1 files changed, 365 insertions, 79 deletions

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 9c462fbd60fa..fc9b87a7975b 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -35,6 +35,49 @@
 #define LOG_INODE_EXISTS 1
 
 /*
+ * directory trouble cases
+ *
+ * 1) on rename or unlink, if the inode being unlinked isn't in the fsync
+ * log, we must force a full commit before doing an fsync of the directory
+ * where the unlink was done.
+ * ---> record transid of last unlink/rename per directory
+ *
+ * mkdir foo/some_dir
+ * normal commit
+ * rename foo/some_dir foo2/some_dir
+ * mkdir foo/some_dir
+ * fsync foo/some_dir/some_file
+ *
+ * The fsync above will unlink the original some_dir without recording
+ * it in its new location (foo2).  After a crash, some_dir will be gone
+ * unless the fsync of some_file forces a full commit
+ *
+ * 2) we must log any new names for any file or dir that is in the fsync
+ * log. ---> check inode while renaming/linking.
+ *
+ * 2a) we must log any new names for any file or dir during rename
+ * when the directory they are being removed from was logged.
+ * ---> check inode and old parent dir during rename
+ *
+ *  2a is actually the more important variant.  With the extra logging
+ *  a crash might unlink the old name without recreating the new one
+ *
+ * 3) after a crash, we must go through any directories with a link count
+ * of zero and redo the rm -rf
+ *
+ * mkdir f1/foo
+ * normal commit
+ * rm -rf f1/foo
+ * fsync(f1)
+ *
+ * The directory f1 was fully removed from the FS, but fsync was never
+ * called on f1, only its parent dir.  After a crash the rm -rf must
+ * be replayed.  This must be able to recurse down the entire
+ * directory tree.  The inode link count fixup code takes care of the
+ * ugly details.
+ */
+
+/*
  * stages for the tree walking.  The first
  * stage (0) is to only pin down the blocks we find
  * the second stage (1) is to make sure that all the inodes
@@ -47,12 +90,17 @@
 #define LOG_WALK_REPLAY_INODES 1
 #define LOG_WALK_REPLAY_ALL 2
 
-static int __btrfs_log_inode(struct btrfs_trans_handle *trans,
+static int btrfs_log_inode(struct btrfs_trans_handle *trans,
                              struct btrfs_root *root, struct inode *inode,
                              int inode_only);
 static int link_to_fixup_dir(struct btrfs_trans_handle *trans,
                              struct btrfs_root *root,
                              struct btrfs_path *path, u64 objectid);
+static noinline int replay_dir_deletes(struct btrfs_trans_handle *trans,
+                                       struct btrfs_root *root,
+                                       struct btrfs_root *log,
+                                       struct btrfs_path *path,
+                                       u64 dirid, int del_all);
 
 /*
  * tree logging is a special write ahead log used to make sure that
@@ -133,10 +181,25 @@ static int join_running_log_trans(struct btrfs_root *root)
 }
 
 /*
+ * This either makes the current running log transaction wait
+ * until you call btrfs_end_log_trans() or it makes any future
+ * log transactions wait until you call btrfs_end_log_trans()
+ */
+int btrfs_pin_log_trans(struct btrfs_root *root)
+{
+        int ret = -ENOENT;
+
+        mutex_lock(&root->log_mutex);
+        atomic_inc(&root->log_writers);
+        mutex_unlock(&root->log_mutex);
+        return ret;
+}
+
+/*
  * indicate we're done making changes to the log tree
  * and wake up anyone waiting to do a sync
  */
-static int end_log_trans(struct btrfs_root *root)
+int btrfs_end_log_trans(struct btrfs_root *root)
 {
         if (atomic_dec_and_test(&root->log_writers)) {
                 smp_mb();
@@ -203,7 +266,6 @@ static int process_one_buffer(struct btrfs_root *log,
                 mutex_lock(&log->fs_info->pinned_mutex);
                 btrfs_update_pinned_extents(log->fs_info->extent_root,
                                             eb->start, eb->len, 1);
-                mutex_unlock(&log->fs_info->pinned_mutex);
         }
 
         if (btrfs_buffer_uptodate(eb, gen)) {
@@ -603,6 +665,7 @@ static noinline int drop_one_dir_item(struct btrfs_trans_handle *trans,
 
         ret = link_to_fixup_dir(trans, root, path, location.objectid);
         BUG_ON(ret);
+
         ret = btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
         BUG_ON(ret);
         kfree(name);
@@ -804,6 +867,7 @@ conflict_again:
                                             victim_name_len)) {
                                 btrfs_inc_nlink(inode);
                                 btrfs_release_path(root, path);
+
                                 ret = btrfs_unlink_inode(trans, root, dir,
                                                          inode, victim_name,
                                                          victim_name_len);
@@ -922,13 +986,20 @@ static noinline int fixup_inode_link_count(struct btrfs_trans_handle *trans,
                 key.offset--;
                 btrfs_release_path(root, path);
         }
-        btrfs_free_path(path);
+        btrfs_release_path(root, path);
         if (nlink != inode->i_nlink) {
                 inode->i_nlink = nlink;
                 btrfs_update_inode(trans, root, inode);
         }
         BTRFS_I(inode)->index_cnt = (u64)-1;
 
+        if (inode->i_nlink == 0 && S_ISDIR(inode->i_mode)) {
+                ret = replay_dir_deletes(trans, root, NULL, path,
+                                         inode->i_ino, 1);
+                BUG_ON(ret);
+        }
+        btrfs_free_path(path);
+
         return 0;
 }
 
@@ -971,9 +1042,12 @@ static noinline int fixup_inode_link_counts(struct btrfs_trans_handle *trans,
 
                 iput(inode);
 
-                if (key.offset == 0)
-                        break;
-                key.offset--;
+                /*
+                 * fixup on a directory may create new entries,
+                 * make sure we always look for the highset possible
+                 * offset
+                 */
+                key.offset = (u64)-1;
         }
         btrfs_release_path(root, path);
         return 0;
@@ -1313,11 +1387,11 @@ again:
                 read_extent_buffer(eb, name, (unsigned long)(di + 1),
                                   name_len);
                 log_di = NULL;
-                if (dir_key->type == BTRFS_DIR_ITEM_KEY) {
+                if (log && dir_key->type == BTRFS_DIR_ITEM_KEY) {
                         log_di = btrfs_lookup_dir_item(trans, log, log_path,
                                                        dir_key->objectid,
                                                        name, name_len, 0);
-                } else if (dir_key->type == BTRFS_DIR_INDEX_KEY) {
+                } else if (log && dir_key->type == BTRFS_DIR_INDEX_KEY) {
                         log_di = btrfs_lookup_dir_index_item(trans, log,
                                                      log_path,
                                                      dir_key->objectid,
@@ -1378,7 +1452,7 @@ static noinline int replay_dir_deletes(struct btrfs_trans_handle *trans,
                                        struct btrfs_root *root,
                                        struct btrfs_root *log,
                                        struct btrfs_path *path,
-                                       u64 dirid)
+                                       u64 dirid, int del_all)
 {
         u64 range_start;
         u64 range_end;
@@ -1408,10 +1482,14 @@ again:
         range_start = 0;
         range_end = 0;
         while (1) {
-                ret = find_dir_range(log, path, dirid, key_type,
-                                     &range_start, &range_end);
-                if (ret != 0)
-                        break;
+                if (del_all)
+                        range_end = (u64)-1;
+                else {
+                        ret = find_dir_range(log, path, dirid, key_type,
+                                             &range_start, &range_end);
+                        if (ret != 0)
+                                break;
+                }
 
                 dir_key.offset = range_start;
                 while (1) {
@@ -1437,7 +1515,8 @@ again:
                                 break;
 
                         ret = check_item_in_log(trans, root, log, path,
-                                                log_path, dir, &found_key);
+                                                log_path, dir,
+                                                &found_key);
                         BUG_ON(ret);
                         if (found_key.offset == (u64)-1)
                                 break;
@@ -1514,7 +1593,7 @@ static int replay_one_buffer(struct btrfs_root *log, struct extent_buffer *eb,
                         mode = btrfs_inode_mode(eb, inode_item);
                         if (S_ISDIR(mode)) {
                                 ret = replay_dir_deletes(wc->trans,
-                                         root, log, path, key.objectid);
+                                         root, log, path, key.objectid, 0);
                                 BUG_ON(ret);
                         }
                         ret = overwrite_item(wc->trans, root, path,
@@ -1533,6 +1612,17 @@ static int replay_one_buffer(struct btrfs_root *log, struct extent_buffer *eb,
                                         root, inode, inode->i_size,
                                         BTRFS_EXTENT_DATA_KEY);
                                 BUG_ON(ret);
+
+                                /* if the nlink count is zero here, the iput
+                                 * will free the inode.  We bump it to make
+                                 * sure it doesn't get freed until the link
+                                 * count fixup is done
+                                 */
+                                if (inode->i_nlink == 0) {
+                                        btrfs_inc_nlink(inode);
+                                        btrfs_update_inode(wc->trans,
+                                                           root, inode);
+                                }
                                 iput(inode);
                         }
                         ret = link_to_fixup_dir(wc->trans, root,
@@ -1840,7 +1930,8 @@ static int update_log_root(struct btrfs_trans_handle *trans,
         return ret;
 }
 
-static int wait_log_commit(struct btrfs_root *root, unsigned long transid)
+static int wait_log_commit(struct btrfs_trans_handle *trans,
+                           struct btrfs_root *root, unsigned long transid)
 {
         DEFINE_WAIT(wait);
         int index = transid % 2;
@@ -1854,9 +1945,12 @@ static int wait_log_commit(struct btrfs_root *root, unsigned long transid)
                 prepare_to_wait(&root->log_commit_wait[index],
                                 &wait, TASK_UNINTERRUPTIBLE);
                 mutex_unlock(&root->log_mutex);
-                if (root->log_transid < transid + 2 &&
+
+                if (root->fs_info->last_trans_log_full_commit !=
+                    trans->transid && root->log_transid < transid + 2 &&
                     atomic_read(&root->log_commit[index]))
                         schedule();
+
                 finish_wait(&root->log_commit_wait[index], &wait);
                 mutex_lock(&root->log_mutex);
         } while (root->log_transid < transid + 2 &&
@@ -1864,14 +1958,16 @@ static int wait_log_commit(struct btrfs_root *root, unsigned long transid)
         return 0;
 }
 
-static int wait_for_writer(struct btrfs_root *root)
+static int wait_for_writer(struct btrfs_trans_handle *trans,
+                           struct btrfs_root *root)
 {
         DEFINE_WAIT(wait);
         while (atomic_read(&root->log_writers)) {
                 prepare_to_wait(&root->log_writer_wait,
                                 &wait, TASK_UNINTERRUPTIBLE);
                 mutex_unlock(&root->log_mutex);
-                if (atomic_read(&root->log_writers))
+                if (root->fs_info->last_trans_log_full_commit !=
+                    trans->transid && atomic_read(&root->log_writers))
                         schedule();
                 mutex_lock(&root->log_mutex);
                 finish_wait(&root->log_writer_wait, &wait);
@@ -1882,7 +1978,14 @@ static int wait_for_writer(struct btrfs_root *root)
 /*
  * btrfs_sync_log does sends a given tree log down to the disk and
  * updates the super blocks to record it.  When this call is done,
- * you know that any inodes previously logged are safely on disk
+ * you know that any inodes previously logged are safely on disk only
+ * if it returns 0.
+ *
+ * Any other return value means you need to call btrfs_commit_transaction.
+ * Some of the edge cases for fsyncing directories that have had unlinks
+ * or renames done in the past mean that sometimes the only safe
+ * fsync is to commit the whole FS.  When btrfs_sync_log returns -EAGAIN,
+ * that has happened.
  */
 int btrfs_sync_log(struct btrfs_trans_handle *trans,
                    struct btrfs_root *root)
@@ -1896,7 +1999,7 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
         mutex_lock(&root->log_mutex);
         index1 = root->log_transid % 2;
         if (atomic_read(&root->log_commit[index1])) {
-                wait_log_commit(root, root->log_transid);
+                wait_log_commit(trans, root, root->log_transid);
                 mutex_unlock(&root->log_mutex);
                 return 0;
         }
@@ -1904,18 +2007,26 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
 
         /* wait for previous tree log sync to complete */
         if (atomic_read(&root->log_commit[(index1 + 1) % 2]))
-                wait_log_commit(root, root->log_transid - 1);
+                wait_log_commit(trans, root, root->log_transid - 1);
 
         while (1) {
                 unsigned long batch = root->log_batch;
                 mutex_unlock(&root->log_mutex);
                 schedule_timeout_uninterruptible(1);
                 mutex_lock(&root->log_mutex);
-                wait_for_writer(root);
+
+                wait_for_writer(trans, root);
                 if (batch == root->log_batch)
                         break;
         }
 
+        /* bail out if we need to do a full commit */
+        if (root->fs_info->last_trans_log_full_commit == trans->transid) {
+                ret = -EAGAIN;
+                mutex_unlock(&root->log_mutex);
+                goto out;
+        }
+
         ret = btrfs_write_and_wait_marked_extents(log, &log->dirty_log_pages);
         BUG_ON(ret);
 
@@ -1951,16 +2062,29 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
 
         index2 = log_root_tree->log_transid % 2;
         if (atomic_read(&log_root_tree->log_commit[index2])) {
-                wait_log_commit(log_root_tree, log_root_tree->log_transid);
+                wait_log_commit(trans, log_root_tree,
+                                log_root_tree->log_transid);
                 mutex_unlock(&log_root_tree->log_mutex);
                 goto out;
         }
         atomic_set(&log_root_tree->log_commit[index2], 1);
 
-        if (atomic_read(&log_root_tree->log_commit[(index2 + 1) % 2]))
-                wait_log_commit(log_root_tree, log_root_tree->log_transid - 1);
+        if (atomic_read(&log_root_tree->log_commit[(index2 + 1) % 2])) {
+                wait_log_commit(trans, log_root_tree,
+                                log_root_tree->log_transid - 1);
+        }
+
+        wait_for_writer(trans, log_root_tree);
 
-        wait_for_writer(log_root_tree);
+        /*
+         * now that we've moved on to the tree of log tree roots,
+         * check the full commit flag again
+         */
+        if (root->fs_info->last_trans_log_full_commit == trans->transid) {
+                mutex_unlock(&log_root_tree->log_mutex);
+                ret = -EAGAIN;
+                goto out_wake_log_root;
+        }
 
         ret = btrfs_write_and_wait_marked_extents(log_root_tree,
                                 &log_root_tree->dirty_log_pages);
@@ -1985,7 +2109,9 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
          * in and cause problems either.
          */
         write_ctree_super(trans, root->fs_info->tree_root, 2);
+        ret = 0;
 
+out_wake_log_root:
         atomic_set(&log_root_tree->log_commit[index2], 0);
         smp_mb();
         if (waitqueue_active(&log_root_tree->log_commit_wait[index2]))
@@ -1998,7 +2124,8 @@ out:
         return 0;
 }
 
-/* * free all the extents used by the tree log.  This should be called
+/*
+ * free all the extents used by the tree log.  This should be called
  * at commit time of the full transaction
  */
 int btrfs_free_log(struct btrfs_trans_handle *trans, struct btrfs_root *root)
@@ -2132,7 +2259,7 @@ int btrfs_del_dir_entries_in_log(struct btrfs_trans_handle *trans,
 
         btrfs_free_path(path);
         mutex_unlock(&BTRFS_I(dir)->log_mutex);
-        end_log_trans(root);
+        btrfs_end_log_trans(root);
 
         return 0;
 }
@@ -2159,7 +2286,7 @@ int btrfs_del_inode_ref_in_log(struct btrfs_trans_handle *trans,
         ret = btrfs_del_inode_ref(trans, log, name, name_len, inode->i_ino,
                                   dirid, &index);
         mutex_unlock(&BTRFS_I(inode)->log_mutex);
-        end_log_trans(root);
+        btrfs_end_log_trans(root);
 
         return ret;
 }
@@ -2559,7 +2686,7 @@ static noinline int copy_items(struct btrfs_trans_handle *trans,
  *
  * This handles both files and directories.
  */
-static int __btrfs_log_inode(struct btrfs_trans_handle *trans,
+static int btrfs_log_inode(struct btrfs_trans_handle *trans,
                              struct btrfs_root *root, struct inode *inode,
                              int inode_only)
 {
@@ -2585,28 +2712,17 @@ static int __btrfs_log_inode(struct btrfs_trans_handle *trans,
         min_key.offset = 0;
 
         max_key.objectid = inode->i_ino;
+
+        /* today the code can only do partial logging of directories */
+        if (!S_ISDIR(inode->i_mode))
+            inode_only = LOG_INODE_ALL;
+
         if (inode_only == LOG_INODE_EXISTS || S_ISDIR(inode->i_mode))
                 max_key.type = BTRFS_XATTR_ITEM_KEY;
         else
                 max_key.type = (u8)-1;
         max_key.offset = (u64)-1;
 
-        /*
-         * if this inode has already been logged and we're in inode_only
-         * mode, we don't want to delete the things that have already
-         * been written to the log.
-         *
-         * But, if the inode has been through an inode_only log,
-         * the logged_trans field is not set.  This allows us to catch
-         * any new names for this inode in the backrefs by logging it
-         * again
-         */
-        if (inode_only == LOG_INODE_EXISTS &&
-            BTRFS_I(inode)->logged_trans == trans->transid) {
-                btrfs_free_path(path);
-                btrfs_free_path(dst_path);
-                goto out;
-        }
         mutex_lock(&BTRFS_I(inode)->log_mutex);
 
         /*
@@ -2693,7 +2809,6 @@ next_slot:
         if (inode_only == LOG_INODE_ALL && S_ISDIR(inode->i_mode)) {
                 btrfs_release_path(root, path);
                 btrfs_release_path(log, dst_path);
-                BTRFS_I(inode)->log_dirty_trans = 0;
                 ret = log_directory_changes(trans, root, inode, path, dst_path);
                 BUG_ON(ret);
         }
@@ -2702,19 +2817,69 @@ next_slot:
 
         btrfs_free_path(path);
         btrfs_free_path(dst_path);
-out:
         return 0;
 }
 
-int btrfs_log_inode(struct btrfs_trans_handle *trans,
-                    struct btrfs_root *root, struct inode *inode,
-                    int inode_only)
+/*
+ * follow the dentry parent pointers up the chain and see if any
+ * of the directories in it require a full commit before they can
+ * be logged.  Returns zero if nothing special needs to be done or 1 if
+ * a full commit is required.
+ */
+static noinline int check_parent_dirs_for_sync(struct btrfs_trans_handle *trans,
+                                               struct inode *inode,
+                                               struct dentry *parent,
+                                               struct super_block *sb,
+                                               u64 last_committed)
 {
-        int ret;
+        int ret = 0;
+        struct btrfs_root *root;
 
-        start_log_trans(trans, root);
-        ret = __btrfs_log_inode(trans, root, inode, inode_only);
-        end_log_trans(root);
+        /*
+         * for regular files, if its inode is already on disk, we don't
+         * have to worry about the parents at all.  This is because
+         * we can use the last_unlink_trans field to record renames
+         * and other fun in this file.
+         */
+        if (S_ISREG(inode->i_mode) &&
+            BTRFS_I(inode)->generation <= last_committed &&
+            BTRFS_I(inode)->last_unlink_trans <= last_committed)
+                        goto out;
+
+        if (!S_ISDIR(inode->i_mode)) {
+                if (!parent || !parent->d_inode || sb != parent->d_inode->i_sb)
+                        goto out;
+                inode = parent->d_inode;
+        }
+
+        while (1) {
+                BTRFS_I(inode)->logged_trans = trans->transid;
+                smp_mb();
+
+                if (BTRFS_I(inode)->last_unlink_trans > last_committed) {
+                        root = BTRFS_I(inode)->root;
+
+                        /*
+                         * make sure any commits to the log are forced
+                         * to be full commits
+                         */
+                        root->fs_info->last_trans_log_full_commit =
+                                trans->transid;
+                        ret = 1;
+                        break;
+                }
+
+                if (!parent || !parent->d_inode || sb != parent->d_inode->i_sb)
+                        break;
+
+                if (parent == sb->s_root)
+                        break;
+
+                parent = parent->d_parent;
+                inode = parent->d_inode;
+
+        }
+out:
         return ret;
 }
 
@@ -2724,31 +2889,65 @@ int btrfs_log_inode(struct btrfs_trans_handle *trans,
  * only logging is done of any parent directories that are older than
  * the last committed transaction
  */
-int btrfs_log_dentry(struct btrfs_trans_handle *trans,
-                    struct btrfs_root *root, struct dentry *dentry)
+int btrfs_log_inode_parent(struct btrfs_trans_handle *trans,
+                    struct btrfs_root *root, struct inode *inode,
+                    struct dentry *parent, int exists_only)
 {
-        int inode_only = LOG_INODE_ALL;
+        int inode_only = exists_only ? LOG_INODE_EXISTS : LOG_INODE_ALL;
         struct super_block *sb;
-        int ret;
+        int ret = 0;
+        u64 last_committed = root->fs_info->last_trans_committed;
+
+        sb = inode->i_sb;
+
+        if (root->fs_info->last_trans_log_full_commit >
+            root->fs_info->last_trans_committed) {
+                ret = 1;
+                goto end_no_trans;
+        }
+
+        ret = check_parent_dirs_for_sync(trans, inode, parent,
+                                         sb, last_committed);
+        if (ret)
+                goto end_no_trans;
 
         start_log_trans(trans, root);
-        sb = dentry->d_inode->i_sb;
-        while (1) {
-                ret = __btrfs_log_inode(trans, root, dentry->d_inode,
-                                        inode_only);
-                BUG_ON(ret);
-                inode_only = LOG_INODE_EXISTS;
 
-                dentry = dentry->d_parent;
-                if (!dentry || !dentry->d_inode || sb != dentry->d_inode->i_sb)
+        ret = btrfs_log_inode(trans, root, inode, inode_only);
+        BUG_ON(ret);
+
+        /*
+         * for regular files, if its inode is already on disk, we don't
+         * have to worry about the parents at all.  This is because
+         * we can use the last_unlink_trans field to record renames
+         * and other fun in this file.
+         */
+        if (S_ISREG(inode->i_mode) &&
+            BTRFS_I(inode)->generation <= last_committed &&
+            BTRFS_I(inode)->last_unlink_trans <= last_committed)
+                        goto no_parent;
+
+        inode_only = LOG_INODE_EXISTS;
+        while (1) {
+                if (!parent || !parent->d_inode || sb != parent->d_inode->i_sb)
                         break;
 
-                if (BTRFS_I(dentry->d_inode)->generation <=
-                    root->fs_info->last_trans_committed)
+                inode = parent->d_inode;
+                if (BTRFS_I(inode)->generation >
+                    root->fs_info->last_trans_committed) {
+                        ret = btrfs_log_inode(trans, root, inode, inode_only);
+                        BUG_ON(ret);
+                }
+                if (parent == sb->s_root)
                         break;
+
+                parent = parent->d_parent;
         }
-        end_log_trans(root);
-        return 0;
+no_parent:
+        ret = 0;
+        btrfs_end_log_trans(root);
+end_no_trans:
+        return ret;
 }
 
 /*
@@ -2760,12 +2959,8 @@ int btrfs_log_dentry(struct btrfs_trans_handle *trans,
 int btrfs_log_dentry_safe(struct btrfs_trans_handle *trans,
                           struct btrfs_root *root, struct dentry *dentry)
 {
-        u64 gen;
-        gen = root->fs_info->last_trans_new_blockgroup;
-        if (gen > root->fs_info->last_trans_committed)
-                return 1;
-        else
-                return btrfs_log_dentry(trans, root, dentry);
+        return btrfs_log_inode_parent(trans, root, dentry->d_inode,
+                                      dentry->d_parent, 0);
 }
 
 /*
@@ -2884,3 +3079,94 @@ again:
         kfree(log_root_tree);
         return 0;
 }
+
+/*
+ * there are some corner cases where we want to force a full
+ * commit instead of allowing a directory to be logged.
+ *
+ * They revolve around files there were unlinked from the directory, and
+ * this function updates the parent directory so that a full commit is
+ * properly done if it is fsync'd later after the unlinks are done.
+ */
+void btrfs_record_unlink_dir(struct btrfs_trans_handle *trans,
+                             struct inode *dir, struct inode *inode,
+                             int for_rename)
+{
+        /*
+         * when we're logging a file, if it hasn't been renamed
+         * or unlinked, and its inode is fully committed on disk,
+         * we don't have to worry about walking up the directory chain
+         * to log its parents.
+         *
+         * So, we use the last_unlink_trans field to put this transid
+         * into the file.  When the file is logged we check it and
+         * don't log the parents if the file is fully on disk.
+         */
+        if (S_ISREG(inode->i_mode))
+                BTRFS_I(inode)->last_unlink_trans = trans->transid;
+
+        /*
+         * if this directory was already logged any new
+         * names for this file/dir will get recorded
+         */
+        smp_mb();
+        if (BTRFS_I(dir)->logged_trans == trans->transid)
+                return;
+
+        /*
+         * if the inode we're about to unlink was logged,
+         * the log will be properly updated for any new names
+         */
+        if (BTRFS_I(inode)->logged_trans == trans->transid)
+                return;
+
+        /*
+         * when renaming files across directories, if the directory
+         * there we're unlinking from gets fsync'd later on, there's
+         * no way to find the destination directory later and fsync it
+         * properly.  So, we have to be conservative and force commits
+         * so the new name gets discovered.
+         */
+        if (for_rename)
+                goto record;
+
+        /* we can safely do the unlink without any special recording */
+        return;
+
+record:
+        BTRFS_I(dir)->last_unlink_trans = trans->transid;
+}
+
+/*
+ * Call this after adding a new name for a file and it will properly
+ * update the log to reflect the new name.
+ *
+ * It will return zero if all goes well, and it will return 1 if a
+ * full transaction commit is required.
+ */
+int btrfs_log_new_name(struct btrfs_trans_handle *trans,
+                        struct inode *inode, struct inode *old_dir,
+                        struct dentry *parent)
+{
+        struct btrfs_root * root = BTRFS_I(inode)->root;
+
+        /*
+         * this will force the logging code to walk the dentry chain
+         * up for the file
+         */
+        if (S_ISREG(inode->i_mode))
+                BTRFS_I(inode)->last_unlink_trans = trans->transid;
+
+        /*
+         * if this inode hasn't been logged and directory we're renaming it
+         * from hasn't been logged, we don't need to log it
+         */
+        if (BTRFS_I(inode)->logged_trans <=
+            root->fs_info->last_trans_committed &&
+            (!old_dir || BTRFS_I(old_dir)->logged_trans <=
+                    root->fs_info->last_trans_committed))
+                return 0;
+
+        return btrfs_log_inode_parent(trans, root, inode, parent, 1);
+}
+