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authorJeff Layton <jlayton@redhat.com>2013-02-20 11:19:05 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2013-02-26 02:46:09 -0500
commitecf3d1f1aa74da0d632b651a2e05a911f60e92c0 (patch)
tree62a2e0a46bfd993a24a1154ec1331c57bbd50482 /include/linux/dcache.h
parent4f4a4faddea0fe45bf508e723c3a810c5190ed62 (diff)
vfs: kill FS_REVAL_DOT by adding a d_weak_revalidate dentry op
The following set of operations on a NFS client and server will cause server# mkdir a client# cd a server# mv a a.bak client# sleep 30 # (or whatever the dir attrcache timeout is) client# stat . stat: cannot stat `.': Stale NFS file handle Obviously, we should not be getting an ESTALE error back there since the inode still exists on the server. The problem is that the lookup code will call d_revalidate on the dentry that "." refers to, because NFS has FS_REVAL_DOT set. nfs_lookup_revalidate will see that the parent directory has changed and will try to reverify the dentry by redoing a LOOKUP. That of course fails, so the lookup code returns ESTALE. The problem here is that d_revalidate is really a bad fit for this case. What we really want to know at this point is whether the inode is still good or not, but we don't really care what name it goes by or whether the dcache is still valid. Add a new d_op->d_weak_revalidate operation and have complete_walk call that instead of d_revalidate. The intent there is to allow for a "weaker" d_revalidate that just checks to see whether the inode is still good. This is also gives us an opportunity to kill off the FS_REVAL_DOT special casing. [AV: changed method name, added note in porting, fixed confusion re having it possibly called from RCU mode (it won't be)] Cc: NeilBrown <neilb@suse.de> Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include/linux/dcache.h')
-rw-r--r--include/linux/dcache.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 03d169288423..1a6bb81f0fe5 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -145,6 +145,7 @@ enum dentry_d_lock_class
struct dentry_operations {
int (*d_revalidate)(struct dentry *, unsigned int);
+ int (*d_weak_revalidate)(struct dentry *, unsigned int);
int (*d_hash)(const struct dentry *, const struct inode *,
struct qstr *);
int (*d_compare)(const struct dentry *, const struct inode *,
@@ -192,6 +193,8 @@ struct dentry_operations {
#define DCACHE_GENOCIDE 0x0200
#define DCACHE_SHRINK_LIST 0x0400
+#define DCACHE_OP_WEAK_REVALIDATE 0x0800
+
#define DCACHE_NFSFS_RENAMED 0x1000
/* this dentry has been "silly renamed" and has to be deleted on the last
* dput() */