Commit bc965ab3 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

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
......@@ -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'.
......
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