On Thu, Jul 28, 2022 at 11:17:26AM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@xxxxxxxxxx>
>
> liuyd.fnst@xxxxxxxxxxx reported that my recent change to the seek sanity
> test broke NFS. I foolishly thought that st_blksize was sufficient to
> find the file allocation unit size so that applications could figure out
> the SEEK_HOLE granularity. Replace that with an explicit callout to XFS
> ioctls so that xfs realtime will work again.
>
> Fixes: e861a302 ("seek_sanity_test: fix allocation unit detection on XFS realtime")
> Reported-by: liuyd.fnst@xxxxxxxxxxx
> Tested-by: liuyd.fnst@xxxxxxxxxxx
> Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
> ---
This patch looks good to me, and I can reproduce the regression on nfs, then
test passed after merge this patch. So I'd like to merge this patch at first,
to fix that regression for nfs. Others 2 patches are still under discussion,
I'll wait.
Reviewed-by: Zorro Lang <zlang@xxxxxxxxxx>
> src/seek_sanity_test.c | 36 +++++++++++++++++++++++++++---------
> 1 file changed, 27 insertions(+), 9 deletions(-)
>
>
> diff --git a/src/seek_sanity_test.c b/src/seek_sanity_test.c
> index 1030d0c5..78f835e8 100644
> --- a/src/seek_sanity_test.c
> +++ b/src/seek_sanity_test.c
> @@ -40,6 +40,28 @@ static void get_file_system(int fd)
> }
> }
>
> +/* Compute the file allocation unit size for an XFS file. */
> +static int detect_xfs_alloc_unit(int fd)
> +{
> + struct fsxattr fsx;
> + struct xfs_fsop_geom fsgeom;
> + int ret;
> +
> + ret = ioctl(fd, XFS_IOC_FSGEOMETRY, &fsgeom);
> + if (ret)
> + return -1;
> +
> + ret = ioctl(fd, XFS_IOC_FSGETXATTR, &fsx);
> + if (ret)
> + return -1;
> +
> + alloc_size = fsgeom.blocksize;
> + if (fsx.fsx_xflags & XFS_XFLAG_REALTIME)
> + alloc_size *= fsgeom.rtextsize;
> +
> + return 0;
> +}
> +
> static int get_io_sizes(int fd)
> {
> off_t pos = 0, offset = 1;
> @@ -47,6 +69,10 @@ static int get_io_sizes(int fd)
> int shift, ret;
> int pagesz = sysconf(_SC_PAGE_SIZE);
>
> + ret = detect_xfs_alloc_unit(fd);
> + if (!ret)
> + goto done;
> +
> ret = fstat(fd, &buf);
> if (ret) {
> fprintf(stderr, " ERROR %d: Failed to find io blocksize\n",
> @@ -54,16 +80,8 @@ static int get_io_sizes(int fd)
> return ret;
> }
>
> - /*
> - * 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.
> - */
> + /* st_blksize is typically also the allocation size */
> alloc_size = buf.st_blksize;
> - if (alloc_size != pagesz)
> - goto done;
>
> /* try to discover the actual alloc size */
> while (pos == 0 && offset < alloc_size) {
>
