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2020-01-19fuse: verify attributesMiklos Szeredi
commit eb59bd17d2fa6e5e84fba61a5ebdea984222e6d5 upstream. 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> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2019-10-05fuse: fix deadlock with aio poll and fuse_iqueue::waitq.lockEric Biggers
commit 76e43c8ccaa35c30d5df853013561145a0f750a5 upstream. When IOCB_CMD_POLL is used on the FUSE device, aio_poll() disables IRQs and takes kioctx::ctx_lock, then fuse_iqueue::waitq.lock. This may have to wait for fuse_iqueue::waitq.lock to be released by one of many places that take it with IRQs enabled. Since the IRQ handler may take kioctx::ctx_lock, lockdep reports that a deadlock is possible. Fix it by protecting the state of struct fuse_iqueue with a separate spinlock, and only accessing fuse_iqueue::waitq using the versions of the waitqueue functions which do IRQ-safe locking internally. Reproducer: #include <fcntl.h> #include <stdio.h> #include <sys/mount.h> #include <sys/stat.h> #include <sys/syscall.h> #include <unistd.h> #include <linux/aio_abi.h> int main() { char opts[128]; int fd = open("/dev/fuse", O_RDWR); aio_context_t ctx = 0; struct iocb cb = { .aio_lio_opcode = IOCB_CMD_POLL, .aio_fildes = fd }; struct iocb *cbp = &cb; sprintf(opts, "fd=%d,rootmode=040000,user_id=0,group_id=0", fd); mkdir("mnt", 0700); mount("foo", "mnt", "fuse", 0, opts); syscall(__NR_io_setup, 1, &ctx); syscall(__NR_io_submit, ctx, 1, &cbp); } Beginning of lockdep output: ===================================================== WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected 5.3.0-rc5 #9 Not tainted ----------------------------------------------------- syz_fuse/135 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: 000000003590ceda (&fiq->waitq){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline] 000000003590ceda (&fiq->waitq){+.+.}, at: aio_poll fs/aio.c:1751 [inline] 000000003590ceda (&fiq->waitq){+.+.}, at: __io_submit_one.constprop.0+0x203/0x5b0 fs/aio.c:1825 and this task is already holding: 0000000075037284 (&(&ctx->ctx_lock)->rlock){..-.}, at: spin_lock_irq include/linux/spinlock.h:363 [inline] 0000000075037284 (&(&ctx->ctx_lock)->rlock){..-.}, at: aio_poll fs/aio.c:1749 [inline] 0000000075037284 (&(&ctx->ctx_lock)->rlock){..-.}, at: __io_submit_one.constprop.0+0x1f4/0x5b0 fs/aio.c:1825 which would create a new lock dependency: (&(&ctx->ctx_lock)->rlock){..-.} -> (&fiq->waitq){+.+.} but this new dependency connects a SOFTIRQ-irq-safe lock: (&(&ctx->ctx_lock)->rlock){..-.} [...] Reported-by: syzbot+af05535bb79520f95431@syzkaller.appspotmail.com Reported-by: syzbot+d86c4426a01f60feddc7@syzkaller.appspotmail.com Fixes: bfe4037e722e ("aio: implement IOCB_CMD_POLL") Cc: <stable@vger.kernel.org> # v4.19+ Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-24fuse: allow filesystems to have precise control over data cacheKirill Smelkov
On networked filesystems file data can be changed externally. FUSE provides notification messages for filesystem to inform kernel that metadata or data region of a file needs to be invalidated in local page cache. That provides the basis for filesystem implementations to invalidate kernel cache explicitly based on observed filesystem-specific events. FUSE has also "automatic" invalidation mode(*) when the kernel automatically invalidates data cache of a file if it sees mtime change. It also automatically invalidates whole data cache of a file if it sees file size being changed. The automatic mode has corresponding capability - FUSE_AUTO_INVAL_DATA. However, due to probably historical reason, that capability controls only whether mtime change should be resulting in automatic invalidation or not. A change in file size always results in invalidating whole data cache of a file irregardless of whether FUSE_AUTO_INVAL_DATA was negotiated(+). The filesystem I write[1] represents data arrays stored in networked database as local files suitable for mmap. It is read-only filesystem - changes to data are committed externally via database interfaces and the filesystem only glues data into contiguous file streams suitable for mmap and traditional array processing. The files are big - starting from hundreds gigabytes and more. The files change regularly, and frequently by data being appended to their end. The size of files thus changes frequently. If a file was accessed locally and some part of its data got into page cache, we want that data to stay cached unless there is memory pressure, or unless corresponding part of the file was actually changed. However current FUSE behaviour - when it sees file size change - is to invalidate the whole file. The data cache of the file is thus completely lost even on small size change, and despite that the filesystem server is careful to accurately translate database changes into FUSE invalidation messages to kernel. Let's fix it: if a filesystem, through new FUSE_EXPLICIT_INVAL_DATA capability, indicates to kernel that it is fully responsible for data cache invalidation, then the kernel won't invalidate files data cache on size change and only truncate that cache to new size in case the size decreased. (*) see 72d0d248ca "fuse: add FUSE_AUTO_INVAL_DATA init flag", eed2179efe "fuse: invalidate inode mapping if mtime changes" (+) in writeback mode the kernel does not invalidate data cache on file size change, but neither it allows the filesystem to set the size due to external event (see 8373200b12 "fuse: Trust kernel i_size only") [1] https://lab.nexedi.com/kirr/wendelin.core/blob/a50f1d9f/wcfs/wcfs.go#L20 Signed-off-by: Kirill Smelkov <kirr@nexedi.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-04-24fuse: convert printk -> pr_*Kirill Smelkov
Functions, like pr_err, are a more modern variant of printing compared to printk. They could be used to denoise sources by using needed level in the print function name, and by automatically inserting per-driver / function / ... print prefix as defined by pr_fmt macro. pr_* are also said to be used in Documentation/process/coding-style.rst and more recent code - for example overlayfs - uses them instead of printk. Convert CUSE and FUSE to use the new pr_* functions. CUSE output stays completely unchanged, while FUSE output is amended a bit for "trying to steal weird page" warning - the second line now comes also with "fuse:" prefix. I hope it is ok. Suggested-by: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Kirill Smelkov <kirr@nexedi.com> Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-02-13fuse: support clients that don't implement 'opendir'Chad Austin
Allow filesystems to return ENOSYS from opendir, preventing the kernel from sending opendir and releasedir messages in the future. This avoids userspace transitions when filesystems don't need to keep track of state per directory handle. A new capability flag, FUSE_NO_OPENDIR_SUPPORT, parallels FUSE_NO_OPEN_SUPPORT, indicating the new semantics for returning ENOSYS from opendir. Signed-off-by: Chad Austin <chadaustin@fb.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-02-13fuse: use atomic64_t for khctrMiklos Szeredi
...to get rid of one more fc->lock use. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-02-13fuse: clean up abortedMiklos Szeredi
The only caller that needs fc->aborted set is fuse_conn_abort_write(). Setting fc->aborted is now racy (fuse_abort_conn() may already be in progress or finished) but there's no reason to care. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-02-13fuse: Protect ff->reserved_req via corresponding fi->lockKirill Tkhai
This is rather natural action after previous patches, and it just decreases load of fc->lock. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-02-13fuse: Introduce fi->lock to protect write related fieldsKirill Tkhai
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>
2019-02-13fuse: Convert fc->attr_version into atomic64_tKirill Tkhai
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>
2019-02-13fuse: Add fuse_inode argument to fuse_prepare_release()Kirill Tkhai
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>
2018-12-11fuse: continue to send FUSE_RELEASEDIR when FUSE_OPEN returns ENOSYSChad Austin
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>
2018-12-03fuse: fix fsync on directoryMiklos Szeredi
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>
2018-10-15fuse: enable caching of symlinksDan Schatzberg
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>
2018-10-15fuse: allow fine grained attr cache invaldationMiklos Szeredi
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>
2018-10-01fuse: realloc page arrayMiklos Szeredi
Writeback caching currently allocates requests with the maximum number of possible pages, while the actual number of pages per request depends on a couple of factors that cannot be determined when the request is allocated (whether page is already under writeback, whether page is contiguous with previous pages already added to a request). This patch allows such requests to start with no page allocation (all pages inline) and grow the page array on demand. If the max_pages tunable remains the default value, then this will mean just one allocation that is the same size as before. If the tunable is larger, then this adds at most 3 additional memory allocations (which is generously compensated by the improved performance from the larger request). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-01fuse: add max_pages to init_outConstantine Shulyupin
Replace FUSE_MAX_PAGES_PER_REQ with the configurable parameter max_pages to improve performance. Old RFC with detailed description of the problem and many fixes by Mitsuo Hayasaka (mitsuo.hayasaka.hu@hitachi.com): - https://lkml.org/lkml/2012/7/5/136 We've encountered performance degradation and fixed it on a big and complex virtual environment. Environment to reproduce degradation and improvement: 1. Add lag to user mode FUSE Add nanosleep(&(struct timespec){ 0, 1000 }, NULL); to xmp_write_buf in passthrough_fh.c 2. patch UM fuse with configurable max_pages parameter. The patch will be provided latter. 3. run test script and perform test on tmpfs fuse_test() { cd /tmp mkdir -p fusemnt passthrough_fh -o max_pages=$1 /tmp/fusemnt grep fuse /proc/self/mounts dd conv=fdatasync oflag=dsync if=/dev/zero of=fusemnt/tmp/tmp \ count=1K bs=1M 2>&1 | grep -v records rm fusemnt/tmp/tmp killall passthrough_fh } Test results: passthrough_fh /tmp/fusemnt fuse.passthrough_fh \ rw,nosuid,nodev,relatime,user_id=0,group_id=0 0 0 1073741824 bytes (1.1 GB) copied, 1.73867 s, 618 MB/s passthrough_fh /tmp/fusemnt fuse.passthrough_fh \ rw,nosuid,nodev,relatime,user_id=0,group_id=0,max_pages=256 0 0 1073741824 bytes (1.1 GB) copied, 1.15643 s, 928 MB/s Obviously with bigger lag the difference between 'before' and 'after' will be more significant. Mitsuo Hayasaka, in 2012 (https://lkml.org/lkml/2012/7/5/136), observed improvement from 400-550 to 520-740. Signed-off-by: Constantine Shulyupin <const@MakeLinux.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-01fuse: reduce size of struct fuse_inodeMiklos Szeredi
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>
2018-10-01fuse: use iversion for readdir cache verificationMiklos Szeredi
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>
2018-10-01fuse: use mtime for readdir cache verificationMiklos Szeredi
Store the modification time of the directory in the cache, obtained before starting to fill the cache. When reading the cache, verify that the directory hasn't changed, by checking if current modification time is the same as the one stored in the cache. This only needs to be done when the current file position is at the beginning of the directory, as mandated by POSIX. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-01fuse: add readdir cache versionMiklos Szeredi
Allow the cache to be invalidated when page(s) have gone missing. In this case increment the version of the cache and reset to an empty state. Add a version number to the directory stream in struct fuse_file as well, indicating the version of the cache it's supposed to be reading. If the cache version doesn't match the stream's version, then reset the stream to the beginning of the cache. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-01fuse: allow using readdir cacheMiklos Szeredi
The cache is only used if it's completed, not while it's still being filled; this constraint could be lifted later, if it turns out to be useful. Introduce state in struct fuse_file that indicates the position within the cache. After a seek, reset the position to the beginning of the cache and search the cache for the current position. If the current position is not found in the cache, then fall back to uncached readdir. It can also happen that page(s) disappear from the cache, in which case we must also fall back to uncached readdir. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-01fuse: allow caching readdirMiklos Szeredi
This patch just adds the cache filling functions, which are invoked if FOPEN_CACHE_DIR flag is set in the OPENDIR reply. Cache reading and cache invalidation are added by subsequent patches. The directory cache uses the page cache. Directory entries are packed into a page in the same format as in the READDIR reply. A page only contains whole entries, the space at the end of the page is cleared. The page is locked while being modified. Multiple parallel readdirs on the same directory can fill the cache; the only constraint is that continuity must be maintained (d_off of last entry points to position of current entry). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-09-28fuse: split out readdir.cMiklos Szeredi
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>
2018-09-28fuse: Use hash table to link processing requestKirill Tkhai
We noticed the performance bottleneck in FUSE running our Virtuozzo storage over rdma. On some types of workload we observe 20% of times spent in request_find() in profiler. This function is iterating over long requests list, and it scales bad. The patch introduces hash table to reduce the number of iterations, we do in this function. Hash generating algorithm is taken from hash_add() function, while 256 lines table is used to store pending requests. This fixes problem and improves the performance. Reported-by: Alexey Kuznetsov <kuznet@virtuozzo.com> Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-09-28fuse: kill req->intr_uniqueKirill Tkhai
This field is not needed after the previous patch, since we can easily convert request ID to interrupt request ID and vice versa. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-09-28fuse: do not take fc->lock in fuse_request_send_background()Kirill Tkhai
Currently, we take fc->lock there only to check for fc->connected. But this flag is changed only on connection abort, which is very rare operation. So allow checking fc->connected under just fc->bg_lock and use this lock (as well as fc->lock) when resetting fc->connected. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-09-28fuse: introduce fc->bg_lockKirill Tkhai
To reduce contention of fc->lock, this patch introduces bg_lock for protection of fields related to background queue. These are: max_background, congestion_threshold, num_background, active_background, bg_queue and blocked. This allows next patch to make async reads not requiring fc->lock, so async reads and writes will have better performance executed in parallel. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-09-28fuse: add support for copy_file_range()Niels de Vos
There are several FUSE filesystems that can implement server-side copy or other efficient copy/duplication/clone methods. The copy_file_range() syscall is the standard interface that users have access to while not depending on external libraries that bypass FUSE. Signed-off-by: Niels de Vos <ndevos@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-07-26fuse: fix initial parallel diropsMiklos Szeredi
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>
2018-07-26fuse: umount should wait for all requestsMiklos Szeredi
fuse_abort_conn() does not guarantee that all async requests have actually finished aborting (i.e. their ->end() function is called). This could actually result in still used inodes after umount. Add a helper to wait until all requests are fully done. This is done by looking at the "num_waiting" counter. When this counter drops to zero, we can be sure that no more requests are outstanding. Fixes: 0d8e84b0432b ("fuse: simplify request abort") Cc: <stable@vger.kernel.org> # v4.2 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-05-31fuse: Ensure posix acls are translated outside of init_user_nsEric W. Biederman
Ensure the translation happens by failing to read or write posix acls when the filesystem has not indicated it supports posix acls. This ensures that modern cached posix acl support is available and used when dealing with posix acls. This is important because only that path has the code to convernt the uids and gids in posix acls into the user namespace of a fuse filesystem. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-03-20fuse: Support fuse filesystems outside of init_user_nsEric W. Biederman
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>
2018-03-20fuse: return -ECONNABORTED on /dev/fuse read after abortSzymon Lukasz
Currently the userspace has no way of knowing whether the fuse connection ended because of umount or abort via sysfs. It makes it hard for filesystems to free the mountpoint after abort without worrying about removing some new mount. The patch fixes it by returning different errors when userspace reads from /dev/fuse (-ENODEV for umount and -ECONNABORTED for abort). Add a new capability flag FUSE_ABORT_ERROR. If set and the connection is gone because of sysfs abort, reading from the device will return -ECONNABORTED. Signed-off-by: Szymon Lukasz <noh4hss@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-27fs: annotate ->poll() instancesAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-09-12fuse: getattr cleanupMiklos Szeredi
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>
2017-09-12fuse: honor iocb sync flags on writeMiklos Szeredi
If the IOCB_DSYNC flag is set a sync is not being performed by fuse_file_write_iter. Honor IOCB_DSYNC/IOCB_SYNC by setting O_DYSNC/O_SYNC respectively in the flags filed of the write request. We don't need to sync data or metadata, since fuse_perform_write() does write-through and the filesystem is responsible for updating file times. Original patch by Vitaly Zolotusky. Reported-by: Nate Clark <nate@neworld.us> Cc: Vitaly Zolotusky <vitaly@unitc.com>. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-08-03fuse: Dont call set_page_dirty_lock() for ITER_BVEC pages for async_dioAshish Samant
Commit 8fba54aebbdf ("fuse: direct-io: don't dirty ITER_BVEC pages") fixes the ITER_BVEC page deadlock for direct io in fuse by checking in fuse_direct_io(), whether the page is a bvec page or not, before locking it. However, this check is missed when the "async_dio" mount option is enabled. In this case, set_page_dirty_lock() is called from the req->end callback in request_end(), when the fuse thread is returning from userspace to respond to the read request. This will cause the same deadlock because the bvec condition is not checked in this path. Here is the stack of the deadlocked thread, while returning from userspace: [13706.656686] INFO: task glusterfs:3006 blocked for more than 120 seconds. [13706.657808] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [13706.658788] glusterfs D ffffffff816c80f0 0 3006 1 0x00000080 [13706.658797] ffff8800d6713a58 0000000000000086 ffff8800d9ad7000 ffff8800d9ad5400 [13706.658799] ffff88011ffd5cc0 ffff8800d6710008 ffff88011fd176c0 7fffffffffffffff [13706.658801] 0000000000000002 ffffffff816c80f0 ffff8800d6713a78 ffffffff816c790e [13706.658803] Call Trace: [13706.658809] [<ffffffff816c80f0>] ? bit_wait_io_timeout+0x80/0x80 [13706.658811] [<ffffffff816c790e>] schedule+0x3e/0x90 [13706.658813] [<ffffffff816ca7e5>] schedule_timeout+0x1b5/0x210 [13706.658816] [<ffffffff81073ffb>] ? gup_pud_range+0x1db/0x1f0 [13706.658817] [<ffffffff810668fe>] ? kvm_clock_read+0x1e/0x20 [13706.658819] [<ffffffff81066909>] ? kvm_clock_get_cycles+0x9/0x10 [13706.658822] [<ffffffff810f5792>] ? ktime_get+0x52/0xc0 [13706.658824] [<ffffffff816c6f04>] io_schedule_timeout+0xa4/0x110 [13706.658826] [<ffffffff816c8126>] bit_wait_io+0x36/0x50 [13706.658828] [<ffffffff816c7d06>] __wait_on_bit_lock+0x76/0xb0 [13706.658831] [<ffffffffa0545636>] ? lock_request+0x46/0x70 [fuse] [13706.658834] [<ffffffff8118800a>] __lock_page+0xaa/0xb0 [13706.658836] [<ffffffff810c8500>] ? wake_atomic_t_function+0x40/0x40 [13706.658838] [<ffffffff81194d08>] set_page_dirty_lock+0x58/0x60 [13706.658841] [<ffffffffa054d968>] fuse_release_user_pages+0x58/0x70 [fuse] [13706.658844] [<ffffffffa0551430>] ? fuse_aio_complete+0x190/0x190 [fuse] [13706.658847] [<ffffffffa0551459>] fuse_aio_complete_req+0x29/0x90 [fuse] [13706.658849] [<ffffffffa05471e9>] request_end+0xd9/0x190 [fuse] [13706.658852] [<ffffffffa0549126>] fuse_dev_do_write+0x336/0x490 [fuse] [13706.658854] [<ffffffffa054963e>] fuse_dev_write+0x6e/0xa0 [fuse] [13706.658857] [<ffffffff812a9ef3>] ? security_file_permission+0x23/0x90 [13706.658859] [<ffffffff81205300>] do_iter_readv_writev+0x60/0x90 [13706.658862] [<ffffffffa05495d0>] ? fuse_dev_splice_write+0x350/0x350 [fuse] [13706.658863] [<ffffffff812062a1>] do_readv_writev+0x171/0x1f0 [13706.658866] [<ffffffff810b3d00>] ? try_to_wake_up+0x210/0x210 [13706.658868] [<ffffffff81206361>] vfs_writev+0x41/0x50 [13706.658870] [<ffffffff81206496>] SyS_writev+0x56/0xf0 [13706.658872] [<ffffffff810257a1>] ? syscall_trace_leave+0xf1/0x160 [13706.658874] [<ffffffff816cbb2e>] system_call_fastpath+0x12/0x71 Fix this by making should_dirty a fuse_io_priv parameter that can be checked in fuse_aio_complete_req(). Reported-by: Tiger Yang <tiger.yang@oracle.com> Signed-off-by: Ashish Samant <ashish.samant@oracle.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-05-10Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse Pull fuse updates from Miklos Szeredi: "Support for pid namespaces from Seth and refcount_t work from Elena" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: fuse: Add support for pid namespaces fuse: convert fuse_conn.count from atomic_t to refcount_t fuse: convert fuse_req.count from atomic_t to refcount_t fuse: convert fuse_file.count from atomic_t to refcount_t
2017-04-20fuse: Get rid of bdi_initializedJan Kara
It is not needed anymore since bdi is initialized whenever superblock exists. CC: Miklos Szeredi <miklos@szeredi.hu> CC: linux-fsdevel@vger.kernel.org Suggested-by: Miklos Szeredi <mszeredi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-20fuse: Convert to separately allocated bdiJan Kara
Allocate struct backing_dev_info separately instead of embedding it inside the superblock. This unifies handling of bdi among users. CC: Miklos Szeredi <miklos@szeredi.hu> CC: linux-fsdevel@vger.kernel.org Acked-by: Miklos Szeredi <mszeredi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-18fuse: Add support for pid namespacesSeth Forshee
When the userspace process servicing fuse requests is running in a pid namespace then pids passed via the fuse fd are not being translated into that process' namespace. Translation is necessary for the pid to be useful to that process. Since no use case currently exists for changing namespaces all translations can be done relative to the pid namespace in use when fuse_conn_init() is called. For fuse this translates to mount time, and for cuse this is when /dev/cuse is opened. IO for this connection from another namespace will return errors. Requests from processes whose pid cannot be translated into the target namespace will have a value of 0 for in.h.pid. File locking changes based on previous work done by Eric Biederman. Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-04-18fuse: convert fuse_conn.count from atomic_t to refcount_tElena Reshetova
refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David Windsor <dwindsor@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-04-18fuse: convert fuse_req.count from atomic_t to refcount_tElena Reshetova
refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David Windsor <dwindsor@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-04-18fuse: convert fuse_file.count from atomic_t to refcount_tElena Reshetova
refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David Windsor <dwindsor@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-03-03Merge branch 'for-linus' of ↵Linus Torvalds
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
2017-02-22fuse: cleanup fuse_file refcountingMiklos Szeredi
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>
2017-01-14locking/atomic, kref: Add KREF_INIT()Peter Zijlstra
Since we need to change the implementation, stop exposing internals. Provide KREF_INIT() to allow static initialization of struct kref. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-10-18fuse: fix root dentry initializationMiklos Szeredi
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>
2016-10-10Merge branch 'work.misc' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc vfs updates from Al Viro: "Assorted misc bits and pieces. There are several single-topic branches left after this (rename2 series from Miklos, current_time series from Deepa Dinamani, xattr series from Andreas, uaccess stuff from from me) and I'd prefer to send those separately" * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (39 commits) proc: switch auxv to use of __mem_open() hpfs: support FIEMAP cifs: get rid of unused arguments of CIFSSMBWrite() posix_acl: uapi header split posix_acl: xattr representation cleanups fs/aio.c: eliminate redundant loads in put_aio_ring_file fs/internal.h: add const to ns_dentry_operations declaration compat: remove compat_printk() fs/buffer.c: make __getblk_slow() static proc: unsigned file descriptors fs/file: more unsigned file descriptors fs: compat: remove redundant check of nr_segs cachefiles: Fix attempt to read i_blocks after deleting file [ver #2] cifs: don't use memcpy() to copy struct iov_iter get rid of separate multipage fault-in primitives fs: Avoid premature clearing of capabilities fs: Give dentry to inode_change_ok() instead of inode fuse: Propagate dentry down to inode_change_ok() ceph: Propagate dentry down to inode_change_ok() xfs: Propagate dentry down to inode_change_ok() ...