Linux-NFS Archive on lore.kernel.org
 help / color / Atom feed
* [PATCH v2] NFS: Don't skip lookup when holding a delegation
@ 2019-09-19 14:49 Benjamin Coddington
  0 siblings, 0 replies; only message in thread
From: Benjamin Coddington @ 2019-09-19 14:49 UTC (permalink / raw)
  To: trond.myklebust, anna.schumaker; +Cc: linux-nfs

If we skip lookup revalidation while holding a delegation, we might miss
that the file has changed directories on the server.  The directory's
change attribute should still be checked against the dentry's d_time to
perform a complete revalidation.

V2 - Add some commentary as suggested-by J. Bruce Fields.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
---
 fs/nfs/dir.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 0adfd8840110..8723e82f5c9d 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1197,12 +1197,20 @@ nfs_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
 		goto out_bad;
 	}
 
-	if (NFS_PROTO(dir)->have_delegation(inode, FMODE_READ))
-		return nfs_lookup_revalidate_delegated(dir, dentry, inode);
-
 	/* Force a full look up iff the parent directory has changed */
 	if (!(flags & (LOOKUP_EXCL | LOOKUP_REVAL)) &&
 	    nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU)) {
+
+		/*
+		 * Note that the file can't move while we hold a
+		 * delegation.  But this dentry could have been cached
+		 * before we got a delegation.  So it's only safe to
+		 * skip revalidation when the parent directory is
+		 * unchanged:
+		 */
+		if (NFS_PROTO(dir)->have_delegation(inode, FMODE_READ))
+			return nfs_lookup_revalidate_delegated(dir, dentry, inode);
+
 		error = nfs_lookup_verify_inode(inode, flags);
 		if (error) {
 			if (error == -ESTALE)
@@ -1635,9 +1643,6 @@ nfs4_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
 	if (inode == NULL)
 		goto full_reval;
 
-	if (NFS_PROTO(dir)->have_delegation(inode, FMODE_READ))
-		return nfs_lookup_revalidate_delegated(dir, dentry, inode);
-
 	/* NFS only supports OPEN on regular files */
 	if (!S_ISREG(inode->i_mode))
 		goto full_reval;
-- 
2.20.1


^ permalink raw reply	[flat|nested] only message in thread

only message in thread, back to index

Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-09-19 14:49 [PATCH v2] NFS: Don't skip lookup when holding a delegation Benjamin Coddington

Linux-NFS Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-nfs/0 linux-nfs/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-nfs linux-nfs/ https://lore.kernel.org/linux-nfs \
		linux-nfs@vger.kernel.org
	public-inbox-index linux-nfs

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-nfs


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git