diff mbox series

[1/4] xfs: match lock mode in xfs_buffered_write_iomap_begin()

Message ID 20240311122255.2637311-2-yi.zhang@huaweicloud.com (mailing list archive)
State New
Headers show
Series xfs/iomap: fix non-atomic clone operation and don't update size when zeroing range post eof | expand

Commit Message

Zhang Yi March 11, 2024, 12:22 p.m. UTC 
From: Zhang Yi <yi.zhang@huawei.com>

Commit 1aa91d9c9933 ("xfs: Add async buffered write support") replace
xfs_ilock(XFS_ILOCK_EXCL) with xfs_ilock_for_iomap() when locking the
writing inode, and a new variable lockmode is used to indicate the lock
mode. Although the lockmode should always be XFS_ILOCK_EXCL, it's still
better to use this variable instead of useing XFS_ILOCK_EXCL directly
when unlocking the inode.

Fixes: 1aa91d9c9933 ("xfs: Add async buffered write support")
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
---
 fs/xfs/xfs_iomap.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

Comments

Darrick J. Wong March 11, 2024, 3:34 p.m. UTC | #1 
On Mon, Mar 11, 2024 at 08:22:52PM +0800, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@huawei.com>
> 
> Commit 1aa91d9c9933 ("xfs: Add async buffered write support") replace
> xfs_ilock(XFS_ILOCK_EXCL) with xfs_ilock_for_iomap() when locking the
> writing inode, and a new variable lockmode is used to indicate the lock
> mode. Although the lockmode should always be XFS_ILOCK_EXCL, it's still
> better to use this variable instead of useing XFS_ILOCK_EXCL directly
> when unlocking the inode.
> 
> Fixes: 1aa91d9c9933 ("xfs: Add async buffered write support")

AFAICT, xfs_ilock_for_iomap can change lockmode from SHARED->EXCL, but
never changed away from EXCL, right?  And xfs_buffered_write_iomap_begin
sets it to EXCL (and never changes it), right?

This seems like more of a code cleanup/logic bomb removal than an actual
defect that someone could actually hit, correct?

If the answers are {yes, yes, yes} then:
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D


> Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
> ---
>  fs/xfs/xfs_iomap.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index 18c8f168b153..ccf83e72d8ca 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -1149,13 +1149,13 @@ xfs_buffered_write_iomap_begin(
>  	 * them out if the write happens to fail.
>  	 */
>  	seq = xfs_iomap_inode_sequence(ip, IOMAP_F_NEW);
> -	xfs_iunlock(ip, XFS_ILOCK_EXCL);
> +	xfs_iunlock(ip, lockmode);
>  	trace_xfs_iomap_alloc(ip, offset, count, allocfork, &imap);
>  	return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, IOMAP_F_NEW, seq);
>  
>  found_imap:
>  	seq = xfs_iomap_inode_sequence(ip, 0);
> -	xfs_iunlock(ip, XFS_ILOCK_EXCL);
> +	xfs_iunlock(ip, lockmode);
>  	return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0, seq);
>  
>  found_cow:
> @@ -1165,17 +1165,17 @@ xfs_buffered_write_iomap_begin(
>  		if (error)
>  			goto out_unlock;
>  		seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
> -		xfs_iunlock(ip, XFS_ILOCK_EXCL);
> +		xfs_iunlock(ip, lockmode);
>  		return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags,
>  					 IOMAP_F_SHARED, seq);
>  	}
>  
>  	xfs_trim_extent(&cmap, offset_fsb, imap.br_startoff - offset_fsb);
> -	xfs_iunlock(ip, XFS_ILOCK_EXCL);
> +	xfs_iunlock(ip, lockmode);
>  	return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, 0, seq);
>  
>  out_unlock:
> -	xfs_iunlock(ip, XFS_ILOCK_EXCL);
> +	xfs_iunlock(ip, lockmode);
>  	return error;
>  }
>  
> -- 
> 2.39.2
> 
>
Zhang Yi March 12, 2024, 8:18 a.m. UTC | #2 
On 2024/3/11 23:34, Darrick J. Wong wrote:
> On Mon, Mar 11, 2024 at 08:22:52PM +0800, Zhang Yi wrote:
>> From: Zhang Yi <yi.zhang@huawei.com>
>>
>> Commit 1aa91d9c9933 ("xfs: Add async buffered write support") replace
>> xfs_ilock(XFS_ILOCK_EXCL) with xfs_ilock_for_iomap() when locking the
>> writing inode, and a new variable lockmode is used to indicate the lock
>> mode. Although the lockmode should always be XFS_ILOCK_EXCL, it's still
>> better to use this variable instead of useing XFS_ILOCK_EXCL directly
>> when unlocking the inode.
>>
>> Fixes: 1aa91d9c9933 ("xfs: Add async buffered write support")
> 
> AFAICT, xfs_ilock_for_iomap can change lockmode from SHARED->EXCL, but
> never changed away from EXCL, right?  

Yes.

> And xfs_buffered_write_iomap_begin
> sets it to EXCL (and never changes it), right?

Yes.

> 
> This seems like more of a code cleanup/logic bomb removal than an actual
> defect that someone could actually hit, correct?
> 

Yes, it's not a real problem.

> If the answers are {yes, yes, yes} then:
> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
> 
> --D
> 
> 
>> Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
>> ---
>>  fs/xfs/xfs_iomap.c | 10 +++++-----
>>  1 file changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
>> index 18c8f168b153..ccf83e72d8ca 100644
>> --- a/fs/xfs/xfs_iomap.c
>> +++ b/fs/xfs/xfs_iomap.c
>> @@ -1149,13 +1149,13 @@ xfs_buffered_write_iomap_begin(
>>  	 * them out if the write happens to fail.
>>  	 */
>>  	seq = xfs_iomap_inode_sequence(ip, IOMAP_F_NEW);
>> -	xfs_iunlock(ip, XFS_ILOCK_EXCL);
>> +	xfs_iunlock(ip, lockmode);
>>  	trace_xfs_iomap_alloc(ip, offset, count, allocfork, &imap);
>>  	return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, IOMAP_F_NEW, seq);
>>  
>>  found_imap:
>>  	seq = xfs_iomap_inode_sequence(ip, 0);
>> -	xfs_iunlock(ip, XFS_ILOCK_EXCL);
>> +	xfs_iunlock(ip, lockmode);
>>  	return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0, seq);
>>  
>>  found_cow:
>> @@ -1165,17 +1165,17 @@ xfs_buffered_write_iomap_begin(
>>  		if (error)
>>  			goto out_unlock;
>>  		seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
>> -		xfs_iunlock(ip, XFS_ILOCK_EXCL);
>> +		xfs_iunlock(ip, lockmode);
>>  		return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags,
>>  					 IOMAP_F_SHARED, seq);
>>  	}
>>  
>>  	xfs_trim_extent(&cmap, offset_fsb, imap.br_startoff - offset_fsb);
>> -	xfs_iunlock(ip, XFS_ILOCK_EXCL);
>> +	xfs_iunlock(ip, lockmode);
>>  	return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, 0, seq);
>>  
>>  out_unlock:
>> -	xfs_iunlock(ip, XFS_ILOCK_EXCL);
>> +	xfs_iunlock(ip, lockmode);
>>  	return error;
>>  }
>>  
>> -- 
>> 2.39.2
>>
>>
Christoph Hellwig March 12, 2024, 12:16 p.m. UTC | #3 
Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>
diff mbox series

Patch

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 18c8f168b153..ccf83e72d8ca 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -1149,13 +1149,13 @@  xfs_buffered_write_iomap_begin(
 	 * them out if the write happens to fail.
 	 */
 	seq = xfs_iomap_inode_sequence(ip, IOMAP_F_NEW);
-	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	xfs_iunlock(ip, lockmode);
 	trace_xfs_iomap_alloc(ip, offset, count, allocfork, &imap);
 	return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, IOMAP_F_NEW, seq);
 
 found_imap:
 	seq = xfs_iomap_inode_sequence(ip, 0);
-	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	xfs_iunlock(ip, lockmode);
 	return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0, seq);
 
 found_cow:
@@ -1165,17 +1165,17 @@  xfs_buffered_write_iomap_begin(
 		if (error)
 			goto out_unlock;
 		seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
-		xfs_iunlock(ip, XFS_ILOCK_EXCL);
+		xfs_iunlock(ip, lockmode);
 		return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags,
 					 IOMAP_F_SHARED, seq);
 	}
 
 	xfs_trim_extent(&cmap, offset_fsb, imap.br_startoff - offset_fsb);
-	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	xfs_iunlock(ip, lockmode);
 	return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, 0, seq);
 
 out_unlock:
-	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	xfs_iunlock(ip, lockmode);
 	return error;
 }