summaryrefslogtreecommitdiff
path: root/fs
AgeCommit message (Collapse)Author
2019-05-01overlayfs: make use of ->free_inode()Al Viro
synchronous parts are left in ->destroy_inode() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01jfs: switch to ->free_inode()Al Viro
synchronous part can be moved to ->evict_inode(), the rest - ->free_inode() fodder Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01fuse: switch to ->free_inode()Al Viro
fuse_destroy_inode() is gone - sanity checks that need the stack trace of the caller get moved into ->evict_inode(), the rest joins the RCU-delayed part which becomes ->free_inode(). While we are at it, don't just pass the address of what happens to be the first member of structure to kmem_cache_free() - get_fuse_inode() is there for purpose and it gives the proper container_of() use. No behaviour change, but verifying correctness is easier that way. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01ext4: make use of ->free_inode()Al Viro
the rest of this ->destroy_inode() instance could probably be folded into ext4_evict_inode() Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01ecryptfs: make use of ->free_inode()Al Viro
no idea if crypto destruction could be moved there as well Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01ceph: use ->free_inode()Al Viro
a lot of non-delayed work in this case; all of that is left in ->destroy_inode() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01btrfs: use ->free_inode()Al Viro
a lot of stuff remains in ->destroy_inode() Acked-by: David Sterba <dsterba@suse.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01afs: switch to use of ->free_inode()Al Viro
debugging printks left in ->destroy_inode() and so's the update of inode count; we could take the latter to RCU-delayed part (would take only moving the check on module exit past rcu_barrier() there), but debugging output ought to either stay where it is or go into ->evict_inode() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01ntfs: switch to ->free_inode()Al Viro
move the synchronous stuff from ->destroy_inode() to ->evict_inode(), turn the RCU-delayed part into ->free_inode() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01ufs: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01coda: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01sysv: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01udf: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01ubifs: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01squashfs: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01romfs: convert to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01reiserfs: convert to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01qnx6: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01qnx4: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01procfs: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01openpromfs: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01ocfs2: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01dlmfs: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01nilfs2: switch to ->free_inode()Al Viro
kill an extern that went stale 9 years ago, while we are at it... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01nfs{,4}: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01minix: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01jffs2: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01isofs: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01hpfs: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01hostfs: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01hfsplus: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01hfs: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01gfs2: switch to ->free_inode()Al Viro
... and use GFS2_I() to get the containing gfs2_inode by inode; yes, we can feed the address of the first member of structure to kmem_cache_free(), but let's do it in an obviously safe way. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01freevxfs: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01fat: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01f2fs: switch to ->free_inode()Al Viro
Acked-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01ext2: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01efs: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01debugfs: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01cifs: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01bdev: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01bfs: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01befs: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01affs: switch to ->free_inode()Al Viro
Acked-by: David Sterba <dsterba@suse.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01adfs: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-019p: switch to ->free_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-01new inode method: ->free_inode()Al Viro
A lot of ->destroy_inode() instances end with call_rcu() of a callback that does RCU-delayed part of freeing. Introduce a new method for doing just that, with saner signature. Rules: ->destroy_inode ->free_inode f g immediate call of f(), RCU-delayed call of g() f NULL immediate call of f(), no RCU-delayed calls NULL g RCU-delayed call of g() NULL NULL RCU-delayed default freeing IOW, NULL ->free_inode gives the same behaviour as now. Note that NULL, NULL is equivalent to NULL, free_inode_nonrcu; we could mandate the latter form, but that would have very little benefit beyond making rules a bit more symmetric. It would break backwards compatibility, require extra boilerplate and expected semantics for (NULL, NULL) pair would have no use whatsoever... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-04-10Merge branch 'fixes' into work.icacheAl Viro
2019-04-07Merge tag 'for-linus-20190407' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block fixes from Jens Axboe: - Fixups for the pf/pcd queue handling (YueHaibing) - Revert of the three direct issue changes as they have been proven to cause an issue with dm-mpath (Bart) - Plug rq_count reset fix (Dongli) - io_uring double free in fileset registration error handling (me) - Make null_blk handle bad numa node passed in (John) - BFQ ifdef fix (Konstantin) - Flush queue leak fix (Shenghui) - Plug trace fix (Yufen) * tag 'for-linus-20190407' of git://git.kernel.dk/linux-block: xsysace: Fix error handling in ace_setup null_blk: prevent crash from bad home_node value block: Revert v5.0 blk_mq_request_issue_directly() changes paride/pcd: Fix potential NULL pointer dereference and mem leak blk-mq: do not reset plug->rq_count before the list is sorted paride/pf: Fix potential NULL pointer dereference io_uring: fix double free in case of fileset regitration failure blk-mq: add trace block plug and unplug for multiple queues block: use blk_free_flush_queue() to free hctx->fq in blk_mq_init_hctx block/bfq: fix ifdef for CONFIG_BFQ_GROUP_IOSCHED=y
2019-04-06fs: stream_open - opener for stream-like files so that read and write can ↵Kirill Smelkov
run simultaneously without deadlock Commit 9c225f2655e3 ("vfs: atomic f_pos accesses as per POSIX") added locking for file.f_pos access and in particular made concurrent read and write not possible - now both those functions take f_pos lock for the whole run, and so if e.g. a read is blocked waiting for data, write will deadlock waiting for that read to complete. This caused regression for stream-like files where previously read and write could run simultaneously, but after that patch could not do so anymore. See e.g. commit 581d21a2d02a ("xenbus: fix deadlock on writes to /proc/xen/xenbus") which fixes such regression for particular case of /proc/xen/xenbus. The patch that added f_pos lock in 2014 did so to guarantee POSIX thread safety for read/write/lseek and added the locking to file descriptors of all regular files. In 2014 that thread-safety problem was not new as it was already discussed earlier in 2006. However even though 2006'th version of Linus's patch was adding f_pos locking "only for files that are marked seekable with FMODE_LSEEK (thus avoiding the stream-like objects like pipes and sockets)", the 2014 version - the one that actually made it into the tree as 9c225f2655e3 - is doing so irregardless of whether a file is seekable or not. See https://lore.kernel.org/lkml/53022DB1.4070805@gmail.com/ https://lwn.net/Articles/180387 https://lwn.net/Articles/180396 for historic context. The reason that it did so is, probably, that there are many files that are marked non-seekable, but e.g. their read implementation actually depends on knowing current position to correctly handle the read. Some examples: kernel/power/user.c snapshot_read fs/debugfs/file.c u32_array_read fs/fuse/control.c fuse_conn_waiting_read + ... drivers/hwmon/asus_atk0110.c atk_debugfs_ggrp_read arch/s390/hypfs/inode.c hypfs_read_iter ... Despite that, many nonseekable_open users implement read and write with pure stream semantics - they don't depend on passed ppos at all. And for those cases where read could wait for something inside, it creates a situation similar to xenbus - the write could be never made to go until read is done, and read is waiting for some, potentially external, event, for potentially unbounded time -> deadlock. Besides xenbus, there are 14 such places in the kernel that I've found with semantic patch (see below): drivers/xen/evtchn.c:667:8-24: ERROR: evtchn_fops: .read() can deadlock .write() drivers/isdn/capi/capi.c:963:8-24: ERROR: capi_fops: .read() can deadlock .write() drivers/input/evdev.c:527:1-17: ERROR: evdev_fops: .read() can deadlock .write() drivers/char/pcmcia/cm4000_cs.c:1685:7-23: ERROR: cm4000_fops: .read() can deadlock .write() net/rfkill/core.c:1146:8-24: ERROR: rfkill_fops: .read() can deadlock .write() drivers/s390/char/fs3270.c:488:1-17: ERROR: fs3270_fops: .read() can deadlock .write() drivers/usb/misc/ldusb.c:310:1-17: ERROR: ld_usb_fops: .read() can deadlock .write() drivers/hid/uhid.c:635:1-17: ERROR: uhid_fops: .read() can deadlock .write() net/batman-adv/icmp_socket.c:80:1-17: ERROR: batadv_fops: .read() can deadlock .write() drivers/media/rc/lirc_dev.c:198:1-17: ERROR: lirc_fops: .read() can deadlock .write() drivers/leds/uleds.c:77:1-17: ERROR: uleds_fops: .read() can deadlock .write() drivers/input/misc/uinput.c:400:1-17: ERROR: uinput_fops: .read() can deadlock .write() drivers/infiniband/core/user_mad.c:985:7-23: ERROR: umad_fops: .read() can deadlock .write() drivers/gnss/core.c:45:1-17: ERROR: gnss_fops: .read() can deadlock .write() In addition to the cases above another regression caused by f_pos locking is that now FUSE filesystems that implement open with FOPEN_NONSEEKABLE flag, can no longer implement bidirectional stream-like files - for the same reason as above e.g. read can deadlock write locking on file.f_pos in the kernel. FUSE's FOPEN_NONSEEKABLE was added in 2008 in a7c1b990f715 ("fuse: implement nonseekable open") to support OSSPD. OSSPD implements /dev/dsp in userspace with FOPEN_NONSEEKABLE flag, with corresponding read and write routines not depending on current position at all, and with both read and write being potentially blocking operations: See https://github.com/libfuse/osspd https://lwn.net/Articles/308445 https://github.com/libfuse/osspd/blob/14a9cff0/osspd.c#L1406 https://github.com/libfuse/osspd/blob/14a9cff0/osspd.c#L1438-L1477 https://github.com/libfuse/osspd/blob/14a9cff0/osspd.c#L1479-L1510 Corresponding libfuse example/test also describes FOPEN_NONSEEKABLE as "somewhat pipe-like files ..." with read handler not using offset. However that test implements only read without write and cannot exercise the deadlock scenario: https://github.com/libfuse/libfuse/blob/fuse-3.4.2-3-ga1bff7d/example/poll.c#L124-L131 https://github.com/libfuse/libfuse/blob/fuse-3.4.2-3-ga1bff7d/example/poll.c#L146-L163 https://github.com/libfuse/libfuse/blob/fuse-3.4.2-3-ga1bff7d/example/poll.c#L209-L216 I've actually hit the read vs write deadlock for real while implementing my FUSE filesystem where there is /head/watch file, for which open creates separate bidirectional socket-like stream in between filesystem and its user with both read and write being later performed simultaneously. And there it is semantically not easy to split the stream into two separate read-only and write-only channels: https://lab.nexedi.com/kirr/wendelin.core/blob/f13aa600/wcfs/wcfs.go#L88-169 Let's fix this regression. The plan is: 1. We can't change nonseekable_open to include &~FMODE_ATOMIC_POS - doing so would break many in-kernel nonseekable_open users which actually use ppos in read/write handlers. 2. Add stream_open() to kernel to open stream-like non-seekable file descriptors. Read and write on such file descriptors would never use nor change ppos. And with that property on stream-like files read and write will be running without taking f_pos lock - i.e. read and write could be running simultaneously. 3. With semantic patch search and convert to stream_open all in-kernel nonseekable_open users for which read and write actually do not depend on ppos and where there is no other methods in file_operations which assume @offset access. 4. Add FOPEN_STREAM to fs/fuse/ and open in-kernel file-descriptors via steam_open if that bit is present in filesystem open reply. It was tempting to change fs/fuse/ open handler to use stream_open instead of nonseekable_open on just FOPEN_NONSEEKABLE flags, but grepping through Debian codesearch shows users of FOPEN_NONSEEKABLE, and in particular GVFS which actually uses offset in its read and write handlers https://codesearch.debian.net/search?q=-%3Enonseekable+%3D https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1080 https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1247-1346 https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1399-1481 so if we would do such a change it will break a real user. 5. Add stream_open and FOPEN_STREAM handling to stable kernels starting from v3.14+ (the kernel where 9c225f2655 first appeared). This will allow to patch OSSPD and other FUSE filesystems that provide stream-like files to return FOPEN_STREAM | FOPEN_NONSEEKABLE in their open handler and this way avoid the deadlock on all kernel versions. This should work because fs/fuse/ ignores unknown open flags returned from a filesystem and so passing FOPEN_STREAM to a kernel that is not aware of this flag cannot hurt. In turn the kernel that is not aware of FOPEN_STREAM will be < v3.14 where just FOPEN_NONSEEKABLE is sufficient to implement streams without read vs write deadlock. This patch adds stream_open, converts /proc/xen/xenbus to it and adds semantic patch to automatically locate in-kernel places that are either required to be converted due to read vs write deadlock, or that are just safe to be converted because read and write do not use ppos and there are no other funky methods in file_operations. Regarding semantic patch I've verified each generated change manually - that it is correct to convert - and each other nonseekable_open instance left - that it is either not correct to convert there, or that it is not converted due to current stream_open.cocci limitations. The script also does not convert files that should be valid to convert, but that currently have .llseek = noop_llseek or generic_file_llseek for unknown reason despite file being opened with nonseekable_open (e.g. drivers/input/mousedev.c) Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Yongzhi Pan <panyongzhi@gmail.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Juergen Gross <jgross@suse.com> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Tejun Heo <tj@kernel.org> Cc: Kirill Tkhai <ktkhai@virtuozzo.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Julia Lawall <Julia.Lawall@lip6.fr> Cc: Nikolaus Rath <Nikolaus@rath.org> Cc: Han-Wen Nienhuys <hanwen@google.com> Signed-off-by: Kirill Smelkov <kirr@nexedi.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
generated by cgit v1.2.3-70-g09d2 (git 2.47.1) at 2025-02-05 13:09:21 +0000