From b91889d79e1d92e22860504e40108a2e4d054c33 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Thu, 28 Jul 2022 11:17:26 -0700 Subject: [PATCH] seek_sanity_test: use XFS ioctls to determine file allocation unit size liuyd.fnst@fujitsu.com 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@fujitsu.com Tested-by: liuyd.fnst@fujitsu.com Signed-off-by: Darrick J. Wong Reviewed-by: Zorro Lang Signed-off-by: Zorro Lang --- 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) { -- 2.30.2