On Fri, Jul 19, 2013 at 04:55:59PM -0700, Darrick J. Wong wrote:
> If we detect either a discrepancy between the inode bitmap and the inode counts
> or the inode bitmap fails to pass validation checks, mark the block group
> corrupt and refuse to allocate or deallocate inodes from the group.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> fs/ext4/ext4.h | 3 +++
> fs/ext4/ialloc.c | 29 +++++++++++++++++++++++++----
> 2 files changed, 28 insertions(+), 4 deletions(-)
>
>
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 45cc955..b8ac53d 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -2449,11 +2449,14 @@ struct ext4_group_info {
> #define EXT4_GROUP_INFO_NEED_INIT_BIT 0
> #define EXT4_GROUP_INFO_WAS_TRIMMED_BIT 1
> #define EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT 2
> +#define EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT 4
>
> #define EXT4_MB_GRP_NEED_INIT(grp) \
> (test_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &((grp)->bb_state)))
> #define EXT4_MB_GRP_BBITMAP_CORRUPT(grp) \
> (test_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &((grp)->bb_state)))
> +#define EXT4_MB_GRP_IBITMAP_CORRUPT(grp) \
> + (test_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &((grp)->bb_state)))
>
> #define EXT4_MB_GRP_WAS_TRIMMED(grp) \
> (test_bit(EXT4_GROUP_INFO_WAS_TRIMMED_BIT, &((grp)->bb_state)))
> diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
> index f03598c..08c7fa7 100644
> --- a/fs/ext4/ialloc.c
> +++ b/fs/ext4/ialloc.c
> @@ -117,6 +117,7 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
> struct ext4_group_desc *desc;
> struct buffer_head *bh = NULL;
> ext4_fsblk_t bitmap_blk;
> + struct ext4_group_info *grp;
>
> desc = ext4_get_group_desc(sb, block_group, NULL);
> if (!desc)
> @@ -185,6 +186,8 @@ verify:
> put_bh(bh);
> ext4_error(sb, "Corrupt inode bitmap - block_group = %u, "
> "inode_bitmap = %llu", block_group, bitmap_blk);
> + grp = ext4_get_group_info(sb, block_group);
> + set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
> return NULL;
> }
> ext4_unlock_group(sb, block_group);
> @@ -221,6 +224,7 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
> struct ext4_super_block *es;
> struct ext4_sb_info *sbi;
> int fatal = 0, err, count, cleared;
> + struct ext4_group_info *grp;
>
> if (!sb) {
> printk(KERN_ERR "EXT4-fs: %s:%d: inode on "
> @@ -266,7 +270,9 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
> block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
> bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
> bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
> - if (!bitmap_bh)
> + /* Don't bother if the inode bitmap is corrupt. */
> + grp = ext4_get_group_info(sb, block_group);
> + if (unlikely(EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) || !bitmap_bh)
> goto error_return;
It seems that this is a duplicated check. If we encounters a currupted
inode bitmap, ext4_read_inode_bitmap() will return null.
>
> BUFFER_TRACE(bitmap_bh, "get_write_access");
> @@ -315,8 +321,10 @@ out:
> err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
> if (!fatal)
> fatal = err;
> - } else
> + } else {
> ext4_error(sb, "bit already cleared for inode %lu", ino);
> + set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
> + }
>
> error_return:
> brelse(bitmap_bh);
> @@ -652,6 +660,7 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
> struct inode *ret;
> ext4_group_t i;
> ext4_group_t flex_group;
> + struct ext4_group_info *grp;
>
> /* Cannot create files in a deleted directory */
> if (!dir || !dir->i_nlink)
> @@ -725,10 +734,22 @@ got_group:
> continue;
> }
>
> + grp = ext4_get_group_info(sb, group);
> + /* Skip groups with already-known suspicious inode tables */
> + if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
> + if (++group == ngroups)
> + group = 0;
> + continue;
> + }
> +
> brelse(inode_bitmap_bh);
> inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
> - if (!inode_bitmap_bh)
> - goto out;
> + /* Skip groups with suspicious inode tables */
> + if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp) || !inode_bitmap_bh) {
> + if (++group == ngroups)
> + group = 0;
> + continue;
> + }
The same as above.
- Zheng
>
> repeat_in_this_group:
> ino = ext4_find_next_zero_bit((unsigned long *)
>
> --
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