ext4: start handle at the last possible moment when creating inodes

In ext4_{create,mknod,mkdir,symlink}(), don't start the journal handle
until the inode has been succesfully allocated.  In order to do this,
we need to start the handle in the ext4_new_inode().  So create a new
variant of this function, ext4_new_inode_start_handle(), so the handle
can be created at the last possible minute, before we need to modify
the inode allocation bitmap block.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 13 insertions, 2 deletions

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 10bd6fecc9ff..91d8fe3aced3 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -634,8 +634,10 @@ static int find_group_other(struct super_block *sb, struct inode *parent,
  * For other inodes, search forward from the parent directory's block
  * group to find a free inode.
  */
-struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, umode_t mode,
-                             const struct qstr *qstr, __u32 goal, uid_t *owner)
+struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
+                               umode_t mode, const struct qstr *qstr,
+                               __u32 goal, uid_t *owner, int handle_type,
+                               unsigned int line_no, int nblocks)
 {
         struct super_block *sb;
         struct buffer_head *inode_bitmap_bh = NULL;
@@ -725,6 +727,15 @@ repeat_in_this_group:
                                    "inode=%lu", ino + 1);
                         continue;
                 }
+                if (!handle) {
+                        BUG_ON(nblocks <= 0);
+                        handle = __ext4_journal_start_sb(dir->i_sb, line_no,
+                                                         handle_type, nblocks);
+                        if (IS_ERR(handle)) {
+                                err = PTR_ERR(handle);
+                                goto fail;
+                        }
+                }
                 BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
                 err = ext4_journal_get_write_access(handle, inode_bitmap_bh);
                 if (err)