* [PATCH] xfs: restore shutdown check in mapped write fault path
@ 2021-02-10 17:01 Brian Foster
2021-02-10 18:31 ` Eric Sandeen
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Brian Foster @ 2021-02-10 17:01 UTC (permalink / raw)
To: linux-xfs
XFS triggers an iomap warning in the write fault path due to a
!PageUptodate() page if a write fault happens to occur on a page
that recently failed writeback. The iomap writeback error handling
code can clear the Uptodate flag if no portion of the page is
submitted for I/O. This is reproduced by fstest generic/019, which
combines various forms of I/O with simulated disk failures that
inevitably lead to filesystem shutdown (which then unconditionally
fails page writeback).
This is a regression introduced by commit f150b4234397 ("xfs: split
the iomap ops for buffered vs direct writes") due to the removal of
a shutdown check and explicit error return in the ->iomap_begin()
path used by the write fault path. The explicit error return
historically translated to a SIGBUS, but now carries on with iomap
processing where it complains about the unexpected state. Restore
the shutdown check to xfs_buffered_write_iomap_begin() to restore
historical behavior.
Fixes: f150b4234397 ("xfs: split the iomap ops for buffered vs direct writes")
Signed-off-by: Brian Foster <bfoster@redhat.com>
---
fs/xfs/xfs_iomap.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 70c341658c01..6594f572096e 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -860,6 +860,9 @@ xfs_buffered_write_iomap_begin(
int allocfork = XFS_DATA_FORK;
int error = 0;
+ if (XFS_FORCED_SHUTDOWN(mp))
+ return -EIO;
+
/* we can't use delayed allocations when using extent size hints */
if (xfs_get_extsz_hint(ip))
return xfs_direct_write_iomap_begin(inode, offset, count,
--
2.26.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] xfs: restore shutdown check in mapped write fault path
2021-02-10 17:01 [PATCH] xfs: restore shutdown check in mapped write fault path Brian Foster
@ 2021-02-10 18:31 ` Eric Sandeen
2021-02-11 1:27 ` Darrick J. Wong
2021-02-11 7:01 ` Gao Xiang
2 siblings, 0 replies; 4+ messages in thread
From: Eric Sandeen @ 2021-02-10 18:31 UTC (permalink / raw)
To: Brian Foster, linux-xfs
On 2/10/21 11:01 AM, Brian Foster wrote:
> XFS triggers an iomap warning in the write fault path due to a
> !PageUptodate() page if a write fault happens to occur on a page
> that recently failed writeback. The iomap writeback error handling
> code can clear the Uptodate flag if no portion of the page is
> submitted for I/O. This is reproduced by fstest generic/019, which
> combines various forms of I/O with simulated disk failures that
> inevitably lead to filesystem shutdown (which then unconditionally
> fails page writeback).
>
> This is a regression introduced by commit f150b4234397 ("xfs: split
> the iomap ops for buffered vs direct writes") due to the removal of
> a shutdown check and explicit error return in the ->iomap_begin()
> path used by the write fault path. The explicit error return
> historically translated to a SIGBUS, but now carries on with iomap
> processing where it complains about the unexpected state. Restore
> the shutdown check to xfs_buffered_write_iomap_begin() to restore
> historical behavior.
>
> Fixes: f150b4234397 ("xfs: split the iomap ops for buffered vs direct writes")
> Signed-off-by: Brian Foster <bfoster@redhat.com>
Looks good to me
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
> ---
> fs/xfs/xfs_iomap.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index 70c341658c01..6594f572096e 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -860,6 +860,9 @@ xfs_buffered_write_iomap_begin(
> int allocfork = XFS_DATA_FORK;
> int error = 0;
>
> + if (XFS_FORCED_SHUTDOWN(mp))
> + return -EIO;
> +
> /* we can't use delayed allocations when using extent size hints */
> if (xfs_get_extsz_hint(ip))
> return xfs_direct_write_iomap_begin(inode, offset, count,
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] xfs: restore shutdown check in mapped write fault path
2021-02-10 17:01 [PATCH] xfs: restore shutdown check in mapped write fault path Brian Foster
2021-02-10 18:31 ` Eric Sandeen
@ 2021-02-11 1:27 ` Darrick J. Wong
2021-02-11 7:01 ` Gao Xiang
2 siblings, 0 replies; 4+ messages in thread
From: Darrick J. Wong @ 2021-02-11 1:27 UTC (permalink / raw)
To: Brian Foster; +Cc: linux-xfs
On Wed, Feb 10, 2021 at 12:01:12PM -0500, Brian Foster wrote:
> XFS triggers an iomap warning in the write fault path due to a
> !PageUptodate() page if a write fault happens to occur on a page
> that recently failed writeback. The iomap writeback error handling
> code can clear the Uptodate flag if no portion of the page is
> submitted for I/O. This is reproduced by fstest generic/019, which
> combines various forms of I/O with simulated disk failures that
> inevitably lead to filesystem shutdown (which then unconditionally
> fails page writeback).
>
> This is a regression introduced by commit f150b4234397 ("xfs: split
> the iomap ops for buffered vs direct writes") due to the removal of
> a shutdown check and explicit error return in the ->iomap_begin()
> path used by the write fault path. The explicit error return
> historically translated to a SIGBUS, but now carries on with iomap
> processing where it complains about the unexpected state. Restore
> the shutdown check to xfs_buffered_write_iomap_begin() to restore
> historical behavior.
>
> Fixes: f150b4234397 ("xfs: split the iomap ops for buffered vs direct writes")
> Signed-off-by: Brian Foster <bfoster@redhat.com>
Looks fine,
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
--D
> ---
> fs/xfs/xfs_iomap.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index 70c341658c01..6594f572096e 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -860,6 +860,9 @@ xfs_buffered_write_iomap_begin(
> int allocfork = XFS_DATA_FORK;
> int error = 0;
>
> + if (XFS_FORCED_SHUTDOWN(mp))
> + return -EIO;
> +
> /* we can't use delayed allocations when using extent size hints */
> if (xfs_get_extsz_hint(ip))
> return xfs_direct_write_iomap_begin(inode, offset, count,
> --
> 2.26.2
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] xfs: restore shutdown check in mapped write fault path
2021-02-10 17:01 [PATCH] xfs: restore shutdown check in mapped write fault path Brian Foster
2021-02-10 18:31 ` Eric Sandeen
2021-02-11 1:27 ` Darrick J. Wong
@ 2021-02-11 7:01 ` Gao Xiang
2 siblings, 0 replies; 4+ messages in thread
From: Gao Xiang @ 2021-02-11 7:01 UTC (permalink / raw)
To: Brian Foster; +Cc: linux-xfs
On Wed, Feb 10, 2021 at 12:01:12PM -0500, Brian Foster wrote:
> XFS triggers an iomap warning in the write fault path due to a
> !PageUptodate() page if a write fault happens to occur on a page
> that recently failed writeback. The iomap writeback error handling
> code can clear the Uptodate flag if no portion of the page is
> submitted for I/O. This is reproduced by fstest generic/019, which
> combines various forms of I/O with simulated disk failures that
> inevitably lead to filesystem shutdown (which then unconditionally
> fails page writeback).
>
> This is a regression introduced by commit f150b4234397 ("xfs: split
> the iomap ops for buffered vs direct writes") due to the removal of
> a shutdown check and explicit error return in the ->iomap_begin()
> path used by the write fault path. The explicit error return
> historically translated to a SIGBUS, but now carries on with iomap
> processing where it complains about the unexpected state. Restore
> the shutdown check to xfs_buffered_write_iomap_begin() to restore
> historical behavior.
>
> Fixes: f150b4234397 ("xfs: split the iomap ops for buffered vs direct writes")
> Signed-off-by: Brian Foster <bfoster@redhat.com>
Taking some time on the internal discussion thread, I also think
SIGBUS is also appropriate after fs shutdown rather than dirty
this page anyway.
Reviewed-by: Gao Xiang <hsiangkao@redhat.com>
Thanks,
Gao Xiang
^ permalink raw reply [flat|nested] 4+ messages in thread
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2021-02-10 17:01 [PATCH] xfs: restore shutdown check in mapped write fault path Brian Foster
2021-02-10 18:31 ` Eric Sandeen
2021-02-11 1:27 ` Darrick J. Wong
2021-02-11 7:01 ` Gao Xiang
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