From 033777858aa2f24750d23ab80b9e5e6e080d0fb5 Mon Sep 17 00:00:00 2001 From: Eric Sandeen Date: Mon, 14 Apr 2014 16:13:54 +1000 Subject: [PATCH] xfs_io: fix random pread/pwrite to honor offset xfs_io's pread & pwrite claim to support a random IO mode where it will do random IOs between offset & offset+len. However, offset was ignored, and we did the IOs between 0 and len instead. Clang caught this by pointing out that the calculated/normalized "offset" variable was never read. (NB: If the range is larger than RAND_MAX, these functions don't work, but that's always been true, so I'll leave it for another day...) Signed-off-by: Eric Sandeen Reviewed-by: Brian Foster Reviewed-by: Dave Chinner Signed-off-by: Dave Chinner --- io/pread.c | 2 +- io/pwrite.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/io/pread.c b/io/pread.c index a42baeddd..cff327575 100644 --- a/io/pread.c +++ b/io/pread.c @@ -246,7 +246,7 @@ read_random( *total = 0; while (count > 0) { - off = ((random() % range) / buffersize) * buffersize; + off = ((offset + (random() % range)) / buffersize) * buffersize; bytes = do_pread(fd, off, buffersize, buffersize); if (bytes == 0) break; diff --git a/io/pwrite.c b/io/pwrite.c index a2f0a81e3..0674c01b2 100644 --- a/io/pwrite.c +++ b/io/pwrite.c @@ -129,7 +129,7 @@ write_random( *total = 0; while (count > 0) { - off = ((random() % range) / buffersize) * buffersize; + off = ((offset + (random() % range)) / buffersize) * buffersize; bytes = do_pwrite(file->fd, off, buffersize, buffersize); if (bytes == 0) break; -- 2.47.2