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-rw-r--r--fs/nfs/file.c19
1 files changed, 16 insertions, 3 deletions
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 39672b73173..c3f2477c16c 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -758,6 +758,11 @@ do_unlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
}
static int
+is_time_granular(struct timespec *ts) {
+ return ((ts->tv_sec == 0) && (ts->tv_nsec <= 1000));
+}
+
+static int
do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
{
struct inode *inode = filp->f_mapping->host;
@@ -781,13 +786,21 @@ do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
status = do_vfs_lock(filp, fl);
if (status < 0)
goto out;
+
/*
- * Make sure we clear the cache whenever we try to get the lock.
+ * Revalidate the cache if the server has time stamps granular
+ * enough to detect subsecond changes. Otherwise, clear the
+ * cache to prevent missing any changes.
+ *
* This makes locking act as a cache coherency point.
*/
nfs_sync_mapping(filp->f_mapping);
- if (!nfs_have_delegation(inode, FMODE_READ))
- nfs_zap_caches(inode);
+ if (!nfs_have_delegation(inode, FMODE_READ)) {
+ if (is_time_granular(&NFS_SERVER(inode)->time_delta))
+ __nfs_revalidate_inode(NFS_SERVER(inode), inode);
+ else
+ nfs_zap_caches(inode);
+ }
out:
return status;
}