On 08.12.2016 18:01, Konstantin Khorenko wrote:
Please consider to RK.
Queued, thanks.
--
Best regards,
Konstantin Khorenko,
Virtuozzo Linux Kernel Team
On 12/08/2016 06:01 PM, Konstantin Khorenko wrote:
The commit is pushed to "branch-rh7-3.10.0-327.36.1.vz7.20.x-ovz" and
will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-327.36.1.vz7.20.12
------>
commit d9db74f4ea93d48aebf0f3f298ff7da1e92d4e5b
Author: Maxim Patlasov <[email protected]>
Date: Thu Dec 8 19:01:07 2016 +0400
fuse: fuse_send_writepage() must check FUSE_S_FAIL_IMMEDIATELY
The patch fixes the following race (leading to deadlock):
1. Thread A. Enter fuse_prepare_write() checks for
FUSE_S_FAIL_IMMEDIATELY,
but it was not set yet, so it doesn't return -EIO.
2. Thread B. Enter fuse_invalidate_files(). It sets
FUSE_S_FAIL_IMMEDIATELY,
calls filemap_write_and_wait() and fuse_kill_requests(), then release
fc->lock.
3. Thread A. fuse_commit_write() marks page as "Dirty", then
fuse_write_end() unlocks the page.
4. Thread B. fuse_invalidate_files() calls
invalidate_inode_pages2(). The
page is dirty, so it ends up in fuse_launder_page() calling
fuse_writepage_locked(). The latter successfully proceeds queuing
fuse-write-back request, but then fuse_launder_page() calls
fuse_wait_on_page_writeback() that blocks forever because Thread A
is still
blocked in fuse_invalidate_files().
Signed-off-by: Maxim Patlasov <[email protected]>
---
fs/fuse/file.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 641b570..a14c929 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1875,7 +1875,8 @@ __acquires(fc->lock)
struct fuse_write_in *inarg = &req->misc.write.in;
__u64 data_size = req->num_pages * PAGE_CACHE_SIZE;
- if (!fc->connected)
+ if (!fc->connected ||
+ test_bit(FUSE_S_FAIL_IMMEDIATELY, &req->ff->ff_state))
goto out_free;
if (inarg->offset + data_size <= size) {
.
.
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