Messages in this thread Patch in this message | | | Date | Thu, 22 Jan 2009 17:13:16 -0800 | From | Greg KH <> | Subject | [patch 46/46] fs: sys_sync fix |
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2.6.28-stable review patch. If anyone has any objections, please let us know.
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From: Nick Piggin <npiggin@suse.de>
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>
--- fs/fs-writeback.c | 20 +------------------- include/linux/fs.h | 1 - 2 files changed, 1 insertion(+), 20 deletions(-)
--- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -652,18 +652,6 @@ void sync_inodes_sb(struct super_block * 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); - } } /** --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1124,7 +1124,6 @@ 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
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