Merge tag 'ext4_for_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 fixes from Ted Ts'o:
 "Fix a regression which caused us to fail to interpret symlinks in very
  ancient ext3 file system images.

  Also fix two xfstests failures, one of which could cause an OOPS, plus
  an additional bug fix caught by fuzz testing"

* tag 'ext4_for_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: fix crash when a directory's i_size is too small
  ext4: add missing error check in __ext4_new_inode()
  ext4: fix fdatasync(2) after fallocate(2) operation
  ext4: support fast symlinks from ext3 file systems

Author: torvalds

fs/ext4/extents.c

@@ -4722,6 +4722,7 @@ static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
 						    EXT4_INODE_EOFBLOCKS);
 		}
 		ext4_mark_inode_dirty(handle, inode);
+		ext4_update_inode_fsync_trans(handle, inode, 1);
 		ret2 = ext4_journal_stop(handle);
 		if (ret2)
 			break;

fs/ext4/ialloc.c

@@ -816,6 +816,8 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 		struct posix_acl *p = get_acl(dir, ACL_TYPE_DEFAULT);
 
+		if (IS_ERR(p))
+			return ERR_CAST(p);
 		if (p) {
 			int acl_size = p->a_count * sizeof(ext4_acl_entry);
 

fs/ext4/inode.c

@@ -149,6 +149,15 @@ static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
  */
 int ext4_inode_is_fast_symlink(struct inode *inode)
 {
+	if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
+		int ea_blocks = EXT4_I(inode)->i_file_acl ?
+				EXT4_CLUSTER_SIZE(inode->i_sb) >> 9 : 0;
+
+		if (ext4_has_inline_data(inode))
+			return 0;
+
+		return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
+	}
 	return S_ISLNK(inode->i_mode) && inode->i_size &&
 	       (inode->i_size < EXT4_N_BLOCKS * 4);
 }

fs/ext4/namei.c

@@ -1399,6 +1399,10 @@ static struct buffer_head * ext4_find_entry (struct inode *dir,
 			       "falling back\n"));
 	}
 	nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
+	if (!nblocks) {
+		ret = NULL;
+		goto cleanup_and_exit;
+	}
 	start = EXT4_I(dir)->i_dir_start_lookup;
 	if (start >= nblocks)
 		start = 0;