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authorNeilBrown <neilb@suse.com>2017-08-25 17:34:41 +1000
committerAnna Schumaker <Anna.Schumaker@Netapp.com>2017-10-16 13:51:27 -0400
commitb688741cb06695312f18b730653d6611e1bad28d (patch)
treefe9d267f6433e78db556eaeea66b468569411624
parent1750d929b08764dd293d5bdddaa9bc4d3f94d228 (diff)
NFS: revalidate "." etc correctly on "open".
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>
-rw-r--r--fs/nfs/dir.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index db482d4c15d5..c583093a066b 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1241,8 +1241,7 @@ static int nfs_weak_revalidate(struct dentry *dentry, unsigned int flags)
return 0;
}
- if (nfs_mapping_need_revalidate_inode(inode))
- 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;
@@ -1393,6 +1392,7 @@ static int nfs4_lookup_revalidate(struct dentry *, unsigned int);
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,