From c4e64b0036a3f85f6fbfbe7a52846bf34bce8e6e Mon Sep 17 00:00:00 2001 From: Ashish Samant Date: Thu, 18 Aug 2016 13:54:26 -0700 Subject: [PATCH] fuse: direct-io: don't dirty ITER_BVEC pages When reading from a loop device backed by a fuse file it deadlocks on lock_page(). This is because the page is already locked by the read() operation done on the loop device. In this case we don't want to either lock the page or dirty it. So do what fs/direct-io.c does: only dirty the page for ITER_IOVEC vectors. Orabug : 22652336 Reported-by: Alexey Kodanev Signed-off-by: Miklos Szeredi Signed-off-by: Ashish Samant Acked-by: Srinivas Eeda --- fs/fuse/file.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 46d7242b568a..19aa68c4b911 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -516,13 +516,13 @@ void fuse_read_fill(struct fuse_req *req, struct file *file, loff_t pos, req->out.args[0].size = count; } -static void fuse_release_user_pages(struct fuse_req *req, int write) +static void fuse_release_user_pages(struct fuse_req *req, bool should_dirty) { unsigned i; for (i = 0; i < req->num_pages; i++) { struct page *page = req->pages[i]; - if (write) + if (should_dirty) set_page_dirty_lock(page); put_page(page); } @@ -1300,6 +1300,7 @@ 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; @@ -1343,7 +1344,7 @@ 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, !write); + fuse_release_user_pages(req, should_dirty); if (req->out.h.error) { if (!res) err = req->out.h.error; -- 2.50.1