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authorNick Piggin <npiggin@suse.de>2009-01-06 14:40:26 -0800
committerGreg Kroah-Hartman <gregkh@suse.de>2009-01-24 16:36:28 -0800
commite2a60f48bfd758fc85afbd278950e989a9814a50 (patch)
treeed7c274f1c69091d4b90d9969380c0cb84e2fe53
parent229dfbd9fb66befda9abbc7fd58bb0cafcd4d0d7 (diff)
downloadlinux-linaro-stable-e2a60f48bfd758fc85afbd278950e989a9814a50.tar.gz
fs: sys_sync fix
commit 856bf4d717feb8c55d4e2f817b71ebb70cfbc67b upstream. s_syncing livelock avoidance was breaking data integrity guarantee of sys_sync, by allowing sys_sync to skip writing or waiting for superblocks if there is a concurrent sys_sync happening. This livelock avoidance is much less important now that we don't have the get_super_to_sync() call after every sb that we sync. This was replaced by __put_super_and_need_restart. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--fs/fs-writeback.c20
-rw-r--r--include/linux/fs.h1
2 files changed, 1 insertions, 20 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 9d2f9dc..c8616a0 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -652,18 +652,6 @@ void sync_inodes_sb(struct super_block *sb, int wait)
sync_sb_inodes(sb, &wbc);
}
-/*
- * Rather lame livelock avoidance.
- */
-static void set_sb_syncing(int val)
-{
- struct super_block *sb;
- spin_lock(&sb_lock);
- list_for_each_entry_reverse(sb, &super_blocks, s_list)
- sb->s_syncing = val;
- spin_unlock(&sb_lock);
-}
-
/**
* sync_inodes - writes all inodes to disk
* @wait: wait for completion
@@ -690,9 +678,6 @@ static void __sync_inodes(int wait)
spin_lock(&sb_lock);
restart:
list_for_each_entry(sb, &super_blocks, s_list) {
- if (sb->s_syncing)
- continue;
- sb->s_syncing = 1;
sb->s_count++;
spin_unlock(&sb_lock);
down_read(&sb->s_umount);
@@ -710,13 +695,10 @@ restart:
void sync_inodes(int wait)
{
- set_sb_syncing(0);
__sync_inodes(0);
- if (wait) {
- set_sb_syncing(0);
+ if (wait)
__sync_inodes(1);
- }
}
/**
diff --git a/include/linux/fs.h b/include/linux/fs.h
index d621217..d1b3e22 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1080,7 +1080,6 @@ struct super_block {
struct rw_semaphore s_umount;
struct mutex s_lock;
int s_count;
- int s_syncing;
int s_need_sync_fs;
atomic_t s_active;
#ifdef CONFIG_SECURITY