UBIFS: fix file-system synchronization

[~andy/linux] / fs / ubifs / super.c

diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 13097830e8bce58b843bb70ad33cda772659fb80..471301799c52cc94f5c70e43ade04c11f814070c 100644 (file)
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -35,6 +35,7 @@
 #include <linux/seq_file.h>
 #include <linux/mount.h>
 #include <linux/math64.h>
+#include <linux/writeback.h>
 #include "ubifs.h"
 
 /*
@@ -431,6 +432,23 @@ static int ubifs_sync_fs(struct super_block *sb, int wait)
        struct ubifs_info *c = sb->s_fs_info;
        int i, ret = 0, err;
        long long bud_bytes;
+       struct writeback_control wbc = {
+               .sync_mode   = wait ? WB_SYNC_ALL : WB_SYNC_HOLD,
+               .range_start = 0,
+               .range_end   = LLONG_MAX,
+               .nr_to_write = LONG_MAX,
+       };
+
+       /*
+        * VFS calls '->sync_fs()' before synchronizing all dirty inodes and
+        * pages, so synchronize them first, then commit the journal. Strictly
+        * speaking, it is not necessary to commit the journal here,
+        * synchronizing write-buffers would be enough. But committing makes
+        * UBIFS free space predictions much more accurate, so we want to let
+        * the user be able to get more accurate results of 'statfs()' after
+        * they synchronize the file system.
+        */
+       generic_sync_sb_inodes(sb, &wbc);
 
        if (c->jheads) {
                for (i = 0; i < c->jhead_cnt; i++) {