[PATCH] nfsd: fix inclusive vfs_fsync_range() end

From: Zach Brown
Date: Mon Oct 06 2014 - 19:43:09 EST


The vfs_fsync_range() call during write processing got the end of the
range off by one. The range is inclusive, not exclusive. The error has
nfsd sync more data than requested -- it's correct but unnecessary
overhead.

The call during commit processing is correct so I copied that pattern in
write processing. Maybe a helper would be nice but I kept it trivial.

This is untested. I found it while reviewing code for something else
entirely.

Signed-off-by: Zach Brown <zab@xxxxxxxxx>
---
fs/nfsd/vfs.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index f501a9b..825250e 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -921,6 +921,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
int stable = *stablep;
int use_wgather;
loff_t pos = offset;
+ loff_t end = LLONG_MAX;
unsigned int pflags = current->flags;

if (rqstp->rq_local)
@@ -952,10 +953,13 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
fsnotify_modify(file);

if (stable) {
- if (use_wgather)
+ if (use_wgather) {
host_err = wait_for_concurrent_writes(file);
- else
- host_err = vfs_fsync_range(file, offset, offset+*cnt, 0);
+ } else {
+ if (*cnt)
+ end = offset + *cnt - 1;
+ host_err = vfs_fsync_range(file, offset, end, 0);
+ }
}

out_nfserr:
--
1.9.3

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