The patch titled
fs: sync_sb_inodes fix
has been added to the -mm tree. Its filename is
fs-sync_sb_inodes-fix.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: fs: sync_sb_inodes fix
From: Nick Piggin <npiggin@xxxxxxx>
Fix data integrity semantics required by sys_sync, by iterating over all
inodes and waiting for any writeback pages after the initial writeout.
Comments explain the exact problem.
Signed-off-by: Nick Piggin <npiggin@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/fs-writeback.c | 60 ++++++++++++++++++++++++++++++++++++++------
1 file changed, 53 insertions(+), 7 deletions(-)
diff -puN fs/fs-writeback.c~fs-sync_sb_inodes-fix fs/fs-writeback.c
--- a/fs/fs-writeback.c~fs-sync_sb_inodes-fix
+++ a/fs/fs-writeback.c
@@ -440,6 +440,7 @@ void generic_sync_sb_inodes(struct super
struct writeback_control *wbc)
{
const unsigned long start = jiffies; /* livelock avoidance */
+ int sync = wbc->sync_mode == WB_SYNC_ALL;
spin_lock(&inode_lock);
if (!wbc->for_kupdate || list_empty(&sb->s_io))
@@ -516,7 +517,49 @@ void generic_sync_sb_inodes(struct super
if (!list_empty(&sb->s_more_io))
wbc->more_io = 1;
}
- spin_unlock(&inode_lock);
+
+ if (sync) {
+ struct inode *inode, *old_inode = NULL;
+
+ /*
+ * Data integrity sync. Must wait for all pages under writeback,
+ * because there may have been pages dirtied before our sync
+ * call, but which had writeout started before we write it out.
+ * In which case, the inode may not be on the dirty list, but
+ * we still have to wait for that writeout.
+ */
+ list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
+ struct address_space *mapping;
+
+ if (inode->i_state & (I_FREEING|I_WILL_FREE))
+ continue;
+ mapping = inode->i_mapping;
+ if (mapping->nrpages == 0)
+ continue;
+ __iget(inode);
+ spin_unlock(&inode_lock);
+ /*
+ * We hold a reference to 'inode' so it couldn't have
+ * been removed from s_inodes list while we dropped the
+ * inode_lock. We cannot iput the inode now as we can
+ * be holding the last reference and we cannot iput it
+ * under inode_lock. So we keep the reference and iput
+ * it later.
+ */
+ iput(old_inode);
+ old_inode = inode;
+
+ filemap_fdatawait(mapping);
+
+ cond_resched();
+
+ spin_lock(&inode_lock);
+ }
+ spin_unlock(&inode_lock);
+ iput(old_inode);
+ } else
+ spin_unlock(&inode_lock);
+
return; /* Leave any unwritten inodes on s_io */
}
EXPORT_SYMBOL_GPL(generic_sync_sb_inodes);
@@ -596,13 +639,16 @@ void sync_inodes_sb(struct super_block *
.range_start = 0,
.range_end = LLONG_MAX,
};
- unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY);
- unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS);
- wbc.nr_to_write = nr_dirty + nr_unstable +
- (inodes_stat.nr_inodes - inodes_stat.nr_unused) +
- nr_dirty + nr_unstable;
- wbc.nr_to_write += wbc.nr_to_write / 2; /* Bit more for luck */
+ if (!wait) {
+ unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY);
+ unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS);
+
+ wbc.nr_to_write = nr_dirty + nr_unstable +
+ (inodes_stat.nr_inodes - inodes_stat.nr_unused);
+ } else
+ wbc.nr_to_write = LONG_MAX; /* doesn't actually matter */
+
sync_sb_inodes(sb, &wbc);
}
_
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
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
