From 6ad84acab972f4dfc78e6fdb04c419f82c497d29 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Fri, 6 Jan 2006 00:19:42 -0800 Subject: [PATCH] [PATCH] fuse: ensure progress in read and write In direct_io mode, send at least one page per reqest. Previously it was possible that reqests with zero data were sent, and hence the read/write didn't make any progress, resulting in an infinite (though interruptible) loop. Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/fuse/file.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/fs/fuse/file.c b/fs/fuse/file.c index c989f0e9456..05dedddf428 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -475,7 +475,7 @@ static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf, nbytes = min(nbytes, (unsigned) FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT); npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT; - npages = min(npages, FUSE_MAX_PAGES_PER_REQ); + npages = min(max(npages, 1), FUSE_MAX_PAGES_PER_REQ); down_read(¤t->mm->mmap_sem); npages = get_user_pages(current, current->mm, user_addr, npages, write, 0, req->pages, NULL); @@ -506,7 +506,6 @@ static ssize_t fuse_direct_io(struct file *file, const char __user *buf, return -EINTR; while (count) { - size_t tmp; size_t nres; size_t nbytes = min(count, nmax); int err = fuse_get_user_pages(req, buf, nbytes, !write); @@ -514,8 +513,8 @@ static ssize_t fuse_direct_io(struct file *file, const char __user *buf, res = err; break; } - tmp = (req->num_pages << PAGE_SHIFT) - req->page_offset; - nbytes = min(nbytes, tmp); + nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset; + nbytes = min(count, nbytes); if (write) nres = fuse_send_write(req, file, inode, pos, nbytes); else -- 2.41.1