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Commit e5d9a0df authored by Miklos Szeredi's avatar Miklos Szeredi Committed by Linus Torvalds
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fuse: fix max i/o size calculation 



Fix a bug that Werner Baumann reported: fuse can send a bigger write request
than the maximum specified.  This only affected direct_io operation.

In addition set a sane minimum for the max_read and max_write tunables, so I/O
always makes some progress.

Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5c5c5e51

fs/fuse/file.c

+4 −3
Original line number Diff line number Diff line
@@ -966,14 +966,15 @@ static ssize_t fuse_direct_io(struct file *file, const char __user *buf, 


	while (count) {

		size_t nres;

		size_t nbytes = min(count, nmax);

		int err = fuse_get_user_pages(req, buf, nbytes, !write);

		size_t nbytes_limit = min(count, nmax);

		size_t nbytes;

		int err = fuse_get_user_pages(req, buf, nbytes_limit, !write);

		if (err) {

			res = err;

			break;

		}

		nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset;

		nbytes = min(count, nbytes);

		nbytes = min(nbytes_limit, nbytes);

		if (write)

			nres = fuse_send_write(req, file, inode, pos, nbytes,

					       current->files);

fs/fuse/inode.c

+2 −1
Original line number Diff line number Diff line
@@ -584,6 +584,7 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) 
		fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);

		fc->minor = arg->minor;

		fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;

		fc->max_write = min_t(unsigned, 4096, fc->max_write);

		fc->conn_init = 1;

	}

	fuse_put_request(fc, req);
@@ -658,7 +659,7 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent) 
	fc->flags = d.flags;

	fc->user_id = d.user_id;

	fc->group_id = d.group_id;

	fc->max_read = d.max_read;

	fc->max_read = min_t(unsigned, 4096, d.max_read);



	/* Used by get_root_inode() */

	sb->s_fs_info = fc;