Commit Graph

298 Commits

Author SHA1 Message Date
Miklos Szeredi
7c98f7cb8f remove call_{read,write}_iter() functions
These have no clear purpose.  This is effectively a revert of commit
bb7462b6fd ("vfs: use helpers for calling f_op->{read,write}_iter()").

The patch was created with the help of a coccinelle script.

Fixes: bb7462b6fd ("vfs: use helpers for calling f_op->{read,write}_iter()")
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-04-15 16:03:25 -04:00
Amir Goldstein
d9e5d31084
fsnotify: optionally pass access range in file permission hooks
In preparation for pre-content permission events with file access range,
move fsnotify_file_perm() hook out of security_file_permission() and into
the callers.

Callers that have the access range information call the new hook
fsnotify_file_area_perm() with the access range.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231212094440.250945-6-amir73il@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-12 16:20:02 +01:00
Amir Goldstein
705bcfcbde
fs: use splice_copy_file_range() inline helper
generic_copy_file_range() is just a wrapper around splice_file_range(),
which caps the maximum copy length.

The only caller of splice_file_range(), namely __ceph_copy_file_range()
is already ready to cope with short copy.

Move the length capping into splice_file_range() and replace the exported
symbol generic_copy_file_range() with a simple inline helper.

Suggested-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/linux-fsdevel/20231204083849.GC32438@lst.de/
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231212094440.250945-3-amir73il@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-12 16:20:02 +01:00
Amir Goldstein
0f292086c2
splice: return type ssize_t from all helpers
Not sure why some splice helpers return long, maybe historic reasons.
Change them all to return ssize_t to conform to the splice methods and
to the rest of the helpers.

Suggested-by: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/r/20231208-horchen-helium-d3ec1535ede5@brauner/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231212094440.250945-2-amir73il@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-12 16:19:59 +01:00
Amir Goldstein
7306512686 fs: use do_splice_direct() for nfsd/ksmbd server-side-copy
nfsd/ksmbd call vfs_copy_file_range() with flag COPY_FILE_SPLICE to
perform kernel copy between two files on any two filesystems.

Splicing input file, while holding file_start_write() on the output file
which is on a different sb, posses a risk for fanotify related deadlocks.

We only need to call splice_file_range() from within the context of
->copy_file_range() filesystem methods with file_start_write() held.

To avoid the possible deadlocks, always use do_splice_direct() instead of
splice_file_range() for the kernel copy fallback in vfs_copy_file_range()
without holding file_start_write().

Reported-and-tested-by: Bert Karwatzki <spasswolf@web.de>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231130141624.3338942-4-amir73il@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-05 12:58:02 +01:00
Amir Goldstein
da40448ce4 fs: move file_start_write() into direct_splice_actor()
The callers of do_splice_direct() hold file_start_write() on the output
file.

This may cause file permission hooks to be called indirectly on an
overlayfs lower layer, which is on the same filesystem of the output
file and could lead to deadlock with fanotify permission events.

To fix this potential deadlock, move file_start_write() from the callers
into the direct_splice_actor(), so file_start_write() will not be held
while splicing from the input file.

Suggested-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20231128214258.GA2398475@perftesting/
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231130141624.3338942-3-amir73il@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-01 11:39:50 +01:00
Amir Goldstein
488e8f6852 fs: fork splice_file_range() from do_splice_direct()
In preparation of calling do_splice_direct() without file_start_write()
held, create a new helper splice_file_range(), to be called from context
of ->copy_file_range() methods instead of do_splice_direct().

Currently, the only difference is that splice_file_range() does not take
flags argument and that it asserts that file_start_write() is held, but
we factor out a common helper do_splice_direct_actor() that will be used
later.

Use the new helper from __ceph_copy_file_range(), that was incorrectly
passing to do_splice_direct() the copy flags argument as splice flags.
The value of copy flags in ceph is always 0, so it is a smenatic bug fix.

Move the declaration of both helpers to linux/splice.h.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231130141624.3338942-2-amir73il@gmail.com
Acked-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-01 11:39:50 +01:00
Amir Goldstein
3d5cd4911e fs: create file_write_started() helper
Convenience wrapper for sb_write_started(file_inode(inode)->i_sb)), which
has a single occurrence in the code right now.

Document the false negatives of those helpers, which makes them unusable
to assert that sb_start_write() is not held.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231122122715.2561213-16-amir73il@gmail.com
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-11-24 10:39:19 +01:00
Amir Goldstein
6ae654392b fs: move kiocb_start_write() into vfs_iocb_iter_write()
In vfs code, sb_start_write() is usually called after the permission hook
in rw_verify_area().  vfs_iocb_iter_write() is an exception to this rule,
where kiocb_start_write() is called by its callers.

Move kiocb_start_write() from the callers into vfs_iocb_iter_write()
after the rw_verify_area() checks, to make them "start-write-safe".

The semantics of vfs_iocb_iter_write() is changed, so that the caller is
responsible for calling kiocb_end_write() on completion only if async
iocb was queued.  The completion handlers of both callers were adapted
to this semantic change.

This is needed for fanotify "pre content" events.

Suggested-by: Jan Kara <jack@suse.cz>
Suggested-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231122122715.2561213-14-amir73il@gmail.com
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-11-24 10:37:44 +01:00
Amir Goldstein
b8e1425bae fs: move permission hook out of do_iter_read()
We recently moved fsnotify hook, rw_verify_area() and other checks from
do_iter_write() out to its two callers.

for consistency, do the same thing for do_iter_read() - move the
rw_verify_area() checks and fsnotify hook to the callers vfs_iter_read()
and vfs_readv().

This aligns those vfs helpers with the pattern used in vfs_read() and
vfs_iocb_iter_read() and the vfs write helpers, where all the checks are
in the vfs helpers and the do_* or call_* helpers do the work.

This is needed for fanotify "pre content" events.

Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231122122715.2561213-13-amir73il@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-11-24 10:37:44 +01:00
Amir Goldstein
1c8aa83303 fs: move permission hook out of do_iter_write()
In many of the vfs helpers, the rw_verity_area() checks are called before
taking sb_start_write(), making them "start-write-safe".
do_iter_write() is an exception to this rule.

do_iter_write() has two callers - vfs_iter_write() and vfs_writev().
Move rw_verify_area() and other checks from do_iter_write() out to
its callers to make them "start-write-safe".

Move also the fsnotify_modify() hook to align with similar pattern
used in vfs_write() and other vfs helpers.

This is needed for fanotify "pre content" events.

Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231122122715.2561213-12-amir73il@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-11-24 10:37:44 +01:00
Amir Goldstein
269aed7014 fs: move file_start_write() into vfs_iter_write()
All the callers of vfs_iter_write() call file_start_write() just before
calling vfs_iter_write() except for target_core_file's fd_do_rw().

Move file_start_write() from the callers into vfs_iter_write().
fd_do_rw() calls vfs_iter_write() with a non-regular file, so
file_start_write() is a no-op.

This is needed for fanotify "pre content" events.

Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231122122715.2561213-11-amir73il@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-11-24 10:09:51 +01:00
Yang Li
89cbd4c036 fs: Fix one kernel-doc comment
Fix one kernel-doc comment to silence the warning:

fs/read_write.c:88: warning: Function parameter or member 'maxsize' not described in 'generic_file_llseek_size'

Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Message-Id: <20230811014359.4960-1-yang.lee@linux.alibaba.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-15 08:32:45 +02:00
David Howells
2cb1e08985 splice: Use filemap_splice_read() instead of generic_file_splice_read()
Replace pointers to generic_file_splice_read() with calls to
filemap_splice_read().

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: David Hildenbrand <david@redhat.com>
cc: John Hubbard <jhubbard@nvidia.com>
cc: linux-mm@kvack.org
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20230522135018.2742245-29-dhowells@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-05-24 08:42:17 -06:00
Jens Axboe
95e49cf837 iov_iter: add iter_iov_addr() and iter_iov_len() helpers
These just return the address and length of the current iovec segment
in the iterator. Convert existing iov_iter_iovec() users to use them
instead of getting a copy of the current vec.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-03-30 08:12:29 -06:00
Linus Torvalds
75f4d9af8b iov_iter work; most of that is about getting rid of
direction misannotations and (hopefully) preventing
 more of the same for the future.
 
 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull iov_iter updates from Al Viro:
 "iov_iter work; most of that is about getting rid of direction
  misannotations and (hopefully) preventing more of the same for the
  future"

* tag 'pull-iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  use less confusing names for iov_iter direction initializers
  iov_iter: saner checks for attempt to copy to/from iterator
  [xen] fix "direction" argument of iov_iter_kvec()
  [vhost] fix 'direction' argument of iov_iter_{init,bvec}()
  [target] fix iov_iter_bvec() "direction" argument
  [s390] memcpy_real(): WRITE is "data source", not destination...
  [s390] zcore: WRITE is "data source", not destination...
  [infiniband] READ is "data destination", not source...
  [fsi] WRITE is "data source", not destination...
  [s390] copy_oldmem_kernel() - WRITE is "data source", not destination
  csum_and_copy_to_iter(): handle ITER_DISCARD
  get rid of unlikely() on page_copy_sane() calls
2022-12-12 18:29:54 -08:00
Al Viro
de4eda9de2 use less confusing names for iov_iter direction initializers
READ/WRITE proved to be actively confusing - the meanings are
"data destination, as used with read(2)" and "data source, as
used with write(2)", but people keep interpreting those as
"we read data from it" and "we write data to it", i.e. exactly
the wrong way.

Call them ITER_DEST and ITER_SOURCE - at least that is harder
to misinterpret...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2022-11-25 13:01:55 -05:00
Amir Goldstein
10bc8e4af6 vfs: fix copy_file_range() averts filesystem freeze protection
Commit 868f9f2f8e ("vfs: fix copy_file_range() regression in cross-fs
copies") removed fallback to generic_copy_file_range() for cross-fs
cases inside vfs_copy_file_range().

To preserve behavior of nfsd and ksmbd server-side-copy, the fallback to
generic_copy_file_range() was added in nfsd and ksmbd code, but that
call is missing sb_start_write(), fsnotify hooks and more.

Ideally, nfsd and ksmbd would pass a flag to vfs_copy_file_range() that
will take care of the fallback, but that code would be subtle and we got
vfs_copy_file_range() logic wrong too many times already.

Instead, add a flag to explicitly request vfs_copy_file_range() to
perform only generic_copy_file_range() and let nfsd and ksmbd use this
flag only in the fallback path.

This choise keeps the logic changes to minimum in the non-nfsd/ksmbd code
paths to reduce the risk of further regressions.

Fixes: 868f9f2f8e ("vfs: fix copy_file_range() regression in cross-fs copies")
Tested-by: Namjae Jeon <linkinjeon@kernel.org>
Tested-by: Luis Henriques <lhenriques@suse.de>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2022-11-25 00:52:28 -05:00
Al Viro
06bbaa6dc5 [coredump] don't use __kernel_write() on kmap_local_page()
passing kmap_local_page() result to __kernel_write() is unsafe -
random ->write_iter() might (and 9p one does) get unhappy when
passed ITER_KVEC with pointer that came from kmap_local_page().

Fix by providing a variant of __kernel_write() that takes an iov_iter
from caller (__kernel_write() becomes a trivial wrapper) and adding
dump_emit_page() that parallels dump_emit(), except that instead of
__kernel_write() it uses __kernel_write_iter() with ITER_BVEC source.

Fixes: 3159ed5779 "fs/coredump: use kmap_local_page()"
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2022-09-28 14:28:40 -04:00
Al Viro
3e20a751af switch new_sync_{read,write}() to ITER_UBUF
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2022-08-08 22:37:15 -04:00
Linus Torvalds
a782e86649 Saner handling of "lseek should fail with ESPIPE" - gets rid of
magical no_llseek thing and makes checks consistent.  In particular,
 ad-hoc "can we do splice via internal pipe" checks got saner (and
 somewhat more permissive, which is what Jason had been after, AFAICT)
 
 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-work.lseek' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs lseek updates from Al Viro:
 "Jason's lseek series.

  Saner handling of 'lseek should fail with ESPIPE' - this gets rid of
  the magical no_llseek thing and makes checks consistent.

  In particular, the ad-hoc "can we do splice via internal pipe" checks
  got saner (and somewhat more permissive, which is what Jason had been
  after, AFAICT)"

* tag 'pull-work.lseek' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: remove no_llseek
  fs: check FMODE_LSEEK to control internal pipe splicing
  vfio: do not set FMODE_LSEEK flag
  dma-buf: remove useless FMODE_LSEEK flag
  fs: do not compare against ->llseek
  fs: clear or set FMODE_LSEEK based on llseek function
2022-08-03 11:35:20 -07:00
Linus Torvalds
98e2474640 for-5.20/io_uring-buffered-writes-2022-07-29
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Merge tag 'for-5.20/io_uring-buffered-writes-2022-07-29' of git://git.kernel.dk/linux-block

Pull io_uring buffered writes support from Jens Axboe:
 "This contains support for buffered writes, specifically for XFS. btrfs
  is in progress, will be coming in the next release.

  io_uring does support buffered writes on any file type, but since the
  buffered write path just always -EAGAIN (or -EOPNOTSUPP) any attempt
  to do so if IOCB_NOWAIT is set, any buffered write will effectively be
  handled by io-wq offload. This isn't very efficient, and we even have
  specific code in io-wq to serialize buffered writes to the same inode
  to avoid further inefficiencies with thread offload.

  This is particularly sad since most buffered writes don't block, they
  simply copy data to a page and dirty it. With this pull request, we
  can handle buffered writes a lot more effiently.

  If balance_dirty_pages() needs to block, we back off on writes as
  indicated.

  This improves buffered write support by 2-3x.

  Jan Kara helped with the mm bits for this, and Stefan handled the
  fs/iomap/xfs/io_uring parts of it"

* tag 'for-5.20/io_uring-buffered-writes-2022-07-29' of git://git.kernel.dk/linux-block:
  mm: honor FGP_NOWAIT for page cache page allocation
  xfs: Add async buffered write support
  xfs: Specify lockmode when calling xfs_ilock_for_iomap()
  io_uring: Add tracepoint for short writes
  io_uring: fix issue with io_write() not always undoing sb_start_write()
  io_uring: Add support for async buffered writes
  fs: Add async write file modification handling.
  fs: Split off inode_needs_update_time and __file_update_time
  fs: add __remove_file_privs() with flags parameter
  fs: add a FMODE_BUF_WASYNC flags for f_mode
  iomap: Return -EAGAIN from iomap_write_iter()
  iomap: Add async buffered write support
  iomap: Add flags parameter to iomap_page_create()
  mm: Add balance_dirty_pages_ratelimited_flags() function
  mm: Move updates of dirty_exceeded into one place
  mm: Move starting of background writeback into the main balancing loop
2022-08-02 13:27:23 -07:00
Linus Torvalds
39c3c396f8 Thirteen hotfixes, Eight are cc:stable and the remainder are for post-5.18
issues or are too minor to warrant backporting
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Merge tag 'mm-hotfixes-stable-2022-07-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "Thirteen hotfixes.

  Eight are cc:stable and the remainder are for post-5.18 issues or are
  too minor to warrant backporting"

* tag 'mm-hotfixes-stable-2022-07-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mailmap: update Gao Xiang's email addresses
  userfaultfd: provide properly masked address for huge-pages
  Revert "ocfs2: mount shared volume without ha stack"
  hugetlb: fix memoryleak in hugetlb_mcopy_atomic_pte
  fs: sendfile handles O_NONBLOCK of out_fd
  ntfs: fix use-after-free in ntfs_ucsncmp()
  secretmem: fix unhandled fault in truncate
  mm/hugetlb: separate path for hwpoison entry in copy_hugetlb_page_range()
  mm: fix missing wake-up event for FSDAX pages
  mm: fix page leak with multiple threads mapping the same page
  mailmap: update Seth Forshee's email address
  tmpfs: fix the issue that the mount and remount results are inconsistent.
  mm: kfence: apply kmemleak_ignore_phys on early allocated pool
2022-07-26 19:38:46 -07:00
Stefan Roesch
8017553980 fs: add a FMODE_BUF_WASYNC flags for f_mode
This introduces the flag FMODE_BUF_WASYNC. If devices support async
buffered writes, this flag can be set. It also modifies the check in
generic_write_checks to take async buffered writes into consideration.

Signed-off-by: Stefan Roesch <shr@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20220623175157.1715274-8-shr@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:39:31 -06:00
Andrei Vagin
bdeb77bc2c fs: sendfile handles O_NONBLOCK of out_fd
sendfile has to return EAGAIN if out_fd is nonblocking and the write into
it would block.

Here is a small reproducer for the problem:

#define _GNU_SOURCE /* See feature_test_macros(7) */
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/sendfile.h>


#define FILE_SIZE (1UL << 30)
int main(int argc, char **argv) {
        int p[2], fd;

        if (pipe2(p, O_NONBLOCK))
                return 1;

        fd = open(argv[1], O_RDWR | O_TMPFILE, 0666);
        if (fd < 0)
                return 1;
        ftruncate(fd, FILE_SIZE);

        if (sendfile(p[1], fd, 0, FILE_SIZE) == -1) {
                fprintf(stderr, "FAIL\n");
        }
        if (sendfile(p[1], fd, 0, FILE_SIZE) != -1 || errno != EAGAIN) {
                fprintf(stderr, "FAIL\n");
        }
        return 0;
}

It worked before b964bf53e5, it is stuck after b964bf53e5, and it
works again with this fix.

This regression occurred because do_splice_direct() calls pipe_write
that handles O_NONBLOCK.  Here is a trace log from the reproducer:

 1)               |  __x64_sys_sendfile64() {
 1)               |    do_sendfile() {
 1)               |      __fdget()
 1)               |      rw_verify_area()
 1)               |      __fdget()
 1)               |      rw_verify_area()
 1)               |      do_splice_direct() {
 1)               |        rw_verify_area()
 1)               |        splice_direct_to_actor() {
 1)               |          do_splice_to() {
 1)               |            rw_verify_area()
 1)               |            generic_file_splice_read()
 1) + 74.153 us   |          }
 1)               |          direct_splice_actor() {
 1)               |            iter_file_splice_write() {
 1)               |              __kmalloc()
 1)   0.148 us    |              pipe_lock();
 1)   0.153 us    |              splice_from_pipe_next.part.0();
 1)   0.162 us    |              page_cache_pipe_buf_confirm();
... 16 times
 1)   0.159 us    |              page_cache_pipe_buf_confirm();
 1)               |              vfs_iter_write() {
 1)               |                do_iter_write() {
 1)               |                  rw_verify_area()
 1)               |                  do_iter_readv_writev() {
 1)               |                    pipe_write() {
 1)               |                      mutex_lock()
 1)   0.153 us    |                      mutex_unlock();
 1)   1.368 us    |                    }
 1)   1.686 us    |                  }
 1)   5.798 us    |                }
 1)   6.084 us    |              }
 1)   0.174 us    |              kfree();
 1)   0.152 us    |              pipe_unlock();
 1) + 14.461 us   |            }
 1) + 14.783 us   |          }
 1)   0.164 us    |          page_cache_pipe_buf_release();
... 16 times
 1)   0.161 us    |          page_cache_pipe_buf_release();
 1)               |          touch_atime()
 1) + 95.854 us   |        }
 1) + 99.784 us   |      }
 1) ! 107.393 us  |    }
 1) ! 107.699 us  |  }

Link: https://lkml.kernel.org/r/20220415005015.525191-1-avagin@gmail.com
Fixes: b964bf53e5 ("teach sendfile(2) to handle send-to-pipe directly")
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-07-18 15:07:52 -07:00
Jason A. Donenfeld
868941b144 fs: remove no_llseek
Now that all callers of ->llseek are going through vfs_llseek(), we
don't gain anything by keeping no_llseek around. Nothing actually calls
it and setting ->llseek to no_lseek is completely equivalent to
leaving it NULL.

Longer term (== by the end of merge window) we want to remove all such
intializations.  To simplify the merge window this commit does *not*
touch initializers - it only defines no_llseek as NULL (and simplifies
the tests on file opening).

At -rc1 we'll need do a mechanical removal of no_llseek -

git grep -l -w no_llseek | grep -v porting.rst | while read i; do
	sed -i '/\<no_llseek\>/d' $i
done
would do it.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2022-07-16 09:19:47 -04:00
Jason A. Donenfeld
4e3299eadd fs: do not compare against ->llseek
Now vfs_llseek() can simply check for FMODE_LSEEK; if it's set,
we know that ->llseek() won't be NULL and if it's not we should
just fail with -ESPIPE.

A couple of other places where we used to check for special
values of ->llseek() (somewhat inconsistently) switched to
checking FMODE_LSEEK.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2022-07-16 09:19:15 -04:00
Amir Goldstein
868f9f2f8e vfs: fix copy_file_range() regression in cross-fs copies
A regression has been reported by Nicolas Boichat, found while using the
copy_file_range syscall to copy a tracefs file.

Before commit 5dae222a5f ("vfs: allow copy_file_range to copy across
devices") the kernel would return -EXDEV to userspace when trying to
copy a file across different filesystems.  After this commit, the
syscall doesn't fail anymore and instead returns zero (zero bytes
copied), as this file's content is generated on-the-fly and thus reports
a size of zero.

Another regression has been reported by He Zhe - the assertion of
WARN_ON_ONCE(ret == -EOPNOTSUPP) can be triggered from userspace when
copying from a sysfs file whose read operation may return -EOPNOTSUPP.

Since we do not have test coverage for copy_file_range() between any two
types of filesystems, the best way to avoid these sort of issues in the
future is for the kernel to be more picky about filesystems that are
allowed to do copy_file_range().

This patch restores some cross-filesystem copy restrictions that existed
prior to commit 5dae222a5f ("vfs: allow copy_file_range to copy across
devices"), namely, cross-sb copy is not allowed for filesystems that do
not implement ->copy_file_range().

Filesystems that do implement ->copy_file_range() have full control of
the result - if this method returns an error, the error is returned to
the user.  Before this change this was only true for fs that did not
implement the ->remap_file_range() operation (i.e.  nfsv3).

Filesystems that do not implement ->copy_file_range() still fall-back to
the generic_copy_file_range() implementation when the copy is within the
same sb.  This helps the kernel can maintain a more consistent story
about which filesystems support copy_file_range().

nfsd and ksmbd servers are modified to fall-back to the
generic_copy_file_range() implementation in case vfs_copy_file_range()
fails with -EOPNOTSUPP or -EXDEV, which preserves behavior of
server-side-copy.

fall-back to generic_copy_file_range() is not implemented for the smb
operation FSCTL_DUPLICATE_EXTENTS_TO_FILE, which is arguably a correct
change of behavior.

Fixes: 5dae222a5f ("vfs: allow copy_file_range to copy across devices")
Link: https://lore.kernel.org/linux-fsdevel/20210212044405.4120619-1-drinkcat@chromium.org/
Link: https://lore.kernel.org/linux-fsdevel/CANMq1KDZuxir2LM5jOTm0xx+BnvW=ZmpsG47CyHFJwnw7zSX6Q@mail.gmail.com/
Link: https://lore.kernel.org/linux-fsdevel/20210126135012.1.If45b7cdc3ff707bc1efa17f5366057d60603c45f@changeid/
Link: https://lore.kernel.org/linux-fsdevel/20210630161320.29006-1-lhenriques@suse.de/
Reported-by: Nicolas Boichat <drinkcat@chromium.org>
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Luis Henriques <lhenriques@suse.de>
Fixes: 64bf5ff58d ("vfs: no fallback for ->copy_file_range")
Link: https://lore.kernel.org/linux-fsdevel/20f17f64-88cb-4e80-07c1-85cb96c83619@windriver.com/
Reported-by: He Zhe <zhe.he@windriver.com>
Tested-by: Namjae Jeon <linkinjeon@kernel.org>
Tested-by: Luis Henriques <lhenriques@suse.de>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-06-30 15:16:38 -07:00
Guo Ren
59c10c52f5
riscv: compat: syscall: Add compat_sys_call_table implementation
Implement compat sys_call_table and some system call functions:
truncate64, ftruncate64, fallocate, pread64, pwrite64,
sync_file_range, readahead, fadvise64_64 which need argument
translation.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20220405071314.3225832-12-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-04-26 13:36:25 -07:00
Linus Torvalds
88e6c02076 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs updates from Al Viro:
 "Assorted bits and pieces"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  aio: drop needless assignment in aio_read()
  clean overflow checks in count_mounts() a bit
  seq_file: fix NULL pointer arithmetic warning
  uml/x86: use x86 load_unaligned_zeropad()
  asm/user.h: killed unused macros
  constify struct path argument of finish_automount()/do_add_mount()
  fs: Remove FIXME comment in generic_write_checks()
2022-04-01 19:57:03 -07:00
Omar Sandoval
f6f7a25a65 fs: export variant of generic_write_checks without iov_iter
Encoded I/O in Btrfs needs to check a write with a given logical size
without an iov_iter that matches that size (because the iov_iter we have
is for the compressed data). So, factor out the parts of
generic_write_check() that don't need an iov_iter into a new
generic_write_checks_count() function and export that.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-03-14 13:13:50 +01:00
Omar Sandoval
871129332d fs: export rw_verify_area()
I'm adding btrfs ioctls to read and write compressed data, and rather
than duplicating the checks in rw_verify_area(), let's just export it.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-03-14 13:13:50 +01:00
Tal Zussman
c51acdb78f fs: Remove FIXME comment in generic_write_checks()
This patch removes an unnecessary comment that had to do with block special
files from `generic_write_checks()`.

The comment, originally added in Linux v2.4.14.9, was to clarify that we only
set `pos` to the file size when the file was opened with `O_APPEND` if the file
wasn't a block special file. Prior to Linux v2.4, block special files had a
different `write()` function which was unified into a generic `write()` function
in Linux v2.4. This generic `write()` function called `generic_write_checks()`.
For more details, see this earlier conversation:
https://lore.kernel.org/linux-fsdevel/Yc4Czk5A+p5p2Y4W@mit.edu/

Currently, block special devices have their own `write_iter()` function and no
longer share the same `generic_write_checks()`, therefore rendering the comment
irrelevant.

Signed-off-by: Tal Zussman <tz2294@columbia.edu>
Co-authored-by: Xijiao Li <xl2950@columbia.edu>
Co-authored-by: Hans Montero <hjm2133@columbia.edu>
Suggested-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2022-01-30 14:34:55 -05:00
Jeff Layton
482e00075d fs: remove leftover comments from mandatory locking removal
Stragglers from commit f7e33bdbd6 ("fs: remove mandatory file locking
support").

Signed-off-by: Jeff Layton <jlayton@kernel.org>
2021-10-26 12:20:50 -04:00
Lukas Bulwahn
2949e8427a fs: clean up after mandatory file locking support removal
Commit 3efee0567b4a ("fs: remove mandatory file locking support") removes
some operations in functions rw_verify_area().

As these functions are now simplified, do some syntactic clean-up as
follow-up to the removal as well, which was pointed out by compiler
warnings and static analysis.

No functional change.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
2021-08-24 07:52:45 -04:00
Jeff Layton
f7e33bdbd6 fs: remove mandatory file locking support
We added CONFIG_MANDATORY_FILE_LOCKING in 2015, and soon after turned it
off in Fedora and RHEL8. Several other distros have followed suit.

I've heard of one problem in all that time: Someone migrated from an
older distro that supported "-o mand" to one that didn't, and the host
had a fstab entry with "mand" in it which broke on reboot. They didn't
actually _use_ mandatory locking so they just removed the mount option
and moved on.

This patch rips out mandatory locking support wholesale from the kernel,
along with the Kconfig option and the Documentation file. It also
changes the mount code to ignore the "mand" mount option instead of
erroring out, and to throw a big, ugly warning.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
2021-08-23 06:15:36 -04:00
Al Viro
b964bf53e5 teach sendfile(2) to handle send-to-pipe directly
no point going through the intermediate pipe

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2021-01-25 23:29:36 -05:00
Linus Torvalds
c4728cfbed Refactored code for 5.10:
- Move the file range remap generic functions out of mm/filemap.c and
 fs/read_write.c and into fs/remap_range.c to reduce clutter in the first
 two files.
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Merge tag 'vfs-5.10-merge-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull clone/dedupe/remap code refactoring from Darrick Wong:
 "Move the generic file range remap (aka reflink and dedupe) functions
  out of mm/filemap.c and fs/read_write.c and into fs/remap_range.c to
  reduce clutter in the first two files"

* tag 'vfs-5.10-merge-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  vfs: move the generic write and copy checks out of mm
  vfs: move the remap range helpers to remap_range.c
  vfs: move generic_remap_checks out of mm
2020-10-23 11:33:41 -07:00
Linus Torvalds
f56e65dff6 Merge branch 'work.set_fs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull initial set_fs() removal from Al Viro:
 "Christoph's set_fs base series + fixups"

* 'work.set_fs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: Allow a NULL pos pointer to __kernel_read
  fs: Allow a NULL pos pointer to __kernel_write
  powerpc: remove address space overrides using set_fs()
  powerpc: use non-set_fs based maccess routines
  x86: remove address space overrides using set_fs()
  x86: make TASK_SIZE_MAX usable from assembly code
  x86: move PAGE_OFFSET, TASK_SIZE & friends to page_{32,64}_types.h
  lkdtm: remove set_fs-based tests
  test_bitmap: remove user bitmap tests
  uaccess: add infrastructure for kernel builds with set_fs()
  fs: don't allow splice read/write without explicit ops
  fs: don't allow kernel reads and writes without iter ops
  sysctl: Convert to iter interfaces
  proc: add a read_iter method to proc proc_ops
  proc: cleanup the compat vs no compat file ops
  proc: remove a level of indentation in proc_get_inode
2020-10-22 09:59:21 -07:00
Matthew Wilcox (Oracle)
7b84b665c8 fs: Allow a NULL pos pointer to __kernel_read
Match the behaviour of new_sync_read() and __kernel_write().

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-10-15 14:20:42 -04:00
Matthew Wilcox (Oracle)
4c207ef482 fs: Allow a NULL pos pointer to __kernel_write
Linus prefers that callers be allowed to pass in a NULL pointer for ppos
like new_sync_write().

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-10-15 14:20:41 -04:00
Darrick J. Wong
407e9c63ee vfs: move the generic write and copy checks out of mm
The generic write check helpers also don't have much to do with the page
cache, so move them to the vfs.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-10-15 09:50:01 -07:00
Darrick J. Wong
1b2c54d63c vfs: move the remap range helpers to remap_range.c
Complete the migration by moving the file remapping helper functions out
of read_write.c and into remap_range.c.  This reduces the clutter in the
first file and (eventually) will make it so that we can compile out the
second file if it isn't needed.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-10-15 09:48:49 -07:00
Linus Torvalds
85ed13e78d Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull compat iovec cleanups from Al Viro:
 "Christoph's series around import_iovec() and compat variant thereof"

* 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  security/keys: remove compat_keyctl_instantiate_key_iov
  mm: remove compat_process_vm_{readv,writev}
  fs: remove compat_sys_vmsplice
  fs: remove the compat readv/writev syscalls
  fs: remove various compat readv/writev helpers
  iov_iter: transparently handle compat iovecs in import_iovec
  iov_iter: refactor rw_copy_check_uvector and import_iovec
  iov_iter: move rw_copy_check_uvector() into lib/iov_iter.c
  compat.h: fix a spelling error in <linux/compat.h>
2020-10-12 16:35:51 -07:00
Christoph Hellwig
5f764d624a fs: remove the compat readv/writev syscalls
Now that import_iovec handles compat iovecs, the native readv and writev
syscalls can be used for the compat case as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-10-03 00:02:14 -04:00
Christoph Hellwig
3523a9d454 fs: remove various compat readv/writev helpers
Now that import_iovec handles compat iovecs as well, all the duplicated
code in the compat readv/writev helpers is not needed.  Remove them
and switch the compat syscall handlers to use the native helpers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-10-03 00:02:14 -04:00
Christoph Hellwig
89cd35c58b iov_iter: transparently handle compat iovecs in import_iovec
Use in compat_syscall to import either native or the compat iovecs, and
remove the now superflous compat_import_iovec.

This removes the need for special compat logic in most callers, and
the remaining ones can still be simplified by using __import_iovec
with a bool compat parameter.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-10-03 00:02:13 -04:00
Linus Torvalds
90fb702791 autofs: use __kernel_write() for the autofs pipe writing
autofs got broken in some configurations by commit 13c164b1a1
("autofs: switch to kernel_write") because there is now an extra LSM
permission check done by security_file_permission() in rw_verify_area().

autofs is one if the few places that really does want the much more
limited __kernel_write(), because the write is an internal kernel one
that shouldn't do any user permission checks (it also doesn't need the
file_start_write/file_end_write logic, since it's just a pipe).

There are a couple of other cases like that - accounting, core dumping,
and splice - but autofs stands out because it can be built as a module.

As a result, we need to export this internal __kernel_write() function
again.

We really don't want any other module to use this, but we don't have a
"EXPORT_SYMBOL_FOR_AUTOFS_ONLY()".  But we can mark it GPL-only to at
least approximate that "internal use only" for licensing.

While in this area, make autofs pass in NULL for the file position
pointer, since it's always a pipe, and we now use a NULL file pointer
for streaming file descriptors (see file_ppos() and commit 438ab720c6:
"vfs: pass ppos=NULL to .read()/.write() of FMODE_STREAM files")

This effectively reverts commits 9db9775224 ("fs: unexport
__kernel_write") and 13c164b1a1 ("autofs: switch to kernel_write").

Fixes: 13c164b1a1 ("autofs: switch to kernel_write")
Reported-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Acked-by: Ian Kent <raven@themaw.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-29 17:18:34 -07:00
David Laight
fb041b5989 iov_iter: move rw_copy_check_uvector() into lib/iov_iter.c
This lets the compiler inline it into import_iovec() generating
much better code.

Signed-off-by: David Laight <david.laight@aculab.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-09-25 11:36:02 -04:00
Christoph Hellwig
36e2c7421f fs: don't allow splice read/write without explicit ops
default_file_splice_write is the last piece of generic code that uses
set_fs to make the uaccess routines operate on kernel pointers.  It
implements a "fallback loop" for splicing from files that do not actually
provide a proper splice_read method.  The usual file systems and other
high bandwidth instances all provide a ->splice_read, so this just removes
support for various device drivers and procfs/debugfs files.  If splice
support for any of those turns out to be important it can be added back
by switching them to the iter ops and using generic_file_splice_read.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-09-08 22:21:32 -04:00