From: Xiubo Li <xiubli@xxxxxxxxxx>
While the mapped IOs continue if we try to flush a file's buffer
we can see that the fsync() won't complete until the IOs finish.
This is analogous to Jan Kara's commit (f446daaea9d4 mm: implement
writeback livelock avoidance using page tagging), we will try to
avoid livelocks of writeback when some steadily creates dirty pages
in a mapping we are writing out.
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx>
---
fs/ceph/addr.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 5731b82bf368..caf6ac5c1390 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -879,6 +879,7 @@ static int ceph_writepages_start(struct address_space *mapping,
bool should_loop, range_whole = false;
bool done = false;
bool caching = ceph_is_cache_enabled(inode);
+ xa_mark_t tag;
if (wbc->sync_mode == WB_SYNC_NONE &&
fsc->write_congested)
@@ -905,6 +906,11 @@ static int ceph_writepages_start(struct address_space *mapping,
start_index = wbc->range_cyclic ? mapping->writeback_index : 0;
index = start_index;
+ if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages) {
+ tag = PAGECACHE_TAG_TOWRITE;
+ } else {
+ tag = PAGECACHE_TAG_DIRTY;
+ }
retry:
/* find oldest snap context with dirty data */
snapc = get_oldest_context(inode, &ceph_wbc, NULL);
@@ -943,6 +949,9 @@ static int ceph_writepages_start(struct address_space *mapping,
dout(" non-head snapc, range whole\n");
}
+ if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
+ tag_pages_for_writeback(mapping, index, end);
+
ceph_put_snap_context(last_snapc);
last_snapc = snapc;
@@ -959,7 +968,7 @@ static int ceph_writepages_start(struct address_space *mapping,
get_more_pages:
pvec_pages = pagevec_lookup_range_tag(&pvec, mapping, &index,
- end, PAGECACHE_TAG_DIRTY);
+ end, tag);
dout("pagevec_lookup_range_tag got %d\n", pvec_pages);
if (!pvec_pages && !locked_pages)
break;
--
2.31.1
