Changeset 7f59d6c in mainline

Timestamp:

2017-03-18T13:08:17Z (7 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

4f9ab1e

Parents:

39c3b7f9

Message:

Revert the order of link and unlink operations during rename

This changeset reverts the order of link and unlink operations that
occur within a single rename operation to be link first and unlink
second.

The file system implementations are not ready for the opposite ordering.

For example ext4fs decrements the the link count by 2 in total when
removing the last non-dot name of a directory, but increments only by 1
when adding the new name. This results in an assertion failure on the
next unlink, because the linkcount gets out of ballance.

In addition, this changeset fixes a node reference leak in error paths.

File:

• uspace/srv/vfs/vfs_ops.c (modified) (4 diffs)

uspace/srv/vfs/vfs_ops.c

@@ -552 +552 @@
         /* Do not allow one path to be a prefix of the other. */
         if (old[shared] == 0 || new[shared] == 0) {
+                vfs_node_put(base);
                 return EINVAL;
         }
@@ -564 +565 @@
                 rc = vfs_lookup_internal(base, old, L_DIRECTORY, &base_lr);
                 if (rc != EOK) {
+                        vfs_node_put(base);
                         fibril_rwlock_write_unlock(&namespace_rwlock);
                         return rc;
@@ -573 +575 @@
                 old += shared;
                 new += shared;
+        }
+
+        rc = vfs_lookup_internal(base, old, L_DISABLE_MOUNTS,
+            &old_lr);
+        if (rc != EOK) {
+                vfs_node_put(base);
+                fibril_rwlock_write_unlock(&namespace_rwlock);
+                return rc;
         }
                 
@@ -584 +594 @@
                 return rc;
         }
-        
+
+        rc = vfs_link_internal(base, new, &old_lr.triplet);
+        if (rc != EOK) {
+                vfs_link_internal(base, old, &old_lr.triplet);
+                if (orig_unlinked) {
+                        vfs_link_internal(base, new, &new_lr_orig.triplet);
+                }
+                vfs_node_put(base);
+                fibril_rwlock_write_unlock(&namespace_rwlock);
+                return rc;
+        }
+
         rc = vfs_lookup_internal(base, old, L_UNLINK | L_DISABLE_MOUNTS,
             &old_lr);
         if (rc != EOK) {
-                if (orig_unlinked) {
-                        vfs_link_internal(base, new, &new_lr_orig.triplet);
-                }
-                vfs_node_put(base);
-                fibril_rwlock_write_unlock(&namespace_rwlock);
-                return rc;
-        }
-        
-        rc = vfs_link_internal(base, new, &old_lr.triplet);
-        if (rc != EOK) {
-                vfs_link_internal(base, old, &old_lr.triplet);
                 if (orig_unlinked) {
                         vfs_link_internal(base, new, &new_lr_orig.triplet);