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authorJens Axboe <jens.axboe@oracle.com>2010-05-17 12:55:07 +0200
committerJens Axboe <jens.axboe@oracle.com>2010-05-17 12:55:07 +0200
commite913fc825dc685a444cb4c1d0f9d32f372f59861 (patch)
treee470697e43ffe4028ac81c17d3ef90ee9f30bcfb /include/linux/writeback.h
parent69b62d01ec44fe0d505d89917392347732135a4d (diff)
writeback: fix WB_SYNC_NONE writeback from umount
When umount calls sync_filesystem(), we first do a WB_SYNC_NONE writeback to kick off writeback of pending dirty inodes, then follow that up with a WB_SYNC_ALL to wait for it. Since umount already holds the sb s_umount mutex, WB_SYNC_NONE ends up doing nothing and all writeback happens as WB_SYNC_ALL. This can greatly slow down umount, since WB_SYNC_ALL writeback is a data integrity operation and thus a bigger hammer than simple WB_SYNC_NONE. For barrier aware file systems it's a lot slower. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'include/linux/writeback.h')
-rw-r--r--include/linux/writeback.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index eb38a2c645f6..47e1c686cb02 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -65,6 +65,15 @@ struct writeback_control {
* so we use a single control to update them
*/
unsigned no_nrwrite_index_update:1;
+
+ /*
+ * For WB_SYNC_ALL, the sb must always be pinned. For WB_SYNC_NONE,
+ * the writeback code will pin the sb for the caller. However,
+ * for eg umount, the caller does WB_SYNC_NONE but already has
+ * the sb pinned. If the below is set, caller already has the
+ * sb pinned.
+ */
+ unsigned sb_pinned:1;
};
/*
@@ -73,6 +82,7 @@ struct writeback_control {
struct bdi_writeback;
int inode_wait(void *);
void writeback_inodes_sb(struct super_block *);
+void writeback_inodes_sb_locked(struct super_block *);
int writeback_inodes_sb_if_idle(struct super_block *);
void sync_inodes_sb(struct super_block *);
void writeback_inodes_wbc(struct writeback_control *wbc);