cifs: dont overwrite dentry name in d_revalidate

Use vfat's method for dealing with negative dentries to preserve case,
rather than overwrite dentry name in d_revalidate, which is a bit ugly
and also gets in the way of doing lock-free path walking.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>

1 files changed, 24 insertions, 19 deletions

diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index 3840eddbfb7a..521d841b1fd1 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -656,22 +656,34 @@ lookup_out:
 static int
 cifs_d_revalidate(struct dentry *direntry, struct nameidata *nd)
 {
-        int isValid = 1;
-
         if (direntry->d_inode) {
                 if (cifs_revalidate_dentry(direntry))
                         return 0;
-        } else {
-                cFYI(1, "neg dentry 0x%p name = %s",
-                         direntry, direntry->d_name.name);
-                if (time_after(jiffies, direntry->d_time + HZ) ||
-                        !lookupCacheEnabled) {
-                        d_drop(direntry);
-                        isValid = 0;
-                }
+                else
+                        return 1;
         }
 
-        return isValid;
+        /*
+         * This may be nfsd (or something), anyway, we can't see the
+         * intent of this. So, since this can be for creation, drop it.
+         */
+        if (!nd)
+                return 0;
+
+        /*
+         * Drop the negative dentry, in order to make sure to use the
+         * case sensitive name which is specified by user if this is
+         * for creation.
+         */
+        if (!(nd->flags & (LOOKUP_CONTINUE | LOOKUP_PARENT))) {
+                if (nd->flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET))
+                        return 0;
+        }
+
+        if (time_after(jiffies, direntry->d_time + HZ) || !lookupCacheEnabled)
+                return 0;
+
+        return 1;
 }
 
 /* static int cifs_d_delete(struct dentry *direntry)
@@ -709,15 +721,8 @@ static int cifs_ci_compare(struct dentry *dentry, struct qstr *a,
         struct nls_table *codepage = CIFS_SB(dentry->d_inode->i_sb)->local_nls;
 
         if ((a->len == b->len) &&
-            (nls_strnicmp(codepage, a->name, b->name, a->len) == 0)) {
-                /*
-                 * To preserve case, don't let an existing negative dentry's
-                 * case take precedence.  If a is not a negative dentry, this
-                 * should have no side effects
-                 */
-                memcpy((void *)a->name, b->name, a->len);
+            (nls_strnicmp(codepage, a->name, b->name, a->len) == 0))
                 return 0;
-        }
         return 1;
 }