user/sven/linux.git/include/linux/fuse.h, branch v3.4.15

fuse: use flexible array in fuse.h

2012-04-12T10:57:08Z

Use the ISO C standard compliant form instead of the gcc extension in the interface definition. Reported-by: Shachar Sharon Signed-off-by: Miklos Szeredi

FUSE: Notifying the kernel of deletion.

2011-12-13T10:58:49Z

Allows a FUSE file-system to tell the kernel when a file or directory is deleted. If the specified dentry has the specified inode number, the kernel will unhash it. The current 'fuse_notify_inval_entry' does not cause the kernel to clean up directories that are in use properly, and as a result the users of those directories see incorrect semantics from the file-system. The error condition seen when 'fuse_notify_inval_entry' is used to notify of a deleted directory is avoided when 'fuse_notify_delete' is used instead. The following scenario demonstrates the difference: 1. User A chdirs into 'testdir' and starts reading 'testfile'. 2. User B rm -rf 'testdir'. 3. User B creates 'testdir'. 4. User C chdirs into 'testdir'. If you run the above within the same machine on any file-system (including fuse file-systems), there is no problem: user C is able to chdir into the new testdir. The old testdir is removed from the dentry tree, but still open by user A. If operations 2 and 3 are performed via the network such that the fuse file-system uses one of the notify functions to tell the kernel that the nodes are gone, then the following error occurs for user C while user A holds the original directory open: muirj@empacher:~> ls /test/testdir ls: cannot access /test/testdir: No such file or directory The issue here is that the kernel still has a dentry for testdir, and so it is requesting the attributes for the old directory, while the file-system is responding that the directory no longer exists. If on the other hand, if the file-system can notify the kernel that the directory is deleted using the new 'fuse_notify_delete' function, then the above ls will find the new directory as expected. Signed-off-by: John Muir Signed-off-by: Miklos Szeredi

fuse: support ioctl on directories

2011-12-13T10:58:49Z

Multiplexing filesystems may want to support ioctls on the underlying files and directores (e.g. FS_IOC_{GET,SET}FLAGS). Ioctl support on directories was missing so add it now. Reported-by: Antonio SJ Musumeci Signed-off-by: Miklos Szeredi

fuse: fix flock

2011-08-08T14:08:08Z

Commit a9ff4f87 "fuse: support BSD locking semantics" overlooked a number of issues with supporing flock locks over existing POSIX locking infrastructure: - it's not backward compatible, passing flock(2) calls to userspace unconditionally (if userspace sets FUSE_POSIX_LOCKS) - it doesn't cater for the fact that flock locks are automatically unlocked on file release - it doesn't take into account the fact that flock exclusive locks (write locks) don't need an fd opened for write. The last one invalidates the original premise of the patch that flock locks can be emulated with POSIX locks. This patch fixes the first two issues. The last one needs to be fixed in userspace if the filesystem assumed that a write lock will happen only on a file operned for write (as in the case of the current fuse library). Reported-by: Sebastian Pipping Signed-off-by: Miklos Szeredi

fuse: fix ioctl ABI

2010-12-07T19:16:56Z

In kernel ABI version 7.16 and later FUSE_IOCTL_RETRY reply from a unrestricted IOCTL request shall return with an array of 'struct fuse_ioctl_iovec' instead of 'struct iovec'. This fixes the ABI ambiguity of 32bit vs. 64bit. Reported-by: "ccmail111" Signed-off-by: Miklos Szeredi CC: Tejun Heo

fuse: allow batching of FORGET requests

2010-12-07T19:16:56Z

Terje Malmedal reports that a fuse filesystem with 32 million inodes on a machine with lots of memory can take up to 30 minutes to process FORGET requests when all those inodes are evicted from the icache. To solve this, create a BATCH_FORGET request that allows up to about 8000 FORGET requests to be sent in a single message. This request is only sent if userspace supports interface version 7.16 or later, otherwise fall back to sending individual FORGET messages. Reported-by: Terje Malmedal Signed-off-by: Miklos Szeredi

fuse: add retrieve request

2010-07-12T12:41:40Z

Userspace filesystem can request data to be retrieved from the inode's mapping. This request is synchronous and the retrieved data is queued as a new request. If the write to the fuse device returns an error then the retrieve request was not completed and a reply will not be sent. Only present pages are returned in the retrieve reply. Retrieving stops when it finds a non-present page and only data prior to that is returned. This request doesn't change the dirty state of pages. Signed-off-by: Miklos Szeredi

fuse: add store request

2010-07-12T12:41:40Z

Userspace filesystem can request data to be stored in the inode's mapping. This request is synchronous and has no reply. If the write to the fuse device returns an error then the store request was not fully completed (but may have updated some pages). If the stored data overflows the current file size, then the size is extended, similarly to a write(2) on the filesystem. Pages which have been completely stored are marked uptodate. Signed-off-by: Miklos Szeredi

fuse: support splice() writing to fuse device

2010-05-25T13:06:06Z

Allow userspace filesystem implementation to use splice() to write to the fuse device. The semantics of using splice() are: 1) buffer the message header and data in a temporary pipe 2) with a *single* splice() call move the message from the temporary pipe to the fuse device The READ reply message has the most interesting use for this, since now the data from an arbitrary file descriptor (which could be a regular file, a block device or a socket) can be tranferred into the fuse device without having to go through a userspace buffer. It will also allow zero copy moving of pages. One caveat is that the protocol on the fuse device requires the length of the whole message to be written into the header. But the length of the data transferred into the temporary pipe may not be known in advance. The current library implementation works around this by using vmplice to write the header and modifying the header after splicing the data into the pipe (error handling omitted): struct fuse_out_header out; iov.iov_base = &out; iov.iov_len = sizeof(struct fuse_out_header); vmsplice(pip[1], &iov, 1, 0); len = splice(input_fd, input_offset, pip[1], NULL, len, 0); /* retrospectively modify the header: */ out.len = len + sizeof(struct fuse_out_header); splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags); This works since vmsplice only saves a pointer to the data, it does not copy the data itself. Since pipes are currently limited to 16 pages and messages need to be spliced atomically, the length of the data is limited to 15 pages (or 60kB for 4k pages). Signed-off-by: Miklos Szeredi

fuse: document protocol version negotiation

2009-07-08T16:17:58Z

Clarify how the protocol version should be negotiated between kernel and userspace. Notably libfuse didn't correctly handle the case when the supported major versions didn't match. Signed-off-by: Miklos Szeredi