6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Amir Goldstein <amir73il@xxxxxxxxx>
commit 3f29f1c336c0e8a4bec52f1e5217f88835553e5b upstream.
The new fuse init flag FUSE_DIRECT_IO_ALLOW_MMAP breaks assumptions made by
FOPEN_PARALLEL_DIRECT_WRITES and causes test generic/095 to hit
BUG_ON(fi->writectr < 0) assertions in fuse_set_nowrite():
generic/095 5s ...
kernel BUG at fs/fuse/dir.c:1756!
...
? fuse_set_nowrite+0x3d/0xdd
? do_raw_spin_unlock+0x88/0x8f
? _raw_spin_unlock+0x2d/0x43
? fuse_range_is_writeback+0x71/0x84
fuse_sync_writes+0xf/0x19
fuse_direct_io+0x167/0x5bd
fuse_direct_write_iter+0xf0/0x146
Auto disable FOPEN_PARALLEL_DIRECT_WRITES when server negotiated
FUSE_DIRECT_IO_ALLOW_MMAP.
Fixes: e78662e818f9 ("fuse: add a new fuse init flag to relax restrictions in no cache mode")
Cc: <stable@xxxxxxxxxxxxxxx> # v6.6
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/fuse/file.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 89e870d1a526..a660f1f21540 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1574,6 +1574,7 @@ static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
ssize_t res;
bool exclusive_lock =
!(ff->open_flags & FOPEN_PARALLEL_DIRECT_WRITES) ||
+ get_fuse_conn(inode)->direct_io_allow_mmap ||
iocb->ki_flags & IOCB_APPEND ||
fuse_direct_write_extending_i_size(iocb, from);
@@ -1581,6 +1582,7 @@ static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
* Take exclusive lock if
* - Parallel direct writes are disabled - a user space decision
* - Parallel direct writes are enabled and i_size is being extended.
+ * - Shared mmap on direct_io file is supported (FUSE_DIRECT_IO_ALLOW_MMAP).
* This might not be needed at all, but needs further investigation.
*/
if (exclusive_lock)
--
2.43.0
