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path: root/fs/fuse/fuse_i.h
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2020-12-10fuse: fix bad inodeMiklos Szeredi
Jan Kara's analysis of the syzbot report (edited): The reproducer opens a directory on FUSE filesystem, it then attaches dnotify mark to the open directory. After that a fuse_do_getattr() call finds that attributes returned by the server are inconsistent, and calls make_bad_inode() which, among other things does: inode->i_mode = S_IFREG; This then confuses dnotify which doesn't tear down its structures properly and eventually crashes. Avoid calling make_bad_inode() on a live inode: switch to a private flag on the fuse inode. Also add the test to ops which the bad_inode_ops would have caught. This bug goes back to the initial merge of fuse in 2.6.14... Reported-by: syzbot+f427adf9324b92652ccc@syzkaller.appspotmail.com Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Tested-by: Jan Kara <jack@suse.cz> Cc: <stable@vger.kernel.org>
2020-11-11fuse: introduce the notion of FUSE_HANDLE_KILLPRIV_V2Vivek Goyal
We already have FUSE_HANDLE_KILLPRIV flag that says that file server will remove suid/sgid/caps on truncate/chown/write. But that's little different from what Linux VFS implements. To be consistent with Linux VFS behavior what we want is. - caps are always cleared on chown/write/truncate - suid is always cleared on chown, while for truncate/write it is cleared only if caller does not have CAP_FSETID. - sgid is always cleared on chown, while for truncate/write it is cleared only if caller does not have CAP_FSETID as well as file has group execute permission. As previous flag did not provide above semantics. Implement a V2 of the protocol with above said constraints. Server does not know if caller has CAP_FSETID or not. So for the case of write()/truncate(), client will send information in special flag to indicate whether to kill priviliges or not. These changes are in subsequent patches. FUSE_HANDLE_KILLPRIV_V2 relies on WRITE being sent to server to clear suid/sgid/security.capability. But with ->writeback_cache, WRITES are cached in guest. So it is not recommended to use FUSE_HANDLE_KILLPRIV_V2 and writeback_cache together. Though it probably might be good enough for lot of use cases. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-11-11fuse: simplify get_fuse_conn*()Miklos Szeredi
All callers dereference the result, so no point in checking for NULL pointer dereference here. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-11-11fuse: get rid of fuse_mount refcountMiklos Szeredi
Fuse mount now only ever has a refcount of one (before being freed) so the count field is unnecessary. Remove the refcounting and fold fuse_mount_put() into callers. The only caller of fuse_mount_put() where fm->fc was NULL is fuse_dentry_automount() and here the fuse_conn_put() can simply be omitted. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-11-11virtiofs: simplify sb setupMiklos Szeredi
Currently when acquiring an sb for virtiofs fuse_mount_get() is being called from virtio_fs_set_super() if a new sb is being filled and fuse_mount_put() is called unconditionally after sget_fc() returns. The exact same result can be obtained by checking whether fs_contex->s_fs_info was set to NULL (ref trasferred to sb->s_fs_info) and only calling fuse_mount_put() if the ref wasn't transferred (error or matching sb found). This allows getting rid of virtio_fs_set_super() and fuse_mount_get(). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-10-09fuse: implement crossmountsMax Reitz
FUSE servers can indicate crossmount points by setting FUSE_ATTR_SUBMOUNT in fuse_attr.flags. The inode will then be marked as S_AUTOMOUNT, and the .d_automount implementation creates a new submount at that location, so that the submount gets a distinct st_dev value. Note that all submounts get a distinct superblock and a distinct st_dev value, so for virtio-fs, even if the same filesystem is mounted more than once on the host, none of its mount points will have the same st_dev. We need distinct superblocks because the superblock points to the root node, but the different host mounts may show different trees (e.g. due to submounts in some of them, but not in others). Right now, this behavior is only enabled when fuse_conn.auto_submounts is set, which is the case only for virtio-fs. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-18fuse: Allow fuse_fill_super_common() for submountsMax Reitz
Submounts have their own superblock, which needs to be initialized. However, they do not have a fuse_fs_context associated with them, and the root node's attributes should be taken from the mountpoint's node. Extend fuse_fill_super_common() to work for submounts by making the @ctx parameter optional, and by adding a @submount_finode parameter. (There is a plain "unsigned" in an existing code block that is being indented by this commit. Extend it to "unsigned int" so checkpatch does not complain.) Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-18fuse: split fuse_mount off of fuse_connMax Reitz
We want to allow submounts for the same fuse_conn, but with different superblocks so that each of the submounts has its own device ID. To do so, we need to split all mount-specific information off of fuse_conn into a new fuse_mount structure, so that multiple mounts can share a single fuse_conn. We need to take care only to perform connection-level actions once (i.e. when the fuse_conn and thus the first fuse_mount are established, or when the last fuse_mount and thus the fuse_conn are destroyed). For example, fuse_sb_destroy() must invoke fuse_send_destroy() until the last superblock is released. To do so, we keep track of which fuse_mount is the root mount and perform all fuse_conn-level actions only when this fuse_mount is involved. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-18fuse: drop fuse_conn parameter where possibleMax Reitz
With the last commit, all functions that handle some existing fuse_req no longer need to be given the associated fuse_conn, because they can get it from the fuse_req object. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-18fuse: store fuse_conn in fuse_reqMax Reitz
Every fuse_req belongs to a fuse_conn. Right now, we always know which fuse_conn that is based on the respective device, but we want to allow multiple (sub)mounts per single connection, and then the corresponding filesystem is not going to be so trivial to obtain. Storing a pointer to the associated fuse_conn in every fuse_req will allow us to trivially find any request's superblock (and thus filesystem) even then. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-10virtiofs: add logic to free up a memory rangeVivek Goyal
Add logic to free up a busy memory range. Freed memory range will be returned to free pool. Add a worker which can be started to select and free some busy memory ranges. Process can also steal one of its busy dax ranges if free range is not available. I will refer it to as direct reclaim. If free range is not available and nothing can't be stolen from same inode, caller waits on a waitq for free range to become available. For reclaiming a range, as of now we need to hold following locks in specified order. down_write(&fi->i_mmap_sem); down_write(&fi->dax->sem); We look for a free range in following order. A. Try to get a free range. B. If not, try direct reclaim. C. If not, wait for a memory range to become free Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-10virtiofs: serialize truncate/punch_hole and dax fault pathVivek Goyal
Currently in fuse we don't seem have any lock which can serialize fault path with truncate/punch_hole path. With dax support I need one for following reasons. 1. Dax requirement DAX fault code relies on inode size being stable for the duration of fault and want to serialize with truncate/punch_hole and they explicitly mention it. static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, const struct iomap_ops *ops) /* * Check whether offset isn't beyond end of file now. Caller is * supposed to hold locks serializing us with truncate / punch hole so * this is a reliable test. */ max_pgoff = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE); 2. Make sure there are no users of pages being truncated/punch_hole get_user_pages() might take references to page and then do some DMA to said pages. Filesystem might truncate those pages without knowing that a DMA is in progress or some I/O is in progress. So use dax_layout_busy_page() to make sure there are no such references and I/O is not in progress on said pages before moving ahead with truncation. 3. Limitation of kvm page fault error reporting If we are truncating file on host first and then removing mappings in guest lateter (truncate page cache etc), then this could lead to a problem with KVM. Say a mapping is in place in guest and truncation happens on host. Now if guest accesses that mapping, then host will take a fault and kvm will either exit to qemu or spin infinitely. IOW, before we do truncation on host, we need to make sure that guest inode does not have any mapping in that region or whole file. 4. virtiofs memory range reclaim Soon I will introduce the notion of being able to reclaim dax memory ranges from a fuse dax inode. There also I need to make sure that no I/O or fault is going on in the reclaimed range and nobody is using it so that range can be reclaimed without issues. Currently if we take inode lock, that serializes read/write. But it does not do anything for faults. So I add another semaphore fuse_inode->i_mmap_sem for this purpose. It can be used to serialize with faults. As of now, I am adding taking this semaphore only in dax fault path and not regular fault path because existing code does not have one. May be existing code can benefit from it as well to take care of some races, but that we can fix later if need be. For now, I am just focussing only on DAX path which is new path. Also added logic to take fuse_inode->i_mmap_sem in truncate/punch_hole/open(O_TRUNC) path to make sure file truncation and fuse dax fault are mutually exlusive and avoid all the above problems. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-10virtiofs: implement dax read/write operationsVivek Goyal
This patch implements basic DAX support. mmap() is not implemented yet and will come in later patches. This patch looks into implemeting read/write. We make use of interval tree to keep track of per inode dax mappings. Do not use dax for file extending writes, instead just send WRITE message to daemon (like we do for direct I/O path). This will keep write and i_size change atomic w.r.t crash. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com> Signed-off-by: Peng Tao <tao.peng@linux.alibaba.com> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-10virtiofs: implement FUSE_INIT map_alignment fieldStefan Hajnoczi
The device communicates FUSE_SETUPMAPPING/FUSE_REMOVMAPPING alignment constraints via the FUST_INIT map_alignment field. Parse this field and ensure our DAX mappings meet the alignment constraints. We don't actually align anything differently since our mappings are already 2MB aligned. Just check the value when the connection is established. If it becomes necessary to honor arbitrary alignments in the future we'll have to adjust how mappings are sized. The upshot of this commit is that we can be confident that mappings will work even when emulating x86 on Power and similar combinations where the host page sizes are different. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-10virtiofs: add a mount option to enable daxVivek Goyal
Add a mount option to allow using dax with virtio_fs. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-10virtiofs: get rid of no_mount_optionsVivek Goyal
This option was introduced so that for virtio_fs we don't show any mounts options fuse_show_options(). Because we don't offer any of these options to be controlled by mounter. Very soon we are planning to introduce option "dax" which mounter should be able to specify. And no_mount_options does not work anymore. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-05-19fuse: optimize writepages searchMaxim Patlasov
Re-work fi->writepages, replacing list with rb-tree. This improves performance because kernel fuse iterates through fi->writepages for each writeback page and typical number of entries is about 800 (for 100MB of fuse writeback). Before patch: 10240+0 records in 10240+0 records out 10737418240 bytes (11 GB) copied, 41.3473 s, 260 MB/s 2 1 0 57445400 40416 6323676 0 0 33 374743 8633 19210 1 8 88 3 0 29.86% [kernel] [k] _raw_spin_lock 26.62% [fuse] [k] fuse_page_is_writeback After patch: 10240+0 records in 10240+0 records out 10737418240 bytes (11 GB) copied, 21.4954 s, 500 MB/s 2 9 0 53676040 31744 10265984 0 0 64 854790 10956 48387 1 6 88 6 0 23.55% [kernel] [k] copy_user_enhanced_fast_string 9.87% [kernel] [k] __memcpy 3.10% [kernel] [k] _raw_spin_lock Signed-off-by: Maxim Patlasov <mpatlasov@virtuozzo.com> Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-04-20virtiofs: schedule blocking async replies in separate workerVivek Goyal
In virtiofs (unlike in regular fuse) processing of async replies is serialized. This can result in a deadlock in rare corner cases when there's a circular dependency between the completion of two or more async replies. Such a deadlock can be reproduced with xfstests:generic/503 if TEST_DIR == SCRATCH_MNT (which is a misconfiguration): - Process A is waiting for page lock in worker thread context and blocked (virtio_fs_requests_done_work()). - Process B is holding page lock and waiting for pending writes to finish (fuse_wait_on_page_writeback()). - Write requests are waiting in virtqueue and can't complete because worker thread is blocked on page lock (process A). Fix this by creating a unique work_struct for each async reply that can block (O_DIRECT read). Fixes: a62a8ef9d97d ("virtio-fs: add virtiofs filesystem") Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-02-13fuse: fix stack use after returnMiklos Szeredi
Normal, synchronous requests will have their args allocated on the stack. After the FR_FINISHED bit is set by receiving the reply from the userspace fuse server, the originating task may return and reuse the stack frame, resulting in an Oops if the args structure is dereferenced. Fix by setting a flag in the request itself upon initializing, indicating whether it has an asynchronous ->end() callback. Reported-by: Kyle Sanderson <kyle.leet@gmail.com> Reported-by: Michael Stapelberg <michael+lkml@stapelberg.ch> Fixes: 2b319d1f6f92 ("fuse: don't dereference req->args on finished request") Cc: <stable@vger.kernel.org> # v5.4 Tested-by: Michael Stapelberg <michael+lkml@stapelberg.ch> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-11-12fuse: verify attributesMiklos Szeredi
If a filesystem returns negative inode sizes, future reads on the file were causing the cpu to spin on truncate_pagecache. Create a helper to validate the attributes. This now does two things: - check the file mode - check if the file size fits in i_size without overflowing Reported-by: Arijit Banerjee <arijit@rubrik.com> Fixes: d8a5ba45457e ("[PATCH] FUSE - core") Cc: <stable@vger.kernel.org> # v2.6.14 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-10-15virtio-fs: don't show mount optionsMiklos Szeredi
Virtio-fs does not accept any mount options, so it's confusing and wrong to show any in /proc/mounts. Reported-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-18virtio-fs: add virtiofs filesystemStefan Hajnoczi
Add a basic file system module for virtio-fs. This does not yet contain shared data support between host and guest or metadata coherency speedups. However it is already significantly faster than virtio-9p. Design Overview =============== With the goal of designing something with better performance and local file system semantics, a bunch of ideas were proposed. - Use fuse protocol (instead of 9p) for communication between guest and host. Guest kernel will be fuse client and a fuse server will run on host to serve the requests. - For data access inside guest, mmap portion of file in QEMU address space and guest accesses this memory using dax. That way guest page cache is bypassed and there is only one copy of data (on host). This will also enable mmap(MAP_SHARED) between guests. - For metadata coherency, there is a shared memory region which contains version number associated with metadata and any guest changing metadata updates version number and other guests refresh metadata on next access. This is yet to be implemented. How virtio-fs differs from existing approaches ============================================== The unique idea behind virtio-fs is to take advantage of the co-location of the virtual machine and hypervisor to avoid communication (vmexits). DAX allows file contents to be accessed without communication with the hypervisor. The shared memory region for metadata avoids communication in the common case where metadata is unchanged. By replacing expensive communication with cheaper shared memory accesses, we expect to achieve better performance than approaches based on network file system protocols. In addition, this also makes it easier to achieve local file system semantics (coherency). These techniques are not applicable to network file system protocols since the communications channel is bypassed by taking advantage of shared memory on a local machine. This is why we decided to build virtio-fs rather than focus on 9P or NFS. Caching Modes ============= Like virtio-9p, different caching modes are supported which determine the coherency level as well. The “cache=FOO” and “writeback” options control the level of coherence between the guest and host filesystems. - cache=none metadata, data and pathname lookup are not cached in guest. They are always fetched from host and any changes are immediately pushed to host. - cache=always metadata, data and pathname lookup are cached in guest and never expire. - cache=auto metadata and pathname lookup cache expires after a configured amount of time (default is 1 second). Data is cached while the file is open (close to open consistency). - writeback/no_writeback These options control the writeback strategy. If writeback is disabled, then normal writes will immediately be synchronized with the host fs. If writeback is enabled, then writes may be cached in the guest until the file is closed or an fsync(2) performed. This option has no effect on mmap-ed writes or writes going through the DAX mechanism. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-12fuse: allow skipping control interface and forced unmountVivek Goyal
virtio-fs does not support aborting requests which are being processed. That is requests which have been sent to fuse daemon on host. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-12fuse: dissociate DESTROY from fuseblkMiklos Szeredi
Allow virtio-fs to also send DESTROY request. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-12fuse: delete dentry if timeout is zeroMiklos Szeredi
Don't hold onto dentry in lru list if need to re-lookup it anyway at next access. Only do this if explicitly enabled, otherwise it could result in performance regression. More advanced version of this patch would periodically flush out dentries from the lru which have gone stale. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-12fuse: separate fuse device allocation and installation in fuse_connVivek Goyal
As of now fuse_dev_alloc() both allocates a fuse device and installs it in fuse_conn list. fuse_dev_alloc() can fail if fuse_device allocation fails. virtio-fs needs to initialize multiple fuse devices (one per virtio queue). It initializes one fuse device as part of call to fuse_fill_super_common() and rest of the devices are allocated and installed after that. But, we can't afford to fail after calling fuse_fill_super_common() as we don't have a way to undo all the actions done by fuse_fill_super_common(). So to avoid failures after the call to fuse_fill_super_common(), pre-allocate all fuse devices early and install them into fuse connection later. This patch provides two separate helpers for fuse device allocation and fuse device installation in fuse_conn. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-12fuse: add fuse_iqueue_ops callbacksStefan Hajnoczi
The /dev/fuse device uses fiq->waitq and fasync to signal that requests are available. These mechanisms do not apply to virtio-fs. This patch introduces callbacks so alternative behavior can be used. Note that queue_interrupt() changes along these lines: spin_lock(&fiq->waitq.lock); wake_up_locked(&fiq->waitq); + kill_fasync(&fiq->fasync, SIGIO, POLL_IN); spin_unlock(&fiq->waitq.lock); - kill_fasync(&fiq->fasync, SIGIO, POLL_IN); Since queue_request() and queue_forget() also call kill_fasync() inside the spinlock this should be safe. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-12fuse: extract fuse_fill_super_common()Stefan Hajnoczi
fuse_fill_super() includes code to process the fd= option and link the struct fuse_dev to the fd's struct file. In virtio-fs there is no file descriptor because /dev/fuse is not used. This patch extracts fuse_fill_super_common() so that both classic fuse and virtio-fs can share the code to initialize a mount. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-12fuse: export fuse_dequeue_forget() functionVivek Goyal
File systems like virtio-fs need to do not have to play directly with forget list data structures. There is a helper function use that instead. Rename dequeue_forget() to fuse_dequeue_forget() and export it so that stacked filesystems can use it. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-12fuse: export fuse_get_unique()Stefan Hajnoczi
virtio-fs will need unique IDs for FORGET requests from outside fs/fuse/dev.c. Make the symbol visible. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-12fuse: export fuse_send_init_request()Vivek Goyal
This will be used by virtio-fs to send init request to fuse server after initialization of virt queues. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-12fuse: export fuse_len_args()Stefan Hajnoczi
virtio-fs will need to query the length of fuse_arg lists. Make the symbol visible. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-12fuse: export fuse_end_request()Stefan Hajnoczi
virtio-fs will need to complete requests from outside fs/fuse/dev.c. Make the symbol visible. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-10fuse: stop copying pages to fuse_reqMiklos Szeredi
The page array pointers are also duplicated across fuse_args_pages and fuse_req. Get rid of the fuse_req ones. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-10fuse: stop copying args to fuse_reqMiklos Szeredi
No need to duplicate the argument arrays in fuse_req, so just dereference req->args instead of copying to the fuse_req internal ones. This allows further cleanup of the fuse_req structure. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-10fuse: clean up fuse_reqMiklos Szeredi
Get rid of request specific fields in fuse_req that are not used anymore. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-10fuse: simplify request allocationMiklos Szeredi
Page arrays are not allocated together with the request anymore. Get rid of the dead code Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-10fuse: unexport request opsMiklos Szeredi
All requests are now sent with one of the fuse_simple_... helpers. Get rid of the old api from the fuse internal header. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-10fuse: convert release to simple apiMiklos Szeredi
Since we cannot reserve the request structure up-front, make sure that the request allocation doesn't fail using __GFP_NOFAIL. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-10fuse: convert writepages to simple apiMiklos Szeredi
Derive fuse_writepage_args from fuse_io_args. Sending the request is tricky since it was done with fi->lock held, hence we must either use atomic allocation or release the lock. Both are possible so try atomic first and if it fails, release the lock and do the regular allocation with GFP_NOFS and __GFP_NOFAIL. Both flags are necessary for correct operation. Move the page realloc function from dev.c to file.c and convert to using fuse_writepage_args. The last caller of fuse_write_fill() is gone, so get rid of it. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-10fuse: convert readdir to simple apiMiklos Szeredi
The old fuse_read_fill() helper can be deleted, now that the last user is gone. The fuse_io_args struct is moved to fuse_i.h so it can be shared between readdir/read code. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-10fuse: add simple background helperMiklos Szeredi
Create a helper named fuse_simple_background() that is similar to fuse_simple_request(). Unlike the latter, it returns immediately and calls the supplied 'end' callback when the reply is received. The supplied 'args' pointer is stored in 'fuse_req' which allows the callback to interpret the output arguments decoded from the reply. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-10fuse: move page allocMiklos Szeredi
fuse_req_pages_alloc() is moved to file.c, since its internal use by the device code will eventually be removed. Rename to fuse_pages_alloc() to signify that it's not only usable for fuse_req page array. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-10fuse: add pages to fuse_argsMiklos Szeredi
Derive fuse_args_pages from fuse_args. This is used to handle requests which use pages for input or output. The related flags are added to fuse_args. New FR_ALLOC_PAGES flags is added to indicate whether the page arrays in fuse_req need to be freed by fuse_put_request() or not. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-10fuse: convert destroy to simple apiMiklos Szeredi
We can use the "force" flag to make sure the DESTROY request is always sent to userspace. So no need to keep it allocated during the lifetime of the filesystem. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-10fuse: add nocreds to fuse_argsMiklos Szeredi
In some cases it makes no sense to set pid/uid/gid fields in the request header. Allow fuse_simple_background() to omit these. This is only required in the "force" case, so for now just WARN if set otherwise. Fold fuse_get_req_nofail_nopages() into its only caller. Comment is obsolete anyway. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-10fuse: convert fuse_force_forget() to simple apiMiklos Szeredi
Move this function to the readdir.c where its only caller resides. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-10fuse: add noreply to fuse_argsMiklos Szeredi
This will be used by fuse_force_forget(). We can expand fuse_request_send() into fuse_simple_request(). The FR_WAITING bit has already been set, no need to check. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-10fuse: convert flush to simple apiMiklos Szeredi
Add 'force' to fuse_args and use fuse_get_req_nofail_nopages() to allocate the request in that case. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-10fuse: simplify 'nofail' requestMiklos Szeredi
Instead of complex games with a reserved request, just use __GFP_NOFAIL. Both calers (flush, readdir) guarantee that connection was already initialized, so no need to wait for fc->initialized. Also remove unneeded clearing of FR_BACKGROUND flag. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>