* [PATCH 1/2] xfs: Initialize xfs_alloc_arg->total correctly when allocating minlen extents
@ 2021-03-25 14:03 Chandan Babu R
2021-03-25 14:03 ` [PATCH 2/2] xfs: Fix dax inode extent calculation when direct write is performed on an unwritten extent Chandan Babu R
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Chandan Babu R @ 2021-03-25 14:03 UTC (permalink / raw)
To: linux-xfs; +Cc: Chandan Babu R, djwong
xfs/538 can cause the following call trace to be printed when executing on a
multi-block directory configuration,
WARNING: CPU: 1 PID: 2578 at fs/xfs/libxfs/xfs_bmap.c:717 xfs_bmap_extents_to_btree+0x520/0x5d0
Call Trace:
? xfs_buf_rele+0x4f/0x450
xfs_bmap_add_extent_hole_real+0x747/0x960
xfs_bmapi_allocate+0x39a/0x440
xfs_bmapi_write+0x507/0x9e0
xfs_da_grow_inode_int+0x1cd/0x330
? up+0x12/0x60
xfs_dir2_grow_inode+0x62/0x110
? xfs_trans_log_inode+0x234/0x2d0
xfs_dir2_sf_to_block+0x103/0x940
? xfs_dir2_sf_check+0x8c/0x210
? xfs_da_compname+0x19/0x30
? xfs_dir2_sf_lookup+0xd0/0x3d0
xfs_dir2_sf_addname+0x10d/0x910
xfs_dir_createname+0x1ad/0x210
xfs_create+0x404/0x620
xfs_generic_create+0x24c/0x320
path_openat+0xda6/0x1030
do_filp_open+0x88/0x130
? kmem_cache_alloc+0x50/0x210
? __cond_resched+0x16/0x40
? kmem_cache_alloc+0x50/0x210
do_sys_openat2+0x97/0x150
__x64_sys_creat+0x49/0x70
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xae
This occurs because xfs_bmap_exact_minlen_extent_alloc() initializes
xfs_alloc_arg->total to xfs_bmalloca->minlen. In the context of
xfs_bmap_exact_minlen_extent_alloc(), xfs_bmalloca->minlen has a value of 1
and hence the space allocator could choose an AG which has less than
xfs_bmalloca->total number of free blocks available. As the transaction
proceeds, one of the future space allocation requests could fail due to
non-availability of free blocks in the AG that was originally chosen.
This commit fixes the bug by assigning xfs_alloc_arg->total to the value of
xfs_bmalloca->total.
Fixes: 301519674699 ("xfs: Introduce error injection to allocate only minlen size extents for files")
Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
---
fs/xfs/libxfs/xfs_bmap.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index e0905ad171f0..585f7e795023 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -3586,7 +3586,8 @@ xfs_bmap_exact_minlen_extent_alloc(
args.fsbno = ap->blkno;
args.oinfo = XFS_RMAP_OINFO_SKIP_UPDATE;
args.type = XFS_ALLOCTYPE_FIRST_AG;
- args.total = args.minlen = args.maxlen = ap->minlen;
+ args.minlen = args.maxlen = ap->minlen;
+ args.total = ap->total;
args.alignment = 1;
args.minalignslop = 0;
--
2.29.2
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 2/2] xfs: Fix dax inode extent calculation when direct write is performed on an unwritten extent
2021-03-25 14:03 [PATCH 1/2] xfs: Initialize xfs_alloc_arg->total correctly when allocating minlen extents Chandan Babu R
@ 2021-03-25 14:03 ` Chandan Babu R
2021-03-25 18:53 ` Darrick J. Wong
2021-04-02 6:45 ` Christoph Hellwig
2021-03-25 18:54 ` [PATCH 1/2] xfs: Initialize xfs_alloc_arg->total correctly when allocating minlen extents Darrick J. Wong
2021-04-02 6:44 ` Christoph Hellwig
2 siblings, 2 replies; 6+ messages in thread
From: Chandan Babu R @ 2021-03-25 14:03 UTC (permalink / raw)
To: linux-xfs; +Cc: Chandan Babu R, djwong
With dax enabled filesystems, a direct write operation into an existing
unwritten extent results in xfs_iomap_write_direct() zero-ing and converting
the extent into a normal extent before the actual data is copied from the
userspace buffer.
The inode extent count can increase by 2 if the extent range being written to
maps to the middle of the existing unwritten extent range. Hence this commit
uses XFS_IEXT_WRITE_UNWRITTEN_CNT as the extent count delta when such a write
operation is being performed.
Fixes: 727e1acd297c ("xfs: Check for extent overflow when trivally adding a new extent")
Reported-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
---
fs/xfs/xfs_iomap.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index e17ab7f42928..8b27c10a3d08 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -198,6 +198,7 @@ xfs_iomap_write_direct(
bool force = false;
int error;
int bmapi_flags = XFS_BMAPI_PREALLOC;
+ int nr_exts = XFS_IEXT_ADD_NOSPLIT_CNT;
ASSERT(count_fsb > 0);
@@ -232,6 +233,7 @@ xfs_iomap_write_direct(
bmapi_flags = XFS_BMAPI_CONVERT | XFS_BMAPI_ZERO;
if (imap->br_state == XFS_EXT_UNWRITTEN) {
force = true;
+ nr_exts = XFS_IEXT_WRITE_UNWRITTEN_CNT;
dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
}
}
@@ -241,8 +243,7 @@ xfs_iomap_write_direct(
if (error)
return error;
- error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
- XFS_IEXT_ADD_NOSPLIT_CNT);
+ error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK, nr_exts);
if (error)
goto out_trans_cancel;
--
2.29.2
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH 2/2] xfs: Fix dax inode extent calculation when direct write is performed on an unwritten extent
2021-03-25 14:03 ` [PATCH 2/2] xfs: Fix dax inode extent calculation when direct write is performed on an unwritten extent Chandan Babu R
@ 2021-03-25 18:53 ` Darrick J. Wong
2021-04-02 6:45 ` Christoph Hellwig
1 sibling, 0 replies; 6+ messages in thread
From: Darrick J. Wong @ 2021-03-25 18:53 UTC (permalink / raw)
To: Chandan Babu R; +Cc: linux-xfs
On Thu, Mar 25, 2021 at 07:33:39PM +0530, Chandan Babu R wrote:
> With dax enabled filesystems, a direct write operation into an existing
> unwritten extent results in xfs_iomap_write_direct() zero-ing and converting
> the extent into a normal extent before the actual data is copied from the
> userspace buffer.
>
> The inode extent count can increase by 2 if the extent range being written to
> maps to the middle of the existing unwritten extent range. Hence this commit
> uses XFS_IEXT_WRITE_UNWRITTEN_CNT as the extent count delta when such a write
> operation is being performed.
>
> Fixes: 727e1acd297c ("xfs: Check for extent overflow when trivally adding a new extent")
> Reported-by: Darrick J. Wong <djwong@kernel.org>
> Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
Pretty much what I was expecting,
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
--D
> ---
> fs/xfs/xfs_iomap.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index e17ab7f42928..8b27c10a3d08 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -198,6 +198,7 @@ xfs_iomap_write_direct(
> bool force = false;
> int error;
> int bmapi_flags = XFS_BMAPI_PREALLOC;
> + int nr_exts = XFS_IEXT_ADD_NOSPLIT_CNT;
>
> ASSERT(count_fsb > 0);
>
> @@ -232,6 +233,7 @@ xfs_iomap_write_direct(
> bmapi_flags = XFS_BMAPI_CONVERT | XFS_BMAPI_ZERO;
> if (imap->br_state == XFS_EXT_UNWRITTEN) {
> force = true;
> + nr_exts = XFS_IEXT_WRITE_UNWRITTEN_CNT;
> dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
> }
> }
> @@ -241,8 +243,7 @@ xfs_iomap_write_direct(
> if (error)
> return error;
>
> - error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
> - XFS_IEXT_ADD_NOSPLIT_CNT);
> + error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK, nr_exts);
> if (error)
> goto out_trans_cancel;
>
> --
> 2.29.2
>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH 2/2] xfs: Fix dax inode extent calculation when direct write is performed on an unwritten extent
2021-03-25 14:03 ` [PATCH 2/2] xfs: Fix dax inode extent calculation when direct write is performed on an unwritten extent Chandan Babu R
2021-03-25 18:53 ` Darrick J. Wong
@ 2021-04-02 6:45 ` Christoph Hellwig
1 sibling, 0 replies; 6+ messages in thread
From: Christoph Hellwig @ 2021-04-02 6:45 UTC (permalink / raw)
To: Chandan Babu R; +Cc: linux-xfs, djwong
On Thu, Mar 25, 2021 at 07:33:39PM +0530, Chandan Babu R wrote:
> With dax enabled filesystems, a direct write operation into an existing
> unwritten extent results in xfs_iomap_write_direct() zero-ing and converting
> the extent into a normal extent before the actual data is copied from the
> userspace buffer.
>
> The inode extent count can increase by 2 if the extent range being written to
> maps to the middle of the existing unwritten extent range. Hence this commit
> uses XFS_IEXT_WRITE_UNWRITTEN_CNT as the extent count delta when such a write
> operation is being performed.
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] xfs: Initialize xfs_alloc_arg->total correctly when allocating minlen extents
2021-03-25 14:03 [PATCH 1/2] xfs: Initialize xfs_alloc_arg->total correctly when allocating minlen extents Chandan Babu R
2021-03-25 14:03 ` [PATCH 2/2] xfs: Fix dax inode extent calculation when direct write is performed on an unwritten extent Chandan Babu R
@ 2021-03-25 18:54 ` Darrick J. Wong
2021-04-02 6:44 ` Christoph Hellwig
2 siblings, 0 replies; 6+ messages in thread
From: Darrick J. Wong @ 2021-03-25 18:54 UTC (permalink / raw)
To: Chandan Babu R; +Cc: linux-xfs
On Thu, Mar 25, 2021 at 07:33:38PM +0530, Chandan Babu R wrote:
> xfs/538 can cause the following call trace to be printed when executing on a
> multi-block directory configuration,
>
> WARNING: CPU: 1 PID: 2578 at fs/xfs/libxfs/xfs_bmap.c:717 xfs_bmap_extents_to_btree+0x520/0x5d0
> Call Trace:
> ? xfs_buf_rele+0x4f/0x450
> xfs_bmap_add_extent_hole_real+0x747/0x960
> xfs_bmapi_allocate+0x39a/0x440
> xfs_bmapi_write+0x507/0x9e0
> xfs_da_grow_inode_int+0x1cd/0x330
> ? up+0x12/0x60
> xfs_dir2_grow_inode+0x62/0x110
> ? xfs_trans_log_inode+0x234/0x2d0
> xfs_dir2_sf_to_block+0x103/0x940
> ? xfs_dir2_sf_check+0x8c/0x210
> ? xfs_da_compname+0x19/0x30
> ? xfs_dir2_sf_lookup+0xd0/0x3d0
> xfs_dir2_sf_addname+0x10d/0x910
> xfs_dir_createname+0x1ad/0x210
> xfs_create+0x404/0x620
> xfs_generic_create+0x24c/0x320
> path_openat+0xda6/0x1030
> do_filp_open+0x88/0x130
> ? kmem_cache_alloc+0x50/0x210
> ? __cond_resched+0x16/0x40
> ? kmem_cache_alloc+0x50/0x210
> do_sys_openat2+0x97/0x150
> __x64_sys_creat+0x49/0x70
> do_syscall_64+0x33/0x40
> entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> This occurs because xfs_bmap_exact_minlen_extent_alloc() initializes
> xfs_alloc_arg->total to xfs_bmalloca->minlen. In the context of
> xfs_bmap_exact_minlen_extent_alloc(), xfs_bmalloca->minlen has a value of 1
> and hence the space allocator could choose an AG which has less than
> xfs_bmalloca->total number of free blocks available. As the transaction
> proceeds, one of the future space allocation requests could fail due to
> non-availability of free blocks in the AG that was originally chosen.
>
> This commit fixes the bug by assigning xfs_alloc_arg->total to the value of
> xfs_bmalloca->total.
>
> Fixes: 301519674699 ("xfs: Introduce error injection to allocate only minlen size extents for files")
> Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
Sounds resonable to me, I guess I'll give it a try...
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
--D
> ---
> fs/xfs/libxfs/xfs_bmap.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> index e0905ad171f0..585f7e795023 100644
> --- a/fs/xfs/libxfs/xfs_bmap.c
> +++ b/fs/xfs/libxfs/xfs_bmap.c
> @@ -3586,7 +3586,8 @@ xfs_bmap_exact_minlen_extent_alloc(
> args.fsbno = ap->blkno;
> args.oinfo = XFS_RMAP_OINFO_SKIP_UPDATE;
> args.type = XFS_ALLOCTYPE_FIRST_AG;
> - args.total = args.minlen = args.maxlen = ap->minlen;
> + args.minlen = args.maxlen = ap->minlen;
> + args.total = ap->total;
>
> args.alignment = 1;
> args.minalignslop = 0;
> --
> 2.29.2
>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH 1/2] xfs: Initialize xfs_alloc_arg->total correctly when allocating minlen extents
2021-03-25 14:03 [PATCH 1/2] xfs: Initialize xfs_alloc_arg->total correctly when allocating minlen extents Chandan Babu R
2021-03-25 14:03 ` [PATCH 2/2] xfs: Fix dax inode extent calculation when direct write is performed on an unwritten extent Chandan Babu R
2021-03-25 18:54 ` [PATCH 1/2] xfs: Initialize xfs_alloc_arg->total correctly when allocating minlen extents Darrick J. Wong
@ 2021-04-02 6:44 ` Christoph Hellwig
2 siblings, 0 replies; 6+ messages in thread
From: Christoph Hellwig @ 2021-04-02 6:44 UTC (permalink / raw)
To: Chandan Babu R; +Cc: linux-xfs, djwong
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-04-02 6:45 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2021-03-25 14:03 [PATCH 1/2] xfs: Initialize xfs_alloc_arg->total correctly when allocating minlen extents Chandan Babu R
2021-03-25 14:03 ` [PATCH 2/2] xfs: Fix dax inode extent calculation when direct write is performed on an unwritten extent Chandan Babu R
2021-03-25 18:53 ` Darrick J. Wong
2021-04-02 6:45 ` Christoph Hellwig
2021-03-25 18:54 ` [PATCH 1/2] xfs: Initialize xfs_alloc_arg->total correctly when allocating minlen extents Darrick J. Wong
2021-04-02 6:44 ` Christoph Hellwig
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