Calling ext4_fc_mark_ineligible() with a NULL handle is racy and may result
in a fast-commit being done before the filesystem is effectively marked as
ineligible.  This patch moves the call to this function so that an handle
can be used.  If a transaction fails to start, then there's not point in
trying to mark the filesystem as ineligible, and an error will eventually be
returned to user-space.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Luis Henriques (SUSE) <luis.henriques@linux.dev>
---
 fs/ext4/xattr.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 46ce2f21fef9..aea9e3c405f1 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -2559,6 +2559,8 @@ ext4_xattr_set(struct inode *inode, int name_index, const char *name,
 
 		error = ext4_xattr_set_handle(handle, inode, name_index, name,
 					      value, value_len, flags);
+		ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR,
+					handle);
 		error2 = ext4_journal_stop(handle);
 		if (error == -ENOSPC &&
 		    ext4_should_retry_alloc(sb, &retries))
@@ -2566,7 +2568,6 @@ ext4_xattr_set(struct inode *inode, int name_index, const char *name,
 		if (error == 0)
 			error = error2;
 	}
-	ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, NULL);
 
 	return error;
 }

On Mon 23-09-24 11:49:09, Luis Henriques (SUSE) wrote:
> Calling ext4_fc_mark_ineligible() with a NULL handle is racy and may result
> in a fast-commit being done before the filesystem is effectively marked as
> ineligible.  This patch moves the call to this function so that an handle
> can be used.  If a transaction fails to start, then there's not point in
> trying to mark the filesystem as ineligible, and an error will eventually be
> returned to user-space.
> 
> Suggested-by: Jan Kara <jack@suse.cz>
> Signed-off-by: Luis Henriques (SUSE) <luis.henriques@linux.dev>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/ext4/xattr.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
> index 46ce2f21fef9..aea9e3c405f1 100644
> --- a/fs/ext4/xattr.c
> +++ b/fs/ext4/xattr.c
> @@ -2559,6 +2559,8 @@ ext4_xattr_set(struct inode *inode, int name_index, const char *name,
>  
>  		error = ext4_xattr_set_handle(handle, inode, name_index, name,
>  					      value, value_len, flags);
> +		ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR,
> +					handle);
>  		error2 = ext4_journal_stop(handle);
>  		if (error == -ENOSPC &&
>  		    ext4_should_retry_alloc(sb, &retries))
> @@ -2566,7 +2568,6 @@ ext4_xattr_set(struct inode *inode, int name_index, const char *name,
>  		if (error == 0)
>  			error = error2;
>  	}
> -	ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, NULL);
>  
>  	return error;
>  }
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR