ocfs2: Introduce dir lookup helper struct

Many directory manipulation calls pass around a tuple of dirent, and it's
containing buffer_head. Dir indexing has a bit more state, but instead of
adding yet more arguments to functions, we introduce 'struct
ocfs2_dir_lookup_result'. In this patch, it simply holds the same tuple, but
future patches will add more state.

Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Acked-by: Joel Becker <joel.becker@oracle.com>

1 files changed, 54 insertions, 45 deletions

diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index f2c4098cf337..76ffb5c10b3e 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -152,6 +152,11 @@ static void ocfs2_init_dir_trailer(struct inode *inode,
         trailer->db_blkno = cpu_to_le64(bh->b_blocknr);
 }
 
+void ocfs2_free_dir_lookup_result(struct ocfs2_dir_lookup_result *res)
+{
+        brelse(res->dl_leaf_bh);
+}
+
 /*
  * bh passed here can be an inode block or a dir data block, depending
  * on the inode inline data flag.
@@ -483,36 +488,46 @@ cleanup_and_exit:
 /*
  * Try to find an entry of the provided name within 'dir'.
  *
- * If nothing was found, NULL is returned. Otherwise, a buffer_head
- * and pointer to the dir entry are passed back.
+ * If nothing was found, -ENOENT is returned. Otherwise, zero is
+ * returned and the struct 'res' will contain information useful to
+ * other directory manipulation functions.
  *
  * Caller can NOT assume anything about the contents of the
- * buffer_head - it is passed back only so that it can be passed into
+ * buffer_heads - they are passed back only so that it can be passed into
  * any one of the manipulation functions (add entry, delete entry,
  * etc). As an example, bh in the extent directory case is a data
  * block, in the inline-data case it actually points to an inode.
  */
-struct buffer_head *ocfs2_find_entry(const char *name, int namelen,
-                                     struct inode *dir,
-                                     struct ocfs2_dir_entry **res_dir)
+int ocfs2_find_entry(const char *name, int namelen,
+                     struct inode *dir, struct ocfs2_dir_lookup_result *lookup)
 {
-        *res_dir = NULL;
+        struct buffer_head *bh;
+        struct ocfs2_dir_entry *res_dir = NULL;
 
         if (OCFS2_I(dir)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
-                return ocfs2_find_entry_id(name, namelen, dir, res_dir);
+                bh = ocfs2_find_entry_id(name, namelen, dir, &res_dir);
+        else
+                bh = ocfs2_find_entry_el(name, namelen, dir, &res_dir);
 
-        return ocfs2_find_entry_el(name, namelen, dir, res_dir);
+        if (bh == NULL)
+                return -ENOENT;
+
+        lookup->dl_leaf_bh = bh;
+        lookup->dl_entry = res_dir;
+        return 0;
 }
 
 /*
  * Update inode number and type of a previously found directory entry.
  */
 int ocfs2_update_entry(struct inode *dir, handle_t *handle,
-                       struct buffer_head *de_bh, struct ocfs2_dir_entry *de,
+                       struct ocfs2_dir_lookup_result *res,
                        struct inode *new_entry_inode)
 {
         int ret;
         ocfs2_journal_access_func access = ocfs2_journal_access_db;
+        struct ocfs2_dir_entry *de = res->dl_entry;
+        struct buffer_head *de_bh = res->dl_leaf_bh;
 
         /*
          * The same code works fine for both inline-data and extent
@@ -629,13 +644,14 @@ static inline int ocfs2_delete_entry_el(handle_t *handle,
  */
 int ocfs2_delete_entry(handle_t *handle,
                        struct inode *dir,
-                       struct ocfs2_dir_entry *de_del,
-                       struct buffer_head *bh)
+                       struct ocfs2_dir_lookup_result *res)
 {
         if (OCFS2_I(dir)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
-                return ocfs2_delete_entry_id(handle, dir, de_del, bh);
+                return ocfs2_delete_entry_id(handle, dir, res->dl_entry,
+                                             res->dl_leaf_bh);
 
-        return ocfs2_delete_entry_el(handle, dir, de_del, bh);
+        return ocfs2_delete_entry_el(handle, dir, res->dl_entry,
+                                     res->dl_leaf_bh);
 }
 
 /*
@@ -666,15 +682,15 @@ static inline int ocfs2_dirent_would_fit(struct ocfs2_dir_entry *de,
 /* we don't always have a dentry for what we want to add, so people
  * like orphan dir can call this instead.
  *
- * If you pass me insert_bh, I'll skip the search of the other dir
- * blocks and put the record in there.
+ * The lookup context must have been filled from
+ * ocfs2_prepare_dir_for_insert.
  */
 int __ocfs2_add_entry(handle_t *handle,
                       struct inode *dir,
                       const char *name, int namelen,
                       struct inode *inode, u64 blkno,
                       struct buffer_head *parent_fe_bh,
-                      struct buffer_head *insert_bh)
+                      struct ocfs2_dir_lookup_result *lookup)
 {
         unsigned long offset;
         unsigned short rec_len;
@@ -683,6 +699,7 @@ int __ocfs2_add_entry(handle_t *handle,
         struct super_block *sb = dir->i_sb;
         int retval, status;
         unsigned int size = sb->s_blocksize;
+        struct buffer_head *insert_bh = lookup->dl_leaf_bh;
         char *data_start = insert_bh->b_data;
 
         mlog_entry_void();
@@ -1071,31 +1088,22 @@ int ocfs2_find_files_on_disk(const char *name,
                              int namelen,
                              u64 *blkno,
                              struct inode *inode,
-                             struct buffer_head **dirent_bh,
-                             struct ocfs2_dir_entry **dirent)
+                             struct ocfs2_dir_lookup_result *lookup)
 {
         int status = -ENOENT;
 
-        mlog_entry("(name=%.*s, blkno=%p, inode=%p, dirent_bh=%p, dirent=%p)\n",
-                   namelen, name, blkno, inode, dirent_bh, dirent);
+        mlog(0, "name=%.*s, blkno=%p, inode=%llu\n", namelen, name, blkno,
+             (unsigned long long)OCFS2_I(inode)->ip_blkno);
 
-        *dirent_bh = ocfs2_find_entry(name, namelen, inode, dirent);
-        if (!*dirent_bh || !*dirent) {
-                status = -ENOENT;
+        status = ocfs2_find_entry(name, namelen, inode, lookup);
+        if (status)
                 goto leave;
-        }
 
-        *blkno = le64_to_cpu((*dirent)->inode);
+        *blkno = le64_to_cpu(lookup->dl_entry->inode);
 
         status = 0;
 leave:
-        if (status < 0) {
-                *dirent = NULL;
-                brelse(*dirent_bh);
-                *dirent_bh = NULL;
-        }
 
-        mlog_exit(status);
         return status;
 }
 
@@ -1107,11 +1115,10 @@ int ocfs2_lookup_ino_from_name(struct inode *dir, const char *name,
                                int namelen, u64 *blkno)
 {
         int ret;
-        struct buffer_head *bh = NULL;
-        struct ocfs2_dir_entry *dirent = NULL;
+        struct ocfs2_dir_lookup_result lookup = { NULL, };
 
-        ret = ocfs2_find_files_on_disk(name, namelen, blkno, dir, &bh, &dirent);
-        brelse(bh);
+        ret = ocfs2_find_files_on_disk(name, namelen, blkno, dir, &lookup);
+        ocfs2_free_dir_lookup_result(&lookup);
 
         return ret;
 }
@@ -1128,20 +1135,18 @@ int ocfs2_check_dir_for_entry(struct inode *dir,
                               int namelen)
 {
         int ret;
-        struct buffer_head *dirent_bh = NULL;
-        struct ocfs2_dir_entry *dirent = NULL;
+        struct ocfs2_dir_lookup_result lookup = { NULL, };
 
         mlog_entry("dir %llu, name '%.*s'\n",
                    (unsigned long long)OCFS2_I(dir)->ip_blkno, namelen, name);
 
         ret = -EEXIST;
-        dirent_bh = ocfs2_find_entry(name, namelen, dir, &dirent);
-        if (dirent_bh)
+        if (ocfs2_find_entry(name, namelen, dir, &lookup) == 0)
                 goto bail;
 
         ret = 0;
 bail:
-        brelse(dirent_bh);
+        ocfs2_free_dir_lookup_result(&lookup);
 
         mlog_exit(ret);
         return ret;
@@ -1970,12 +1975,18 @@ bail:
         return status;
 }
 
+/*
+ * Get a directory ready for insert. Any directory allocation required
+ * happens here. Success returns zero, and enough context in the dir
+ * lookup result that ocfs2_add_entry() will be able complete the task
+ * with minimal performance impact.
+ */
 int ocfs2_prepare_dir_for_insert(struct ocfs2_super *osb,
                                  struct inode *dir,
                                  struct buffer_head *parent_fe_bh,
                                  const char *name,
                                  int namelen,
-                                 struct buffer_head **ret_de_bh)
+                                 struct ocfs2_dir_lookup_result *lookup)
 {
         int ret;
         unsigned int blocks_wanted = 1;
@@ -1984,8 +1995,6 @@ int ocfs2_prepare_dir_for_insert(struct ocfs2_super *osb,
         mlog(0, "getting ready to insert namelen %d into dir %llu\n",
              namelen, (unsigned long long)OCFS2_I(dir)->ip_blkno);
 
-        *ret_de_bh = NULL;
-
         if (!namelen) {
                 ret = -EINVAL;
                 mlog_errno(ret);
@@ -2020,7 +2029,7 @@ int ocfs2_prepare_dir_for_insert(struct ocfs2_super *osb,
                 BUG_ON(!bh);
         }
 
-        *ret_de_bh = bh;
+        lookup->dl_leaf_bh = bh;
         bh = NULL;
 out:
         brelse(bh);