ext4: Don't set EXTENTS_FL flag for fast symlinks

For fast symbolic links, the file content is stored in the i_block[]
array, which is not compatible with the new file extents format.
e2fsck reports error on such files because EXTENTS_FL is set.
Don't set the EXTENTS_FL flag when creating fast symlinks.

In the case of file migration, skip fast symbolic links.
Signed-off-by: Valerie Clement <valerie.clement@bull.net>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/migrate.c

@@ -414,6 +414,12 @@ int ext4_ext_migrate(struct inode *inode, struct file *filp,
 	if ((EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
 		return -EINVAL;
 
+	if (S_ISLNK(inode->i_mode) && inode->i_blocks == 0)
+		/*
+		 * don't migrate fast symlink
+		 */
+		return retval;
+
 	down_write(&EXT4_I(inode)->i_data_sem);
 	handle = ext4_journal_start(inode,
 					EXT4_DATA_TRANS_BLOCKS(inode->i_sb) +

fs/ext4/namei.c

@@ -2223,6 +2223,7 @@ retry:
 		inode->i_op = &ext4_fast_symlink_inode_operations;
 		memcpy((char*)&EXT4_I(inode)->i_data,symname,l);
 		inode->i_size = l-1;
+		EXT4_I(inode)->i_flags &= ~EXT4_EXTENTS_FL;
 	}
 	EXT4_I(inode)->i_disksize = inode->i_size;
 	err = ext4_add_nondir(handle, dentry, inode);