ext4: create function to read journal inode

Factor out the code used in ext4_get_journal() to read a valid journal
inode from storage, enabling its reuse in other functions.

Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 50912cc5fb96537544c0f6617a24e75e5d19b81a..056ca1bea2ac048919780a12e007edb57ed0ba43 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -78,6 +78,8 @@ static int ext4_feature_set_ok(struct super_block *sb, int readonly);
 static void ext4_destroy_lazyinit_thread(void);
 static void ext4_unregister_li_request(struct super_block *sb);
 static void ext4_clear_request_list(void);
+static struct inode *ext4_get_journal_inode(struct super_block *sb,
+                                           unsigned int journal_inum);
 
 /*
  * Lock ordering
@@ -4237,18 +4239,16 @@ static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
        write_unlock(&journal->j_state_lock);
 }
 
-static journal_t *ext4_get_journal(struct super_block *sb,
-                                  unsigned int journal_inum)
+static struct inode *ext4_get_journal_inode(struct super_block *sb,
+                                            unsigned int journal_inum)
 {
        struct inode *journal_inode;
-       journal_t *journal;
-
-       BUG_ON(!ext4_has_feature_journal(sb));
-
-       /* First, test for the existence of a valid inode on disk.  Bad
-        * things happen if we iget() an unused inode, as the subsequent
-        * iput() will try to delete it. */
 
+       /*
+        * Test for the existence of a valid inode on disk.  Bad things
+        * happen if we iget() an unused inode, as the subsequent iput()
+        * will try to delete it.
+        */
        journal_inode = ext4_iget(sb, journal_inum);
        if (IS_ERR(journal_inode)) {
                ext4_msg(sb, KERN_ERR, "no journal found");
@@ -4268,6 +4268,20 @@ static journal_t *ext4_get_journal(struct super_block *sb,
                iput(journal_inode);
                return NULL;
        }
+       return journal_inode;
+}
+
+static journal_t *ext4_get_journal(struct super_block *sb,
+                                  unsigned int journal_inum)
+{
+       struct inode *journal_inode;
+       journal_t *journal;
+
+       BUG_ON(!ext4_has_feature_journal(sb));
+
+       journal_inode = ext4_get_journal_inode(sb, journal_inum);
+       if (!journal_inode)
+               return NULL;
 
        journal = jbd2_journal_init_inode(journal_inode);
        if (!journal) {