summaryrefslogtreecommitdiff
path: root/include/uapi/linux/fuse.h (follow)
Commit message (Collapse)AuthorAge
* fuse: Add FOPEN_STREAM to use stream_open()Kirill Smelkov2019-06-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit bbd84f33652f852ce5992d65db4d020aba21f882 upstream. Starting from commit 9c225f2655e3 ("vfs: atomic f_pos accesses as per POSIX") files opened even via nonseekable_open gate read and write via lock and do not allow them to be run simultaneously. This can create read vs write deadlock if a filesystem is trying to implement a socket-like file which is intended to be simultaneously used for both read and write from filesystem client. See commit 10dce8af3422 ("fs: stream_open - opener for stream-like files so that read and write can run simultaneously without deadlock") for details and e.g. commit 581d21a2d02a ("xenbus: fix deadlock on writes to /proc/xen/xenbus") for a similar deadlock example on /proc/xen/xenbus. To avoid such deadlock it was tempting to adjust fuse_finish_open to use stream_open instead of nonseekable_open on just FOPEN_NONSEEKABLE flags, but grepping through Debian codesearch shows users of FOPEN_NONSEEKABLE, and in particular GVFS which actually uses offset in its read and write handlers https://codesearch.debian.net/search?q=-%3Enonseekable+%3D https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1080 https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1247-1346 https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1399-1481 so if we would do such a change it will break a real user. Add another flag (FOPEN_STREAM) for filesystem servers to indicate that the opened handler is having stream-like semantics; does not use file position and thus the kernel is free to issue simultaneous read and write request on opened file handle. This patch together with stream_open() should be added to stable kernels starting from v3.14+. This will allow to patch OSSPD and other FUSE filesystems that provide stream-like files to return FOPEN_STREAM | FOPEN_NONSEEKABLE in open handler and this way avoid the deadlock on all kernel versions. This should work because fuse_finish_open ignores unknown open flags returned from a filesystem and so passing FOPEN_STREAM to a kernel that is not aware of this flag cannot hurt. In turn the kernel that is not aware of FOPEN_STREAM will be < v3.14 where just FOPEN_NONSEEKABLE is sufficient to implement streams without read vs write deadlock. Cc: stable@vger.kernel.org # v3.14+ Signed-off-by: Kirill Smelkov <kirr@nexedi.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* fuse: device fd cloneMiklos Szeredi2015-07-01
| | | | | | | | | | | | Allow an open fuse device to be "cloned". Userspace can create a clone by: newfd = open("/dev/fuse", O_RDWR) ioctl(newfd, FUSE_DEV_IOC_CLONE, &oldfd); At this point newfd will refer to the same fuse connection as oldfd. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: add FUSE_NO_OPEN_SUPPORT flag to INITAndrew Gallagher2014-07-22
| | | | | | | | | | | | | | | Here some additional changes to set a capability flag so that clients can detect when it's appropriate to return -ENOSYS from open. This amends the following commit introduced in 3.14: 7678ac50615d fuse: support clients that don't implement 'open' However we can only add the flag to 3.15 and later since there was no protocol version update in 3.14. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: <stable@vger.kernel.org> # v3.15+
* fuse: add renameat2 supportMiklos Szeredi2014-04-28
| | | | | | Support RENAME_EXCHANGE and RENAME_NOREPLACE flags on the userspace ABI. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* fuse: allow ctime flushing to userspaceMaxim Patlasov2014-04-28
| | | | | | | | | The patch extends fuse_setattr_in, and extends the flush procedure (fuse_flush_times()) called on ->write_inode() to send the ctime as well as mtime. Signed-off-by: Maxim Patlasov <MPatlasov@parallels.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* fuse: fuse: add time_gran to INIT_OUTMiklos Szeredi2014-04-28
| | | | | | | | | | | | | | Allow userspace fs to specify time granularity. This is needed because with writeback_cache mode the kernel is responsible for generating mtime and ctime, but if the underlying filesystem doesn't support nanosecond granularity then the cache will contain a different value from the one stored on the filesystem resulting in a change of times after a cache flush. Make the default granularity 1s. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* fuse: Turn writeback cache onPavel Emelyanov2014-04-02
| | | | | | | | | | | | Introduce a bit kernel and userspace exchange between each-other on the init stage and turn writeback on if the userspace want this and mount option 'allow_wbcache' is present (controlled by fusermount). Also add each writable file into per-inode write list and call the generic_file_aio_write to make use of the Linux page cache engine. Signed-off-by: Maxim Patlasov <MPatlasov@parallels.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* fuse: add flag to turn on async direct IOMiklos Szeredi2013-05-01
| | | | | | | | | | Without async DIO write requests to a single file were always serialized. With async DIO that's no longer the case. So don't turn on async DIO by default for fear of breaking backward compatibility. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* fuse: fix type definitions in uapi headerMiklos Szeredi2013-04-17
| | | | | | | | | | | | | | | | Commit 7e98d53086d18c877cb44e9065219335184024de (Synchronize fuse header with one used in library) added #ifdef __linux__ around defines if it is not set. The kernel build is self-contained and can be built on non-Linux toolchains. After the mentioned commit builds on non-Linux toolchains will try to include stdint.h and fail due to -nostdinc, and then fail with a bunch of undefined type errors. Fix by checking for __KERNEL__ instead of __linux__ and using the standard int types instead of the linux specific ones. Reported-by: Arve Hjønnevåg <arve@android.com> Reported-by: Colin Cross <ccross@android.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* fuse: allow control of adaptive readdirplus useEric Wong2013-02-07
| | | | | | | | | | | | | For some filesystems (e.g. GlusterFS), the cost of performing a normal readdir and readdirplus are identical. Since adaptively using readdirplus has no benefit for those systems, give users/filesystems the option to control adaptive readdirplus use. v2 of this patch incorporates Miklos's suggestion to simplify the code, as well as improving consistency of macro names and documentation. Signed-off-by: Eric Wong <normalperson@yhbt.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* Synchronize fuse header with one used in libraryMiklos Szeredi2013-02-07
| | | | | | | The library one has provisions for use in *BSD, add them to the kernel one too. They don't hurt and ease maintenance. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* fuse: send poll eventsEnke Chen2013-02-04
| | | | | | | commit 626cf23660 "poll: add poll_requested_events()..." enabled us to send the requested events to the filesystem. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* fuse: bump version for READDIRPLUSMiklos Szeredi2013-01-31
| | | | | | | Yeah, we have a capability flag for this as well, so this is not strictly necessary, but it doesn't hurt either. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* fuse: implement NFS-like readdirplus supportAnand V. Avati2013-01-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch implements readdirplus support in FUSE, similar to NFS. The payload returned in the readdirplus call contains 'fuse_entry_out' structure thereby providing all the necessary inputs for 'faking' a lookup() operation on the spot. If the dentry and inode already existed (for e.g. in a re-run of ls -l) then just the inode attributes timeout and dentry timeout are refreshed. With a simple client->network->server implementation of a FUSE based filesystem, the following performance observations were made: Test: Performing a filesystem crawl over 20,000 files with sh# time ls -lR /mnt Without readdirplus: Run 1: 18.1s Run 2: 16.0s Run 3: 16.2s With readdirplus: Run 1: 4.1s Run 2: 3.8s Run 3: 3.8s The performance improvement is significant as it avoided 20,000 upcalls calls (lookup). Cache consistency is no worse than what already is. Signed-off-by: Anand V. Avati <avati@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* UAPI: (Scripted) Disintegrate include/linuxDavid Howells2012-10-13
Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Dave Jones <davej@redhat.com>