From efef020df5b257085831106847d318c93d46531c Mon Sep 17 00:00:00 2001 From: Benjamin Coddington Date: Mon, 24 Oct 2016 09:52:41 -0400 Subject: [PATCH] src/seek_sanity_test: discover allocation size Try to discover the allocation size. For NFS, the st_blksize is optimized for the network, and will usually be much larger than the allocation size of the exported filesystem, which may trigger preallocation strategies in the exported filesystem causing the seek tests here to fail. Signed-off-by: Benjamin Coddington Reviewed-by: Eryu Guan Signed-off-by: Eryu Guan --- src/seek_sanity_test.c | 41 ++++++++++++++++++++++++++++++++++------- 1 file changed, 34 insertions(+), 7 deletions(-) diff --git a/src/seek_sanity_test.c b/src/seek_sanity_test.c index 18262c2b..a6dd48cc 100644 --- a/src/seek_sanity_test.c +++ b/src/seek_sanity_test.c @@ -700,8 +700,8 @@ static int run_test(struct testrec *tr) static int test_basic_support(void) { - int ret = -1, fd; - off_t pos; + int ret = -1, fd, shift; + off_t pos = 0, offset = 1; char *buf = NULL; int bufsz, filsz; @@ -715,6 +715,35 @@ static int test_basic_support(void) if (ret) goto out; + /* try to discover the actual alloc size */ + while (pos == 0 && offset < alloc_size) { + offset <<= 1; + ftruncate(fd, 0); + pwrite(fd, "a", 1, offset); + pos = lseek(fd, 0, SEEK_DATA); + } + + /* bisect */ + shift = offset >> 2; + while (shift && offset < alloc_size) { + ftruncate(fd, 0); + pwrite(fd, "a", 1, offset); + pos = lseek(fd, 0, SEEK_DATA); + offset += pos ? -shift : shift; + shift >>= 1; + } + if (!shift) + offset += pos ? 0 : 1; + alloc_size = offset; + + if (pos == -1) { + fprintf(stderr, "Kernel does not support llseek(2) extension " + "SEEK_DATA. Aborting.\n"); + ret = -1; + goto out; + } + + ftruncate(fd, 0); bufsz = alloc_size * 2; filsz = bufsz * 2; @@ -734,12 +763,10 @@ static int test_basic_support(void) goto out; /* Is SEEK_DATA and SEEK_HOLE supported in the kernel? */ - pos = lseek(fd, 0, SEEK_DATA); - if (pos != -1) - pos = lseek(fd, 0, SEEK_HOLE); + pos = lseek(fd, 0, SEEK_HOLE); if (pos == -1) { - fprintf(stderr, "Kernel does not support llseek(2) extensions " - "SEEK_HOLE and/or SEEK_DATA. Aborting.\n"); + fprintf(stderr, "Kernel does not support llseek(2) extension " + "SEEK_HOLE. Aborting.\n"); ret = -1; goto out; } -- 2.39.5