The patch titled
fs: sys_sync fix
has been added to the -mm tree. Its filename is
fs-sys_sync-fix.patch
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------------------------------------------------------
Subject: fs: sys_sync fix
From: Nick Piggin <npiggin@xxxxxxx>
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@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/fs-writeback.c | 20 +-------------------
include/linux/fs.h | 1 -
2 files changed, 1 insertion(+), 20 deletions(-)
diff -puN fs/fs-writeback.c~fs-sys_sync-fix fs/fs-writeback.c
--- a/fs/fs-writeback.c~fs-sys_sync-fix
+++ a/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);
- }
}
/**
diff -puN include/linux/fs.h~fs-sys_sync-fix include/linux/fs.h
--- a/include/linux/fs.h~fs-sys_sync-fix
+++ a/include/linux/fs.h
@@ -1112,7 +1112,6 @@ 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
_
Patches currently in -mm which might be from npiggin@xxxxxxx are
linux-next.patch
mm-dont-mark_page_accessed-in-fault-path.patch
mm-dont-mark_page_accessed-in-shmem_fault.patch
mm-invoke-oom-killer-from-page-fault.patch
mm-invoke-oom-killer-from-page-fault-fix.patch
mm-invoke-oom-killer-from-page-fault-fix-fix-2.patch
mm-write_cache_pages-cyclic-fix.patch
mm-write_cache_pages-cyclic-fix-fix.patch
mm-write_cache_pages-early-loop-termination.patch
mm-write_cache_pages-writepage-error-fix.patch
mm-write_cache_pages-integrity-fix.patch
mm-write_cache_pages-cleanups.patch
mm-write_cache_pages-optimise-page-cleaning.patch
mm-write_cache_pages-terminate-quickly.patch
mm-write_cache_pages-more-terminate-quickly.patch
mm-do_sync_mapping_range-integrity-fix.patch
mm-get-rid-of-pagevec_release_nonlru.patch
mm-more-likely-reclaim-madv_sequential-mappings.patch
mm-vmalloc-tweak-failure-printk.patch
mm-vmalloc-improve-vmallocinfo.patch
mm-vmalloc-use-mutex-for-purge.patch
mm-vmalloc-make-lazy-unmapping-configurable.patch
fs-truncate-blocks-outside-i_size-after-o_direct-write-error.patch
fs-truncate-blocks-outside-i_size-after-o_direct-write-error-fix.patch
hugetlb-unsigned-ret-cannot-be-negative.patch
page_fault-retry-with-nopage_retry.patch
page_fault-retry-with-nopage_retry-fix.patch
page_fault-retry-with-nopage_retry-fix-fix.patch
mm-direct-io-starvation-improvement.patch
fs-remove-wb_sync_hold.patch
fs-sync_sb_inodes-fix.patch
fs-sys_sync-fix.patch
radix-tree-gang-set-if-tagged-operation.patch
mm-fsync-livelock-avoidance.patch
reiser4.patch
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