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-rw-r--r--fs/fs-writeback.c9
-rw-r--r--include/linux/writeback.h1
2 files changed, 8 insertions, 2 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 3be57189efd5..a85ac4e33436 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -45,6 +45,7 @@ struct wb_writeback_work {
unsigned int for_kupdate:1;
unsigned int range_cyclic:1;
unsigned int for_background:1;
+ unsigned int for_sync:1; /* sync(2) WB_SYNC_ALL writeback */
enum wb_reason reason; /* why was writeback initiated? */
struct list_head list; /* pending work list */
@@ -443,9 +444,11 @@ __writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
/*
* Make sure to wait on the data before writing out the metadata.
* This is important for filesystems that modify metadata on data
- * I/O completion.
+ * I/O completion. We don't do it for sync(2) writeback because it has a
+ * separate, external IO completion path and ->sync_fs for guaranteeing
+ * inode metadata is written back correctly.
*/
- if (wbc->sync_mode == WB_SYNC_ALL) {
+ if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync) {
int err = filemap_fdatawait(mapping);
if (ret == 0)
ret = err;
@@ -578,6 +581,7 @@ static long writeback_sb_inodes(struct super_block *sb,
.tagged_writepages = work->tagged_writepages,
.for_kupdate = work->for_kupdate,
.for_background = work->for_background,
+ .for_sync = work->for_sync,
.range_cyclic = work->range_cyclic,
.range_start = 0,
.range_end = LLONG_MAX,
@@ -1362,6 +1366,7 @@ void sync_inodes_sb(struct super_block *sb)
.range_cyclic = 0,
.done = &done,
.reason = WB_REASON_SYNC,
+ .for_sync = 1,
};
/* Nothing to do? */
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 579a5007c696..abfe11787af3 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -78,6 +78,7 @@ struct writeback_control {
unsigned tagged_writepages:1; /* tag-and-write to avoid livelock */
unsigned for_reclaim:1; /* Invoked from the page allocator */
unsigned range_cyclic:1; /* range_start is cyclic */
+ unsigned for_sync:1; /* sync(2) WB_SYNC_ALL writeback */
};
/*