4.4-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 61c12b49e1c9c77d7a1bcc161de540d0fd21cf0c ]
Commit 8fba54aebbdf ("fuse: direct-io: don't dirty ITER_BVEC pages") fixes the ITER_BVEC page deadlock for direct io in fuse by checking in fuse_direct_io(), whether the page is a bvec page or not, before locking it. However, this check is missed when the "async_dio" mount option is enabled. In this case, set_page_dirty_lock() is called from the req->end callback in request_end(), when the fuse thread is returning from userspace to respond to the read request. This will cause the same deadlock because the bvec condition is not checked in this path.
Here is the stack of the deadlocked thread, while returning from userspace:
[13706.656686] INFO: task glusterfs:3006 blocked for more than 120 seconds. [13706.657808] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [13706.658788] glusterfs D ffffffff816c80f0 0 3006 1 0x00000080 [13706.658797] ffff8800d6713a58 0000000000000086 ffff8800d9ad7000 ffff8800d9ad5400 [13706.658799] ffff88011ffd5cc0 ffff8800d6710008 ffff88011fd176c0 7fffffffffffffff [13706.658801] 0000000000000002 ffffffff816c80f0 ffff8800d6713a78 ffffffff816c790e [13706.658803] Call Trace: [13706.658809] [<ffffffff816c80f0>] ? bit_wait_io_timeout+0x80/0x80 [13706.658811] [<ffffffff816c790e>] schedule+0x3e/0x90 [13706.658813] [<ffffffff816ca7e5>] schedule_timeout+0x1b5/0x210 [13706.658816] [<ffffffff81073ffb>] ? gup_pud_range+0x1db/0x1f0 [13706.658817] [<ffffffff810668fe>] ? kvm_clock_read+0x1e/0x20 [13706.658819] [<ffffffff81066909>] ? kvm_clock_get_cycles+0x9/0x10 [13706.658822] [<ffffffff810f5792>] ? ktime_get+0x52/0xc0 [13706.658824] [<ffffffff816c6f04>] io_schedule_timeout+0xa4/0x110 [13706.658826] [<ffffffff816c8126>] bit_wait_io+0x36/0x50 [13706.658828] [<ffffffff816c7d06>] __wait_on_bit_lock+0x76/0xb0 [13706.658831] [<ffffffffa0545636>] ? lock_request+0x46/0x70 [fuse] [13706.658834] [<ffffffff8118800a>] __lock_page+0xaa/0xb0 [13706.658836] [<ffffffff810c8500>] ? wake_atomic_t_function+0x40/0x40 [13706.658838] [<ffffffff81194d08>] set_page_dirty_lock+0x58/0x60 [13706.658841] [<ffffffffa054d968>] fuse_release_user_pages+0x58/0x70 [fuse] [13706.658844] [<ffffffffa0551430>] ? fuse_aio_complete+0x190/0x190 [fuse] [13706.658847] [<ffffffffa0551459>] fuse_aio_complete_req+0x29/0x90 [fuse] [13706.658849] [<ffffffffa05471e9>] request_end+0xd9/0x190 [fuse] [13706.658852] [<ffffffffa0549126>] fuse_dev_do_write+0x336/0x490 [fuse] [13706.658854] [<ffffffffa054963e>] fuse_dev_write+0x6e/0xa0 [fuse] [13706.658857] [<ffffffff812a9ef3>] ? security_file_permission+0x23/0x90 [13706.658859] [<ffffffff81205300>] do_iter_readv_writev+0x60/0x90 [13706.658862] [<ffffffffa05495d0>] ? fuse_dev_splice_write+0x350/0x350 [fuse] [13706.658863] [<ffffffff812062a1>] do_readv_writev+0x171/0x1f0 [13706.658866] [<ffffffff810b3d00>] ? try_to_wake_up+0x210/0x210 [13706.658868] [<ffffffff81206361>] vfs_writev+0x41/0x50 [13706.658870] [<ffffffff81206496>] SyS_writev+0x56/0xf0 [13706.658872] [<ffffffff810257a1>] ? syscall_trace_leave+0xf1/0x160 [13706.658874] [<ffffffff816cbb2e>] system_call_fastpath+0x12/0x71
Fix this by making should_dirty a fuse_io_priv parameter that can be checked in fuse_aio_complete_req().
Reported-by: Tiger Yang tiger.yang@oracle.com Signed-off-by: Ashish Samant ashish.samant@oracle.com Signed-off-by: Miklos Szeredi mszeredi@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/fuse/file.c | 6 +++--- fs/fuse/fuse_i.h | 1 + 2 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 8577f3ba6dc6..7014318f6d18 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -625,7 +625,7 @@ static void fuse_aio_complete_req(struct fuse_conn *fc, struct fuse_req *req) struct fuse_io_priv *io = req->io; ssize_t pos = -1;
- fuse_release_user_pages(req, !io->write); + fuse_release_user_pages(req, io->should_dirty);
if (io->write) { if (req->misc.write.in.size != req->misc.write.out.size) @@ -1333,7 +1333,6 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter, loff_t *ppos, int flags) { int write = flags & FUSE_DIO_WRITE; - bool should_dirty = !write && iter_is_iovec(iter); int cuse = flags & FUSE_DIO_CUSE; struct file *file = io->file; struct inode *inode = file->f_mapping->host; @@ -1362,6 +1361,7 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter, mutex_unlock(&inode->i_mutex); }
+ io->should_dirty = !write && iter_is_iovec(iter); while (count) { size_t nres; fl_owner_t owner = current->files; @@ -1378,7 +1378,7 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter, nres = fuse_send_read(req, io, pos, nbytes, owner);
if (!io->async) - fuse_release_user_pages(req, should_dirty); + fuse_release_user_pages(req, io->should_dirty); if (req->out.h.error) { if (!res) res = req->out.h.error; diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 7aafe9acc6c0..c6eb35a95fcc 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -252,6 +252,7 @@ struct fuse_io_priv { size_t size; __u64 offset; bool write; + bool should_dirty; int err; struct kiocb *iocb; struct file *file;