afs: Fix afs_d_validate() to set the right directory version

commit 40fc81027f892284ce31f8b6de1e497f5b47e71f upstream.

If a dentry's version is somewhere between invalid_before and the current
directory version, we should be setting it forward to the current version,
not backwards to the invalid_before version.  Note that we're only doing
this at all because dentry::d_fsdata isn't large enough on a 32-bit system.

Fix this by using a separate variable for invalid_before so that we don't
accidentally clobber the current dir version.

Fixes: a4ff7401fbfa ("afs: Keep track of invalid-before version for dentry coherency")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index 31d297e..6cc685c 100644 (file)
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -1032,7 +1032,7 @@ static int afs_d_revalidate(struct dentry *dentry, unsigned int flags)
        struct dentry *parent;
        struct inode *inode;
        struct key *key;
-       afs_dataversion_t dir_version;
+       afs_dataversion_t dir_version, invalid_before;
        long de_version;
        int ret;
 
@@ -1084,8 +1084,8 @@ static int afs_d_revalidate(struct dentry *dentry, unsigned int flags)
        if (de_version == (long)dir_version)
                goto out_valid_noupdate;
 
-       dir_version = dir->invalid_before;
-       if (de_version - (long)dir_version >= 0)
+       invalid_before = dir->invalid_before;
+       if (de_version - (long)invalid_before >= 0)
                goto out_valid;
 
        _debug("dir modified");