kernel/git/stable/linux.git/fs/fuse/file.c, branch linux-5.14.y

fuse: wait for writepages in syncfs

2021-09-15T08:02:35+00:00

commit 660585b56e63ca034ad506ea53c807c5cdca3196 upstream. In case of fuse the MM subsystem doesn't guarantee that page writeback completes by the time ->sync_fs() is called. This is because fuse completes page writeback immediately to prevent DoS of memory reclaim by the userspace file server. This means that fuse itself must ensure that writes are synced before sending the SYNCFS request to the server. Introduce sync buckets, that hold a counter for the number of outstanding write requests. On syncfs replace the current bucket with a new one and wait until the old bucket's counter goes down to zero. It is possible to have multiple syncfs calls in parallel, in which case there could be more than one waited-on buckets. Descendant buckets must not complete until the parent completes. Add a count to the child (new) bucket until the (parent) old bucket completes. Use RCU protection to dereference the current bucket and to wake up an emptied bucket. Use fc->lock to protect against parallel assignments to the current bucket. This leaves just the counter to be a possible scalability issue. The fc->num_waiting counter has a similar issue, so both should be addressed at the same time. Reported-by: Amir Goldstein Fixes: 2d82ab251ef0 ("virtiofs: propagate sync() to file server") Cc: # v5.14 Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

fuse: flush extending writes

2021-09-15T08:02:35+00:00

commit 59bda8ecee2ffc6a602b7bf2b9e43ca669cdbdcd upstream. Callers of fuse_writeback_range() assume that the file is ready for modification by the server in the supplied byte range after the call returns. If there's a write that extends the file beyond the end of the supplied range, then the file needs to be extended to at least the end of the range, but currently that's not done. There are at least two cases where this can cause problems: - copy_file_range() will return short count if the file is not extended up to end of the source range. - FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE will not extend the file, hence the region may not be fully allocated. Fix by flushing writes from the start of the range up to the end of the file. This could be optimized if the writes are non-extending, etc, but it's probably not worth the trouble. Fixes: a2bc92362941 ("fuse: fix copy_file_range() in the writeback case") Fixes: 6b1bdb56b17c ("fuse: allow fallocate(FALLOC_FL_ZERO_RANGE)") Cc: # v5.2 Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

fuse: truncate pagecache on atomic_o_trunc

2021-09-15T08:02:35+00:00

commit 76224355db7570cbe6b6f75c8929a1558828dd55 upstream. fuse_finish_open() will be called with FUSE_NOWRITE in case of atomic O_TRUNC. This can deadlock with fuse_wait_on_page_writeback() in fuse_launder_page() triggered by invalidate_inode_pages2(). Fix by replacing invalidate_inode_pages2() in fuse_finish_open() with a truncate_pagecache() call. This makes sense regardless of FOPEN_KEEP_CACHE or fc->writeback cache, so do it unconditionally. Reported-by: Xie Yongji Reported-and-tested-by: syzbot+bea44a5189836d956894@syzkaller.appspotmail.com Fixes: e4648309b85a ("fuse: truncate pending writes on O_TRUNC") Cc: Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

Merge tag 'fuse-update-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

2021-07-06T18:17:41+00:00

Pull fuse updates from Miklos Szeredi: - Fixes for virtiofs submounts - Misc fixes and cleanups * tag 'fuse-update-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: virtiofs: Fix spelling mistakes fuse: use DIV_ROUND_UP helper macro for calculations fuse: fix illegal access to inode with reused nodeid fuse: allow fallocate(FALLOC_FL_ZERO_RANGE) fuse: Make fuse_fill_super_submount() static fuse: Switch to fc_mount() for submounts fuse: Call vfs_get_tree() for submounts fuse: add dedicated filesystem context ops for submounts virtiofs: propagate sync() to file server fuse: reject internal errno fuse: check connected before queueing on fpq->io fuse: ignore PG_workingset after stealing fuse: Fix infinite loop in sget_fc() fuse: Fix crash if superblock of submount gets killed early fuse: Fix crash in fuse_dentry_automount() error path

virtiofs: Fix spelling mistakes

2021-06-22T07:15:36+00:00

Fix some spelling mistakes in comments: refernce ==> reference happnes ==> happens threhold ==> threshold splitted ==> split mached ==> matched Signed-off-by: Zheng Yongjun Signed-off-by: Miklos Szeredi

fuse: use DIV_ROUND_UP helper macro for calculations

2021-06-22T07:15:36+00:00

Replace open coded divisor calculations with the DIV_ROUND_UP kernel macro for better readability. Signed-off-by: Wu Bo Signed-off-by: Miklos Szeredi

fuse: allow fallocate(FALLOC_FL_ZERO_RANGE)

2021-06-22T07:15:36+00:00

The current fuse module filters out fallocate(FALLOC_FL_ZERO_RANGE) returning -EOPNOTSUPP. libnbd's nbdfuse would like to translate FALLOC_FL_ZERO_RANGE requests into the NBD command NBD_CMD_WRITE_ZEROES which allows NBD servers that support it to do zeroing efficiently. This commit treats this flag exactly like FALLOC_FL_PUNCH_HOLE. A way to test this, requiring fuse >= 3, nbdkit >= 1.8 and the latest nbdfuse from https://gitlab.com/nbdkit/libnbd/-/tree/master/fuse is to create a file containing some data and "mirror" it to a fuse file: $ dd if=/dev/urandom of=disk.img bs=1M count=1 $ nbdkit file disk.img $ touch mirror.img $ nbdfuse mirror.img nbd://localhost & (mirror.img -> nbdfuse -> NBD over loopback -> nbdkit -> disk.img) You can then run commands such as: $ fallocate -z -o 1024 -l 1024 mirror.img and check that the content of the original file ("disk.img") stays synchronized. To show NBD commands, export LIBNBD_DEBUG=1 before running nbdfuse. To clean up: $ fusermount3 -u mirror.img $ killall nbdkit Signed-off-by: Richard W.M. Jones Signed-off-by: Miklos Szeredi

iov_iter: replace iov_iter_copy_from_user_atomic() with iterator-advancing variant

2021-06-10T15:45:14+00:00

Replacement is called copy_page_from_iter_atomic(); unlike the old primitive the callers do *not* need to do iov_iter_advance() after it. In case when they end up consuming less than they'd been given they need to do iov_iter_revert() on everything they had not consumed. That, however, needs to be done only on slow paths. All in-tree callers converted. And that kills the last user of iterate_all_kinds() Signed-off-by: Al Viro

fuse_fill_write_pages(): don't bother with iov_iter_single_seg_count()

2021-06-03T14:34:55+00:00

another rudiment of fault-in originally having been limited to the first segment, same as in generic_perform_write() and friends. Signed-off-by: Al Viro

Merge tag 'fuse-update-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

2021-04-30T22:23:16+00:00

Pull fuse updates from Miklos Szeredi: - Fix a page locking bug in write (introduced in 2.6.26) - Allow sgid bit to be killed in setacl() - Miscellaneous fixes and cleanups * tag 'fuse-update-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: cuse: simplify refcount cuse: prevent clone virtiofs: fix userns virtiofs: remove useless function virtiofs: split requests that exceed virtqueue size virtiofs: fix memory leak in virtio_fs_probe() fuse: invalidate attrs when page writeback completes fuse: add a flag FUSE_SETXATTR_ACL_KILL_SGID to kill SGID fuse: extend FUSE_SETXATTR request fuse: fix matching of FUSE_DEV_IOC_CLONE command fuse: fix a typo fuse: don't zero pages twice fuse: fix typo for fuse_conn.max_pages comment fuse: fix write deadlock