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bb737bbe48
In virtiofs (unlike in regular fuse) processing of async replies is
serialized. This can result in a deadlock in rare corner cases when
there's a circular dependency between the completion of two or more async
replies.
Such a deadlock can be reproduced with xfstests:generic/503 if TEST_DIR ==
SCRATCH_MNT (which is a misconfiguration):
- Process A is waiting for page lock in worker thread context and blocked
(virtio_fs_requests_done_work()).
- Process B is holding page lock and waiting for pending writes to
finish (fuse_wait_on_page_writeback()).
- Write requests are waiting in virtqueue and can't complete because
worker thread is blocked on page lock (process A).
Fix this by creating a unique work_struct for each async reply that can
block (O_DIRECT read).
Fixes:
|
||
|---|---|---|
| .. | ||
| acl.c | ||
| control.c | ||
| cuse.c | ||
| dev.c | ||
| dir.c | ||
| file.c | ||
| fuse_i.h | ||
| inode.c | ||
| Kconfig | ||
| Makefile | ||
| readdir.c | ||
| virtio_fs.c | ||
| xattr.c | ||