_uptodate(bh)) { + /* + * if not uninit if bh is uptodate, + * bitmap is also uptodate + */ + set_bitmap_uptodate(bh); + unlock_buffer(bh); + goto verify; + } + /* + * submit the buffer_head for reading + */ + set_buffer_new(bh); + trace_ext4_read_block_bitmap_load(sb, block_group); + bh->b_end_io = ext4_end_bitmap_read; + get_bh(bh); + submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh); + return bh; +verify: + err = ext4_validate_block_bitmap(sb, desc, block_group, bh); + if (err) + goto out; + return bh; +out: + put_bh(bh); + return ERR_PTR(err); +} + +/* Returns 0 on success, 1 on error */ +int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group, + struct buffer_head *bh) +{ + struct ext4_group_desc *desc; + + if (!buffer_new(bh)) + return 0; + desc = ext4_get_group_desc(sb, block_group, NULL); + if (!desc) + return -EFSCORRUPTED; + wait_on_buffer(bh); + if (!buffer_uptodate(bh)) { + ext4_error(sb, "Cannot read block bitmap - " + "block_group = %u, block_bitmap = %llu", + block_group, (unsigned long long) bh->b_blocknr); + ext4_mark_group_bitmap_corrupted(sb, block_group, + EXT4_GROUP_INFO_BBITMAP_CORRUPT); + return -EIO; + } + clear_buffer_new(bh); + /* Panic or remount fs read-only if block bitmap is invalid */ + return ext4_validate_block_bitmap(sb, desc, block_group, bh); +} + +struct buffer_head * +ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) +{ + struct buffer_head *bh; + int err; + + bh = ext4_read_block_bitmap_nowait(sb, block_group); + if (IS_ERR(bh)) + return bh; + err = ext4_wait_block_bitmap(sb, block_group, bh); + if (err) { + put_bh(bh); + return ERR_PTR(err); + } + return bh; +} + +/** + * ext4_has_free_clusters() + * @sbi: in-core super block structure. + * @nclusters: number of needed blocks + * @flags: flags from ext4_mb_new_blocks() + * + * Check if filesystem has nclusters free & available for allocation. + * On success return 1, return 0 on failure. + */ +static int ext4_has_free_clusters(struct ext4_sb_info *sbi, + s64 nclusters, unsigned int flags) +{ + s64 free_clusters, dirty_clusters, rsv, resv_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); + resv_clusters = atomic64_read(&sbi->s_resv_clusters); + + /* + * r_blocks_count should always be multiple of the cluster ratio so + * we are safe to do a plane bit shift only. + */ + rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) + + resv_clusters; + + if (free_clusters - (nclusters + rsv + dirty_clusters) < + EXT4_FREECLUSTERS_WATERMARK) { + free_clusters = percpu_counter_sum_positive(fcc); + dirty_clusters = percpu_counter_sum_positive(dcc); + } + /* Check whether we have space after accounting for current + * dirty clusters & root reserved clusters. + */ + if (free_clusters >= (rsv + nclusters + dirty_clusters)) + return 1; + + /* Hm, nope. Are (enough) root reserved clusters available? */ + if (uid_eq(sbi->s_resuid, current_fsuid()) || + (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) || + capable(CAP_SYS_RESOURCE) || + (flags & EXT4_MB_USE_ROOT_BLOCKS)) { + + if (free_clusters >= (nclusters + dirty_clusters + + resv_clusters)) + return 1; + } + /* No free blocks. Let's see if we can dip into reserved pool */ + if (flags & EXT4_MB_USE_RESERVED) { + if (free_clusters >= (nclusters + dirty_clusters)) + return 1; + } + + return 0; +} + +int ext4_claim_free_clusters(struct ext4_sb_info *sbi, + s64 nclusters, unsigned int flags) +{ + if (ext4_has_free_clusters(sbi, nclusters, flags)) { + percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters); + return 0; + } else + return -ENOSPC; +} + +/** + * ext4_should_retry_alloc() + * @sb: super block + * @retries number of attemps has been made + * + * ext4_should_retry_alloc() is called when ENOSPC is returned, and if + * it is profitable to retry the operation, this function will wait + * for the current or committing transaction to complete, and then + * return TRUE. We will only retry once. + */ +int ext4_should_retry_alloc(struct super_block *sb, int *retries) +{ + if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) || + (*retries)++ > 1 || + !EXT4_SB(sb)->s_journal) + return 0; + + smp_mb(); + if (EXT4_SB(sb)->s_mb_free_pending == 0) + return 0; + + jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id); + jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal); + return 1; +} + +/* + * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks + * + * @handle: handle to this transaction + * @inode: file inode + * @goal: given target block(filesystem wide) + * @count: pointer to total number of clusters needed + * @errp: error code + * + * Return 1st allocated block number on success, *count stores total account + * error stores in errp pointer + */ +ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode, + ext4_fsblk_t goal, unsigned int flags, + unsigned long *count, int *errp) +{ + struct ext4_allocation_request ar; + ext4_fsblk_t ret; + + memset(&ar, 0, sizeof(ar)); + /* Fill with neighbour allocated blocks */ + ar.inode = inode; + ar.goal = goal; + ar.len = count ? *count : 1; + ar.flags = flags; + + ret = ext4_mb_new_blocks(handle, &ar, errp); + if (count) + *count = ar.len; + /* + * Account for the allocated meta blocks. We will never + * fail EDQUOT for metdata, but we do account for it. + */ + if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) { + dquot_alloc_block_nofail(inode, + EXT4_C2B(EXT4_SB(inode->i_sb), ar.len)); + } + return ret; +} + +/** + * ext4_count_free_clusters() -- count filesystem free clusters + * @sb: superblock + * + * Adds up the number of free clusters from each block group. + */ +ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb) +{ + ext4_fsblk_t desc_count; + struct ext4_group_desc *gdp; + ext4_group_t i; + ext4_group_t ngroups = ext4_get_groups_count(sb); + struct ext4_group_info *grp; +#ifdef EXT4FS_DEBUG + struct ext4_super_block *es; + ext4_fsblk_t bitmap_count; + unsigned int x; + struct buffer_head *bitmap_bh = NULL; + + es = EXT4_SB(sb)->s_es; + desc_count = 0; + bitmap_count = 0; + gdp = NULL; + + for (i = 0; i < ngroups; i++) { + gdp = ext4_get_group_desc(sb, i, NULL); + if (!gdp) + continue; + grp = NULL; + if (EXT4_SB(sb)->s_group_info) + grp = ext4_get_group_info(sb, i); + if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) + desc_count += ext4_free_group_clusters(sb, gdp); + brelse(bitmap_bh); + bitmap_bh = ext4_read_block_bitmap(sb, i); + if (IS_ERR(bitmap_bh)) { + bitmap_bh = NULL; + continue; + } + + x = ext4_count_free(bitmap_bh->b_data, + EXT4_CLUSTERS_PER_GROUP(sb) / 8); + printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n", + i, ext4_free_group_clusters(sb, gdp), x); + bitmap_count += x; + } + brelse(bitmap_bh); + printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu" + ", computed = %llu, %llu\n", + EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)), + desc_count, bitmap_count); + return bitmap_count; +#else + desc_count = 0; + for (i = 0; i < ngroups; i++) { + gdp = ext4_get_group_desc(sb, i, NULL); + if (!gdp) + continue; + grp = NULL; + if (EXT4_SB(sb)->s_group_info) + grp = ext4_get_group_info(sb, i); + if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) + desc_count += ext4_free_group_clusters(sb, gdp); + } + + return desc_count; +#endif +} + +static inline int test_root(ext4_group_t a, int b) +{ + while (1) { + if (a < b) + return 0; + if (a == b) + return 1; + if ((a % b) != 0) + return 0; + a = a / b; + } +} + +/** + * ext4_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 ext4_bg_has_super(struct super_block *sb, ext4_group_t group) +{ + struct ext4_super_block *es = EXT4_SB(sb)->s_es; + + if (group == 0) + return 1; + if (ext4_has_feature_sparse_super2(sb)) { + if (group == le32_to_cpu(es->s_backup_bgs[0]) || + group == le32_to_cpu(es->s_backup_bgs[1])) + return 1; + return 0; + } + if ((group <= 1) || !ext4_has_feature_sparse_super(sb)) + return 1; + if (!(group & 1)) + return 0; + if (test_root(group, 3) || (test_root(group, 5)) || + test_root(group, 7)) + return 1; + + return 0; +} + +static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, + ext4_group_t group) +{ + unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); + ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb); + ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1; + + if (group == first || group == first + 1 || group == last) + return 1; + return 0; +} + +static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, + ext4_group_t group) +{ + if (!ext4_bg_has_super(sb, group)) + return 0; + + if (ext4_has_feature_meta_bg(sb)) + return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); + else + return EXT4_SB(sb)->s_gdb_count; +} + +/** + * ext4_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 ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) +{ + unsigned long first_meta_bg = + le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); + unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); + + if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) + return ext4_bg_num_gdb_nometa(sb, group); + + return ext4_bg_num_gdb_meta(sb,group); + +} + +/* + * This function returns the number of file system metadata clusters at + * the beginning of a block group, including the reserved gdt blocks. + */ +static 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_feature_meta_bg(sb) || + 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 + * + * Return the ideal location to start allocating blocks for a + * newly created inode. + */ +ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode) +{ + struct ext4_inode_info *ei = EXT4_I(inode); + ext4_group_t block_group; + ext4_grpblk_t colour; + int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb)); + ext4_fsblk_t bg_start; + ext4_fsblk_t last_block; + + block_group = ei->i_block_group; + if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { + /* + * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME + * block groups per flexgroup, reserve the first block + * group for directories and special files. Regular + * files will start at the second block group. This + * tends to speed up directory access and improves + * fsck times. + */ + block_group &= ~(flex_size-1); + if (S_ISREG(inode->i_mode)) + block_group++; + } + bg_start = ext4_group_first_block_no(inode->i_sb, block_group); + last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; + + /* + * If we are doing delayed allocation, we don't need take + * colour into account. + */ + if (test_opt(inode->i_sb, DELALLOC)) + return bg_start; + + if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) + colour = (current->pid % 16) * + (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); + else + colour = (current->pid % 16) * ((last_block - bg_start) / 16); + return bg_start + colour; +} + |