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* fuse: implement crossmountsMax Reitz2020-10-091-1/+77
| | | | | | | | | | | | | | | | | | | | 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>
* fuse: split fuse_mount off of fuse_connMax Reitz2020-09-181-54/+56
| | | | | | | | | | | | | | | | | | | | | | 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>
* virtiofs: serialize truncate/punch_hole and dax fault pathVivek Goyal2020-09-101-7/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* fuse: always allow query of st_devMiklos Szeredi2020-05-191-1/+11
| | | | | | | | | | | | Fuse mounts without "allow_other" are off-limits to all non-owners. Yet it makes sense to allow querying st_dev on the root, since this value is provided by the kernel, not the userspace filesystem. Allow statx(2) with a zero request mask to succeed on a fuse mounts for all users. Reported-by: Nikolaus Rath <Nikolaus@rath.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: Support RENAME_WHITEOUT flagVivek Goyal2020-02-061-1/+1
| | | | | | | | | | | Allow fuse to pass RENAME_WHITEOUT to fuse server. Overlayfs on top of virtiofs uses RENAME_WHITEOUT. Without this patch renaming a directory in overlayfs (dir is on lower) fails with -EINVAL. With this patch it works. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: verify nlinkMiklos Szeredi2019-11-121-1/+2
| | | | | | | | When adding a new hard link, make sure that i_nlink doesn't overflow. Fixes: ac45d61357e8 ("fuse: fix nlink after unlink") Cc: <stable@vger.kernel.org> # v3.4 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: verify attributesMiklos Szeredi2019-11-121-6/+16
| | | | | | | | | | | | | | | 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>
* fuse: flush dirty data/metadata before non-truncate setattrMiklos Szeredi2019-10-231-0/+13
| | | | | | | | | | | | | | | | | | | | | | | If writeback cache is enabled, then writes might get reordered with chmod/chown/utimes. The problem with this is that performing the write in the fuse daemon might itself change some of these attributes. In such case the following sequence of operations will result in file ending up with the wrong mode, for example: int fd = open ("suid", O_WRONLY|O_CREAT|O_EXCL); write (fd, "1", 1); fchown (fd, 0, 0); fchmod (fd, 04755); close (fd); This patch fixes this by flushing pending writes before performing chown/chmod/utimes. Reported-by: Giuseppe Scrivano <gscrivan@redhat.com> Tested-by: Giuseppe Scrivano <gscrivan@redhat.com> Fixes: 4d99ff8f12eb ("fuse: Turn writeback cache on") Cc: <stable@vger.kernel.org> # v3.15+ Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: don't advise readdirplus for negative lookupMiklos Szeredi2019-10-211-1/+2
| | | | | | | | | If the FUSE_READDIRPLUS_AUTO feature is enabled, then lookups on a directory before/during readdir are used as an indication that READDIRPLUS should be used instead of READDIR. However if the lookup turns out to be negative, then selecting READDIRPLUS makes no sense. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: kmemcg account fs dataKhazhismel Kumykov2019-09-241-1/+2
| | | | | | | | | | | account per-file, dentry, and inode data blockdev/superblock and temporary per-request data was left alone, as this usually isn't accounted Reviewed-by: Shakeel Butt <shakeelb@google.com> Signed-off-by: Khazhismel Kumykov <khazhy@google.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: on 64-bit store time in d_fsdata directlyKhazhismel Kumykov2019-09-241-6/+30
| | | | | | | | | | | Implements the optimization noted in commit f75fdf22b0a8 ("fuse: don't use ->d_time"), as the additional memory can be significant. (In particular, on SLAB configurations this 8-byte alloc becomes 32 bytes). Per-dentry, this can consume significant memory. Reviewed-by: Shakeel Butt <shakeelb@google.com> Signed-off-by: Khazhismel Kumykov <khazhy@google.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: delete dentry if timeout is zeroMiklos Szeredi2019-09-121-3/+25
| | | | | | | | | | | 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>
* fuse: convert readlink to simple apiMiklos Szeredi2019-09-101-27/+25
| | | | | | Also turn BUG_ON into gracefully recovered WARN_ON. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: flatten 'struct fuse_args'Miklos Szeredi2019-09-101-88/+88
| | | | | | | | | ...to make future expansion simpler. The hiearachical structure is a historical thing that does not serve any practical purpose. The generated code is excatly the same before and after the patch. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: Protect fi->nlookup with fi->lockKirill Tkhai2019-02-131-2/+2
| | | | | | | | This continues previous patch and introduces the same protection for nlookup field. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: Introduce fi->lock to protect write related fieldsKirill Tkhai2019-02-131-13/+12
| | | | | | | | | | | | | | | | | | | | | | | | To minimize contention of fc->lock, this patch introduces a new spinlock for protection fuse_inode metadata: fuse_inode: writectr writepages write_files queued_writes attr_version inode: i_size i_nlink i_mtime i_ctime Also, it protects the fields changed in fuse_change_attributes_common() (too many to list). Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: Convert fc->attr_version into atomic64_tKirill Tkhai2019-02-131-17/+2
| | | | | | | | This patch makes fc->attr_version of atomic64_t type, so fc->lock won't be needed to read or modify it anymore. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: Add fuse_inode argument to fuse_prepare_release()Kirill Tkhai2019-02-131-2/+4
| | | | | | | | | | Here is preparation for next patches, which introduce new fi->lock for protection of ff->write_entry linked into fi->write_files. This patch just passes new argument to the function. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: continue to send FUSE_RELEASEDIR when FUSE_OPEN returns ENOSYSChad Austin2018-12-111-1/+1
| | | | | | | | | | | | | | | | When FUSE_OPEN returns ENOSYS, the no_open bit is set on the connection. Because the FUSE_RELEASE and FUSE_RELEASEDIR paths share code, this incorrectly caused the FUSE_RELEASEDIR request to be dropped and never sent to userspace. Pass an isdir bool to distinguish between FUSE_RELEASE and FUSE_RELEASEDIR inside of fuse_file_put. Fixes: 7678ac50615d ("fuse: support clients that don't implement 'open'") Cc: <stable@vger.kernel.org> # v3.14 Signed-off-by: Chad Austin <chadaustin@fb.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: fix revalidation of attributes for permission checkMiklos Szeredi2018-12-031-1/+3
| | | | | | | | fuse_invalidate_attr() now sets fi->inval_mask instead of fi->i_time, hence we need to check the inval mask in fuse_permission() as well. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 2f1e81965fd0 ("fuse: allow fine grained attr cache invaldation")
* fuse: fix fsync on directoryMiklos Szeredi2018-12-031-1/+19
| | | | | | | | | | | | | | Commit ab2257e9941b ("fuse: reduce size of struct fuse_inode") moved parts of fields related to writeback on regular file and to directory caching into a union. However fuse_fsync_common() called from fuse_dir_fsync() touches some writeback related fields, resulting in a crash. Move writeback related parts from fuse_fsync_common() to fuse_fysnc(). Reported-by: Brett Girton <btgirton@gmail.com> Tested-by: Brett Girton <btgirton@gmail.com> Fixes: ab2257e9941b ("fuse: reduce size of struct fuse_inode") Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: enable caching of symlinksDan Schatzberg2018-10-151-25/+83
| | | | | | | | | | | | | FUSE file reads are cached in the page cache, but symlink reads are not. This patch enables FUSE READLINK operations to be cached which can improve performance of some FUSE workloads. In particular, I'm working on a FUSE filesystem for access to source code and discovered that about a 10% improvement to build times is achieved with this patch (there are a lot of symlinks in the source tree). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: don't need GETATTR after every READMiklos Szeredi2018-10-151-1/+3
| | | | | | | | | | | | | | | | | | | | | | If 'auto_inval_data' mode is active, then fuse_file_read_iter() will call fuse_update_attributes(), which will check the attribute validity and send a GETATTR request if some of the attributes are no longer valid. The page cache is then invalidated if the size or mtime have changed. Then, if a READ request was sent and reply received (which is the case if the data wasn't cached yet, or if the file is opened for O_DIRECT), the atime attribute is invalidated. This will result in the next read() also triggering a GETATTR, ... This can be fixed by only sending GETATTR if the mode or size are invalid, we don't need to do a refresh if only atime is invalid. More generally, none of the callers of fuse_update_attributes() need an up-to-date atime value, so for now just remove STATX_ATIME from the request mask when attributes are updated for internal use. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: allow fine grained attr cache invaldationMiklos Szeredi2018-10-151-5/+13
| | | | | | | | | | | This patch adds the infrastructure for more fine grained attribute invalidation. Currently only 'atime' is invalidated separately. The use of this infrastructure is extended to the statx(2) interface, which for now means that if only 'atime' is invalid and STATX_ATIME is not specified in the mask argument, then no GETATTR request will be generated. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: reduce size of struct fuse_inodeMiklos Szeredi2018-10-011-1/+12
| | | | | | | | Do this by grouping fields used for cached writes and putting them into a union with fileds used for cached readdir (with obviously no overlap, since we don't have hybrid objects). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: use iversion for readdir cache verificationMiklos Szeredi2018-10-011-7/+14
| | | | | | | | Use the internal iversion counter to make sure modifications of the directory through this filesystem are not missed by the mtime check (due to mtime granularity). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: split out readdir.cMiklos Szeredi2018-09-281-257/+2
| | | | | | | Directory reading code is about to grow larger, so split it out from dir.c into a new source file. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* Merge tag 'fuse-update-4.19' of ↵Linus Torvalds2018-08-211-4/+6
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse Pull fuse update from Miklos Szeredi: "Various bug fixes and cleanups" * tag 'fuse-update-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: fuse: reduce allocation size for splice_write fuse: use kvmalloc to allocate array of pipe_buffer structs. fuse: convert last timespec use to timespec64 fs: fuse: Adding new return type vm_fault_t fuse: simplify fuse_abort_conn() fuse: Add missed unlock_page() to fuse_readpages_fill() fuse: Don't access pipe->buffers without pipe_lock() fuse: fix initial parallel dirops fuse: Fix oops at process_init_reply() fuse: umount should wait for all requests fuse: fix unlocked access to processing queue fuse: fix double request_end()
| * fuse: fix initial parallel diropsMiklos Szeredi2018-07-261-4/+6
| | | | | | | | | | | | | | | | | | | | If parallel dirops are enabled in FUSE_INIT reply, then first operation may leave fi->mutex held. Reported-by: syzbot <syzbot+3f7b29af1baa9d0a55be@syzkaller.appspotmail.com> Fixes: 5c672ab3f0ee ("fuse: serialize dirops by default") Cc: <stable@vger.kernel.org> # v4.7 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* | Merge branch 'work.mkdir' of ↵Linus Torvalds2018-08-131-4/+11
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs icache updates from Al Viro: - NFS mkdir/open_by_handle race fix - analogous solution for FUSE, replacing the one currently in mainline - new primitive to be used when discarding halfway set up inodes on failed object creation; gives sane warranties re icache lookups not returning such doomed by still not freed inodes. A bunch of filesystems switched to that animal. - Miklos' fix for last cycle regression in iget5_locked(); -stable will need a slightly different variant, unfortunately. - misc bits and pieces around things icache-related (in adfs and jfs). * 'work.mkdir' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: jfs: don't bother with make_bad_inode() in ialloc() adfs: don't put inodes into icache new helper: inode_fake_hash() vfs: don't evict uninitialized inode jfs: switch to discard_new_inode() ext2: make sure that partially set up inodes won't be returned by ext2_iget() udf: switch to discard_new_inode() ufs: switch to discard_new_inode() btrfs: switch to discard_new_inode() new primitive: discard_new_inode() kill d_instantiate_no_diralias() nfs_instantiate(): prevent multiple aliases for directory inode
| * | kill d_instantiate_no_diralias()Al Viro2018-08-011-4/+11
| |/ | | | | | | | | | | | | | | | | | | | | | | | | The only user is fuse_create_new_entry(), and there it's used to mitigate the same mkdir/open-by-handle race as in nfs_mkdir(). The same solution applies - unhash the mkdir argument, then call d_splice_alias() and if that returns a reference to preexisting alias, dput() and report success. ->mkdir() argument left unhashed negative with the preexisting alias moved in the right place is just fine from the ->mkdir() callers point of view. Cc: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | get rid of 'opened' argument of ->atomic_open() - part 3Al Viro2018-07-121-1/+1
| | | | | | | | | | | | | | now it can be done... Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | getting rid of 'opened' argument of ->atomic_open() - part 2Al Viro2018-07-121-2/+2
| | | | | | | | | | | | | | | | __gfs2_lookup(), gfs2_create_inode(), nfs_finish_open() and fuse_create_open() don't need 'opened' anymore. Get rid of that argument in those. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | getting rid of 'opened' argument of ->atomic_open() - part 1Al Viro2018-07-121-1/+1
| | | | | | | | | | | | 'opened' argument of finish_open() is unused. Kill it. Signed-off-by Al Viro <viro@zeniv.linux.org.uk>
* | introduce FMODE_CREATED and switch to itAl Viro2018-07-121-1/+1
|/ | | | | | | | | | | | | | Parallel to FILE_CREATED, goes into ->f_mode instead of *opened. NFS is a bit of a wart here - it doesn't have file at the point where FILE_CREATED used to be set, so we need to propagate it there (for now). IMA is another one (here and everywhere)... Note that this needs do_dentry_open() to leave old bits in ->f_mode alone - we want it to preserve FMODE_CREATED if it had been already set (no other bit can be there). Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fuse: honor AT_STATX_FORCE_SYNCMiklos Szeredi2018-03-201-2/+9
| | | | | | Force a refresh of attributes from the fuse server in this case. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: honor AT_STATX_DONT_SYNCMiklos Szeredi2018-03-201-4/+5
| | | | | | | | The description of this flag says "Don't sync attributes with the server". In other words: always use the attributes cached in the kernel and don't send network or local messages to refresh the attributes. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: Restrict allow_other to the superblock's namespace or a descendantSeth Forshee2018-03-201-1/+1
| | | | | | | | | | | | | | | | | Unprivileged users are normally restricted from mounting with the allow_other option by system policy, but this could be bypassed for a mount done with user namespace root permissions. In such cases allow_other should not allow users outside the userns to access the mount as doing so would give the unprivileged user the ability to manipulate processes it would otherwise be unable to manipulate. Restrict allow_other to apply to users in the same userns used at mount or a descendant of that namespace. Also export current_in_userns() for use by fuse when built as a module. Reviewed-by: Serge Hallyn <serge@hallyn.com> Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: Dongsu Park <dongsu@kinvolk.io> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: Support fuse filesystems outside of init_user_nsEric W. Biederman2018-03-201-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In order to support mounts from namespaces other than init_user_ns, fuse must translate uids and gids to/from the userns of the process servicing requests on /dev/fuse. This patch does that, with a couple of restrictions on the namespace: - The userns for the fuse connection is fixed to the namespace from which /dev/fuse is opened. - The namespace must be the same as s_user_ns. These restrictions simplify the implementation by avoiding the need to pass around userns references and by allowing fuse to rely on the checks in setattr_prepare for ownership changes. Either restriction could be relaxed in the future if needed. For cuse the userns used is the opener of /dev/cuse. Semantically the cuse support does not appear safe for unprivileged users. Practically the permissions on /dev/cuse only make it accessible to the global root user. If something slips through the cracks in a user namespace the only users who will be able to use the cuse device are those users mapped into the user namespace. Translation in the posix acl is updated to use the uuser namespace of the filesystem. Avoiding cases which might bypass this translation is handled in a following change. This change is stronlgy based on a similar change from Seth Forshee and Dongsu Park. Cc: Seth Forshee <seth.forshee@canonical.com> Cc: Dongsu Park <dongsu@kinvolk.io> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* fuse: atomic_o_trunc should truncate pagecacheMiklos Szeredi2018-03-201-1/+12
| | | | | | | | | | | | | | | | | Fuse has an "atomic_o_trunc" mode, where userspace filesystem uses the O_TRUNC flag in the OPEN request to truncate the file atomically with the open. In this mode there's no need to send a SETATTR request to userspace after the open, so fuse_do_setattr() checks this mode and returns. But this misses the important step of truncating the pagecache. Add the missing parts of truncation to the ATTR_OPEN branch. Reported-by: Chad Austin <chadaustin@fb.com> Fixes: 6ff958edbf39 ("fuse: add atomic open+truncate support") Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Cc: <stable@vger.kernel.org>
* fuse: fix READDIRPLUS skipping an entryMiklos Szeredi2017-10-251-1/+2
| | | | | | | | | | | | | | | | | Marios Titas running a Haskell program noticed a problem with fuse's readdirplus: when it is interrupted by a signal, it skips one directory entry. The reason is that fuse erronously updates ctx->pos after a failed dir_emit(). The issue originates from the patch adding readdirplus support. Reported-by: Jakob Unterwurzacher <jakobunt@gmail.com> Tested-by: Marios Titas <redneb@gmx.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 0b05b18381ee ("fuse: implement NFS-like readdirplus support") Cc: <stable@vger.kernel.org> # v3.9
* fuse: getattr cleanupMiklos Szeredi2017-09-121-17/+13
| | | | | | | | The refreshed argument isn't used by any caller, get rid of it. Use a helper for just updating the inode (no need to fill in a kstat). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* Merge branch 'for-linus' of ↵Linus Torvalds2017-03-031-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse Pull fuse update from Miklos Szeredi: "A bugfix and cleanups" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: fuse: release: private_data cannot be NULL fuse: cleanup fuse_file refcounting fuse: add missing FR_FORCE
| * fuse: cleanup fuse_file refcountingMiklos Szeredi2017-02-221-1/+1
| | | | | | | | | | | | | | | | | | | | struct fuse_file is stored in file->private_data. Make this always be a counting reference for consistency. This also allows fuse_sync_release() to call fuse_file_put() instead of partially duplicating its functionality. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* | statx: Add a system call to make enhanced file info availableDavid Howells2017-03-021-3/+3
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a system call to make extended file information available, including file creation and some attribute flags where available through the underlying filesystem. The getattr inode operation is altered to take two additional arguments: a u32 request_mask and an unsigned int flags that indicate the synchronisation mode. This change is propagated to the vfs_getattr*() function. Functions like vfs_stat() are now inline wrappers around new functions vfs_statx() and vfs_statx_fd() to reduce stack usage. ======== OVERVIEW ======== The idea was initially proposed as a set of xattrs that could be retrieved with getxattr(), but the general preference proved to be for a new syscall with an extended stat structure. A number of requests were gathered for features to be included. The following have been included: (1) Make the fields a consistent size on all arches and make them large. (2) Spare space, request flags and information flags are provided for future expansion. (3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an __s64). (4) Creation time: The SMB protocol carries the creation time, which could be exported by Samba, which will in turn help CIFS make use of FS-Cache as that can be used for coherency data (stx_btime). This is also specified in NFSv4 as a recommended attribute and could be exported by NFSD [Steve French]. (5) Lightweight stat: Ask for just those details of interest, and allow a netfs (such as NFS) to approximate anything not of interest, possibly without going to the server [Trond Myklebust, Ulrich Drepper, Andreas Dilger] (AT_STATX_DONT_SYNC). (6) Heavyweight stat: Force a netfs to go to the server, even if it thinks its cached attributes are up to date [Trond Myklebust] (AT_STATX_FORCE_SYNC). And the following have been left out for future extension: (7) Data version number: Could be used by userspace NFS servers [Aneesh Kumar]. Can also be used to modify fill_post_wcc() in NFSD which retrieves i_version directly, but has just called vfs_getattr(). It could get it from the kstat struct if it used vfs_xgetattr() instead. (There's disagreement on the exact semantics of a single field, since not all filesystems do this the same way). (8) BSD stat compatibility: Including more fields from the BSD stat such as creation time (st_btime) and inode generation number (st_gen) [Jeremy Allison, Bernd Schubert]. (9) Inode generation number: Useful for FUSE and userspace NFS servers [Bernd Schubert]. (This was asked for but later deemed unnecessary with the open-by-handle capability available and caused disagreement as to whether it's a security hole or not). (10) Extra coherency data may be useful in making backups [Andreas Dilger]. (No particular data were offered, but things like last backup timestamp, the data version number and the DOS archive bit would come into this category). (11) Allow the filesystem to indicate what it can/cannot provide: A filesystem can now say it doesn't support a standard stat feature if that isn't available, so if, for instance, inode numbers or UIDs don't exist or are fabricated locally... (This requires a separate system call - I have an fsinfo() call idea for this). (12) Store a 16-byte volume ID in the superblock that can be returned in struct xstat [Steve French]. (Deferred to fsinfo). (13) Include granularity fields in the time data to indicate the granularity of each of the times (NFSv4 time_delta) [Steve French]. (Deferred to fsinfo). (14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags. Note that the Linux IOC flags are a mess and filesystems such as Ext4 define flags that aren't in linux/fs.h, so translation in the kernel may be a necessity (or, possibly, we provide the filesystem type too). (Some attributes are made available in stx_attributes, but the general feeling was that the IOC flags were to ext[234]-specific and shouldn't be exposed through statx this way). (15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer, Michael Kerrisk]. (Deferred, probably to fsinfo. Finding out if there's an ACL or seclabal might require extra filesystem operations). (16) Femtosecond-resolution timestamps [Dave Chinner]. (A __reserved field has been left in the statx_timestamp struct for this - if there proves to be a need). (17) A set multiple attributes syscall to go with this. =============== NEW SYSTEM CALL =============== The new system call is: int ret = statx(int dfd, const char *filename, unsigned int flags, unsigned int mask, struct statx *buffer); The dfd, filename and flags parameters indicate the file to query, in a similar way to fstatat(). There is no equivalent of lstat() as that can be emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is also no equivalent of fstat() as that can be emulated by passing a NULL filename to statx() with the fd of interest in dfd. Whether or not statx() synchronises the attributes with the backing store can be controlled by OR'ing a value into the flags argument (this typically only affects network filesystems): (1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this respect. (2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise its attributes with the server - which might require data writeback to occur to get the timestamps correct. (3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a network filesystem. The resulting values should be considered approximate. mask is a bitmask indicating the fields in struct statx that are of interest to the caller. The user should set this to STATX_BASIC_STATS to get the basic set returned by stat(). It should be noted that asking for more information may entail extra I/O operations. buffer points to the destination for the data. This must be 256 bytes in size. ====================== MAIN ATTRIBUTES RECORD ====================== The following structures are defined in which to return the main attribute set: struct statx_timestamp { __s64 tv_sec; __s32 tv_nsec; __s32 __reserved; }; struct statx { __u32 stx_mask; __u32 stx_blksize; __u64 stx_attributes; __u32 stx_nlink; __u32 stx_uid; __u32 stx_gid; __u16 stx_mode; __u16 __spare0[1]; __u64 stx_ino; __u64 stx_size; __u64 stx_blocks; __u64 __spare1[1]; struct statx_timestamp stx_atime; struct statx_timestamp stx_btime; struct statx_timestamp stx_ctime; struct statx_timestamp stx_mtime; __u32 stx_rdev_major; __u32 stx_rdev_minor; __u32 stx_dev_major; __u32 stx_dev_minor; __u64 __spare2[14]; }; The defined bits in request_mask and stx_mask are: STATX_TYPE Want/got stx_mode & S_IFMT STATX_MODE Want/got stx_mode & ~S_IFMT STATX_NLINK Want/got stx_nlink STATX_UID Want/got stx_uid STATX_GID Want/got stx_gid STATX_ATIME Want/got stx_atime{,_ns} STATX_MTIME Want/got stx_mtime{,_ns} STATX_CTIME Want/got stx_ctime{,_ns} STATX_INO Want/got stx_ino STATX_SIZE Want/got stx_size STATX_BLOCKS Want/got stx_blocks STATX_BASIC_STATS [The stuff in the normal stat struct] STATX_BTIME Want/got stx_btime{,_ns} STATX_ALL [All currently available stuff] stx_btime is the file creation time, stx_mask is a bitmask indicating the data provided and __spares*[] are where as-yet undefined fields can be placed. Time fields are structures with separate seconds and nanoseconds fields plus a reserved field in case we want to add even finer resolution. Note that times will be negative if before 1970; in such a case, the nanosecond fields will also be negative if not zero. The bits defined in the stx_attributes field convey information about a file, how it is accessed, where it is and what it does. The following attributes map to FS_*_FL flags and are the same numerical value: STATX_ATTR_COMPRESSED File is compressed by the fs STATX_ATTR_IMMUTABLE File is marked immutable STATX_ATTR_APPEND File is append-only STATX_ATTR_NODUMP File is not to be dumped STATX_ATTR_ENCRYPTED File requires key to decrypt in fs Within the kernel, the supported flags are listed by: KSTAT_ATTR_FS_IOC_FLAGS [Are any other IOC flags of sufficient general interest to be exposed through this interface?] New flags include: STATX_ATTR_AUTOMOUNT Object is an automount trigger These are for the use of GUI tools that might want to mark files specially, depending on what they are. Fields in struct statx come in a number of classes: (0) stx_dev_*, stx_blksize. These are local system information and are always available. (1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino, stx_size, stx_blocks. These will be returned whether the caller asks for them or not. The corresponding bits in stx_mask will be set to indicate whether they actually have valid values. If the caller didn't ask for them, then they may be approximated. For example, NFS won't waste any time updating them from the server, unless as a byproduct of updating something requested. If the values don't actually exist for the underlying object (such as UID or GID on a DOS file), then the bit won't be set in the stx_mask, even if the caller asked for the value. In such a case, the returned value will be a fabrication. Note that there are instances where the type might not be valid, for instance Windows reparse points. (2) stx_rdev_*. This will be set only if stx_mode indicates we're looking at a blockdev or a chardev, otherwise will be 0. (3) stx_btime. Similar to (1), except this will be set to 0 if it doesn't exist. ======= TESTING ======= The following test program can be used to test the statx system call: samples/statx/test-statx.c Just compile and run, passing it paths to the files you want to examine. The file is built automatically if CONFIG_SAMPLES is enabled. Here's some example output. Firstly, an NFS directory that crosses to another FSID. Note that the AUTOMOUNT attribute is set because transiting this directory will cause d_automount to be invoked by the VFS. [root@andromeda ~]# /tmp/test-statx -A /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:26 Inode: 1703937 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------) Secondly, the result of automounting on that directory. [root@andromeda ~]# /tmp/test-statx /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:27 Inode: 2 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fuse: fix time_to_jiffies nsec sanity checkDavid Sheets2017-01-131-1/+1
| | | | | | | | | | | | Commit bcb6f6d2b9c2 ("fuse: use timespec64") introduced clamped nsec values in time_to_jiffies but used the max of nsec and NSEC_PER_SEC - 1 instead of the min. Because of this, dentries would stay in the cache longer than requested and go stale in scenarios that relied on their timely eviction. Fixes: bcb6f6d2b9c2 ("fuse: use timespec64") Signed-off-by: David Sheets <dsheets@docker.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Cc: <stable@vger.kernel.org> # 4.9
* Merge uncontroversial parts of branch 'readlink' of ↵Linus Torvalds2016-12-171-1/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull partial readlink cleanups from Miklos Szeredi. This is the uncontroversial part of the readlink cleanup patch-set that simplifies the default readlink handling. Miklos and Al are still discussing the rest of the series. * git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: vfs: make generic_readlink() static vfs: remove ".readlink = generic_readlink" assignments vfs: default to generic_readlink() vfs: replace calling i_op->readlink with vfs_readlink() proc/self: use generic_readlink ecryptfs: use vfs_get_link() bad_inode: add missing i_op initializers
| * vfs: remove ".readlink = generic_readlink" assignmentsMiklos Szeredi2016-12-091-1/+0
| | | | | | | | | | | | | | | | | | | | | | If .readlink == NULL implies generic_readlink(). Generated by: to_del="\.readlink.*=.*generic_readlink" for i in `git grep -l $to_del`; do sed -i "/$to_del"/d $i; done Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* | fuse: fix clearing suid, sgid for chown()Miklos Szeredi2016-12-061-5/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | Basically, the pjdfstests set the ownership of a file to 06555, and then chowns it (as root) to a new uid/gid. Prior to commit a09f99eddef4 ("fuse: fix killing s[ug]id in setattr"), fuse would send down a setattr with both the uid/gid change and a new mode. Now, it just sends down the uid/gid change. Technically this is NOTABUG, since POSIX doesn't _require_ that we clear these bits for a privileged process, but Linux (wisely) has done that and I think we don't want to change that behavior here. This is caused by the use of should_remove_suid(), which will always return 0 when the process has CAP_FSETID. In fact we really don't need to be calling should_remove_suid() at all, since we've already been indicated that we should remove the suid, we just don't want to use a (very) stale mode for that. This patch should fix the above as well as simplify the logic. Reported-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: a09f99eddef4 ("fuse: fix killing s[ug]id in setattr") Cc: <stable@vger.kernel.org> Reviewed-by: Jeff Layton <jlayton@redhat.com>
* fuse: fix root dentry initializationMiklos Szeredi2016-10-181-0/+5
| | | | | | | | Add missing dentry initialization to root dentry. Fixes: f75fdf22b0a8 ("fuse: don't use ->d_time") Reported-by: Andreas Reis <andreas.reis@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-06 23:50:40 +0000