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Commit bc965ab3 authored by Theodore Ts'o's avatar Theodore Ts'o
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ext4: Fix lack of credits BUG() when deleting a badly fragmented inode 



The extents codepath for ext4_truncate() requests journal transaction
credits in very small chunks, requesting only what is needed.  This
means there may not be enough credits left on the transaction handle
after ext4_truncate() returns and then when ext4_delete_inode() tries
finish up its work, it may not have enough transaction credits,
causing a BUG() oops in the jbd2 core.

Also, reserve an extra 2 blocks when starting an ext4_delete_inode()
since we need to update the inode bitmap, as well as update the
orphaned inode linked list.

Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 0123c939

fs/ext4/inode.c

+29 −1
Original line number Diff line number Diff line
@@ -191,6 +191,7 @@ static int ext4_journal_test_restart(handle_t *handle, struct inode *inode) 
void ext4_delete_inode (struct inode * inode)

{

	handle_t *handle;

	int err;



	if (ext4_should_order_data(inode))

		ext4_begin_ordered_truncate(inode, 0);
@@ -199,8 +200,9 @@ void ext4_delete_inode (struct inode * inode) 
	if (is_bad_inode(inode))

		goto no_delete;



	handle = start_transaction(inode);

	handle = ext4_journal_start(inode, blocks_for_truncate(inode)+3);

	if (IS_ERR(handle)) {

		ext4_std_error(inode->i_sb, PTR_ERR(handle));

		/*

		 * If we're going to skip the normal cleanup, we still need to

		 * make sure that the in-core orphan linked list is properly
@@ -213,8 +215,34 @@ void ext4_delete_inode (struct inode * inode) 
	if (IS_SYNC(inode))

		handle->h_sync = 1;

	inode->i_size = 0;

	err = ext4_mark_inode_dirty(handle, inode);

	if (err) {

		ext4_warning(inode->i_sb, __func__,

			     "couldn't mark inode dirty (err %d)", err);

		goto stop_handle;

	}

	if (inode->i_blocks)

		ext4_truncate(inode);



	/*

	 * ext4_ext_truncate() doesn't reserve any slop when it

	 * restarts journal transactions; therefore there may not be

	 * enough credits left in the handle to remove the inode from

	 * the orphan list and set the dtime field.

	 */

	if (handle->h_buffer_credits < 3) {

		err = ext4_journal_extend(handle, 3);

		if (err > 0)

			err = ext4_journal_restart(handle, 3);

		if (err != 0) {

			ext4_warning(inode->i_sb, __func__,

				     "couldn't extend journal (err %d)", err);

		stop_handle:

			ext4_journal_stop(handle);

			goto no_delete;

		}

	}



	/*

	 * Kill off the orphan record which ext4_truncate created.

	 * AKPM: I think this can be inside the above `if'.