[lustre-devel] [PATCH 31/45] lustre: llite: fix possible divide zero in ll_use_fast_io()
James Simmons
jsimmons at infradead.org
Mon May 25 15:08:08 PDT 2020
From: Wang Shilong <wshilong at ddn.com>
ll_use_fast_io() is used to check wheather we could use fast IO.
Since it is called in fast path, we don't hold ras_lock to protect
access, there might have the race @ras_stride_bytes is reset after
stride_io_mode() check.
Fixes: 52fa1b524a84 ("lustre: llite: try fast io for stride io correctly")
WC-bug-id: https://jira.whamcloud.com/browse/LU-13541
Lustre-commit: 7cd0afe58321 ("LU-13541 llite: fix possible divide zero in ll_use_fast_io()")
Signed-off-by: Wang Shilong <wshilong at ddn.com>
Reviewed-on: https://review.whamcloud.com/38545
Reviewed-by: Andreas Dilger <adilger at whamcloud.com>
Tested-by: Andreas Dilger <adilger at whamcloud.com>
Reviewed-by: Jian Yu <yujian at whamcloud.com>
Reviewed-by: James Nunez <jnunez at whamcloud.com>
Signed-off-by: James Simmons <jsimmons at infradead.org>
---
fs/lustre/llite/rw.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/lustre/llite/rw.c b/fs/lustre/llite/rw.c
index 9e004f4..fd0bed6 100644
--- a/fs/lustre/llite/rw.c
+++ b/fs/lustre/llite/rw.c
@@ -1609,10 +1609,11 @@ static bool ll_use_fast_io(struct file *file,
unsigned long fast_read_pages =
max(RA_REMAIN_WINDOW_MIN, ras->ras_rpc_pages);
loff_t skip_pages;
+ loff_t stride_bytes = ras->ras_stride_bytes;
- if (stride_io_mode(ras)) {
+ if (stride_io_mode(ras) && stride_bytes) {
skip_pages = (ras->ras_stride_length +
- ras->ras_stride_bytes - 1) / ras->ras_stride_bytes;
+ ras->ras_stride_bytes - 1) / stride_bytes;
skip_pages *= fast_read_pages;
} else {
skip_pages = fast_read_pages;
--
1.8.3.1
More information about the lustre-devel
mailing list