linux-kernel - [PATCH 3.16 048/136] CIFS: Force reval dentry if LOOKUP

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Message-ID: <lsq.1576543535.913579306@decadent.org.uk>
Date:   Tue, 17 Dec 2019 00:46:22 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, Denis Kirjanov <kda@...ux-powerpc.org>,
        "Steve French" <stfrench@...rosoft.com>,
        "Pavel Shilovsky" <piastryyy@...il.com>,
        "Pavel Shilovsky" <pshilov@...rosoft.com>
Subject: [PATCH 3.16 048/136] CIFS: Force reval dentry if LOOKUP_REVAL
 flag is set

3.16.80-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Pavel Shilovsky <piastryyy@...il.com>

commit 0b3d0ef9840f7be202393ca9116b857f6f793715 upstream.

Mark inode for force revalidation if LOOKUP_REVAL flag is set.
This tells the client to actually send a QueryInfo request to
the server to obtain the latest metadata in case a directory
or a file were changed remotely. Only do that if the client
doesn't have a lease for the file to avoid unneeded round
trips to the server.

Signed-off-by: Pavel Shilovsky <pshilov@...rosoft.com>
Signed-off-by: Steve French <stfrench@...rosoft.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 fs/cifs/dir.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -817,10 +817,16 @@ lookup_out:
 static int
 cifs_d_revalidate(struct dentry *direntry, unsigned int flags)
 {
+	struct inode *inode;
+
 	if (flags & LOOKUP_RCU)
 		return -ECHILD;
 
 	if (direntry->d_inode) {
+		inode = d_inode(direntry);
+		if ((flags & LOOKUP_REVAL) && !CIFS_CACHE_READ(CIFS_I(inode)))
+			CIFS_I(inode)->time = 0; /* force reval */
+
 		if (cifs_revalidate_dentry(direntry))
 			return 0;
 		else {
@@ -831,7 +837,7 @@ cifs_d_revalidate(struct dentry *direntr
 			 * attributes will have been updated by
 			 * cifs_revalidate_dentry().
 			 */
-			if (IS_AUTOMOUNT(direntry->d_inode) &&
+			if (IS_AUTOMOUNT(inode) &&
 			   !(direntry->d_flags & DCACHE_NEED_AUTOMOUNT)) {
 				spin_lock(&direntry->d_lock);
 				direntry->d_flags |= DCACHE_NEED_AUTOMOUNT;