LINUX: Avoid d_revalidate failure on mtpt mismatch

[openafs.git] / src / afs / LINUX / osi_vnodeops.c

diff --git a/src/afs/LINUX/osi_vnodeops.c b/src/afs/LINUX/osi_vnodeops.c
index 0c907d8..b2ab9d5 100644 (file)
--- a/src/afs/LINUX/osi_vnodeops.c
+++ b/src/afs/LINUX/osi_vnodeops.c
@@ -627,16 +627,6 @@ afs_linux_lock(struct file *fp, int cmd, struct file_lock *flp)
 #endif /* F_GETLK64 && F_GETLK != F_GETLK64 */
 
     AFS_GLOCK();
-    if ((vcp->f.states & CRO)) {
-       if (flp->fl_type == F_WRLCK) {
-           code = EBADF;
-       } else {
-           code = 0;
-       }
-       AFS_GUNLOCK();
-       crfree(credp);
-       return code;
-    }
     code = afs_convert_code(afs_lockctl(vcp, &flock, cmd, credp));
     AFS_GUNLOCK();
 
@@ -964,10 +954,11 @@ static inline void
 fix_bad_parent(struct dentry *dp, cred_t *credp, struct vcache *vcp, struct vcache *pvc) 
 {
     struct vcache *avc = NULL;
+    int code;
 
     /* force a lookup, so vcp->mvid is fixed up */
-    afs_lookup(pvc, (char *)dp->d_name.name, &avc, credp);
-    if (!avc || vcp != avc) {  /* bad, very bad.. */
+    code = afs_lookup(pvc, (char *)dp->d_name.name, &avc, credp);
+    if (code || vcp != avc) {  /* bad, very bad.. */
        afs_Trace4(afs_iclSetp, CM_TRACE_TMP_1S3L, ICL_TYPE_STRING,
                   "check_bad_parent: bad pointer returned from afs_lookup origvc newvc dentry",
                   ICL_TYPE_POINTER, vcp, ICL_TYPE_POINTER, avc,
@@ -1300,9 +1291,36 @@ afs_linux_dentry_revalidate(struct dentry *dp, int flags)
        if (locked && (parent_dv > dp->d_time || !(vcp->f.states & CStatd))) {
            struct vattr *vattr = NULL;
            int code;
+           int lookup_good;
 
            code = afs_lookup(pvcp, (char *)dp->d_name.name, &tvc, credp);
-           if (!tvc || tvc != vcp) {
+
+           if (code) {
+               /* We couldn't perform the lookup, so we're not okay. */
+               lookup_good = 0;
+
+           } else if (tvc == vcp) {
+               /* We got back the same vcache, so we're good. */
+               lookup_good = 1;
+
+           } else if (tvc == VTOAFS(dp->d_inode)) {
+               /* We got back the same vcache, so we're good. This is
+                * different from the above case, because sometimes 'vcp' is
+                * not the same as the vcache for dp->d_inode, if 'vcp' was a
+                * mtpt and we evaluated it to a root dir. In rare cases,
+                * afs_lookup might not evalute the mtpt when we do, or vice
+                * versa, so the previous case will not succeed. But this is
+                * still 'correct', so make sure not to mark the dentry as
+                * invalid; it still points to the same thing! */
+               lookup_good = 1;
+
+           } else {
+               /* We got back a different file, so we're definitely not
+                * okay. */
+               lookup_good = 0;
+           }
+
+           if (!lookup_good) {
                dput(parent);
                /* Force unhash; the name doesn't point to this file
                 * anymore. */
@@ -1550,7 +1568,7 @@ afs_linux_lookup(struct inode *dip, struct dentry *dp)
     AFS_GLOCK();
     code = afs_lookup(VTOAFS(dip), (char *)comp, &vcp, credp);
     
-    if (vcp) {
+    if (!code) {
        struct vattr *vattr = NULL;
        struct vcache *parent_vc = VTOAFS(dip);
 
@@ -1602,9 +1620,18 @@ afs_linux_lookup(struct inode *dip, struct dentry *dp)
     /* It's ok for the file to not be found. That's noted by the caller by
      * seeing that the dp->d_inode field is NULL.
      */
-    if (!code || code == ENOENT)
-       return newdp;
-    else 
+    if (!code || code == ENOENT) {
+       /*
+        * d_splice_alias can return an error (EIO) if there is an existing
+        * connected directory alias for this dentry.
+        */
+       if (!IS_ERR(newdp))
+           return newdp;
+       else {
+           d_add(dp, ip);
+           return NULL;
+       }
+    } else
        return ERR_PTR(afs_convert_code(code));
 }