* [PATCH] xfs_io: Prevent devide by zero from {pread,pwrite}_random
@ 2016-02-25 15:20 Dmitry Monakhov
2016-03-01 12:09 ` [PATCH] xfs_io: Prevent devide by zero from {pread, pwrite}_random Christoph Hellwig
0 siblings, 1 reply; 2+ messages in thread
From: Dmitry Monakhov @ 2016-02-25 15:20 UTC (permalink / raw)
To: xfs
Math is wrong if range requested is less or equals to block size
xfs_io -c 'pwrite -b 4k 8k 4k -R' \
-c 'pread -b 4k 4k 4k -R' -f file
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
---
io/pread.c | 6 +++++-
io/pwrite.c | 6 +++++-
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/io/pread.c b/io/pread.c
index f16c86c..b98355f 100644
--- a/io/pread.c
+++ b/io/pread.c
@@ -245,7 +245,11 @@ read_random(
*total = 0;
while (count > 0) {
- off = ((offset + (random() % range)) / buffersize) * buffersize;
+ if (range)
+ off = ((offset + (random() % range)) / buffersize) *
+ buffersize;
+ else
+ off = offset;
bytes = do_pread(fd, off, buffersize, buffersize);
if (bytes == 0)
break;
diff --git a/io/pwrite.c b/io/pwrite.c
index 4fc8de6..67631ce 100644
--- a/io/pwrite.c
+++ b/io/pwrite.c
@@ -128,7 +128,11 @@ write_random(
*total = 0;
while (count > 0) {
- off = ((offset + (random() % range)) / buffersize) * buffersize;
+ if (range)
+ off = ((offset + (random() % range)) / buffersize) *
+ buffersize;
+ else
+ off = offset;
bytes = do_pwrite(file->fd, off, buffersize, buffersize);
if (bytes == 0)
break;
--
1.8.3.1
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2016-02-25 15:20 [PATCH] xfs_io: Prevent devide by zero from {pread,pwrite}_random Dmitry Monakhov
2016-03-01 12:09 ` [PATCH] xfs_io: Prevent devide by zero from {pread, pwrite}_random Christoph Hellwig
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