Commit 8c208719 authored Aug 11, 2011 by Eric Sandeen Committed by Linus Torvalds Aug 11, 2011

ext4: Properly count journal credits for long symlinks



Commit df5e6223 ("ext4: fix deadlock in ext4_symlink() in ENOSPC
conditions") recalculated the number of credits needed for a long
symlink, in the process of splitting it into two transactions.  However,
the first credit calculation under-counted because if selinux is
enabled, credits are needed to create the selinux xattr as well.

Overrunning the reservation will result in an OOPS in
jbd2_journal_dirty_metadata() due to this assert:

  J_ASSERT_JH(jh, handle->h_buffer_credits > 0);

Fix this by increasing the reservation size.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent d2db60df

fs/ext4/namei.c

+4 −2

Original line number	Original line	Diff line number	Diff line
	@@ -2253,9 +2253,11 @@ static int ext4_symlink(struct inode *dir,
	/*		/*
	* For non-fast symlinks, we just allocate inode and put it on		* For non-fast symlinks, we just allocate inode and put it on
	* orphan list in the first transaction => we need bitmap,		* orphan list in the first transaction => we need bitmap,
	* group descriptor, sb, inode block, quota blocks.		* group descriptor, sb, inode block, quota blocks, and
			* possibly selinux xattr blocks.
	*/		*/
	credits = 4 + EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb);		credits = 4 + EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
			EXT4_XATTR_TRANS_BLOCKS;
	} else {		} else {
	/*		/*
	* Fast symlink. We have to add entry to directory		* Fast symlink. We have to add entry to directory