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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, NeilBrown <neilb@suse.com>,
	Anna Schumaker <Anna.Schumaker@Netapp.com>
Subject: [PATCH 3.18 10/12] NFS: revalidate "." etc correctly on "open".
Date: Mon,  4 Dec 2017 16:59:24 +0100	[thread overview]
Message-ID: <20171204155916.888639188@linuxfoundation.org> (raw)
In-Reply-To: <20171204155916.489136969@linuxfoundation.org>

3.18-stable review patch.  If anyone has any objections, please let me know.

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

From: NeilBrown <neilb@suse.com>

commit b688741cb06695312f18b730653d6611e1bad28d upstream.

For correct close-to-open semantics, NFS must validate
the change attribute of a directory (or file) on open.

Since commit ecf3d1f1aa74 ("vfs: kill FS_REVAL_DOT by adding a
d_weak_revalidate dentry op"), open() of "." or a path ending ".." is
not revalidated reliably (except when that direct is a mount point).

Prior to that commit, "." was revalidated using nfs_lookup_revalidate()
which checks the LOOKUP_OPEN flag and forces revalidation if the flag is
set.
Since that commit, nfs_weak_revalidate() is used for NFSv3 (which
ignores the flags) and nothing is used for NFSv4.

This is fixed by using nfs_lookup_verify_inode() in
nfs_weak_revalidate().  This does the revalidation exactly when needed.
Also, add a definition of .d_weak_revalidate for NFSv4.

The incorrect behavior is easily demonstrated by running "echo *" in
some non-mountpoint NFS directory while watching network traffic.
Without this patch, "echo *" sometimes doesn't produce any traffic.
With the patch it always does.

Fixes: ecf3d1f1aa74 ("vfs: kill FS_REVAL_DOT by adding a d_weak_revalidate dentry op")
cc: stable@vger.kernel.org (3.9+)
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/nfs/dir.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1266,7 +1266,7 @@ static int nfs_weak_revalidate(struct de
 		return 0;
 	}
 
-	error = nfs_revalidate_inode(NFS_SERVER(inode), inode);
+	error = nfs_lookup_verify_inode(inode, flags);
 	dfprintk(LOOKUPCACHE, "NFS: %s: inode %lu is %s\n",
 			__func__, inode->i_ino, error ? "invalid" : "valid");
 	return !error;
@@ -1426,6 +1426,7 @@ static int nfs4_lookup_revalidate(struct
 
 const struct dentry_operations nfs4_dentry_operations = {
 	.d_revalidate	= nfs4_lookup_revalidate,
+	.d_weak_revalidate	= nfs_weak_revalidate,
 	.d_delete	= nfs_dentry_delete,
 	.d_iput		= nfs_dentry_iput,
 	.d_automount	= nfs_d_automount,

  parent reply	other threads:[~2017-12-04 16:45 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-04 15:59 [PATCH 3.18 00/12] 3.18.86-stable review Greg Kroah-Hartman
2017-12-04 15:59 ` [PATCH 3.18 01/12] netlink: add a start callback for starting a netlink dump Greg Kroah-Hartman
2017-12-04 15:59 ` [PATCH 3.18 02/12] ipsec: Fix aborted xfrm policy dump crash Greg Kroah-Hartman
2017-12-04 15:59 ` [PATCH 3.18 03/12] mm, thp: Do not make page table dirty unconditionally in touch_p[mu]d() Greg Kroah-Hartman
2017-12-04 15:59 ` [PATCH 3.18 04/12] mm/madvise.c: fix madvise() infinite loop under special circumstances Greg Kroah-Hartman
2017-12-04 15:59 ` [PATCH 3.18 05/12] btrfs: clear space cache inode generation always Greg Kroah-Hartman
2017-12-04 15:59 ` [PATCH 3.18 08/12] eeprom: at24: check at24_read/write arguments Greg Kroah-Hartman
2017-12-04 15:59 ` [PATCH 3.18 09/12] drm/panel: simple: Add missing panel_simple_unprepare() calls Greg Kroah-Hartman
2017-12-04 15:59 ` Greg Kroah-Hartman [this message]
2017-12-04 20:14 ` [PATCH 3.18 00/12] 3.18.86-stable review Shuah Khan
2017-12-04 23:45 ` Guenter Roeck

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