jbd2: Remove __GFP_NOFAIL from jbd2 layer
__GFP_NOFAIL is going away, so add our own retry loop. Also add
jbd2__journal_start() and jbd2__journal_restart() which take a gfp
mask, so that file systems can optionally (re)start transaction
handles using GFP_KERNEL. If they do this, then they need to be
prepared to handle receiving an PTR_ERR(-ENOMEM) error, and be ready
to reflect that error up to userspace.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index f7bf157..a79d334 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -41,6 +41,7 @@
#include <linux/hash.h>
#include <linux/log2.h>
#include <linux/vmalloc.h>
+#include <linux/backing-dev.h>
#define CREATE_TRACE_POINTS
#include <trace/events/jbd2.h>
@@ -48,8 +49,6 @@
#include <asm/uaccess.h>
#include <asm/page.h>
-EXPORT_SYMBOL(jbd2_journal_start);
-EXPORT_SYMBOL(jbd2_journal_restart);
EXPORT_SYMBOL(jbd2_journal_extend);
EXPORT_SYMBOL(jbd2_journal_stop);
EXPORT_SYMBOL(jbd2_journal_lock_updates);
@@ -311,7 +310,17 @@
*/
J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in));
- new_bh = alloc_buffer_head(GFP_NOFS|__GFP_NOFAIL);
+retry_alloc:
+ new_bh = alloc_buffer_head(GFP_NOFS);
+ if (!new_bh) {
+ /*
+ * Failure is not an option, but __GFP_NOFAIL is going
+ * away; so we retry ourselves here.
+ */
+ congestion_wait(BLK_RW_ASYNC, HZ/50);
+ goto retry_alloc;
+ }
+
/* keep subsequent assertions sane */
new_bh->b_state = 0;
init_buffer(new_bh, NULL, NULL);
