linux/fs/fuse, branch v3.13

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2013-11-13T06:34:18Z

Pull vfs updates from Al Viro: "All kinds of stuff this time around; some more notable parts: - RCU'd vfsmounts handling - new primitives for coredump handling - files_lock is gone - Bruce's delegations handling series - exportfs fixes plus misc stuff all over the place" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (101 commits) ecryptfs: ->f_op is never NULL locks: break delegations on any attribute modification locks: break delegations on link locks: break delegations on rename locks: helper functions for delegation breaking locks: break delegations on unlink namei: minor vfs_unlink cleanup locks: implement delegations locks: introduce new FL_DELEG lock flag vfs: take i_mutex on renamed file vfs: rename I_MUTEX_QUOTA now that it's not used for quotas vfs: don't use PARENT/CHILD lock classes for non-directories vfs: pull ext4's double-i_mutex-locking into common code exportfs: fix quadratic behavior in filehandle lookup exportfs: better variable name exportfs: move most of reconnect_path to helper function exportfs: eliminate unused "noprogress" counter exportfs: stop retrying once we race with rename/remove exportfs: clear DISCONNECTED on all parents sooner exportfs: more detailed comment for path_reconnect ...

fuse: writepages: protect secondary requests from fuse file release

2013-11-05T09:11:29Z

All async fuse requests must be supplied with extra reference to a fuse file. This is necessary to ensure that the fuse file is not released until all in-flight requests are completed. Fuse secondary writeback requests must obey this rule as well. Signed-off-by: Maxim Patlasov Signed-off-by: Miklos Szeredi

fuse: writepages: update bdi writeout when deleting secondary request

2013-11-05T09:11:28Z

BDI_WRITTEN counter is used to estimate bdi bandwidth. It must be incremented every time as bdi ends page writeback. No matter whether it was fulfilled by actual write or by discarding the request (e.g. due to shrunk i_size). Note that even before writepages patches, the case "Got truncated off completely" was handled in fuse_send_writepage() by calling fuse_writepage_finish() which updated BDI_WRITTEN unconditionally. Signed-off-by: Maxim Patlasov Signed-off-by: Miklos Szeredi

fuse: writepages: crop secondary requests

2013-11-05T09:11:27Z

If writeback happens while fuse is in FUSE_NOWRITE condition, the request will be queued but not processed immediately (see fuse_flush_writepages()). Until FUSE_NOWRITE becomes relaxed, more writebacks can happen. They will be queued as "secondary" requests to that first ("primary") request. Existing implementation crops only primary request. This is not correct because a subsequent extending write(2) may increase i_size and then secondary requests won't be cropped properly. The result would be stale data written to the server to a file offset where zeros must be. Similar problem may happen if secondary requests are attached to an in-flight request that was already cropped. The patch solves the issue by cropping all secondary requests in fuse_writepage_end(). Thanks to Miklos for idea. Signed-off-by: Maxim Patlasov Signed-off-by: Miklos Szeredi

fuse: writepages: roll back changes if request not found

2013-11-05T09:11:26Z

fuse_writepage_in_flight() returns false if it fails to find request with given index in fi->writepages. Then the caller proceeds with populating data->orig_pages[] and incrementing req->num_pages. Hence, fuse_writepage_in_flight() must revert changes it made in request before returning false. Signed-off-by: Maxim Patlasov Signed-off-by: Miklos Szeredi

fuse: rcu-delay freeing fuse_conn

2013-10-25T03:45:13Z

makes ->permission() and ->d_revalidate() safety in RCU mode independent from vfsmount_lock. Signed-off-by: Al Viro

vfs: introduce d_instantiate_no_diralias()

2013-10-25T03:41:37Z

...which just returns -EBUSY if a directory alias would be created. This is to be used by fuse mkdir to make sure that a buggy or malicious userspace filesystem doesn't do anything nasty. Previously fuse used a private mutex for this purpose, which can now go away. Signed-off-by: Miklos Szeredi

cuse: add fix minor number to /dev/cuse

2013-10-01T14:44:54Z

This allows udev (or more recently systemd-tmpfiles) to create /dev/cuse on boot, in the same way as /dev/fuse is currently created, and the corresponding module to be loaded on first access. The corresponding functionalty was introduced for fuse in commit 578454f. Signed-off-by: Tom Gundersen Cc: Kay Sievers Signed-off-by: Miklos Szeredi

fuse: writepage: skip already in flight

2013-10-01T14:44:53Z

If ->writepage() tries to write back a page whose copy is still in flight, then just skip by calling redirty_page_for_writepage(). This is OK, since now ->writepage() should never be called for data integrity sync. Signed-off-by: Miklos Szeredi

fuse: writepages: handle same page rewrites

2013-10-01T14:44:53Z

As Maxim Patlasov pointed out, it's possible to get a dirty page while it's copy is still under writeback, despite fuse_page_mkwrite() doing its thing (direct IO). This could result in two concurrent write request for the same offset, with data corruption if they get mixed up. To prevent this, fuse needs to check and delay such writes. This implementation does this by: 1. check if page is still under writeout, if so create a new, single page secondary request for it 2. chain this secondary request onto the in-flight request 2/a. if a seconday request for the same offset was already chained to the in-flight request, then just copy the contents of the page and discard the new secondary request. This makes sure that for each page will have at most two requests associated with it 3. when the in-flight request finished, send off all secondary requests chained onto it Signed-off-by: Miklos Szeredi