Hi, guys.
Recently I hit a regression during test xfstest. Reverting this commit
could fix that error.
Reproduce steps (only nfs4.2 has this error):
```
# cat local.config
export TEST_DEV=127.0.0.1:/home/nfs/share0
export TEST_DIR=/mnt/test
export SCRATCH_DEV=127.0.0.1:/home/nfs/share1
export SCRATCH_MNT=/mnt/scratch
export FSX_AVOID="-E"
export NFS_MOUNT_OPTIONS="-o rw,relatime,vers=4.2"
# ./check -nfs generic/285
FSTYP -- nfs
PLATFORM -- Linux/aarch64 hpe-apollo80-01-n00
5.14.0-131.el9.aarch64 #1 SMP PREEMPT_DYNAMIC Mon Jul 18 16:13:44 EDT 2022
MKFS_OPTIONS -- 127.0.0.1:/home/nfs/share1
MOUNT_OPTIONS -- -o rw,relatime,vers=4.2 -o
context=system_u:object_r:root_t:s0 127.0.0.1:/home/nfs/share1 /mnt/scratch
generic/285 2s ... [failed, exit status 1]- output mismatch (see
/root/xfstests/results//generic/285.out.bad)
--- tests/generic/285.out 2022-07-27 21:07:43.160268552 -0400
+++ /root/xfstests/results//generic/285.out.bad 2022-07-27
21:31:27.887090532 -0400
@@ -1 +1,3 @@
QA output created by 285
+seek sanity check failed!
+(see /root/xfstests/results//generic/285.full for details)
...
(Run 'diff -u /root/xfstests/tests/generic/285.out
/root/xfstests/results//generic/285.out.bad' to see the entire diff)
Ran: generic/285
Failures: generic/285
Failed 1 of 1 tests
```
Reverting this commit then test pass.
```
# git revert e861a30255c9780425ee5193325d30882fbe7410
# make -j && make install -j
---snip---
# ./check -nfs generic/285
FSTYP -- nfs
PLATFORM -- Linux/aarch64 hpe-apollo80-01-n00
5.14.0-131.el9.aarch64 #1 SMP PREEMPT_DYNAMIC Mon Jul 18 16:13:44 EDT 2022
MKFS_OPTIONS -- 127.0.0.1:/home/nfs/share1
MOUNT_OPTIONS -- -o rw,relatime,vers=4.2 -o
context=system_u:object_r:root_t:s0 127.0.0.1:/home/nfs/share1 /mnt/scratch
generic/285 1s ... 1s
Ran: generic/285
Passed all 1 tests
```
On 6/29/22 04:21, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@xxxxxxxxxx>
>
> The seek sanity test tries to figure out a file space allocation unit by
> calling stat and then using an iterative SEEK_DATA method to try to
> detect a smaller blocksize based on SEEK_DATA's consultation of the
> filesystem's internal block mapping. This was put in (AFAICT) because
> XFS' stat implementation returns max(filesystem blocksize, PAGESIZE) for
> most regular files.
>
> Unfortunately, for a realtime file with an extent size larger than a
> single filesystem block this doesn't work at all because block mappings
> still work at filesystem block granularity, but allocation units do not.
> To fix this, detect the specific case where st_blksize != PAGE_SIZE and
> trust the fstat results.
>
> Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
> ---
> src/seek_sanity_test.c | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
>
> diff --git a/src/seek_sanity_test.c b/src/seek_sanity_test.c
> index 76587b7f..1030d0c5 100644
> --- a/src/seek_sanity_test.c
> +++ b/src/seek_sanity_test.c
> @@ -45,6 +45,7 @@ static int get_io_sizes(int fd)
> off_t pos = 0, offset = 1;
> struct stat buf;
> int shift, ret;
> + int pagesz = sysconf(_SC_PAGE_SIZE);
>
> ret = fstat(fd, &buf);
> if (ret) {
> @@ -53,8 +54,16 @@ static int get_io_sizes(int fd)
> return ret;
> }
>
> - /* st_blksize is typically also the allocation size */
> + /*
> + * st_blksize is typically also the allocation size. However, XFS
> + * rounds this up to the page size, so if the stat blocksize is exactly
> + * one page, use this iterative algorithm to see if SEEK_DATA will hint
> + * at a more precise answer based on the filesystem's (pre)allocation
> + * decisions.
> + */
> alloc_size = buf.st_blksize;
> + if (alloc_size != pagesz)
> + goto done;
>
> /* try to discover the actual alloc size */
> while (pos == 0 && offset < alloc_size) {
> @@ -80,6 +89,7 @@ static int get_io_sizes(int fd)
> if (!shift)
> offset += pos ? 0 : 1;
> alloc_size = offset;
> +done:
> fprintf(stdout, "Allocation size: %ld\n", alloc_size);
> return 0;
>
>
