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ext4: decrement free clusters/inodes counters when block group declar…
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…ed bad

We should decrement free clusters counter when block bitmap is marked
as corrupt and free inodes counter when the allocation bitmap is
marked as corrupt to avoid misunderstanding due to incorrect available
size in statfs result.  User can get immediately ENOSPC error from
write begin without reaching for the writepages.

Cc: Darrick J. Wong<darrick.wong@oracle.com>
Reported-by: Amit Sahrawat <amit.sahrawat83@gmail.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Ashish Sangwan <a.sangwan@samsung.com>
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Namjae Jeon authored and Theodore Ts'o committed Jun 26, 2014
1 parent ec7756a commit e43bb4e
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Showing 3 changed files with 47 additions and 0 deletions.
16 changes: 16 additions & 0 deletions fs/ext4/balloc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -194,7 +194,16 @@ static void ext4_init_block_bitmap(struct super_block *sb,
if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {
ext4_error(sb, "Checksum bad for group %u", block_group);
grp = ext4_get_group_info(sb, block_group);
if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
percpu_counter_sub(&sbi->s_freeclusters_counter,
grp->bb_free);
set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
int count;
count = ext4_free_inodes_count(sb, gdp);
percpu_counter_sub(&sbi->s_freeinodes_counter,
count);
}
set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
return;
}
Expand Down Expand Up @@ -359,6 +368,7 @@ static void ext4_validate_block_bitmap(struct super_block *sb,
{
ext4_fsblk_t blk;
struct ext4_group_info *grp = ext4_get_group_info(sb, block_group);
struct ext4_sb_info *sbi = EXT4_SB(sb);

if (buffer_verified(bh))
return;
Expand All @@ -369,13 +379,19 @@ static void ext4_validate_block_bitmap(struct super_block *sb,
ext4_unlock_group(sb, block_group);
ext4_error(sb, "bg %u: block %llu: invalid block bitmap",
block_group, blk);
if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
percpu_counter_sub(&sbi->s_freeclusters_counter,
grp->bb_free);
set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
return;
}
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);
if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
percpu_counter_sub(&sbi->s_freeclusters_counter,
grp->bb_free);
set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
return;
}
Expand Down
23 changes: 23 additions & 0 deletions fs/ext4/ialloc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -71,14 +71,24 @@ static unsigned ext4_init_inode_bitmap(struct super_block *sb,
struct ext4_group_desc *gdp)
{
struct ext4_group_info *grp;
struct ext4_sb_info *sbi = EXT4_SB(sb);
J_ASSERT_BH(bh, buffer_locked(bh));

/* If checksum is bad mark all blocks and inodes use to prevent
* allocation, essentially implementing a per-group read-only flag. */
if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {
ext4_error(sb, "Checksum bad for group %u", block_group);
grp = ext4_get_group_info(sb, block_group);
if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
percpu_counter_sub(&sbi->s_freeclusters_counter,
grp->bb_free);
set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
int count;
count = ext4_free_inodes_count(sb, gdp);
percpu_counter_sub(&sbi->s_freeinodes_counter,
count);
}
set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
return 0;
}
Expand Down Expand Up @@ -116,6 +126,7 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
struct buffer_head *bh = NULL;
ext4_fsblk_t bitmap_blk;
struct ext4_group_info *grp;
struct ext4_sb_info *sbi = EXT4_SB(sb);

desc = ext4_get_group_desc(sb, block_group, NULL);
if (!desc)
Expand Down Expand Up @@ -185,6 +196,12 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
ext4_error(sb, "Corrupt inode bitmap - block_group = %u, "
"inode_bitmap = %llu", block_group, bitmap_blk);
grp = ext4_get_group_info(sb, block_group);
if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
int count;
count = ext4_free_inodes_count(sb, desc);
percpu_counter_sub(&sbi->s_freeinodes_counter,
count);
}
set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
return NULL;
}
Expand Down Expand Up @@ -321,6 +338,12 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
fatal = err;
} else {
ext4_error(sb, "bit already cleared for inode %lu", ino);
if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
int count;
count = ext4_free_inodes_count(sb, gdp);
percpu_counter_sub(&sbi->s_freeinodes_counter,
count);
}
set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
}

Expand Down
8 changes: 8 additions & 0 deletions fs/ext4/mballoc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -722,6 +722,7 @@ void ext4_mb_generate_buddy(struct super_block *sb,
void *buddy, void *bitmap, ext4_group_t group)
{
struct ext4_group_info *grp = ext4_get_group_info(sb, group);
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
ext4_grpblk_t i = 0;
ext4_grpblk_t first;
Expand Down Expand Up @@ -759,6 +760,9 @@ void ext4_mb_generate_buddy(struct super_block *sb,
* corrupt and update bb_free using bitmap value
*/
grp->bb_free = free;
if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
percpu_counter_sub(&sbi->s_freeclusters_counter,
grp->bb_free);
set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
}
mb_set_largest_free_order(sb, grp);
Expand Down Expand Up @@ -1431,6 +1435,7 @@ static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
right_is_free = !mb_test_bit(last + 1, e4b->bd_bitmap);

if (unlikely(block != -1)) {
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_fsblk_t blocknr;

blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
Expand All @@ -1441,6 +1446,9 @@ static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
"freeing already freed block "
"(bit %u); block bitmap corrupt.",
block);
if (!EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))
percpu_counter_sub(&sbi->s_freeclusters_counter,
e4b->bd_info->bb_free);
/* Mark the block group as corrupt. */
set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT,
&e4b->bd_info->bb_state);
Expand Down

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