Re: error in backport of 'btrfs: fix possible free space tree corruption with online conversion'

[Wang Yugui <wangyugui@e16-tech.com>]

Hi,

> On 2021-02-19 04:17, Wang Yugui wrote:
> > Hi, Josef Bacik
> >
> > We noticed an error in 5.10.x backport of 'btrfs: fix possible free
> > space tree corruption with online conversion'
> >
> > It is wrong in 5.10.13, but right in 5.11.
> >
> > 5.10.13
> > @@ -146,6 +146,9 @@ enum {
> >   	BTRFS_FS_STATE_DEV_REPLACING,
> >   	/* The btrfs_fs_info created for self-tests */
> >   	BTRFS_FS_STATE_DUMMY_FS_INFO,
> > +
> > +	/* Indicate that we can't trust the free space tree for caching yet */
> > +	BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED,
> >   };
> >
> > the usage sample of this enum:
> > set_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state);
> >
> >
> > 5.11
> > enum{
> > ..
> >      /* Indicate that the discard workqueue can service discards. */
> >      BTRFS_FS_DISCARD_RUNNING,
> >
> >      /* Indicate that we need to cleanup space cache v1 */
> >      BTRFS_FS_CLEANUP_SPACE_CACHE_V1,
> >
> >      /* Indicate that we can't trust the free space tree for caching yet */
> >      BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED,
> > };
> >
> > the usage sample of this enum:
> > set_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
> > 
> Out of curiosity I decided to check how this happened, but don't see it.
> Here is the commit that went into 5.10.13 and it looks correct to me:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-5.10.y&id=2175bf57dc9522c58d93dcd474758434a3f05c57

> The patch that went into 5.10 looks identical to the original commit in 5.11.
> What tree are you looking at?

the 5.10.y is the URL that you point out.
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-5.10.y&id=2175bf57dc9522c58d93dcd474758434a3f05c57

but the right one for 5.11 is
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/fs/btrfs?id=2f96e40212d435b328459ba6b3956395eed8fa9f

5.11:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/fs/btrfs?id=2f96e40212d435b328459ba6b3956395eed8fa9f

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 0225c5208f44c..47ca8edafb5e6 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -564,6 +564,9 @@ enum {
 
 	/* Indicate that we need to cleanup space cache v1 */
 	BTRFS_FS_CLEANUP_SPACE_CACHE_V1,
+
+	/* Indicate that we can't trust the free space tree for caching yet */
+	BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED,
 };
 
 /*

but 5.10.y:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-5.10.y&id=2175bf57dc9522c58d93dcd474758434a3f05c57

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index e01545538e07f..30ea9780725ff 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -146,6 +146,9 @@ enum {
 	BTRFS_FS_STATE_DEV_REPLACING,
 	/* The btrfs_fs_info created for self-tests */
 	BTRFS_FS_STATE_DUMMY_FS_INFO,
+
+	/* Indicate that we can't trust the free space tree for caching yet */
+	BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED,
 };
 
 #define BTRFS_BACKREF_REV_MAX		256

Both the line(Line:146 vs Line:564) and the content are wrong.

Best Regards
Wang Yugui (wangyugui@e16-tech.com)
2021/02/19