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2019-06-09vfs: allow copy_file_range to copy across devicesAmir Goldstein
We want to enable cross-filesystem copy_file_range functionality where possible, so push the "same superblock only" checks down to the individual filesystem callouts so they can make their own decisions about cross-superblock copy offload and fallack to generic_copy_file_range() for cross-superblock copy. [Amir] We do not call ->remap_file_range() in case the files are not on the same sb and do not call ->copy_file_range() in case the files do not belong to the same filesystem driver. This changes behavior of the copy_file_range(2) syscall, which will now allow cross filesystem in-kernel copy. CIFS already supports cross-superblock copy, between two shares to the same server. This functionality will now be available via the copy_file_range(2) syscall. Cc: Steve French <stfrench@microsoft.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-06-09vfs: introduce file_modified() helperAmir Goldstein
The combination of file_remove_privs() and file_update_mtime() is quite common in filesystem ->write_iter() methods. Modelled after the helper file_accessed(), introduce file_modified() and use it from generic_remap_file_range_prep(). Note that the order of calling file_remove_privs() before file_update_mtime() in the helper was matched to the more common order by filesystems and not the current order in generic_remap_file_range_prep(). Signed-off-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-06-09vfs: add missing checks to copy_file_rangeAmir Goldstein
Like the clone and dedupe interfaces we've recently fixed, the copy_file_range() implementation is missing basic sanity, limits and boundary condition tests on the parameters that are passed to it from userspace. Create a new "generic_copy_file_checks()" function modelled on the generic_remap_checks() function to provide this missing functionality. [Amir] Shorten copy length instead of checking pos_in limits because input file size already abides by the limits. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-06-09vfs: introduce generic_file_rw_checks()Amir Goldstein
Factor out helper with some checks on in/out file that are common to clone_file_range and copy_file_range. Suggested-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-06-09vfs: no fallback for ->copy_file_rangeDave Chinner
Now that we have generic_copy_file_range(), remove it as a fallback case when offloads fail. This puts the responsibility for executing fallbacks on the filesystems that implement ->copy_file_range and allows us to add operational validity checks to generic_copy_file_range(). Rework vfs_copy_file_range() to call a new do_copy_file_range() helper to execute the copying callout, and move calls to generic_file_copy_range() into filesystem methods where they currently return failures. [Amir] overlayfs is not responsible of executing the fallback. It is the responsibility of the underlying filesystem. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-06-09vfs: introduce generic_copy_file_range()Dave Chinner
Right now if vfs_copy_file_range() does not use any offload mechanism, it falls back to calling do_splice_direct(). This fails to do basic sanity checks on the files being copied. Before we start adding this necessarily functionality to the fallback path, separate it out into generic_copy_file_range(). generic_copy_file_range() has the same prototype as ->copy_file_range() so that filesystems can use it in their custom ->copy_file_range() method if they so choose. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-05-06vfs: pass ppos=NULL to .read()/.write() of FMODE_STREAM filesKirill Smelkov
This amends commit 10dce8af3422 ("fs: stream_open - opener for stream-like files so that read and write can run simultaneously without deadlock") in how position is passed into .read()/.write() handler for stream-like files: Rasmus noticed that we currently pass 0 as position and ignore any position change if that is done by a file implementation. This papers over bugs if ppos is used in files that declare themselves as being stream-like as such bugs will go unnoticed. Even if a file implementation is correctly converted into using stream_open, its read/write later could be changed to use ppos and even though that won't be working correctly, that bug might go unnoticed without someone doing wrong behaviour analysis. It is thus better to pass ppos=NULL into read/write for stream-like files as that don't give any chance for ppos usage bugs because it will oops if ppos is ever used inside .read() or .write(). Note 1: rw_verify_area, new_sync_{read,write} needs to be updated because they are called by vfs_read/vfs_write & friends before file_operations .read/.write . Note 2: if file backend uses new-style .read_iter/.write_iter, position is still passed into there as non-pointer kiocb.ki_pos . Currently stream_open.cocci (semantic patch added by 10dce8af3422) ignores files whose file_operations has *_iter methods. Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Kirill Smelkov <kirr@nexedi.com>
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>
2019-03-12Merge 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 fixes (really no common topic here)" * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: vfs: Make __vfs_write() static vfs: fix preadv64v2 and pwritev64v2 compat syscalls with offset == -1 pipe: stop using ->can_merge splice: don't merge into linked buffers fs: move generic stat response attr handling to vfs_getattr_nosec orangefs: don't reinitialize result_mask in ->getattr fs/devpts: always delete dcache dentry-s in dput()
2019-03-04get rid of legacy 'get_ds()' functionLinus Torvalds
Every in-kernel use of this function defined it to KERNEL_DS (either as an actual define, or as an inline function). It's an entirely historical artifact, and long long long ago used to actually read the segment selector valueof '%ds' on x86. Which in the kernel is always KERNEL_DS. Inspired by a patch from Jann Horn that just did this for a very small subset of users (the ones in fs/), along with Al who suggested a script. I then just took it to the logical extreme and removed all the remaining gunk. Roughly scripted with git grep -l '(get_ds())' -- :^tools/ | xargs sed -i 's/(get_ds())/(KERNEL_DS)/' git grep -lw 'get_ds' -- :^tools/ | xargs sed -i '/^#define get_ds()/d' plus manual fixups to remove a few unusual usage patterns, the couple of inline function cases and to fix up a comment that had become stale. The 'get_ds()' function remains in an x86 kvm selftest, since in user space it actually does something relevant. Inspired-by: Jann Horn <jannh@google.com> Inspired-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-02-22vfs: Make __vfs_write() staticGeert Uytterhoeven
__vfs_write() was unexported, and removed from <linux/fs.h>, but forgotten to be made static. Fixes: eb031849d52e61d2 ("fs: unexport __vfs_read/__vfs_write") Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-02-16vfs: fix preadv64v2 and pwritev64v2 compat syscalls with offset == -1Aurelien Jarno
The preadv2 and pwritev2 syscalls are supposed to emulate the readv and writev syscalls when offset == -1. Therefore the compat code should check for offset before calling do_compat_preadv64 and do_compat_pwritev64. This is the case for the preadv2 and pwritev2 syscalls, but handling of offset == -1 is missing in their 64-bit equivalent. This patch fixes that, calling do_compat_readv and do_compat_writev when offset == -1. This fixes the following glibc tests on x32: - misc/tst-preadvwritev2 - misc/tst-preadvwritev64v2 Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: H.J. Lu <hjl.tools@gmail.com> Signed-off-by: Aurelien Jarno <aurelien@aurel32.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-01-03Remove 'type' argument from access_ok() functionLinus Torvalds
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument of the user address range verification function since we got rid of the old racy i386-only code to walk page tables by hand. It existed because the original 80386 would not honor the write protect bit when in kernel mode, so you had to do COW by hand before doing any user access. But we haven't supported that in a long time, and these days the 'type' argument is a purely historical artifact. A discussion about extending 'user_access_begin()' to do the range checking resulted this patch, because there is no way we're going to move the old VERIFY_xyz interface to that model. And it's best done at the end of the merge window when I've done most of my merges, so let's just get this done once and for all. This patch was mostly done with a sed-script, with manual fix-ups for the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form. There were a couple of notable cases: - csky still had the old "verify_area()" name as an alias. - the iter_iov code had magical hardcoded knowledge of the actual values of VERIFY_{READ,WRITE} (not that they mattered, since nothing really used it) - microblaze used the type argument for a debug printout but other than those oddities this should be a total no-op patch. I tried to fix up all architectures, did fairly extensive grepping for access_ok() uses, and the changes are trivial, but I may have missed something. Any missed conversion should be trivially fixable, though. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-04vfs: allow some remap flags to be passed to vfs_clone_file_rangeDarrick J. Wong
In overlayfs, ovl_remap_file_range calls vfs_clone_file_range on the lower filesystem's inode, passing through whatever remap flags it got from its caller. Since vfs_copy_file_range first tries a filesystem's remap function with REMAP_FILE_CAN_SHORTEN, this can get passed through to the second vfs_copy_file_range call, and this isn't an issue. Change the WARN_ON to look only for the DEDUP flag. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2018-11-21vfs: vfs_dedupe_file_range() doesn't return EOPNOTSUPPDave Chinner
It returns EINVAL when the operation is not supported by the filesystem. Fix it to return EOPNOTSUPP to be consistent with the man page and clone_file_range(). Clean up the inconsistent error return handling while I'm there. (I know, lipstick on a pig, but every little bit helps...) Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-11-02Merge tag 'xfs-4.20-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linuxLinus Torvalds
Pull vfs dedup fixes from Dave Chinner: "This reworks the vfs data cloning infrastructure. We discovered many issues with these interfaces late in the 4.19 cycle - the worst of them (data corruption, setuid stripping) were fixed for XFS in 4.19-rc8, but a larger rework of the infrastructure fixing all the problems was needed. That rework is the contents of this pull request. Rework the vfs_clone_file_range and vfs_dedupe_file_range infrastructure to use a common .remap_file_range method and supply generic bounds and sanity checking functions that are shared with the data write path. The current VFS infrastructure has problems with rlimit, LFS file sizes, file time stamps, maximum filesystem file sizes, stripping setuid bits, etc and so they are addressed in these commits. We also introduce the ability for the ->remap_file_range methods to return short clones so that clones for vfs_copy_file_range() don't get rejected if the entire range can't be cloned. It also allows filesystems to sliently skip deduplication of partial EOF blocks if they are not capable of doing so without requiring errors to be thrown to userspace. Existing filesystems are converted to user the new remap_file_range method, and both XFS and ocfs2 are modified to make use of the new generic checking infrastructure" * tag 'xfs-4.20-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (28 commits) xfs: remove [cm]time update from reflink calls xfs: remove xfs_reflink_remap_range xfs: remove redundant remap partial EOF block checks xfs: support returning partial reflink results xfs: clean up xfs_reflink_remap_blocks call site xfs: fix pagecache truncation prior to reflink ocfs2: remove ocfs2_reflink_remap_range ocfs2: support partial clone range and dedupe range ocfs2: fix pagecache truncation prior to reflink ocfs2: truncate page cache for clone destination file before remapping vfs: clean up generic_remap_file_range_prep return value vfs: hide file range comparison function vfs: enable remap callers that can handle short operations vfs: plumb remap flags through the vfs dedupe functions vfs: plumb remap flags through the vfs clone functions vfs: make remap_file_range functions take and return bytes completed vfs: remap helper should update destination inode metadata vfs: pass remap flags to generic_remap_checks vfs: pass remap flags to generic_remap_file_range_prep vfs: combine the clone and dedupe into a single remap_file_range ...
2018-11-01Merge branch 'work.misc' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc vfs updates from Al Viro: "No common topic, really - a handful of assorted stuff; the least trivial bits are Mark's dedupe patches" * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fs/exofs: only use true/false for asignment of bool type variable fs/exofs: fix potential memory leak in mount option parsing Delete invalid assignment statements in do_sendfile iomap: remove duplicated include from iomap.c vfs: dedupe should return EPERM if permission is not granted vfs: allow dedupe of user owned read-only files ntfs: don't open-code ERR_CAST ext4: don't open-code ERR_CAST
2018-10-30vfs: clean up generic_remap_file_range_prep return valueDarrick J. Wong
Since the remap prep function can update the length of the remap request, we can change this function to return the usual return status instead of the odd behavior it has now. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30vfs: hide file range comparison functionDarrick J. Wong
There are no callers of vfs_dedupe_file_range_compare, so we might as well make it a static helper and remove the export. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30vfs: enable remap callers that can handle short operationsDarrick J. Wong
Plumb in a remap flag that enables the filesystem remap handler to shorten remapping requests for callers that can handle it. Now copy_file_range can report partial success (in case we run up against alignment problems, resource limits, etc.). We also enable CAN_SHORTEN for fideduperange to maintain existing userspace-visible behavior where xfs/btrfs shorten the dedupe range to avoid stale post-eof data exposure. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30vfs: plumb remap flags through the vfs dedupe functionsDarrick J. Wong
Plumb a remap_flags argument through the vfs_dedupe_file_range_one functions so that dedupe can take advantage of it. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30vfs: plumb remap flags through the vfs clone functionsDarrick J. Wong
Plumb a remap_flags argument through the {do,vfs}_clone_file_range functions so that clone can take advantage of it. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30vfs: make remap_file_range functions take and return bytes completedDarrick J. Wong
Change the remap_file_range functions to take a number of bytes to operate upon and return the number of bytes they operated on. This is a requirement for allowing fs implementations to return short clone/dedupe results to the user, which will enable us to obey resource limits in a graceful manner. A subsequent patch will enable copy_file_range to signal to the ->clone_file_range implementation that it can handle a short length, which will be returned in the function's return value. For now the short return is not implemented anywhere so the behavior won't change -- either copy_file_range manages to clone the entire range or it tries an alternative. Neither clone ioctl can take advantage of this, alas. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30vfs: remap helper should update destination inode metadataDarrick J. Wong
Extend generic_remap_file_range_prep to handle inode metadata updates when remapping into a file. If the operation can possibly alter the file contents, we must update the ctime and mtime and remove security privileges, just like we do for regular file writes. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30vfs: pass remap flags to generic_remap_checksDarrick J. Wong
Pass the same remap flags to generic_remap_checks for consistency. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30vfs: pass remap flags to generic_remap_file_range_prepDarrick J. Wong
Plumb the remap flags through the filesystem from the vfs function dispatcher all the way to the prep function to prepare for behavior changes in subsequent patches. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30vfs: combine the clone and dedupe into a single remap_file_rangeDarrick J. Wong
Combine the clone_file_range and dedupe_file_range operations into a single remap_file_range file operation dispatch since they're fundamentally the same operation. The differences between the two can be made in the prep functions. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30vfs: rename clone_verify_area to remap_verify_areaDarrick J. Wong
Since we use clone_verify_area for both clone and dedupe range checks, rename the function to make it clear that it's for both. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30vfs: rename vfs_clone_file_prep to be more descriptiveDarrick J. Wong
The vfs_clone_file_prep is a generic function to be called by filesystem implementations only. Rename the prefix to generic_ and make it more clear that it applies to remap operations, not just clones. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30vfs: skip zero-length dedupe requestsDarrick J. Wong
Don't bother calling the filesystem for a zero-length dedupe request; we can return zero and exit. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30vfs: avoid problematic remapping requests into partial EOF blockDarrick J. Wong
A deduplication data corruption is exposed in XFS and btrfs. It is caused by extending the block match range to include the partial EOF block, but then allowing unknown data beyond EOF to be considered a "match" to data in the destination file because the comparison is only made to the end of the source file. This corrupts the destination file when the source extent is shared with it. The VFS remapping prep functions only support whole block dedupe, but we still need to appear to support whole file dedupe correctly. Hence if the dedupe request includes the last block of the souce file, don't include it in the actual dedupe operation. If the rest of the range dedupes successfully, then reject the entire request. A subsequent patch will enable us to shorten dedupe requests correctly. When reflinking sub-file ranges, a data corruption can occur when the source file range includes a partial EOF block. This shares the unknown data beyond EOF into the second file at a position inside EOF, exposing stale data in the second file. If the reflink request includes the last block of the souce file, only proceed with the reflink operation if it lands at or past the destination file's current EOF. If it lands within the destination file EOF, reject the entire request with -EINVAL and make the caller go the hard way. A subsequent patch will enable us to shorten reflink requests correctly. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30vfs: exit early from zero length remap operationsDarrick J. Wong
If a remap caller asks us to remap to the source file's EOF and the source file length leaves us with a zero byte request, exit early. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30vfs: check file ranges before cloning filesDarrick J. Wong
Move the file range checks from vfs_clone_file_prep into a separate generic_remap_checks function so that all the checks are collected in a central location. This forms the basis for adding more checks from generic_write_checks that will make cloning's input checking more consistent with write input checking. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30vfs: vfs_clone_file_prep_inodes should return EINVAL for a clone from beyond EOFDarrick J. Wong
vfs_clone_file_prep_inodes cannot return 0 if it is asked to remap from a zero byte file because that's what btrfs does. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-25Merge branch 'timers-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timekeeping updates from Thomas Gleixner: "The timers and timekeeping departement provides: - Another large y2038 update with further preparations for providing the y2038 safe timespecs closer to the syscalls. - An overhaul of the SHCMT clocksource driver - SPDX license identifier updates - Small cleanups and fixes all over the place" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (31 commits) tick/sched : Remove redundant cpu_online() check clocksource/drivers/dw_apb: Add reset control clocksource: Remove obsolete CLOCKSOURCE_OF_DECLARE clocksource/drivers: Unify the names to timer-* format clocksource/drivers/sh_cmt: Add R-Car gen3 support dt-bindings: timer: renesas: cmt: document R-Car gen3 support clocksource/drivers/sh_cmt: Properly line-wrap sh_cmt_of_table[] initializer clocksource/drivers/sh_cmt: Fix clocksource width for 32-bit machines clocksource/drivers/sh_cmt: Fixup for 64-bit machines clocksource/drivers/sh_tmu: Convert to SPDX identifiers clocksource/drivers/sh_mtu2: Convert to SPDX identifiers clocksource/drivers/sh_cmt: Convert to SPDX identifiers clocksource/drivers/renesas-ostm: Convert to SPDX identifiers clocksource: Convert to using %pOFn instead of device_node.name tick/broadcast: Remove redundant check RISC-V: Request newstat syscalls y2038: signal: Change rt_sigtimedwait to use __kernel_timespec y2038: socket: Change recvmmsg to use __kernel_timespec y2038: sched: Change sched_rr_get_interval to use __kernel_timespec y2038: utimes: Rework #ifdef guards for compat syscalls ...
2018-10-18Delete invalid assignment statements in do_sendfilenixiaoming
Assigning value -EINVAL to "retval" here, but that stored value is overwritten before it can be used. retval = -EINVAL; .... retval = rw_verify_area(WRITE, out.file, &out_pos, count); value_overwrite: Overwriting previous write to "retval" with value from rw_verify_area delete invalid assignment statements Signed-off-by: n00202754 <nixiaoming@huawei.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-10-17vfs: dedupe should return EPERM if permission is not grantedMark Fasheh
Right now we return EINVAL if a process does not have permission to dedupe a file. This was an oversight on my part. EPERM gives a true description of the nature of our error, and EINVAL is already used for the case that the filesystem does not support dedupe. Signed-off-by: Mark Fasheh <mfasheh@suse.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Acked-by: David Sterba <dsterba@suse.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-10-17vfs: allow dedupe of user owned read-only filesMark Fasheh
The permission check in vfs_dedupe_file_range_one() is too coarse - We only allow dedupe of the destination file if the user is root, or they have the file open for write. This effectively limits a non-root user from deduping their own read-only files. In addition, the write file descriptor that the user is forced to hold open can prevent execution of files. As file data during a dedupe does not change, the behavior is unexpected and this has caused a number of issue reports. For an example, see: https://github.com/markfasheh/duperemove/issues/129 So change the check so we allow dedupe on the target if: - the root or admin is asking for it - the process has write access - the owner of the file is asking for the dedupe - the process could get write access That way users can open read-only and still get dedupe. Signed-off-by: Mark Fasheh <mfasheh@suse.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-09-24vfs: swap names of {do,vfs}_clone_file_range()Amir Goldstein
Commit 031a072a0b8a ("vfs: call vfs_clone_file_range() under freeze protection") created a wrapper do_clone_file_range() around vfs_clone_file_range() moving the freeze protection to former, so overlayfs could call the latter. The more common vfs practice is to call do_xxx helpers from vfs_xxx helpers, where freeze protecction is taken in the vfs_xxx helper, so this anomality could be a source of confusion. It seems that commit 8ede205541ff ("ovl: add reflink/copyfile/dedup support") may have fallen a victim to this confusion - ovl_clone_file_range() calls the vfs_clone_file_range() helper in the hope of getting freeze protection on upper fs, but in fact results in overlayfs allowing to bypass upper fs freeze protection. Swap the names of the two helpers to conform to common vfs practice and call the correct helpers from overlayfs and nfsd. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-08-29asm-generic: Remove unneeded __ARCH_WANT_SYS_LLSEEK macroArnd Bergmann
The sys_llseek sytem call is needed on all 32-bit architectures and none of the 64-bit ones, so we can remove the __ARCH_WANT_SYS_LLSEEK guard and simplify the include/asm-generic/unistd.h header further. Since 32-bit tasks can run either natively or in compat mode on 64-bit architectures, we have to check for both !CONFIG_64BIT and CONFIG_COMPAT. There are a few 64-bit architectures that also reference sys_llseek in their 64-bit ABI (e.g. sparc), but I verified that those all select CONFIG_COMPAT, so the #if check is still correct here. It's a bit odd to include it in the syscall table though, as it's the same as sys_lseek() on 64-bit, but with strange calling conventions. Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2018-07-18vfs: export vfs_dedupe_file_range_one() to modulesMiklos Szeredi
This is needed by the stacked dedupe implementation in overlayfs. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-07-06vfs: dedupe: extract helper for a single dedupMiklos Szeredi
Extract vfs_dedupe_file_range_one() helper to deal with a single dedup request. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2018-07-06vfs: dedupe: rationalize argsMiklos Szeredi
Clean up f_op->dedupe_file_range() interface. 1) Use loff_t for offsets and length instead of u64 2) Order the arguments the same way as {copy|clone}_file_range(). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-07-06vfs: dedupe: return intMiklos Szeredi
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-07-06vfs: limit size of dedupeMiklos Szeredi
Suggested-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-06-12treewide: kmalloc() -> kmalloc_array()Kees Cook
The kmalloc() function has a 2-factor argument form, kmalloc_array(). This patch replaces cases of: kmalloc(a * b, gfp) with: kmalloc_array(a * b, gfp) as well as handling cases of: kmalloc(a * b * c, gfp) with: kmalloc(array3_size(a, b, c), gfp) as it's slightly less ugly than: kmalloc_array(array_size(a, b), c, gfp) This does, however, attempt to ignore constant size factors like: kmalloc(4 * 1024, gfp) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The tools/ directory was manually excluded, since it has its own implementation of kmalloc(). The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( kmalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | kmalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( kmalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(char) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(u8) * COUNT + COUNT , ...) | kmalloc( - sizeof(__u8) * COUNT + COUNT , ...) | kmalloc( - sizeof(char) * COUNT + COUNT , ...) | kmalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( - kmalloc + kmalloc_array ( - sizeof(TYPE) * (COUNT_ID) + COUNT_ID, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * COUNT_ID + COUNT_ID, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * (COUNT_CONST) + COUNT_CONST, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * COUNT_CONST + COUNT_CONST, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (COUNT_ID) + COUNT_ID, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * COUNT_ID + COUNT_ID, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (COUNT_CONST) + COUNT_CONST, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * COUNT_CONST + COUNT_CONST, sizeof(THING) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ - kmalloc + kmalloc_array ( - SIZE * COUNT + COUNT, SIZE , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( kmalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( kmalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kmalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kmalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( kmalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products, // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( kmalloc(C1 * C2 * C3, ...) | kmalloc( - (E1) * E2 * E3 + array3_size(E1, E2, E3) , ...) | kmalloc( - (E1) * (E2) * E3 + array3_size(E1, E2, E3) , ...) | kmalloc( - (E1) * (E2) * (E3) + array3_size(E1, E2, E3) , ...) | kmalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants, // keeping sizeof() as the second factor argument. @@ expression THING, E1, E2; type TYPE; constant C1, C2, C3; @@ ( kmalloc(sizeof(THING) * C2, ...) | kmalloc(sizeof(TYPE) * C2, ...) | kmalloc(C1 * C2 * C3, ...) | kmalloc(C1 * C2, ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * (E2) + E2, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * E2 + E2, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (E2) + E2, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * E2 + E2, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - (E1) * E2 + E1, E2 , ...) | - kmalloc + kmalloc_array ( - (E1) * (E2) + E1, E2 , ...) | - kmalloc + kmalloc_array ( - E1 * E2 + E1, E2 , ...) ) Signed-off-by: Kees Cook <keescook@chromium.org>
2018-04-15fs: avoid fdput() after failed fdget() in vfs_dedupe_file_range()Zev Weiss
It's a fairly inconsequential bug, since fdput() won't actually try to fput() the file due to fd.flags (and thus FDPUT_FPUT) being zero in the failure case, but most other vfs code takes steps to avoid this. Signed-off-by: Zev Weiss <zev@bewilderbeest.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-04-02fs: add ksys_p{read,write}64() helpers; remove in-kernel calls to syscallsDominik Brodowski
Using the ksys_p{read,write}64() wrappers allows us to get rid of in-kernel calls to the sys_pread64() and sys_pwrite64() syscalls. The ksys_ prefix denotes that this function is meant as a drop-in replacement for the syscall. In particular, it uses the same calling convention as sys_p{read,write}64(). This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02fs: add ksys_read() helper; remove in-kernel calls to sys_read()Dominik Brodowski
Using this helper allows us to avoid the in-kernel calls to the sys_read() syscall. The ksys_ prefix denotes that this function is meant as a drop-in replacement for the syscall. In particular, it uses the same calling convention as sys_read(). This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02fs: add ksys_lseek() helper; remove in-kernel calls to sys_lseek()Dominik Brodowski
Using this helper allows us to avoid the in-kernel calls to the sys_lseek() syscall. The ksys_ prefix denotes that this function is meant as a drop-in replacement for the syscall. In particular, it uses the same calling convention as sys_lseek(). This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>