Commit b5e2368b authored Sep 18, 2012 by Theodore Ts'o

ext4: re-enable -o discard functionality in no-journal mode



This is a revert of commit b56ff9d3, which removed the call to
ext4_issue_discard() to fix a BUG reported because
ext4_issue_discard() was being called from inside a block group
spinlock.  As it turns out this bug had already been fixed by Lukas
Czerner in commit 53fdcf99 by the simple expedient of moving when
we call ext4_issue_discard() outside the spinlock.

So it should be safe to re-enable this functionality, which I tested
by putting an BUG_ON(in_atomic) just after the restored callsite to
ext4_issue_discard().

Addresses-Google-Bug: #6750518

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Anatol Pomozov <anatol.pomozov@gmail.com>

parent 90b0a973

fs/ext4/mballoc.c

+2 −0

Original line number	Original line	Diff line number	Diff line
	@@ -4656,6 +4656,8 @@ void ext4_free_blocks(handle_t handle, struct inode inode,
	* with group lock held. generate_buddy look at		* with group lock held. generate_buddy look at
	* them with group lock_held		* them with group lock_held
	*/		*/
			if (test_opt(sb, DISCARD))
			ext4_issue_discard(sb, block_group, bit, count);
	ext4_lock_group(sb, block_group);		ext4_lock_group(sb, block_group);
	mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);		mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);
	mb_free_blocks(inode, &e4b, bit, count_clusters);		mb_free_blocks(inode, &e4b, bit, count_clusters);