Commit eabb26ca authored Dec 21, 2010 by Prasad Joshi Committed by Linus Torvalds Dec 22, 2010

logfs: fix deadlock in logfs_get_wblocks, hold and wait on super->s_write_mutex

do_logfs_journal_wl_pass() should use GFP_NOFS for memory allocation GC
code calls btree_insert32 with GFP_KERNEL while holding a mutex
super->s_write_mutex.

The same mutex is used in address_space_operations->writepage(), and a
call to writepage() could be triggered as a result of memory allocation
in btree_insert32, causing a deadlock.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=20342



Signed-off-by: Prasad Joshi <prasadjoshi124@gmail.com>
Cc: Joern Engel <joern@logfs.org>
Cc: Florian Mickler <florian@mickler.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Maciej Rutecki <maciej.rutecki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 7a2d19bc

fs/logfs/journal.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -828,7 +828,7 @@ void do_logfs_journal_wl_pass(struct super_block *sb)
	super->s_journal_seg[i] = segno;		super->s_journal_seg[i] = segno;
	super->s_journal_ec[i] = ec;		super->s_journal_ec[i] = ec;
	logfs_set_segment_reserved(sb, segno);		logfs_set_segment_reserved(sb, segno);
	err = btree_insert32(head, segno, (void *)1, GFP_KERNEL);		err = btree_insert32(head, segno, (void *)1, GFP_NOFS);
	BUG_ON(err); /* mempool should prevent this */		BUG_ON(err); /* mempool should prevent this */
	err = logfs_erase_segment(sb, segno, 1);		err = logfs_erase_segment(sb, segno, 1);
	BUG_ON(err); /* FIXME: remount-ro would be nicer */		BUG_ON(err); /* FIXME: remount-ro would be nicer */

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