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4 daysMerge tag 'fuse-update-6.19' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse Pull fuse updates from Miklos Szeredi: - Add mechanism for cleaning out unused, stale dentries; controlled via a module option (Luis Henriques) - Fix various bugs - Cleanups * tag 'fuse-update-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: fuse: Uninitialized variable in fuse_epoch_work() fuse: fix io-uring list corruption for terminated non-committed requests fuse: signal that a fuse inode should exhibit local fs behaviors fuse: Always flush the page cache before FOPEN_DIRECT_IO write fuse: Invalidate the page cache after FOPEN_DIRECT_IO write fuse: rename 'namelen' to 'namesize' fuse: use strscpy instead of strcpy fuse: refactor fuse_conn_put() to remove negative logic. fuse: new work queue to invalidate dentries from old epochs fuse: new work queue to periodically invalidate expired dentries dcache: export shrink_dentry_list() and add new helper d_dispose_if_unused() fuse: add WARN_ON and comment for RCU revalidate fuse: Fix whitespace for fuse_uring_args_to_ring() comment fuse: missing copy_finish in fuse-over-io-uring argument copies fuse: fix readahead reclaim deadlock
2025-11-18fuse: signal that a fuse inode should exhibit local fs behaviorsDarrick J. Wong
Create a new fuse inode flag that indicates that the kernel should implement various local filesystem behaviors instead of passing vfs commands straight through to the fuse server and expecting the server to do all the work. For example, this means that we'll use the kernel to transform some ACL updates into mode changes, and later to do enforcement of the immutable and append iflags. Signed-off-by: "Darrick J. Wong" <djwong@kernel.org> Reviewed-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-11-12fuse: new work queue to invalidate dentries from old epochsLuis Henriques
With the infrastructure introduced to periodically invalidate expired dentries, it is now possible to add an extra work queue to invalidate dentries when an epoch is incremented. This work queue will only be triggered when the 'inval_wq' parameter is set. Signed-off-by: Luis Henriques <luis@igalia.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-11-12fuse: new work queue to periodically invalidate expired dentriesLuis Henriques
This patch adds the necessary infrastructure to keep track of all dentries created for FUSE file systems. A set of rbtrees, protected by hashed locks, will be used to keep all these dentries sorted by expiry time. A new module parameter 'inval_wq' is also added. When set, it will start a work queue which will periodically invalidate expired dentries. The value of this new parameter is the period, in seconds, for this work queue. Once this parameter is set, every new dentry will be added to one of the rbtrees. When the work queue is executed, it will check all the rbtrees and will invalidate those dentries that have timed-out. The work queue period can not be smaller than 5 seconds, but can be disabled by setting 'inval_wq' to zero (which is the default). Signed-off-by: Luis Henriques <luis@igalia.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-11-05fuse: remove fc->blkbits workaround for partial writesJoanne Koong
Now that fuse is integrated with iomap for read/readahead, we can remove the workaround that was added in commit bd24d2108e9c ("fuse: fix fuseblk i_blkbits for iomap partial writes"), which was previously needed to avoid a race condition where an iomap partial write may be overwritten by a read if blocksize < PAGE_SIZE. Now that fuse does iomap read/readahead, this is protected against since there is granular uptodate tracking of blocks, which means this workaround can be removed. Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Tested-by: syzbot@syzkaller.appspotmail.com Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-25fuse: move the backing file idr and code into a new source fileDarrick J. Wong
iomap support for fuse is also going to want the ability to attach backing files to a fuse filesystem. Move the fuse_backing code into a separate file so that both can use it. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-09-23fuse: capture the unique id of fuse commands being sentDarrick J. Wong
The fuse_request_{send,end} tracepoints capture the value of req->in.h.unique in the trace output. It would be really nice if we could use this to match a request to its response for debugging and latency analysis, but the call to trace_fuse_request_send occurs before the unique id has been set: fuse_request_send: connection 8388608 req 0 opcode 1 (FUSE_LOOKUP) len 107 fuse_request_end: connection 8388608 req 6 len 16 error -2 (Notice that req moves from 0 to 6) Move the callsites to trace_fuse_request_send to after the unique id has been set by introducing a helper to do that for standard fuse_req requests. FUSE_FORGET requests are not covered by this because they appear to be synthesized into the event stream without a fuse_req object and are never replied to. Requests that are aborted without ever having been submitted to the fuse server retain the behavior that only the fuse_request_end tracepoint shows up in the trace record, and with req==0. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-09-05fuse: add prune notificationMiklos Szeredi
Some fuse servers need to prune their caches, which can only be done if the kernel's own dentry/inode caches are pruned first to avoid dangling references. Add FUSE_NOTIFY_PRUNE, which takes an array of node ID's to try and get rid of. Inodes with active references are skipped. A similar functionality is already provided by FUSE_NOTIFY_INVAL_ENTRY with the FUSE_EXPIRE_ONLY flag. Differences in the interface are FUSE_NOTIFY_INVAL_ENTRY: - can only prune one dentry - dentry is determined by parent ID and name - if inode has multiple aliases (cached hard links), then they would have to be invalidated individually to be able to get rid of the inode FUSE_NOTIFY_PRUNE: - can prune multiple inodes - inodes determined by their node ID - aliases are taken care of automatically Reviewed-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-09-02fuse: allow synchronous FUSE_INITMiklos Szeredi
FUSE_INIT has always been asynchronous with mount. That means that the server processed this request after the mount syscall returned. This means that FUSE_INIT can't supply the root inode's ID, hence it currently has a hardcoded value. There are other limitations such as not being able to perform getxattr during mount, which is needed by selinux. To remove these limitations allow server to process FUSE_INIT while initializing the in-core super block for the fuse filesystem. This can only be done if the server is prepared to handle this, so add FUSE_DEV_IOC_SYNC_INIT ioctl, which a) lets the server know whether this feature is supported, returning ENOTTY othewrwise. b) lets the kernel know to perform a synchronous initialization The implementation is slightly tricky, since fuse_dev/fuse_conn are set up only during super block creation. This is solved by setting the private data of the fuse device file to a special value ((struct fuse_dev *) 1) and waiting for this to be turned into a proper fuse_dev before commecing with operations on the device file. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-08-27fuse: remove unused 'inode' parameter in fuse_passthrough_openChunsheng Luo
The 'inode' parameter in fuse_passthrough_open() is never referenced in the function implementation. Signed-off-by: Chunsheng Luo <luochunsheng@ustc.edu> Reviewed-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-08-27fuse: add COPY_FILE_RANGE_64 that allows large copiesMiklos Szeredi
The FUSE protocol uses struct fuse_write_out to convey the return value of copy_file_range, which is restricted to uint32_t. But the COPY_FILE_RANGE interface supports a 64-bit size copies and there's no reason why copies should be limited to 32-bit. Introduce a new op COPY_FILE_RANGE_64, which is identical, except the number of bytes copied is returned in a 64-bit value. If the fuse server does not support COPY_FILE_RANGE_64, fall back to COPY_FILE_RANGE. Reported-by: Florian Weimer <fweimer@redhat.com> Closes: https://lore.kernel.org/all/lhuh5ynl8z5.fsf@oldenburg.str.redhat.com/ Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-08-26fuse: fix fuseblk i_blkbits for iomap partial writesJoanne Koong
On regular fuse filesystems, i_blkbits is set to PAGE_SHIFT which means any iomap partial writes will mark the entire folio as uptodate. However fuseblk filesystems work differently and allow the blocksize to be less than the page size. As such, this may lead to data corruption if fuseblk sets its blocksize to less than the page size, uses the writeback cache, and does a partial write, then a read and the read happens before the write has undergone writeback, since the folio will not be marked uptodate from the partial write so the read will read in the entire folio from disk, which will overwrite the partial write. The long-term solution for this, which will also be needed for fuse to enable large folios with the writeback cache on, is to have fuse also use iomap for folio reads, but until that is done, the cleanest workaround is to use the page size for fuseblk's internal kernel inode blksize/blkbits values while maintaining current behavior for stat(). This was verified using ntfs-3g: $ sudo mkfs.ntfs -f -c 512 /dev/vdd1 $ sudo ntfs-3g /dev/vdd1 ~/fuseblk $ stat ~/fuseblk/hi.txt IO Block: 512 Fixes: a4c9ab1d4975 ("fuse: use iomap for buffered writes") Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-08-26fuse: reflect cached blocksize if blocksize was changedJoanne Koong
As pointed out by Miklos[1], in the fuse_update_get_attr() path, the attributes returned to stat may be cached values instead of fresh ones fetched from the server. In the case where the server returned a modified blocksize value, we need to cache it and reflect it back to stat if values are not re-fetched since we now no longer directly change inode->i_blkbits. Link: https://lore.kernel.org/linux-fsdevel/CAJfpeguCOxeVX88_zPd1hqziB_C+tmfuDhZP5qO2nKmnb-dTUA@mail.gmail.com/ [1] Fixes: 542ede096e48 ("fuse: keep inode->i_blkbits constant") Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-07-28Merge tag 'vfs-6.17-rc1.fileattr' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull fileattr updates from Christian Brauner: "This introduces the new file_getattr() and file_setattr() system calls after lengthy discussions. Both system calls serve as successors and extensible companions to the FS_IOC_FSGETXATTR and FS_IOC_FSSETXATTR system calls which have started to show their age in addition to being named in a way that makes it easy to conflate them with extended attribute related operations. These syscalls allow userspace to set filesystem inode attributes on special files. One of the usage examples is the XFS quota projects. XFS has project quotas which could be attached to a directory. All new inodes in these directories inherit project ID set on parent directory. The project is created from userspace by opening and calling FS_IOC_FSSETXATTR on each inode. This is not possible for special files such as FIFO, SOCK, BLK etc. Therefore, some inodes are left with empty project ID. Those inodes then are not shown in the quota accounting but still exist in the directory. This is not critical but in the case when special files are created in the directory with already existing project quota, these new inodes inherit extended attributes. This creates a mix of special files with and without attributes. Moreover, special files with attributes don't have a possibility to become clear or change the attributes. This, in turn, prevents userspace from re-creating quota project on these existing files. In addition, these new system calls allow the implementation of additional attributes that we couldn't or didn't want to fit into the legacy ioctls anymore" * tag 'vfs-6.17-rc1.fileattr' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: fs: tighten a sanity check in file_attr_to_fileattr() tree-wide: s/struct fileattr/struct file_kattr/g fs: introduce file_getattr and file_setattr syscalls fs: prepare for extending file_get/setattr() fs: make vfs_fileattr_[get|set] return -EOPNOTSUPP selinux: implement inode_file_[g|s]etattr hooks lsm: introduce new hooks for setting/getting inode fsxattr fs: split fileattr related helpers into separate file
2025-07-28Merge tag 'pull-simple_recursive_removal' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull simple_recursive_removal() update from Al Viro: "Removing subtrees of kernel filesystems is done in quite a few places; unfortunately, it's easy to get wrong. A number of open-coded attempts are out there, with varying amount of bogosities. simple_recursive_removal() had been introduced for doing that with all precautions needed; it does an equivalent of rm -rf, with sufficient locking, eviction of anything mounted on top of the subtree, etc. This series converts a bunch of open-coded instances to using that" * tag 'pull-simple_recursive_removal' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: functionfs, gadgetfs: use simple_recursive_removal() kill binderfs_remove_file() fuse_ctl: use simple_recursive_removal() pstore: switch to locked_recursive_removal() binfmt_misc: switch to locked_recursive_removal() spufs: switch to locked_recursive_removal() add locked_recursive_removal() better lockdep annotations for simple_recursive_removal() simple_recursive_removal(): saner interaction with fsnotify
2025-07-04tree-wide: s/struct fileattr/struct file_kattr/gChristian Brauner
Now that we expose struct file_attr as our uapi struct rename all the internal struct to struct file_kattr to clearly communicate that it is a kernel internal struct. This is similar to struct mount_{k}attr and others. Link: https://lore.kernel.org/20250703-restlaufzeit-baurecht-9ed44552b481@brauner Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-07-02fuse_ctl: use simple_recursive_removal()Al Viro
easier that way - no need to keep that array of dentry references, etc. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-06-10fuse: no need for special dentry_operations for root dentryAl Viro
->d_revalidate() is never called for root anyway... Reviewed-by: Christian Brauner <brauner@kernel.org> Acked-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-04-15fuse: remove tmp folio for writebacks and internal rb treeJoanne Koong
In the current FUSE writeback design (see commit 3be5a52b30aa ("fuse: support writable mmap")), a temp page is allocated for every dirty page to be written back, the contents of the dirty page are copied over to the temp page, and the temp page gets handed to the server to write back. This is done so that writeback may be immediately cleared on the dirty page, and this in turn is done in order to mitigate the following deadlock scenario that may arise if reclaim waits on writeback on the dirty page to complete: * single-threaded FUSE server is in the middle of handling a request that needs a memory allocation * memory allocation triggers direct reclaim * direct reclaim waits on a folio under writeback * the FUSE server can't write back the folio since it's stuck in direct reclaim With a recent change that added AS_WRITEBACK_MAY_DEADLOCK_ON_RECLAIM and mitigates the situation described above, FUSE writeback does not need to use temp pages if it sets AS_WRITEBACK_MAY_DEADLOCK_ON_RECLAIM on its inode mappings. This commit sets AS_WRITEBACK_MAY_DEADLOCK_ON_RECLAIM on the inode mappings and removes the temporary pages + extra copying and the internal rb tree. fio benchmarks -- (using averages observed from 10 runs, throwing away outliers) Setup: sudo mount -t tmpfs -o size=30G tmpfs ~/tmp_mount ./libfuse/build/example/passthrough_ll -o writeback -o max_threads=4 -o source=~/tmp_mount ~/fuse_mount fio --name=writeback --ioengine=sync --rw=write --bs={1k,4k,1M} --size=2G --numjobs=2 --ramp_time=30 --group_reporting=1 --directory=/root/fuse_mount bs = 1k 4k 1M Before 351 MiB/s 1818 MiB/s 1851 MiB/s After 341 MiB/s 2246 MiB/s 2685 MiB/s % diff -3% 23% 45% Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-04-15fuse: add more control over cache invalidation behaviourLuis Henriques
Currently userspace is able to notify the kernel to invalidate the cache for an inode. This means that, if all the inodes in a filesystem need to be invalidated, then userspace needs to iterate through all of them and do this kernel notification separately. This patch adds the concept of 'epoch': each fuse connection will have the current epoch initialized and every new dentry will have it's d_time set to the current epoch value. A new operation will then allow userspace to increment the epoch value. Every time a dentry is d_revalidate()'ed, it's epoch is compared with the current connection epoch and invalidated if it's value is different. Signed-off-by: Luis Henriques <luis@igalia.com> Tested-by: Laura Promberger <laura.promberger@cern.ch> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-04-14fuse: change 'unsigned' to 'unsigned int'Jiale Yang
Prefer 'unsigned int' to bare 'unsigned', as reported by checkpatch.pl: WARNING: Prefer 'unsigned int' to bare use of 'unsigned'. Signed-off-by: Jiale Yang <295107659@qq.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-03-31fuse: Increase FUSE_NAME_MAX to PATH_MAXBernd Schubert
Our file system has a translation capability for S3-to-posix. The current value of 1kiB is enough to cover S3 keys, but does not allow encoding of %xx escape characters. The limit is increased to (PATH_MAX - 1), as we need 3 x 1024 and that is close to PATH_MAX (4kB) already. -1 is used as the terminating null is not included in the length calculation. Testing large file names was hard with libfuse/example file systems, so I created a new memfs that does not have a 255 file name length limitation. https://github.com/libfuse/libfuse/pull/1077 The connection is initialized with FUSE_NAME_LOW_MAX, which is set to the previous value of FUSE_NAME_MAX of 1024. With FUSE_MIN_READ_BUFFER of 8192 that is enough for two file names + fuse headers. When FUSE_INIT reply sets max_pages to a value > 1 we know that fuse daemon supports request buffers of at least 2 pages (+ header) and can therefore hold 2 x PATH_MAX file names - operations like rename or link that need two file names are no issue then. Signed-off-by: Bernd Schubert <bschubert@ddn.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-03-31fuse: add default_request_timeout and max_request_timeout sysctlsJoanne Koong
Introduce two new sysctls, "default_request_timeout" and "max_request_timeout". These control how long (in seconds) a server can take to reply to a request. If the server does not reply by the timeout, then the connection will be aborted. The upper bound on these sysctl values is 65535. "default_request_timeout" sets the default timeout if no timeout is specified by the fuse server on mount. 0 (default) indicates no default timeout should be enforced. If the server did specify a timeout, then default_request_timeout will be ignored. "max_request_timeout" sets the max amount of time the server may take to reply to a request. 0 (default) indicates no maximum timeout. If max_request_timeout is set and the fuse server attempts to set a timeout greater than max_request_timeout, the system will use max_request_timeout as the timeout. Similarly, if default_request_timeout is greater than max_request_timeout, the system will use max_request_timeout as the timeout. If the server does not request a timeout and default_request_timeout is set to 0 but max_request_timeout is set, then the timeout will be max_request_timeout. Please note that these timeouts are not 100% precise. The request may take roughly an extra FUSE_TIMEOUT_TIMER_FREQ seconds beyond the set max timeout due to how it's internally implemented. $ sysctl -a | grep fuse.default_request_timeout fs.fuse.default_request_timeout = 0 $ echo 65536 | sudo tee /proc/sys/fs/fuse/default_request_timeout tee: /proc/sys/fs/fuse/default_request_timeout: Invalid argument $ echo 65535 | sudo tee /proc/sys/fs/fuse/default_request_timeout 65535 $ sysctl -a | grep fuse.default_request_timeout fs.fuse.default_request_timeout = 65535 $ echo 0 | sudo tee /proc/sys/fs/fuse/default_request_timeout 0 $ sysctl -a | grep fuse.default_request_timeout fs.fuse.default_request_timeout = 0 [Luis Henriques: Limit the timeout to the range [FUSE_TIMEOUT_TIMER_FREQ, fuse_max_req_timeout]] Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Bernd Schubert <bschubert@ddn.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> Reviewed-by: Luis Henriques <luis@igalia.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-03-31fuse: add kernel-enforced timeout option for requestsJoanne Koong
There are situations where fuse servers can become unresponsive or stuck, for example if the server is deadlocked. Currently, there's no good way to detect if a server is stuck and needs to be killed manually. This commit adds an option for enforcing a timeout (in seconds) for requests where if the timeout elapses without the server responding to the request, the connection will be automatically aborted. Please note that these timeouts are not 100% precise. For example, the request may take roughly an extra FUSE_TIMEOUT_TIMER_FREQ seconds beyond the requested timeout due to internal implementation, in order to mitigate overhead. [SzM: Bump the API version number] Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-03-31fuse: optmize missing FUSE_LINK supportMiklos Szeredi
If filesystem doesn't support FUSE_LINK (i.e. returns -ENOSYS), then remember this and next time return immediately, without incurring the overhead of a round trip to the server. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-03-31fuse: {io-uring} Fix a possible req cancellation raceBernd Schubert
task-A (application) might be in request_wait_answer and try to remove the request when it has FR_PENDING set. task-B (a fuse-server io-uring task) might handle this request with FUSE_IO_URING_CMD_COMMIT_AND_FETCH, when fetching the next request and accessed the req from the pending list in fuse_uring_ent_assign_req(). That code path was not protected by fiq->lock and so might race with task-A. For scaling reasons we better don't use fiq->lock, but add a handler to remove canceled requests from the queue. This also removes usage of fiq->lock from fuse_uring_add_req_to_ring_ent() altogether, as it was there just to protect against this race and incomplete. Also added is a comment why FR_PENDING is not cleared. Fixes: c090c8abae4b ("fuse: Add io-uring sqe commit and fetch support") Cc: <stable@vger.kernel.org> # v6.14 Reported-by: Joanne Koong <joannelkoong@gmail.com> Closes: https://lore.kernel.org/all/CAJnrk1ZgHNb78dz-yfNTpxmW7wtT88A=m-zF0ZoLXKLUHRjNTw@mail.gmail.com/ Signed-off-by: Bernd Schubert <bschubert@ddn.com> Reviewed-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-01-27fuse: block request allocation until io-uring init is completeBernd Schubert
Avoid races and block request allocation until io-uring queues are ready. This is a especially important for background requests, as bg request completion might cause lock order inversion of the typical queue->lock and then fc->bg_lock fuse_request_end spin_lock(&fc->bg_lock); flush_bg_queue fuse_send_one fuse_uring_queue_fuse_req spin_lock(&queue->lock); Signed-off-by: Bernd Schubert <bernd@bsbernd.com> Reviewed-by: Luis Henriques <luis@igalia.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-01-27fuse: Add io-uring sqe commit and fetch supportBernd Schubert
This adds support for fuse request completion through ring SQEs (FUSE_URING_CMD_COMMIT_AND_FETCH handling). After committing the ring entry it becomes available for new fuse requests. Handling of requests through the ring (SQE/CQE handling) is complete now. Fuse request data are copied through the mmaped ring buffer, there is no support for any zero copy yet. Signed-off-by: Bernd Schubert <bschubert@ddn.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # io_uring Reviewed-by: Luis Henriques <luis@igalia.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-01-24fuse: {io-uring} Make hash-list req unique finding functions non-staticBernd Schubert
fuse-over-io-uring uses existing functions to find requests based on their unique id - make these functions non-static. Signed-off-by: Bernd Schubert <bschubert@ddn.com> Reviewed-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Luis Henriques <luis@igalia.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-01-24fuse: {io-uring} Handle SQEs - register commandsBernd Schubert
This adds basic support for ring SQEs (with opcode=IORING_OP_URING_CMD). For now only FUSE_IO_URING_CMD_REGISTER is handled to register queue entries. Signed-off-by: Bernd Schubert <bschubert@ddn.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # io_uring Reviewed-by: Luis Henriques <luis@igalia.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2025-01-24fuse: make args->in_args[0] to be always the headerBernd Schubert
This change sets up FUSE operations to always have headers in args.in_args[0], even for opcodes without an actual header. This step prepares for a clean separation of payload from headers, initially it is used by fuse-over-io-uring. For opcodes without a header, we use a zero-sized struct as a placeholder. This approach: - Keeps things consistent across all FUSE operations - Will help with payload alignment later - Avoids future issues when header sizes change Op codes that already have an op code specific header do not need modification. Op codes that have neither payload nor op code headers are not modified either (FUSE_READLINK and FUSE_DESTROY). FUSE_BATCH_FORGET already has the header in the right place, but is not using fuse_copy_args - as -over-uring is currently not handling forgets it does not matter for now, but header separation will later need special attention for that op code. Correct the struct fuse_args->in_args array max size. Signed-off-by: Bernd Schubert <bschubert@ddn.com> Reviewed-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Luis Henriques <luis@igalia.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-11-18fuse: check attributes staleness on fuse_iget()Zhang Tianci
Function fuse_direntplus_link() might call fuse_iget() to initialize a new fuse_inode and change its attributes. If fi->attr_version is always initialized with 0, even if the attributes returned by the FUSE_READDIR request is staled, as the new fi->attr_version is 0, fuse_change_attributes will still set the staled attributes to inode. This wrong behaviour may cause file size inconsistency even when there is no changes from server-side. To reproduce the issue, consider the following 2 programs (A and B) are running concurrently, A B ---------------------------------- -------------------------------- { /fusemnt/dir/f is a file path in a fuse mount, the size of f is 0. } readdir(/fusemnt/dir) start //Daemon set size 0 to f direntry fallocate(f, 1024) stat(f) // B see size 1024 echo 2 > /proc/sys/vm/drop_caches readdir(/fusemnt/dir) reply to kernel Kernel set 0 to the I_NEW inode stat(f) // B see size 0 In the above case, only program B is modifying the file size, however, B observes file size changing between the 2 'readonly' stat() calls. To fix this issue, we should make sure readdirplus still follows the rule of attr_version staleness checking even if the fi->attr_version is lost due to inode eviction. To identify this situation, the new fc->evict_ctr is used to record whether the eviction of inodes occurs during the readdirplus request processing. If it does, the result of readdirplus may be inaccurate; otherwise, the result of readdirplus can be trusted. Although this may still lead to incorrect invalidation, considering the relatively low frequency of evict occurrences, it should be acceptable. Link: https://lore.kernel.org/lkml/20230711043405.66256-2-zhangjiachen.jaycee@bytedance.com/ Link: https://lore.kernel.org/lkml/20241114070905.48901-1-zhangtianci.1997@bytedance.com/ Reported-by: Jiachen Zhang <zhangjiachen.jaycee@bytedance.com> Suggested-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Zhang Tianci <zhangtianci.1997@bytedance.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-11-05fuse: remove pages for requests and exclusively use foliosJoanne Koong
All fuse requests use folios instead of pages for transferring data. Remove pages from the requests and exclusively use folios. No functional changes. [SzM: rename back folio_descs -> descs, etc.] Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-11-05fuse: convert direct io to use foliosJoanne Koong
Convert direct io requests to use folios instead of pages. No functional changes. Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-11-05fuse: convert ioctls to use foliosJoanne Koong
Convert ioctl requests to use folios instead of pages. No functional changes. Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-11-05fuse: convert writes (non-writeback) to use foliosJoanne Koong
Convert non-writeback write requests to use folios instead of pages. No functional changes. Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-11-05fuse: convert reads to use foliosJoanne Koong
Convert read requests to use folios instead of pages. No functional changes. Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-11-05fuse: support folios in struct fuse_args_pages and fuse_copy_pages()Joanne Koong
This adds support in struct fuse_args_pages and fuse_copy_pages() for using folios instead of pages for transferring data. Both folios and pages must be supported right now in struct fuse_args_pages and fuse_copy_pages() until all request types have been converted to use folios. Once all have been converted, then struct fuse_args_pages and fuse_copy_pages() will only support folios. Right now in fuse, all folios are one page (large folios are not yet supported). As such, copying folio->page is sufficient for copying the entire folio in fuse_copy_pages(). No functional changes. Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-10-25virtiofs: use pages instead of pointer for kernel direct IOHou Tao
When trying to insert a 10MB kernel module kept in a virtio-fs with cache disabled, the following warning was reported: ------------[ cut here ]------------ WARNING: CPU: 1 PID: 404 at mm/page_alloc.c:4551 ...... Modules linked in: CPU: 1 PID: 404 Comm: insmod Not tainted 6.9.0-rc5+ #123 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ...... RIP: 0010:__alloc_pages+0x2bf/0x380 ...... Call Trace: <TASK> ? __warn+0x8e/0x150 ? __alloc_pages+0x2bf/0x380 __kmalloc_large_node+0x86/0x160 __kmalloc+0x33c/0x480 virtio_fs_enqueue_req+0x240/0x6d0 virtio_fs_wake_pending_and_unlock+0x7f/0x190 queue_request_and_unlock+0x55/0x60 fuse_simple_request+0x152/0x2b0 fuse_direct_io+0x5d2/0x8c0 fuse_file_read_iter+0x121/0x160 __kernel_read+0x151/0x2d0 kernel_read+0x45/0x50 kernel_read_file+0x1a9/0x2a0 init_module_from_file+0x6a/0xe0 idempotent_init_module+0x175/0x230 __x64_sys_finit_module+0x5d/0xb0 x64_sys_call+0x1c3/0x9e0 do_syscall_64+0x3d/0xc0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 ...... </TASK> ---[ end trace 0000000000000000 ]--- The warning is triggered as follows: 1) syscall finit_module() handles the module insertion and it invokes kernel_read_file() to read the content of the module first. 2) kernel_read_file() allocates a 10MB buffer by using vmalloc() and passes it to kernel_read(). kernel_read() constructs a kvec iter by using iov_iter_kvec() and passes it to fuse_file_read_iter(). 3) virtio-fs disables the cache, so fuse_file_read_iter() invokes fuse_direct_io(). As for now, the maximal read size for kvec iter is only limited by fc->max_read. For virtio-fs, max_read is UINT_MAX, so fuse_direct_io() doesn't split the 10MB buffer. It saves the address and the size of the 10MB-sized buffer in out_args[0] of a fuse request and passes the fuse request to virtio_fs_wake_pending_and_unlock(). 4) virtio_fs_wake_pending_and_unlock() uses virtio_fs_enqueue_req() to queue the request. Because virtiofs need DMA-able address, so virtio_fs_enqueue_req() uses kmalloc() to allocate a bounce buffer for all fuse args, copies these args into the bounce buffer and passed the physical address of the bounce buffer to virtiofsd. The total length of these fuse args for the passed fuse request is about 10MB, so copy_args_to_argbuf() invokes kmalloc() with a 10MB size parameter and it triggers the warning in __alloc_pages(): if (WARN_ON_ONCE_GFP(order > MAX_PAGE_ORDER, gfp)) return NULL; 5) virtio_fs_enqueue_req() will retry the memory allocation in a kworker, but it won't help, because kmalloc() will always return NULL due to the abnormal size and finit_module() will hang forever. A feasible solution is to limit the value of max_read for virtio-fs, so the length passed to kmalloc() will be limited. However it will affect the maximal read size for normal read. And for virtio-fs write initiated from kernel, it has the similar problem but now there is no way to limit fc->max_write in kernel. So instead of limiting both the values of max_read and max_write in kernel, introducing use_pages_for_kvec_io in fuse_conn and setting it as true in virtiofs. When use_pages_for_kvec_io is enabled, fuse will use pages instead of pointer to pass the KVEC_IO data. After switching to pages for KVEC_IO data, these pages will be used for DMA through virtio-fs. If these pages are backed by vmalloc(), {flush|invalidate}_kernel_vmap_range() are necessary to flush or invalidate the cache before the DMA operation. So add two new fields in fuse_args_pages to record the base address of vmalloc area and the condition indicating whether invalidation is needed. Perform the flush in fuse_get_user_pages() for write operations and the invalidation in fuse_release_user_pages() for read operations. It may seem necessary to introduce another field in fuse_conn to indicate that these KVEC_IO pages are used for DMA, However, considering that virtio-fs is currently the only user of use_pages_for_kvec_io, just reuse use_pages_for_kvec_io to indicate that these pages will be used for DMA. Fixes: a62a8ef9d97d ("virtio-fs: add virtiofs filesystem") Signed-off-by: Hou Tao <houtao1@huawei.com> Tested-by: Jingbo Xu <jefflexu@linux.alibaba.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-10-25fuse: enable dynamic configuration of fuse max pages limit (FUSE_MAX_MAX_PAGES)Joanne Koong
Introduce the capability to dynamically configure the max pages limit (FUSE_MAX_MAX_PAGES) through a sysctl. This allows system administrators to dynamically set the maximum number of pages that can be used for servicing requests in fuse. Previously, this is gated by FUSE_MAX_MAX_PAGES which is statically set to 256 pages. One result of this is that the buffer size for a write request is limited to 1 MiB on a 4k-page system. The default value for this sysctl is the original limit (256 pages). $ sysctl -a | grep max_pages_limit fs.fuse.max_pages_limit = 256 $ sysctl -n fs.fuse.max_pages_limit 256 $ echo 1024 | sudo tee /proc/sys/fs/fuse/max_pages_limit 1024 $ sysctl -n fs.fuse.max_pages_limit 1024 $ echo 65536 | sudo tee /proc/sys/fs/fuse/max_pages_limit tee: /proc/sys/fs/fuse/max_pages_limit: Invalid argument $ echo 0 | sudo tee /proc/sys/fs/fuse/max_pages_limit tee: /proc/sys/fs/fuse/max_pages_limit: Invalid argument $ echo 65535 | sudo tee /proc/sys/fs/fuse/max_pages_limit 65535 $ sysctl -n fs.fuse.max_pages_limit 65535 Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-09-23fs/fuse: convert to use invalid_mnt_idmapAlexander Mikhalitsyn
We should convert fs/fuse code to use a newly introduced invalid_mnt_idmap instead of passing a NULL as idmap pointer. Suggested-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-09-23fs/fuse: introduce and use fuse_simple_idmap_request() helperAlexander Mikhalitsyn
Let's convert all existing callers properly. No functional changes intended. Suggested-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-09-04fuse: support idmapped ->setattr opAlexander Mikhalitsyn
Need to translate uid and gid in case of chown(2). Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-09-04fuse: add an idmap argument to fuse_simple_requestAlexander Mikhalitsyn
If idmap == NULL *and* filesystem daemon declared idmapped mounts support, then uid/gid values in a fuse header will be -1. No functional changes intended. Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-08-29fuse: use correct name fuse_conn_list in docstringAurelien Aptel
fuse_mount_list doesn't exist, use fuse_conn_list. Signed-off-by: Aurelien Aptel <aaptel@nvidia.com> Reviewed-by: Bernd Schubert <bschubert@ddn.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-08-29fuse: cleanup request queuing towards virtiofsMiklos Szeredi
Virtiofs has its own queuing mechanism, but still requests are first queued on fiq->pending to be immediately dequeued and queued onto the virtio queue. The queuing on fiq->pending is unnecessary and might even have some performance impact due to being a contention point. Forget requests are handled similarly. Move the queuing of requests and forgets into the fiq->ops->*. fuse_iqueue_ops are renamed to reflect the new semantics. Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Fixed-by: Jingbo Xu <jefflexu@linux.alibaba.com> Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com> Tested-by: Peter-Jan Gootzen <pgootzen@nvidia.com> Reviewed-by: Peter-Jan Gootzen <pgootzen@nvidia.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-04-15fuse: fix wrong ff->iomode state changes from parallel dio writeAmir Goldstein
There is a confusion with fuse_file_uncached_io_{start,end} interface. These helpers do two things when called from passthrough open()/release(): 1. Take/drop negative refcount of fi->iocachectr (inode uncached io mode) 2. State change ff->iomode IOM_NONE <-> IOM_UNCACHED (file uncached open) The calls from parallel dio write path need to take a reference on fi->iocachectr, but they should not be changing ff->iomode state, because in this case, the fi->iocachectr reference does not stick around until file release(). Factor out helpers fuse_inode_uncached_io_{start,end}, to be used from parallel dio write path and rename fuse_file_*cached_io_{start,end} helpers to fuse_file_*cached_io_{open,release} to clarify the difference. Fixes: 205c1d802683 ("fuse: allow parallel dio writes with FUSE_DIRECT_IO_ALLOW_MMAP") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-03-15Merge tag 'fuse-update-6.9' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse Pull fuse updates from Miklos Szeredi: - Add passthrough mode for regular file I/O. This allows performing read and write (also via memory maps) on a backing file without incurring the overhead of roundtrips to userspace. For now this is only allowed to privileged servers, but this limitation will go away in the future (Amir Goldstein) - Fix interaction of direct I/O mode with memory maps (Bernd Schubert) - Export filesystem tags through sysfs for virtiofs (Stefan Hajnoczi) - Allow resending queued requests for server crash recovery (Zhao Chen) - Misc fixes and cleanups * tag 'fuse-update-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: (38 commits) fuse: get rid of ff->readdir.lock fuse: remove unneeded lock which protecting update of congestion_threshold fuse: Fix missing FOLL_PIN for direct-io fuse: remove an unnecessary if statement fuse: Track process write operations in both direct and writethrough modes fuse: Use the high bit of request ID for indicating resend requests fuse: Introduce a new notification type for resend pending requests fuse: add support for explicit export disabling fuse: __kuid_val/__kgid_val helpers in fuse_fill_attr_from_inode() fuse: fix typo for fuse_permission comment fuse: Convert fuse_writepage_locked to take a folio fuse: Remove fuse_writepage virtio_fs: remove duplicate check if queue is broken fuse: use FUSE_ROOT_ID in fuse_get_root_inode() fuse: don't unhash root fuse: fix root lookup with nonzero generation fuse: replace remaining make_bad_inode() with fuse_make_bad() virtiofs: drop __exit from virtio_fs_sysfs_exit() fuse: implement passthrough for mmap fuse: implement splice read/write passthrough ...
2024-03-06fuse: get rid of ff->readdir.lockMiklos Szeredi
The same protection is provided by file->f_pos_lock. Note, this relies on the fact that file->f_mode has FMODE_ATOMIC_POS. This flag is cleared by stream_open(), which would prevent locking of f_pos_lock. Prior to commit 7de64d521bf9 ("fuse: break up fuse_open_common()") FOPEN_STREAM on a directory would cause stream_open() to be called. After this commit this is not done anymore, so f_pos_lock will always be locked. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-03-06fuse: Fix missing FOLL_PIN for direct-ioLei Huang
Our user space filesystem relies on fuse to provide POSIX interface. In our test, a known string is written into a file and the content is read back later to verify correct data returned. We observed wrong data returned in read buffer in rare cases although correct data are stored in our filesystem. Fuse kernel module calls iov_iter_get_pages2() to get the physical pages of the user-space read buffer passed in read(). The pages are not pinned to avoid page migration. When page migration occurs, the consequence are two-folds. 1) Applications do not receive correct data in read buffer. 2) fuse kernel writes data into a wrong place. Using iov_iter_extract_pages() to pin pages fixes the issue in our test. An auxiliary variable "struct page **pt_pages" is used in the patch to prepare the 2nd parameter for iov_iter_extract_pages() since iov_iter_get_pages2() uses a different type for the 2nd parameter. [SzM] add iov_iter_extract_will_pin(ii) and unpin only if true. Signed-off-by: Lei Huang <lei.huang@linux.intel.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>