Patchwork [2/2] ext4: check free inode count before allocaing an inode

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Submitter Yongqiang Yang
Date Sept. 2, 2012, 9:45 a.m.
Message ID <1346579109-25016-2-git-send-email-xiaoqiangnk@gmail.com>
Download mbox | patch
Permalink /patch/181174/
State Superseded
Headers show

Comments

Yongqiang Yang - Sept. 2, 2012, 9:45 a.m.
Recnetly, I ecountered some corrupted filesystems in which some
groups' free inode counts were negative, it seemed that free inode
count was overflow.  This patch teaches ext4 to check free inode
count before allocaing an inode.

Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
---
 fs/ext4/ialloc.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)
Yongqiang Yang - Sept. 5, 2012, 2:17 a.m.
On Sun, Sep 2, 2012 at 5:45 PM, Yongqiang Yang <xiaoqiangnk@gmail.com> wrote:
> Recnetly, I ecountered some corrupted filesystems in which some
> groups' free inode counts were negative, it seemed that free inode
This comment is not exactly, it is not negative but 65535.  I will
resend the patch later.

Thanks,
Yongqiang.
> count was overflow.  This patch teaches ext4 to check free inode
> count before allocaing an inode.
>
> Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
> ---
>  fs/ext4/ialloc.c |    9 +++++++++
>  1 files changed, 9 insertions(+), 0 deletions(-)
>
> diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
> index 26154b8..fa36372 100644
> --- a/fs/ext4/ialloc.c
> +++ b/fs/ext4/ialloc.c
> @@ -697,6 +697,15 @@ got_group:
>                 if (!gdp)
>                         goto fail;
>
> +               /*
> +                * Check free inodes count before loading bitmap.
> +                */
> +               if (ext4_free_inodes_count(sb, gdp) == 0) {
> +                       if (++group == ngroups)
> +                               group = 0;
> +                       continue;
> +               }
> +
>                 brelse(inode_bitmap_bh);
>                 inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
>                 if (!inode_bitmap_bh)
> --
> 1.7.5.1
>

Patch

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 26154b8..fa36372 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -697,6 +697,15 @@  got_group:
 		if (!gdp)
 			goto fail;
 
+		/*
+		 * Check free inodes count before loading bitmap.
+		 */
+		if (ext4_free_inodes_count(sb, gdp) == 0) {
+			if (++group == ngroups)
+				group = 0;
+			continue;
+		}
+
 		brelse(inode_bitmap_bh);
 		inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
 		if (!inode_bitmap_bh)