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2021-11-01Merge tag 'for-5.16/ki_complete-2021-10-29' of git://git.kernel.dk/linux-blockLinus Torvalds1-1/+1
Pull kiocb->ki_complete() cleanup from Jens Axboe: "This removes the res2 argument from kiocb->ki_complete(). Only the USB gadget code used it, everybody else passes 0. The USB guys checked the user gadget code they could find, and everybody just uses res as expected for the async interface" * tag 'for-5.16/ki_complete-2021-10-29' of git://git.kernel.dk/linux-block: fs: get rid of the res2 iocb->ki_complete argument usb: remove res2 argument from gadget code completions
2021-10-25fs: get rid of the res2 iocb->ki_complete argumentJens Axboe1-1/+1
The second argument was only used by the USB gadget code, yet everyone pays the overhead of passing a zero to be passed into aio, where it ends up being part of the aio res2 value. Now that everybody is passing in zero, kill off the extra argument. Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-21fuse: clean up error exits in fuse_fill_super()Miklos Szeredi1-6/+2
Instead of "goto err", return error directly, since there's no error cleanup to do now. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-10-21fuse: always initialize sb->s_fs_infoMiklos Szeredi1-25/+25
Syzkaller reports a null pointer dereference in fuse_test_super() that is caused by sb->s_fs_info being NULL. This is due to the fact that fuse_fill_super() is initializing s_fs_info, which is too late, it's already on the fs_supers list. The initialization needs to be done in sget_fc() with the sb_lock held. Move allocation of fuse_mount and fuse_conn from fuse_fill_super() into fuse_get_tree(). After this ->kill_sb() will always be called with non-NULL ->s_fs_info, hence fuse_mount_destroy() can drop the test for non-NULL "fm". Reported-by: syzbot+74a15f02ccb51f398601@syzkaller.appspotmail.com Fixes: 5d5b74aa9c76 ("fuse: allow sharing existing sb") Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-10-21fuse: clean up fuse_mount destructionMiklos Szeredi2-19/+7
1. call fuse_mount_destroy() for open coded variants 2. before deactivate_locked_super() don't need fuse_mount destruction since that will now be done (if ->s_fs_info is not cleared) 3. rearrange fuse_mount setup in fuse_get_tree_submount() so that the regular pattern can be used Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-10-21fuse: get rid of fuse_put_super()Miklos Szeredi3-9/+15
The ->put_super callback is called from generic_shutdown_super() in case of a fully initialized sb. This is called from kill_***_super(), which is called from ->kill_sb instances. Fuse uses ->put_super to destroy the fs specific fuse_mount and drop the reference to the fuse_conn, while it does the same on each error case during sb setup. This patch moves the destruction from fuse_put_super() to fuse_mount_destroy(), called at the end of all ->kill_sb instances. A follup patch will clean up the error paths. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-10-21fuse: check s_root when destroying sbMiklos Szeredi2-2/+2
Checking "fm" works because currently sb->s_fs_info is cleared on error paths; however, sb->s_root is what generic_shutdown_super() checks to determine whether the sb was fully initialized or not. This change will allow cleanup of sb setup error paths. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-09-07Merge tag 'fuse-update-5.15' of ↵Linus Torvalds6-80/+214
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse Pull fuse updates from Miklos Szeredi: - Allow mounting an active fuse device. Previously the fuse device would always be mounted during initialization, and sharing a fuse superblock was only possible through mount or namespace cloning - Fix data flushing in syncfs (virtiofs only) - Fix data flushing in copy_file_range() - Fix a possible deadlock in atomic O_TRUNC - Misc fixes and cleanups * tag 'fuse-update-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: fuse: remove unused arg in fuse_write_file_get() fuse: wait for writepages in syncfs fuse: flush extending writes fuse: truncate pagecache on atomic_o_trunc fuse: allow sharing existing sb fuse: move fget() to fuse_get_tree() fuse: move option checking into fuse_fill_super() fuse: name fs_context consistently fuse: fix use after free in fuse_read_interrupt()
2021-09-06fuse: remove unused arg in fuse_write_file_get()Miklos Szeredi1-9/+6
The struct fuse_conn argument is not used and can be removed. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-09-06fuse: wait for writepages in syncfsMiklos Szeredi3-0/+100
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 <amir73il@gmail.com> Fixes: 2d82ab251ef0 ("virtiofs: propagate sync() to file server") Cc: <stable@vger.kernel.org> # v5.14 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-09-02Merge tag 'ovl-update-5.15' of ↵Linus Torvalds2-2/+5
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull overlayfs update from Miklos Szeredi: - Copy up immutable/append/sync/noatime attributes (Amir Goldstein) - Improve performance by enabling RCU lookup. - Misc fixes and improvements The reason this touches so many files is that the ->get_acl() method now gets a "bool rcu" argument. The ->get_acl() API was updated based on comments from Al and Linus: Link: https://lore.kernel.org/linux-fsdevel/CAJfpeguQxpd6Wgc0Jd3ks77zcsAv_bn0q17L3VNnnmPKu11t8A@mail.gmail.com/ * tag 'ovl-update-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: enable RCU'd ->get_acl() vfs: add rcu argument to ->get_acl() callback ovl: fix BUG_ON() in may_delete() when called from ovl_cleanup() ovl: use kvalloc in xattr copy-up ovl: update ctime when changing fileattr ovl: skip checking lower file's i_writecount on truncate ovl: relax lookup error on mismatch origin ftype ovl: do not set overlay.opaque for new directories ovl: add ovl_allow_offline_changes() helper ovl: disable decoding null uuid with redirect_dir ovl: consistent behavior for immutable/append-only inodes ovl: copy up sync/noatime fileattr flags ovl: pass ovl_fs to ovl_check_setxattr() fs: add generic helper for filling statx attribute flags
2021-08-31fuse: flush extending writesMiklos Szeredi1-1/+1
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: <stable@vger.kernel.org> # v5.2 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-08-30Merge tag 'hole_punch_for_v5.15-rc1' of ↵Linus Torvalds5-44/+35
git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs Pull fs hole punching vs cache filling race fixes from Jan Kara: "Fix races leading to possible data corruption or stale data exposure in multiple filesystems when hole punching races with operations such as readahead. This is the series I was sending for the last merge window but with your objection fixed - now filemap_fault() has been modified to take invalidate_lock only when we need to create new page in the page cache and / or bring it uptodate" * tag 'hole_punch_for_v5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: filesystems/locking: fix Malformed table warning cifs: Fix race between hole punch and page fault ceph: Fix race between hole punch and page fault fuse: Convert to using invalidate_lock f2fs: Convert to using invalidate_lock zonefs: Convert to using invalidate_lock xfs: Convert double locking of MMAPLOCK to use VFS helpers xfs: Convert to use invalidate_lock xfs: Refactor xfs_isilocked() ext2: Convert to using invalidate_lock ext4: Convert to use mapping->invalidate_lock mm: Add functions to lock invalidate_lock for two mappings mm: Protect operations adding pages to page cache with invalidate_lock documentation: Sync file_operations members with reality mm: Fix comments mentioning i_mutex
2021-08-18vfs: add rcu argument to ->get_acl() callbackMiklos Szeredi2-2/+5
Add a rcu argument to the ->get_acl() callback to allow get_cached_acl_rcu() to call the ->get_acl() method in the next patch. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-08-17fuse: truncate pagecache on atomic_o_truncMiklos Szeredi1-2/+5
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 <xieyongji@bytedance.com> Reported-and-tested-by: syzbot+bea44a5189836d956894@syzkaller.appspotmail.com Fixes: e4648309b85a ("fuse: truncate pending writes on O_TRUNC") Cc: <stable@vger.kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-08-11Merge branch 'for-5.14/dax' into libnvdimm-fixesDan Williams1-4/+2
Pick up some small dax cleanups that make some of Ira's follow on work easier.
2021-08-05fuse: allow sharing existing sbMiklos Szeredi1-1/+37
Make it possible to create a new mount from a already working server. Here's a detailed description of the problem from Jakob: "The background for this question is occasional problems we see with our fuse filesystem [1] and mount namespaces. On a usual client, we have system-wide, autofs managed mountpoints. When a new mount namespace is created (which can be done unprivileged in combination with user namespaces), it can happen that a mountpoint is used inside the new namespace but idle in the root mount namespace. So autofs unmounts the parent, system-wide mountpoint. But the fuse module stays active and still serves mountpoint in the child mount namespace. Because the fuse daemon also blocks other system wide resources corresponding to the mountpoint, this situation effectively prevents new mounts until the child mount namespaces closes. [1] https://github.com/cvmfs/cvmfs" Reported-by: Jakob Blomer <jblomer@cern.ch> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-08-05fuse: move fget() to fuse_get_tree()Miklos Szeredi2-23/+22
Affected call chains: fuse_get_tree -> get_tree_(bdev|nodev) -> fuse_fill_super Needed for following patch. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-08-04fuse: move option checking into fuse_fill_super()Miklos Szeredi1-7/+6
Checking whether the "fd=", "rootmode=", "user_id=" and "group_id=" mount options are present can be moved from fuse_get_tree() into fuse_fill_super() where the value of the options are consumed. This relaxes semantics of reusing a fuse blockdev mount using the device name. Before this patch presence of these options were enforced but values ignored, after this patch these options are completely ignored in this case. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-08-04fuse: name fs_context consistentlyMiklos Szeredi3-41/+41
Naming convention under fs/fuse/: struct fuse_conn *fc; struct fs_context *fsc; Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-08-04fuse: fix use after free in fuse_read_interrupt()Miklos Szeredi1-2/+2
There is a potential race between fuse_read_interrupt() and fuse_request_end(). TASK1 in fuse_read_interrupt(): delete req->intr_entry (while holding fiq->lock) TASK2 in fuse_request_end(): req->intr_entry is empty -> skip fiq->lock wake up TASK3 TASK3 request is freed TASK1 in fuse_read_interrupt(): dereference req->in.h.unique ***BAM*** Fix by always grabbing fiq->lock if the request was ever interrupted (FR_INTERRUPTED set) thereby serializing with concurrent fuse_read_interrupt() calls. FR_INTERRUPTED is set before the request is queued on fiq->interrupts. Dequeing the request is done with list_del_init() but FR_INTERRUPTED is not cleared in this case. Reported-by: lijiazi <lijiazi@xiaomi.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-07-13fuse: Convert to using invalidate_lockJan Kara5-44/+35
Use invalidate_lock instead of fuse's private i_mmap_sem. The intended purpose is exactly the same. By this conversion we fix a long standing race between hole punching and read(2) / readahead(2) paths that can lead to stale page cache contents. CC: Miklos Szeredi <miklos@szeredi.hu> Reviewed-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Jan Kara <jack@suse.cz>
2021-07-08fs/fuse: Remove unneeded kaddr parameterIra Weiny1-4/+2
fuse_dax_mem_range_init() does not need the address or the pfn of the memory requested in dax_direct_access(). It is only calling direct access to get the number of pages. Remove the unused variables and stop requesting the kaddr and pfn from dax_direct_access(). Reviewed-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Vivek Goyal <vgoyal@redhat.com> Link: https://lore.kernel.org/r/20210525172428.3634316-2-ira.weiny@intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-07-06Merge tag 'fuse-update-5.14' of ↵Linus Torvalds8-80/+152
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse 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
2021-07-03Merge branch 'work.iov_iter' of ↵Linus Torvalds1-3/+1
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull iov_iter updates from Al Viro: "iov_iter cleanups and fixes. There are followups, but this is what had sat in -next this cycle. IMO the macro forest in there became much thinner and easier to follow..." * 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (37 commits) csum_and_copy_to_pipe_iter(): leave handling of csum_state to caller clean up copy_mc_pipe_to_iter() pipe_zero(): we don't need no stinkin' kmap_atomic()... iov_iter: clean csum_and_copy_...() primitives up a bit copy_page_from_iter(): don't need kmap_atomic() for kvec/bvec cases copy_page_to_iter(): don't bother with kmap_atomic() for bvec/kvec cases iterate_xarray(): only of the first iteration we might get offset != 0 pull handling of ->iov_offset into iterate_{iovec,bvec,xarray} iov_iter: make iterator callbacks use base and len instead of iovec iov_iter: make the amount already copied available to iterator callbacks iov_iter: get rid of separate bvec and xarray callbacks iov_iter: teach iterate_{bvec,xarray}() about possible short copies iterate_bvec(): expand bvec.h macro forest, massage a bit iov_iter: unify iterate_iovec and iterate_kvec iov_iter: massage iterate_iovec and iterate_kvec to logics similar to iterate_bvec iterate_and_advance(): get rid of magic in case when n is 0 csum_and_copy_to_iter(): massage into form closer to csum_and_copy_from_iter() iov_iter: replace iov_iter_copy_from_user_atomic() with iterator-advancing variant [xarray] iov_iter_npages(): just use DIV_ROUND_UP() iov_iter_npages(): don't bother with iterate_all_kinds() ...
2021-06-29mm: move page dirtying prototypes from mm.hMatthew Wilcox (Oracle)1-0/+1
These functions implement the address_space ->set_page_dirty operation and should live in pagemap.h, not mm.h so that the rest of the kernel doesn't get funny ideas about calling them directly. Link: https://lkml.kernel.org/r/20210615162342.1669332-7-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-29fs: remove noop_set_page_dirty()Matthew Wilcox (Oracle)1-1/+1
Use __set_page_dirty_no_writeback() instead. This will set the dirty bit on the page, which will be used to avoid calling set_page_dirty() in the future. It will have no effect on actually writing the page back, as the pages are not on any LRU lists. [akpm@linux-foundation.org: export __set_page_dirty_no_writeback() to modules] Link: https://lkml.kernel.org/r/20210615162342.1669332-6-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-22virtiofs: Fix spelling mistakesZheng Yongjun3-5/+5
Fix some spelling mistakes in comments: refernce ==> reference happnes ==> happens threhold ==> threshold splitted ==> split mached ==> matched Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-06-22fuse: use DIV_ROUND_UP helper macro for calculationsWu Bo1-1/+1
Replace open coded divisor calculations with the DIV_ROUND_UP kernel macro for better readability. Signed-off-by: Wu Bo <wubo40@huawei.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-06-22fuse: fix illegal access to inode with reused nodeidAmir Goldstein4-5/+15
Server responds to LOOKUP and other ops (READDIRPLUS/CREATE/MKNOD/...) with ourarg containing nodeid and generation. If a fuse inode is found in inode cache with the same nodeid but different generation, the existing fuse inode should be unhashed and marked "bad" and a new inode with the new generation should be hashed instead. This can happen, for example, with passhrough fuse filesystem that returns the real filesystem ino/generation on lookup and where real inode numbers can get recycled due to real files being unlinked not via the fuse passthrough filesystem. With current code, this situation will not be detected and an old fuse dentry that used to point to an older generation real inode, can be used to access a completely new inode, which should be accessed only via the new dentry. Note that because the FORGET message carries the nodeid w/o generation, the server should wait to get FORGET counts for the nlookup counts of the old and reused inodes combined, before it can free the resources associated to that nodeid. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-06-22fuse: allow fallocate(FALLOC_FL_ZERO_RANGE)Richard W.M. Jones1-4/+6
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 <rjones@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-06-22fuse: Make fuse_fill_super_submount() staticGreg Kurz2-11/+2
This function used to be called from fuse_dentry_automount(). This code was moved to fuse_get_tree_submount() in the same file since then. It is unlikely there will ever be another user. No need to be extern in this case. Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-06-22fuse: Switch to fc_mount() for submountsGreg Kurz1-23/+6
fc_mount() already handles the vfs_get_tree(), sb->s_umount unlocking and vfs_create_mount() sequence. Using it greatly simplifies fuse_dentry_automount(). Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-06-22fuse: Call vfs_get_tree() for submountsGreg Kurz2-48/+41
We recently fixed an infinite loop by setting the SB_BORN flag on submounts along with the write barrier needed by super_cache_count(). This is the job of vfs_get_tree() and FUSE shouldn't have to care about the barrier at all. Split out some code from fuse_dentry_automount() to the dedicated fuse_get_tree_submount() handler for submounts and call vfs_get_tree(). Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-06-22fuse: add dedicated filesystem context ops for submountsGreg Kurz3-0/+24
The creation of a submount is open-coded in fuse_dentry_automount(). This brings a lot of complexity and we recently had to fix bugs because we weren't setting SB_BORN or because we were unlocking sb->s_umount before sb was fully configured. Most of these could have been avoided by using the mount API instead of open-coding. Basically, this means coming up with a proper ->get_tree() implementation for submounts and call vfs_get_tree(), or better fc_mount(). The creation of the superblock for submounts is quite different from the root mount. Especially, it doesn't require to allocate a FUSE filesystem context, nor to parse parameters. Introduce a dedicated context ops for submounts to make this clear. This is just a placeholder for now, fuse_get_tree_submount() will be populated in a subsequent patch. Only visible change is that we stop allocating/freeing a useless FUSE filesystem context with submounts. Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-06-22virtiofs: propagate sync() to file serverGreg Kurz3-0/+44
Even if POSIX doesn't mandate it, linux users legitimately expect sync() to flush all data and metadata to physical storage when it is located on the same system. This isn't happening with virtiofs though: sync() inside the guest returns right away even though data still needs to be flushed from the host page cache. This is easily demonstrated by doing the following in the guest: $ dd if=/dev/zero of=/mnt/foo bs=1M count=5K ; strace -T -e sync sync 5120+0 records in 5120+0 records out 5368709120 bytes (5.4 GB, 5.0 GiB) copied, 5.22224 s, 1.0 GB/s sync() = 0 <0.024068> and start the following in the host when the 'dd' command completes in the guest: $ strace -T -e fsync /usr/bin/sync virtiofs/foo fsync(3) = 0 <10.371640> There are no good reasons not to honor the expected behavior of sync() actually: it gives an unrealistic impression that virtiofs is super fast and that data has safely landed on HW, which isn't the case obviously. Implement a ->sync_fs() superblock operation that sends a new FUSE_SYNCFS request type for this purpose. Provision a 64-bit placeholder for possible future extensions. Since the file server cannot handle the wait == 0 case, we skip it to avoid a gratuitous roundtrip. Note that this is per-superblock: a FUSE_SYNCFS is send for the root mount and for each submount. Like with FUSE_FSYNC and FUSE_FSYNCDIR, lack of support for FUSE_SYNCFS in the file server is treated as permanent success. This ensures compatibility with older file servers: the client will get the current behavior of sync() not being propagated to the file server. Note that such an operation allows the file server to DoS sync(). Since a typical FUSE file server is an untrusted piece of software running in userspace, this is disabled by default. Only enable it with virtiofs for now since virtiofsd is supposedly trusted by the guest kernel. Reported-by: Robert Krawitz <rlk@redhat.com> Signed-off-by: Greg Kurz <groug@kaod.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-06-22fuse: reject internal errnoMiklos Szeredi1-1/+1
Don't allow userspace to report errors that could be kernel-internal. Reported-by: Anatoly Trosinenko <anatoly.trosinenko@gmail.com> Fixes: 334f485df85a ("[PATCH] FUSE - device functions") Cc: <stable@vger.kernel.org> # v2.6.14 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-06-22fuse: check connected before queueing on fpq->ioMiklos Szeredi1-0/+9
A request could end up on the fpq->io list after fuse_abort_conn() has reset fpq->connected and aborted requests on that list: Thread-1 Thread-2 ======== ======== ->fuse_simple_request() ->shutdown ->__fuse_request_send() ->queue_request() ->fuse_abort_conn() ->fuse_dev_do_read() ->acquire(fpq->lock) ->wait_for(fpq->lock) ->set err to all req's in fpq->io ->release(fpq->lock) ->acquire(fpq->lock) ->add req to fpq->io After the userspace copy is done the request will be ended, but req->out.h.error will remain uninitialized. Also the copy might block despite being already aborted. Fix both issues by not allowing the request to be queued on the fpq->io list after fuse_abort_conn() has processed this list. Reported-by: Pradeep P V K <pragalla@codeaurora.org> Fixes: fd22d62ed0c3 ("fuse: no fc->lock for iqueue parts") Cc: <stable@vger.kernel.org> # v4.2 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-06-18fuse: ignore PG_workingset after stealingMiklos Szeredi1-0/+1
Fix the "fuse: trying to steal weird page" warning. Description from Johannes Weiner: "Think of it as similar to PG_active. It's just another usage/heat indicator of file and anon pages on the reclaim LRU that, unlike PG_active, persists across deactivation and even reclaim (we store it in the page cache / swapper cache tree until the page refaults). So if fuse accepts pages that can legally have PG_active set, PG_workingset is fine too." Reported-by: Thomas Lindroth <thomas.lindroth@gmail.com> Fixes: 1899ad18c607 ("mm: workingset: tell cache transitions from workingset thrashing") Cc: <stable@vger.kernel.org> # v4.20 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-06-10iov_iter: replace iov_iter_copy_from_user_atomic() with iterator-advancing ↵Al Viro1-2/+1
variant 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 <viro@zeniv.linux.org.uk>
2021-06-09fuse: Fix infinite loop in sget_fc()Greg Kurz1-0/+11
We don't set the SB_BORN flag on submounts. This is wrong as these superblocks are then considered as partially constructed or dying in the rest of the code and can break some assumptions. One such case is when you have a virtiofs filesystem with submounts and you try to mount it again : virtio_fs_get_tree() tries to obtain a superblock with sget_fc(). The logic in sget_fc() is to loop until it has either found an existing matching superblock with SB_BORN set or to create a brand new one. It is assumed that a superblock without SB_BORN is transient and the loop is restarted. Forgetting to set SB_BORN on submounts hence causes sget_fc() to retry forever. Setting SB_BORN requires special care, i.e. a write barrier for super_cache_count() which can check SB_BORN without taking any lock. We should call vfs_get_tree() to deal with that but this requires to have a proper ->get_tree() implementation for submounts, which is a bigger piece of work. Go for a simple bug fix in the meatime. Fixes: bf109c64040f ("fuse: implement crossmounts") Cc: stable@vger.kernel.org # v5.10+ Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-06-09fuse: Fix crash if superblock of submount gets killed earlyGreg Kurz1-4/+4
As soon as fuse_dentry_automount() does up_write(&sb->s_umount), the superblock can theoretically be killed. If this happens before the submount was added to the &fc->mounts list, fuse_mount_remove() later crashes in list_del_init() because it assumes the submount to be already there. Add the submount before dropping sb->s_umount to fix the inconsistency. It is okay to nest fc->killsb under sb->s_umount, we already do this on the ->kill_sb() path. Signed-off-by: Greg Kurz <groug@kaod.org> Fixes: bf109c64040f ("fuse: implement crossmounts") Cc: stable@vger.kernel.org # v5.10+ Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-06-09fuse: Fix crash in fuse_dentry_automount() error pathGreg Kurz1-1/+5
If fuse_fill_super_submount() returns an error, the error path triggers a crash: [ 26.206673] BUG: kernel NULL pointer dereference, address: 0000000000000000 [...] [ 26.226362] RIP: 0010:__list_del_entry_valid+0x25/0x90 [...] [ 26.247938] Call Trace: [ 26.248300] fuse_mount_remove+0x2c/0x70 [fuse] [ 26.248892] virtio_kill_sb+0x22/0x160 [virtiofs] [ 26.249487] deactivate_locked_super+0x36/0xa0 [ 26.250077] fuse_dentry_automount+0x178/0x1a0 [fuse] The crash happens because fuse_mount_remove() assumes that the FUSE mount was already added to list under the FUSE connection, but this only done after fuse_fill_super_submount() has returned success. This means that until fuse_fill_super_submount() has returned success, the FUSE mount isn't actually owned by the superblock. We should thus reclaim ownership by clearing sb->s_fs_info, which will skip the call to fuse_mount_remove(), and perform rollback, like virtio_fs_get_tree() already does for the root sb. Fixes: bf109c64040f ("fuse: implement crossmounts") Cc: stable@vger.kernel.org # v5.10+ Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-06-03fuse_fill_write_pages(): don't bother with iov_iter_single_seg_count()Al Viro1-1/+0
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 <viro@zeniv.linux.org.uk>
2021-05-02Merge branch 'work.misc' of ↵Linus Torvalds1-2/+1
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc vfs updates from Al Viro: "Assorted stuff all over the place" * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: useful constants: struct qstr for ".." hostfs_open(): don't open-code file_dentry() whack-a-mole: kill strlen_user() (again) autofs: should_expire() argument is guaranteed to be positive apparmor:match_mn() - constify devpath argument buffer: a small optimization in grow_buffers get rid of autofs_getpath() constify dentry argument of dentry_path()/dentry_path_raw()
2021-05-01Merge tag 'fuse-update-5.13' of ↵Linus Torvalds8-57/+97
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse 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
2021-04-27Merge branch 'miklos.fileattr' of ↵Linus Torvalds5-402/+571
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull fileattr conversion updates from Miklos Szeredi via Al Viro: "This splits the handling of FS_IOC_[GS]ETFLAGS from ->ioctl() into a separate method. The interface is reasonably uniform across the filesystems that support it and gives nice boilerplate removal" * 'miklos.fileattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (23 commits) ovl: remove unneeded ioctls fuse: convert to fileattr fuse: add internal open/release helpers fuse: unsigned open flags fuse: move ioctl to separate source file vfs: remove unused ioctl helpers ubifs: convert to fileattr reiserfs: convert to fileattr ocfs2: convert to fileattr nilfs2: convert to fileattr jfs: convert to fileattr hfsplus: convert to fileattr efivars: convert to fileattr xfs: convert to fileattr orangefs: convert to fileattr gfs2: convert to fileattr f2fs: convert to fileattr ext4: convert to fileattr ext2: convert to fileattr btrfs: convert to fileattr ...
2021-04-27Merge branch 'work.inode-type-fixes' of ↵Linus Torvalds3-5/+5
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs inode type handling updates from Al Viro: "We should never change the type bits of ->i_mode or the method tables (->i_op and ->i_fop) of a live inode. Unfortunately, not all filesystems took care to prevent that" * 'work.inode-type-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: spufs: fix bogosity in S_ISGID handling 9p: missing chunk of "fs/9p: Don't update file type when updating file attributes" openpromfs: don't do unlock_new_inode() until the new inode is set up hostfs_mknod(): don't bother with init_special_inode() cifs: have cifs_fattr_to_inode() refuse to change type on live inode cifs: have ->mkdir() handle race with another client sanely do_cifs_create(): don't set ->i_mode of something we had not created gfs2: be careful with inode refresh ocfs2_inode_lock_update(): make sure we don't change the type bits of i_mode orangefs_inode_is_stale(): i_mode type bits do *not* form a bitmap... vboxsf: don't allow to change the inode type afs: Fix updating of i_mode due to 3rd party change ceph: don't allow type or device number to change on non-I_NEW inodes ceph: fix up error handling with snapdirs new helper: inode_wrong_type()
2021-04-16useful constants: struct qstr for ".."Al Viro1-2/+1
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2021-04-14cuse: simplify refcountMiklos Szeredi1-7/+3
Put extra reference early in cuse_channel_open(). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>