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2024-03-13Merge tag 'lsm-pr-20240312' of ↵Linus Torvalds1-2/+1
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm Pull lsm updates from Paul Moore: - Promote IMA/EVM to a proper LSM This is the bulk of the diffstat, and the source of all the changes in the VFS code. Prior to the start of the LSM stacking work it was important that IMA/EVM were separate from the rest of the LSMs, complete with their own hooks, infrastructure, etc. as it was the only way to enable IMA/EVM at the same time as a LSM. However, now that the bulk of the LSM infrastructure supports multiple simultaneous LSMs, we can simplify things greatly by bringing IMA/EVM into the LSM infrastructure as proper LSMs. This is something I've wanted to see happen for quite some time and Roberto was kind enough to put in the work to make it happen. - Use the LSM hook default values to simplify the call_int_hook() macro Previously the call_int_hook() macro required callers to supply a default return value, despite a default value being specified when the LSM hook was defined. This simplifies the macro by using the defined default return value which makes life easier for callers and should also reduce the number of return value bugs in the future (we've had a few pop up recently, hence this work). - Use the KMEM_CACHE() macro instead of kmem_cache_create() The guidance appears to be to use the KMEM_CACHE() macro when possible and there is no reason why we can't use the macro, so let's use it. - Fix a number of comment typos in the LSM hook comment blocks Not much to say here, we fixed some questionable grammar decisions in the LSM hook comment blocks. * tag 'lsm-pr-20240312' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: (28 commits) cred: Use KMEM_CACHE() instead of kmem_cache_create() lsm: use default hook return value in call_int_hook() lsm: fix typos in security/security.c comment headers integrity: Remove LSM ima: Make it independent from 'integrity' LSM evm: Make it independent from 'integrity' LSM evm: Move to LSM infrastructure ima: Move IMA-Appraisal to LSM infrastructure ima: Move to LSM infrastructure integrity: Move integrity_kernel_module_request() to IMA security: Introduce key_post_create_or_update hook security: Introduce inode_post_remove_acl hook security: Introduce inode_post_set_acl hook security: Introduce inode_post_create_tmpfile hook security: Introduce path_post_mknod hook security: Introduce file_release hook security: Introduce file_post_open hook security: Introduce inode_post_removexattr hook security: Introduce inode_post_setattr hook security: Align inode_setattr hook definition with EVM ...
2024-02-25file: add alloc_file_pseudo_noaccount()Christian Brauner1-0/+24
When we open block devices as files we want to make sure to not charge them against the open file limit of the caller as that can cause spurious failures. Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-1-adbd023e19cc@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-25file: prepare for new helperChristian Brauner1-18/+41
In order to add a helper to open files that aren't accounted split alloc_file() and parts of alloc_file_pseudo() into helpers. One to prepare a path, another one to setup the file. Suggested-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20240129160241.GA2793@lst.de Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-16ima: Move to LSM infrastructureRoberto Sassu1-2/+0
Move hardcoded IMA function calls (not appraisal-specific functions) from various places in the kernel to the LSM infrastructure, by introducing a new LSM named 'ima' (at the end of the LSM list and always enabled like 'integrity'). Having IMA before EVM in the Makefile is sufficient to preserve the relative order of the new 'ima' LSM in respect to the upcoming 'evm' LSM, and thus the order of IMA and EVM function calls as when they were hardcoded. Make moved functions as static (except ima_post_key_create_or_update(), which is not in ima_main.c), and register them as implementation of the respective hooks in the new function init_ima_lsm(). Select CONFIG_SECURITY_PATH, to ensure that the path-based LSM hook path_post_mknod is always available and ima_post_path_mknod() is always executed to mark files as new, as before the move. A slight difference is that IMA and EVM functions registered for the inode_post_setattr, inode_post_removexattr, path_post_mknod, inode_post_create_tmpfile, inode_post_set_acl and inode_post_remove_acl won't be executed for private inodes. Since those inodes are supposed to be fs-internal, they should not be of interest to IMA or EVM. The S_PRIVATE flag is used for anonymous inodes, hugetlbfs, reiserfs xattrs, XFS scrub and kernel-internal tmpfs files. Conditionally register ima_post_key_create_or_update() if CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS is enabled. Also, conditionally register ima_kernel_module_request() if CONFIG_INTEGRITY_ASYMMETRIC_KEYS is enabled. Finally, add the LSM_ID_IMA case in lsm_list_modules_test.c. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Acked-by: Chuck Lever <chuck.lever@oracle.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-16security: Introduce file_release hookRoberto Sassu1-0/+1
In preparation for moving IMA and EVM to the LSM infrastructure, introduce the file_release hook. IMA calculates at file close the new digest of the file content and writes it to security.ima, so that appraisal at next file access succeeds. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Acked-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-01-12Merge tag 'pull-dcache' of ↵Linus Torvalds1-5/+0
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull dcache updates from Al Viro: "Change of locking rules for __dentry_kill(), regularized refcounting rules in that area, assorted cleanups and removal of weird corner cases (e.g. now ->d_iput() on child is always called before the parent might hit __dentry_kill(), etc)" * tag 'pull-dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (40 commits) dcache: remove unnecessary NULL check in dget_dlock() kill DCACHE_MAY_FREE __d_unalias() doesn't use inode argument d_alloc_parallel(): in-lookup hash insertion doesn't need an RCU variant get rid of DCACHE_GENOCIDE d_genocide(): move the extern into fs/internal.h simple_fill_super(): don't bother with d_genocide() on failure nsfs: use d_make_root() d_alloc_pseudo(): move setting ->d_op there from the (sole) caller kill d_instantate_anon(), fold __d_instantiate_anon() into remaining caller retain_dentry(): introduce a trimmed-down lockless variant __dentry_kill(): new locking scheme d_prune_aliases(): use a shrink list switch select_collect{,2}() to use of to_shrink_list() to_shrink_list(): call only if refcount is 0 fold dentry_kill() into dput() don't try to cut corners in shrink_lock_dentry() fold the call of retain_dentry() into fast_dput() Call retain_dentry() with refcount 0 dentry_kill(): don't bother with retain_dentry() on slow path ...
2024-01-11Merge tag 'sysctl-6.8-rc1' of ↵Linus Torvalds1-1/+0
git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux Pull sysctl updates from Luis Chamberlain: "To help make the move of sysctls out of kernel/sysctl.c not incur a size penalty sysctl has been changed to allow us to not require the sentinel, the final empty element on the sysctl array. Joel Granados has been doing all this work. In the v6.6 kernel we got the major infrastructure changes required to support this. For v6.7 we had all arch/ and drivers/ modified to remove the sentinel. For v6.8-rc1 we get a few more updates for fs/ directory only. The kernel/ directory is left but we'll save that for v6.9-rc1 as those patches are still being reviewed. After that we then can expect also the removal of the no longer needed check for procname == NULL. Let us recap the purpose of this work: - this helps reduce the overall build time size of the kernel and run time memory consumed by the kernel by about ~64 bytes per array - the extra 64-byte penalty is no longer inncurred now when we move sysctls out from kernel/sysctl.c to their own files Thomas Weißschuh also sent a few cleanups, for v6.9-rc1 we expect to see further work by Thomas Weißschuh with the constificatin of the struct ctl_table. Due to Joel Granados's work, and to help bring in new blood, I have suggested for him to become a maintainer and he's accepted. So for v6.9-rc1 I look forward to seeing him sent you a pull request for further sysctl changes. This also removes Iurii Zaikin as a maintainer as he has moved on to other projects and has had no time to help at all" * tag 'sysctl-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: sysctl: remove struct ctl_path sysctl: delete unused define SYSCTL_PERM_EMPTY_DIR coda: Remove the now superfluous sentinel elements from ctl_table array sysctl: Remove the now superfluous sentinel elements from ctl_table array fs: Remove the now superfluous sentinel elements from ctl_table array cachefiles: Remove the now superfluous sentinel element from ctl_table array sysclt: Clarify the results of selftest run sysctl: Add a selftest for handling empty dirs sysctl: Fix out of bounds access for empty sysctl registers MAINTAINERS: Add Joel Granados as co-maintainer for proc sysctl MAINTAINERS: remove Iurii Zaikin from proc sysctl
2023-12-28fs: Remove the now superfluous sentinel elements from ctl_table arrayJoel Granados1-1/+0
This commit comes at the tail end of a greater effort to remove the empty elements at the end of the ctl_table arrays (sentinels) which will reduce the overall build time size of the kernel and run time memory bloat by ~64 bytes per sentinel (further information Link : https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/) Remove sentinel elements ctl_table struct. Special attention was placed in making sure that an empty directory for fs/verity was created when CONFIG_FS_VERITY_BUILTIN_SIGNATURES is not defined. In this case we use the register sysctl call that expects a size. Signed-off-by: Joel Granados <j.granados@samsung.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-12-12fs: replace f_rcuhead with f_task_workChristian Brauner1-3/+3
The naming is actively misleading since we switched to SLAB_TYPESAFE_BY_RCU. rcu_head is #define callback_head. Use callback_head directly and rename f_rcuhead to f_task_work. Add comments in there to explain what it's used for. Link: https://lore.kernel.org/r/20231130-vfs-files-fixes-v1-3-e73ca6f4ea83@kernel.org Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-12file: massage cleanup of files that failed to openAl Viro1-12/+4
A file that has never gotten FMODE_OPENED will never have RCU-accessed references, its final fput() is equivalent to file_free() and if it doesn't have FMODE_BACKING either, it can be done from any context and won't need task_work treatment. Now that we have SLAB_TYPESAFE_BY_RCU we can simplify this and have other callers benefit. All of that can be achieved easier is to make fput() recoginze that case and call file_free() directly. No need to introduce a special primitive for that. It also allowed things like failing dentry_open() could benefit from that as well. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> [Christian Brauner <brauner@kernel.org>: massage commit message] Link: https://lore.kernel.org/r/20231126020834.GC38156@ZenIV Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-11-25d_alloc_pseudo(): move setting ->d_op there from the (sole) callerAl Viro1-5/+0
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2023-11-03Merge tag 'mm-nonmm-stable-2023-11-02-14-08' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull non-MM updates from Andrew Morton: "As usual, lots of singleton and doubleton patches all over the tree and there's little I can say which isn't in the individual changelogs. The lengthier patch series are - 'kdump: use generic functions to simplify crashkernel reservation in arch', from Baoquan He. This is mainly cleanups and consolidation of the 'crashkernel=' kernel parameter handling - After much discussion, David Laight's 'minmax: Relax type checks in min() and max()' is here. Hopefully reduces some typecasting and the use of min_t() and max_t() - A group of patches from Oleg Nesterov which clean up and slightly fix our handling of reads from /proc/PID/task/... and which remove task_struct.thread_group" * tag 'mm-nonmm-stable-2023-11-02-14-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (64 commits) scripts/gdb/vmalloc: disable on no-MMU scripts/gdb: fix usage of MOD_TEXT not defined when CONFIG_MODULES=n .mailmap: add address mapping for Tomeu Vizoso mailmap: update email address for Claudiu Beznea tools/testing/selftests/mm/run_vmtests.sh: lower the ptrace permissions .mailmap: map Benjamin Poirier's address scripts/gdb: add lx_current support for riscv ocfs2: fix a spelling typo in comment proc: test ProtectionKey in proc-empty-vm test proc: fix proc-empty-vm test with vsyscall fs/proc/base.c: remove unneeded semicolon do_io_accounting: use sig->stats_lock do_io_accounting: use __for_each_thread() ocfs2: replace BUG_ON() at ocfs2_num_free_extents() with ocfs2_error() ocfs2: fix a typo in a comment scripts/show_delta: add __main__ judgement before main code treewide: mark stuff as __ro_after_init fs: ocfs2: check status values proc: test /proc/${pid}/statm compiler.h: move __is_constexpr() to compiler.h ...
2023-10-19fs: store real path instead of fake path in backing file f_pathAmir Goldstein1-6/+6
A backing file struct stores two path's, one "real" path that is referring to f_inode and one "fake" path, which should be displayed to users in /proc/<pid>/maps. There is a lot more potential code that needs to know the "real" path, then code that needs to know the "fake" path. Instead of code having to request the "real" path with file_real_path(), store the "real" path in f_path and require code that needs to know the "fake" path request it with file_user_path(). Replace the file_real_path() helper with a simple const accessor f_path(). After this change, file_dentry() is not expected to observe any files with overlayfs f_path and real f_inode, so the call to ->d_real() should not be needed. Leave the ->d_real() call for now and add an assertion in ovl_d_real() to catch if we made wrong assumptions. Suggested-by: Miklos Szeredi <miklos@szeredi.hu> Link: https://lore.kernel.org/r/CAJfpegtt48eXhhjDFA1ojcHPNKj3Go6joryCPtEFAKpocyBsnw@mail.gmail.com/ Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231009153712.1566422-4-amir73il@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-19backing file: free directlyChristian Brauner1-8/+1
Backing files as used by overlayfs are never installed into file descriptor tables and are explicitly documented as such. They aren't subject to rcu access conditions like regular files are. Their lifetime is bound to the lifetime of the overlayfs file, i.e., they're stashed in ovl_file->private_data and go away otherwise. If they're set as vma->vm_file - which is their main purpose - then they're subject to regular refcount rules and vma->vm_file can't be installed into an fdtable after having been set. All in all I don't see any need for rcu delay here. So free it directly. This all hinges on such hybrid beasts to never actually be installed into fdtables which - as mentioned before - is not allowed. So add an explicit WARN_ON_ONCE() so we catch any case where someone is suddenly trying to install one of those things into a file descriptor table so we can have a nice long chat with them. Link: https://lore.kernel.org/r/20231005-sakralbau-wappnen-f5c31755ed70@brauner Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-19file: convert to SLAB_TYPESAFE_BY_RCUChristian Brauner1-17/+23
In recent discussions around some performance improvements in the file handling area we discussed switching the file cache to rely on SLAB_TYPESAFE_BY_RCU which allows us to get rid of call_rcu() based freeing for files completely. This is a pretty sensitive change overall but it might actually be worth doing. The main downside is the subtlety. The other one is that we should really wait for Jann's patch to land that enables KASAN to handle SLAB_TYPESAFE_BY_RCU UAFs. Currently it doesn't but a patch for this exists. With SLAB_TYPESAFE_BY_RCU objects may be freed and reused multiple times which requires a few changes. So it isn't sufficient anymore to just acquire a reference to the file in question under rcu using atomic_long_inc_not_zero() since the file might have already been recycled and someone else might have bumped the reference. In other words, callers might see reference count bumps from newer users. For this reason it is necessary to verify that the pointer is the same before and after the reference count increment. This pattern can be seen in get_file_rcu() and __files_get_rcu(). In addition, it isn't possible to access or check fields in struct file without first aqcuiring a reference on it. Not doing that was always very dodgy and it was only usable for non-pointer data in struct file. With SLAB_TYPESAFE_BY_RCU it is necessary that callers first acquire a reference under rcu or they must hold the files_lock of the fdtable. Failing to do either one of this is a bug. Thanks to Jann for pointing out that we need to ensure memory ordering between reallocations and pointer check by ensuring that all subsequent loads have a dependency on the second load in get_file_rcu() and providing a fixup that was folded into this patch. Cc: Jann Horn <jannh@google.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-19vfs: shave work on failed file openMateusz Guzik1-0/+12
Failed opens (mostly ENOENT) legitimately happen a lot, for example here are stats from stracing kernel build for few seconds (strace -fc make): % time seconds usecs/call calls errors syscall ------ ----------- ----------- --------- --------- ------------------ 0.76 0.076233 5 15040 3688 openat (this is tons of header files tried in different paths) In the common case of there being nothing to close (only the file object to free) there is a lot of overhead which can be avoided. This is most notably delegation of freeing to task_work, which comes with an enormous cost (see 021a160abf62 ("fs: use __fput_sync in close(2)" for an example). Benchmarked with will-it-scale with a custom testcase based on tests/open1.c, stuffed into tests/openneg.c: [snip] while (1) { int fd = open("/tmp/nonexistent", O_RDONLY); assert(fd == -1); (*iterations)++; } [/snip] Sapphire Rapids, openneg_processes -t 1 (ops/s): before: 1950013 after: 2914973 (+49%) file refcount is checked as a safety belt against buggy consumers with an atomic cmpxchg. Technically it is not necessary, but it happens to not be measurable due to several other atomics which immediately follow. Optmizing them away to make this atomic into a problem is left as an exercise for the reader. v2: - unexport fput_badopen and move to fs/internal.h - handle the refcount with cmpxchg, adjust commentary accordingly - tweak the commit message Signed-off-by: Mateusz Guzik <mjguzik@gmail.com> Link: https://lore.kernel.org/r/20230926162228.68666-1-mjguzik@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-19treewide: mark stuff as __ro_after_initAlexey Dobriyan1-1/+1
__read_mostly predates __ro_after_init. Many variables which are marked __read_mostly should have been __ro_after_init from day 1. Also, mark some stuff as "const" and "__init" while I'm at it. [akpm@linux-foundation.org: revert sysctl_nr_open_min, sysctl_nr_open_max changes due to arm warning] [akpm@linux-foundation.org: coding-style cleanups] Link: https://lkml.kernel.org/r/4f6bb9c0-abba-4ee4-a7aa-89265e886817@p183 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-08fs: use __fput_sync in close(2)Linus Torvalds1-4/+1
close(2) is a special case which guarantees a shallow kernel stack, making delegation to task_work machinery unnecessary. Said delegation is problematic as it involves atomic ops and interrupt masking trips, none of which are cheap on x86-64. Forcing close(2) to do it looks like an oversight in the original work. Moreover presence of CONFIG_RSEQ adds an additional overhead as fput() -> task_work_add(..., TWA_RESUME) -> set_notify_resume() makes the thread returning to userspace land in resume_user_mode_work(), where rseq_handle_notify_resume takes a SMAP round-trip if rseq is enabled for the thread (and it is by default with contemporary glibc). Sample result when benchmarking open1_processes -t 1 from will-it-scale (that's an open + close loop) + tmpfs on /tmp, running on the Sapphire Rapid CPU (ops/s): stock+RSEQ: 1329857 stock-RSEQ: 1421667 (+7%) patched: 1523521 (+14.5% / +7%) (with / without rseq) Patched result is the same regardless of rseq as the codepath is avoided. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-07-02fs: move cleanup from init_file() into its callersAmir Goldstein1-4/+10
The use of file_free_rcu() in init_file() to free the struct that was allocated by the caller was hacky and we got what we deserved. Let init_file() and its callers take care of cleaning up each after their own allocated resources on error. Fixes: 62d53c4a1dfe ("fs: use backing_file container for internal files with "fake" f_path") # mainline only Reported-and-tested-by: syzbot+ada42aab05cf51b00e98@syzkaller.appspotmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com> Message-Id: <20230701171134.239409-1-amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-06-19fs: use backing_file container for internal files with "fake" f_pathAmir Goldstein1-2/+48
Overlayfs uses open_with_fake_path() to allocate internal kernel files, with a "fake" path - whose f_path is not on the same fs as f_inode. Allocate a container struct backing_file for those internal files, that is used to hold the "fake" ovl path along with the real path. backing_file_real_path() can be used to access the stored real path. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Message-Id: <20230615112229.2143178-5-amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-06-19fs: move kmem_cache_zalloc() into alloc_empty_file*() helpersAmir Goldstein1-15/+26
Use a common helper init_file() instead of __alloc_file() for alloc_empty_file*() helpers and improrve the documentation. This is needed for a follow up patch that allocates a backing_file container. Suggested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Message-Id: <20230615112229.2143178-4-amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-01-11filelock: move file locking definitions to separate header fileJeff Layton1-0/+1
The file locking definitions have lived in fs.h since the dawn of time, but they are only used by a small subset of the source files that include it. Move the file locking definitions to a new header file, and add the appropriate #include directives to the source files that need them. By doing this we trim down fs.h a bit and limit the amount of rebuilding that has to be done when we make changes to the file locking APIs. Reviewed-by: Xiubo Li <xiubli@redhat.com> Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: David Howells <dhowells@redhat.com> Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Acked-by: Chuck Lever <chuck.lever@oracle.com> Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com> Acked-by: Steve French <stfrench@microsoft.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Jeff Layton <jlayton@kernel.org>
2022-08-16locks: fix TOCTOU race when granting write leaseAmir Goldstein1-6/+1
Thread A trying to acquire a write lease checks the value of i_readcount and i_writecount in check_conflicting_open() to verify that its own fd is the only fd referencing the file. Thread B trying to open the file for read will call break_lease() in do_dentry_open() before incrementing i_readcount, which leaves a small window where thread A can acquire the write lease and then thread B completes the open of the file for read without breaking the write lease that was acquired by thread A. Fix this race by incrementing i_readcount before checking for existing leases, same as the case with i_writecount. Use a helper put_file_access() to decrement i_readcount or i_writecount in do_dentry_open() and __fput(). Fixes: 387e3746d01c ("locks: eliminate false positive conflicts for write lease") Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2022-08-03Merge tag 'pull-work.iov_iter-base' of ↵Linus Torvalds1-8/+9
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs iov_iter updates from Al Viro: "Part 1 - isolated cleanups and optimizations. One of the goals is to reduce the overhead of using ->read_iter() and ->write_iter() instead of ->read()/->write(). new_sync_{read,write}() has a surprising amount of overhead, in particular inside iocb_flags(). That's the explanation for the beginning of the series is in this pile; it's not directly iov_iter-related, but it's a part of the same work..." * tag 'pull-work.iov_iter-base' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: first_iovec_segment(): just return address iov_iter: massage calling conventions for first_{iovec,bvec}_segment() iov_iter: first_{iovec,bvec}_segment() - simplify a bit iov_iter: lift dealing with maxpages out of first_{iovec,bvec}_segment() iov_iter_get_pages{,_alloc}(): cap the maxsize with MAX_RW_COUNT iov_iter_bvec_advance(): don't bother with bvec_iter copy_page_{to,from}_iter(): switch iovec variants to generic keep iocb_flags() result cached in struct file iocb: delay evaluation of IS_SYNC(...) until we want to check IOCB_DSYNC struct file: use anonymous union member for rcuhead and llist btrfs: use IOMAP_DIO_NOSYNC teach iomap_dio_rw() to suppress dsync No need of likely/unlikely on calls of check_copy_size()
2022-07-16fs: remove no_llseekJason A. Donenfeld1-1/+1
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>
2022-07-16fs: clear or set FMODE_LSEEK based on llseek functionJason A. Donenfeld1-0/+2
Pipe-like behaviour on llseek(2) (i.e. unconditionally failing with -ESPIPE) can be expresses in 3 ways: 1) ->llseek set to NULL in file_operations 2) ->llseek set to no_llseek in file_operations 3) FMODE_LSEEK *not* set in ->f_mode. Enforce (3) in cases (1) and (2); that will allow to simplify the checks and eventually get rid of no_llseek boilerplate. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2022-06-10keep iocb_flags() result cached in struct fileAl Viro1-0/+1
* calculate at the time we set FMODE_OPENED (do_dentry_open() for normal opens, alloc_file() for pipe()/socket()/etc.) * update when handling F_SETFL * keep in a new field - file->f_iocb_flags; since that thing is needed only before the refcount reaches zero, we can put it into the same anon union where ->f_rcuhead and ->f_llist live - those are used only after refcount reaches zero. Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2022-06-10struct file: use anonymous union member for rcuhead and llistAl Viro1-8/+8
Once upon a time we couldn't afford anon unions; these days minimal gcc version had been raised enough to take care of that. Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2022-06-05Merge tag 'pull-18-rc1-work.fd' of ↵Linus Torvalds1-7/+2
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull file descriptor updates from Al Viro. - Descriptor handling cleanups * tag 'pull-18-rc1-work.fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: Unify the primitives for file descriptor closing fs: remove fget_many and fput_many interface io_uring_enter(): don't leave f.flags uninitialized
2022-05-15fs: remove fget_many and fput_many interfaceGou Hao1-7/+2
These two interface were added in 091141a42 commit, but now there is no place to call them. The only user of fput/fget_many() was removed in commit 62906e89e63b ("io_uring: remove file batch-get optimisation"). A user of get_file_rcu_many() were removed in commit f073531070d2 ("init: add an init_dup helper"). And replace atomic_long_sub/add to atomic_long_dec/inc can improve performance. Here are the test results of unixbench: Cmd: ./Run -c 64 context1 Without patch: System Benchmarks Partial Index BASELINE RESULT INDEX Pipe-based Context Switching 4000.0 2798407.0 6996.0 ======== System Benchmarks Index Score (Partial Only) 6996.0 With patch: System Benchmarks Partial Index BASELINE RESULT INDEX Pipe-based Context Switching 4000.0 3486268.8 8715.7 ======== System Benchmarks Index Score (Partial Only) 8715.7 Signed-off-by: Gou Hao <gouhao@uniontech.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2022-04-07SUNRPC: Ensure we flush any closed sockets before xs_xprt_free()Trond Myklebust1-0/+1
We must ensure that all sockets are closed before we call xprt_free() and release the reference to the net namespace. The problem is that calling fput() will defer closing the socket until delayed_fput() gets called. Let's fix the situation by allowing rpciod and the transport teardown code (which runs on the system wq) to call __fput_sync(), and directly close the socket. Reported-by: Felix Fu <foyjog@gmail.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Fixes: a73881c96d73 ("SUNRPC: Fix an Oops in udp_poll()") Cc: stable@vger.kernel.org # 5.1.x: 3be232f11a3c: SUNRPC: Prevent immediate close+reconnect Cc: stable@vger.kernel.org # 5.1.x: 89f42494f92f: SUNRPC: Don't call connect() more than once on a TCP socket Cc: stable@vger.kernel.org # 5.1.x Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-02-17fs/file_table: fix adding missing kmemleak_not_leak()Luis Chamberlain1-2/+6
Commit b42bc9a3c511 ("Fix regression due to "fs: move binfmt_misc sysctl to its own file") fixed a regression, however it failed to add a kmemleak_not_leak(). Fixes: b42bc9a3c511 ("Fix regression due to "fs: move binfmt_misc sysctl to its own file") Reported-by: Tong Zhang <ztong0001@gmail.com> Cc: Tong Zhang <ztong0001@gmail.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-02-09Fix regression due to "fs: move binfmt_misc sysctl to its own file"Domenico Andreoli1-0/+2
Commit 3ba442d5331f ("fs: move binfmt_misc sysctl to its own file") did not go unnoticed, binfmt-support stopped to work on my Debian system since v5.17-rc2 (did not check with -rc1). The existance of the /proc/sys/fs/binfmt_misc is a precondition for attempting to mount the binfmt_misc fs, which in turn triggers the autoload of the binfmt_misc module. Without it, no module is loaded and no binfmt is available at boot. Building as built-in or manually loading the module and mounting the fs works fine, it's therefore only a matter of interaction with user-space. I could try to improve the Debian systemd configuration but I can't say anything about the other distributions. This patch restores a working system right after boot. Fixes: 3ba442d5331f ("fs: move binfmt_misc sysctl to its own file") Signed-off-by: Domenico Andreoli <domenico.andreoli@linux.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Tong Zhang <ztong0001@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-01-22fs: move fs stat sysctls to file_table.cLuis Chamberlain1-8/+39
kernel/sysctl.c is a kitchen sink where everyone leaves their dirty dishes, this makes it very difficult to maintain. To help with this maintenance let's start by moving sysctls to places where they actually belong. The proc sysctl maintainers do not want to know what sysctl knobs you wish to add for your own piece of code, we just care about the core logic. We can create the sysctl dynamically on early init for fs stat to help with this clutter. This dusts off the fs stat syctls knobs and puts them into where they are declared. Link: https://lkml.kernel.org/r/20211129205548.605569-3-mcgrof@kernel.org Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Antti Palosaari <crope@iki.fi> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Iurii Zaikin <yzaikin@google.com> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Jeff Layton <jlayton@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Lukas Middendorf <kernel@tuxforce.de> Cc: Stephen Kitt <steve@sk2.org> Cc: Xiaoming Ni <nixiaoming@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-26epoll: take epitem list out of struct fileAl Viro1-1/+0
Move the head of epitem list out of struct file; for epoll ones it's moved into struct eventpoll (->refs there), for non-epoll - into the new object (struct epitem_head). In place of ->f_ep_links we leave a pointer to the list head (->f_ep). ->f_ep is protected by ->f_lock and it's zeroed as soon as the list of epitems becomes empty (that can happen only in ep_remove() by now). The list of files for reverse path check is *not* going through struct file now - it's a single-linked list going through epitem_head instances. It's terminated by ERR_PTR(-1) (== EP_UNACTIVE_POINTER), so the elements of list can be distinguished by head->next != NULL. epitem_head instances are allocated at ep_insert() time (by attach_epitem()) and freed either by ep_remove() (if it empties the set of epitems *and* epitem_head does not belong to the reverse path check list) or by clear_tfile_check_list() when the list is emptied (if the set of epitems is empty by that point). Allocations are done from a separate slab - minimal kmalloc() size is too large on some architectures. As the result, we trim struct file _and_ get rid of the games with temporary file references. Locking and barriers are interesting (aren't they always); see unlist_file() and ep_remove() for details. The non-obvious part is that ep_remove() needs to decide if it will be the one to free the damn thing *before* actually storing NULL to head->epitems.first - that's what smp_load_acquire is for in there. unlist_file() lockless path is safe, since we hit it only if we observe NULL in head->epitems.first and whoever had done that store is guaranteed to have observed non-NULL in head->next. IOW, their last access had been the store of NULL into ->epitems.first and we can safely free the sucker. OTOH, we are under rcu_read_lock() and both epitem and epitem->file have their freeing RCU-delayed. So if we see non-NULL ->epitems.first, we can grab ->f_lock (all epitems in there share the same struct file) and safely recheck the emptiness of ->epitems; again, ->next is still non-NULL, so ep_remove() couldn't have freed head yet. ->f_lock serializes us wrt ep_remove(); the rest is trivial. Note that once head->epitems becomes NULL, nothing can get inserted into it - the only remaining reference to head after that point is from the reverse path check list. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-10-18task_work: cleanup notification modesJens Axboe1-1/+1
A previous commit changed the notification mode from true/false to an int, allowing notify-no, notify-yes, or signal-notify. This was backwards compatible in the sense that any existing true/false user would translate to either 0 (on notification sent) or 1, the latter which mapped to TWA_RESUME. TWA_SIGNAL was assigned a value of 2. Clean this up properly, and define a proper enum for the notification mode. Now we have: - TWA_NONE. This is 0, same as before the original change, meaning no notification requested. - TWA_RESUME. This is 1, same as before the original change, meaning that we use TIF_NOTIFY_RESUME. - TWA_SIGNAL. This uses TIF_SIGPENDING/JOBCTL_TASK_WORK for the notification. Clean up all the callers, switching their 0/1/false/true to using the appropriate TWA_* mode for notifications. Fixes: e91b48162332 ("task_work: teach task_work_add() to do signal_wake_up()") Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-29Revert "fs: Do not check if there is a fsnotify watcher on pseudo inodes"Mel Gorman1-1/+1
This reverts commit e9c15badbb7b ("fs: Do not check if there is a fsnotify watcher on pseudo inodes"). The commit intended to eliminate fsnotify-related overhead for pseudo inodes but it is broken in concept. inotify can receive events of pipe files under /proc/X/fd and chromium relies on close and open events for sandboxing. Maxim Levitsky reported the following Chromium starts as a white rectangle, shows few white rectangles that resemble its notifications and then crashes. The stdout output from chromium: [mlevitsk@starship ~]$chromium-freeworld mesa: for the --simplifycfg-sink-common option: may only occur zero or one times! mesa: for the --global-isel-abort option: may only occur zero or one times! [3379:3379:0628/135151.440930:ERROR:browser_switcher_service.cc(238)] XXX Init() ../../sandbox/linux/seccomp-bpf-helpers/sigsys_handlers.cc:**CRASHING**:seccomp-bpf failure in syscall 0072 Received signal 11 SEGV_MAPERR 0000004a9048 Crashes are not universal but even if chromium does not crash, it certainly does not work properly. While filtering just modify and access might be safe, the benefit is not worth the risk hence the revert. Reported-by: Maxim Levitsky <mlevitsk@redhat.com> Fixes: e9c15badbb7b ("fs: Do not check if there is a fsnotify watcher on pseudo inodes") Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-16fs: Do not check if there is a fsnotify watcher on pseudo inodesMel Gorman1-1/+1
The kernel uses internal mounts created by kern_mount() and populated with files with no lookup path by alloc_file_pseudo() for a variety of reasons. An example of such a mount is for anonymous pipes. For pipes, every vfs_write() regardless of filesystem, calls fsnotify_modify() to notify of any changes which incurs a small amount of overhead in fsnotify even when there are no watchers. It can also trigger for reads and readv and writev, it was simply vfs_write() that was noticed first. A patch is pending that reduces, but does not eliminate, the overhead of fsnotify but for files that cannot be looked up via a path, even that small overhead is unnecessary. The user API for all notification subsystems (inotify, fanotify, ...) is based on the pathname and a dirfd and proc entries appear to be the only visible representation of the files. Proc does not have the same pathname as the internal entry and the proc inode is not the same as the internal inode so even if fanotify is used on a file under /proc/XX/fd, no useful events are notified. This patch changes alloc_file_pseudo() to always opt out of fsnotify by setting FMODE_NONOTIFY flag so that no check is made for fsnotify watchers on pseudo files. This should be safe as the underlying helper for the dentry is d_alloc_pseudo() which explicitly states that no lookups are ever performed meaning that fanotify should have nothing useful to attach to. The test motivating this was "perf bench sched messaging --pipe". On a single-socket machine using threads the difference of the patch was as follows. 5.7.0 5.7.0 vanilla nofsnotify-v1r1 Amean 1 1.3837 ( 0.00%) 1.3547 ( 2.10%) Amean 3 3.7360 ( 0.00%) 3.6543 ( 2.19%) Amean 5 5.8130 ( 0.00%) 5.7233 * 1.54%* Amean 7 8.1490 ( 0.00%) 7.9730 * 2.16%* Amean 12 14.6843 ( 0.00%) 14.1820 ( 3.42%) Amean 18 21.8840 ( 0.00%) 21.7460 ( 0.63%) Amean 24 28.8697 ( 0.00%) 29.1680 ( -1.03%) Amean 30 36.0787 ( 0.00%) 35.2640 * 2.26%* Amean 32 38.0527 ( 0.00%) 38.1223 ( -0.18%) The difference is small but in some cases it's outside the noise so while marginal, there is still some small benefit to ignoring fsnotify for files allocated via alloc_file_pseudo() in some cases. Link: https://lore.kernel.org/r/20200615121358.GF3183@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
2020-06-04Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextLinus Torvalds1-2/+2
Pull networking updates from David Miller: 1) Allow setting bluetooth L2CAP modes via socket option, from Luiz Augusto von Dentz. 2) Add GSO partial support to igc, from Sasha Neftin. 3) Several cleanups and improvements to r8169 from Heiner Kallweit. 4) Add IF_OPER_TESTING link state and use it when ethtool triggers a device self-test. From Andrew Lunn. 5) Start moving away from custom driver versions, use the globally defined kernel version instead, from Leon Romanovsky. 6) Support GRO vis gro_cells in DSA layer, from Alexander Lobakin. 7) Allow hard IRQ deferral during NAPI, from Eric Dumazet. 8) Add sriov and vf support to hinic, from Luo bin. 9) Support Media Redundancy Protocol (MRP) in the bridging code, from Horatiu Vultur. 10) Support netmap in the nft_nat code, from Pablo Neira Ayuso. 11) Allow UDPv6 encapsulation of ESP in the ipsec code, from Sabrina Dubroca. Also add ipv6 support for espintcp. 12) Lots of ReST conversions of the networking documentation, from Mauro Carvalho Chehab. 13) Support configuration of ethtool rxnfc flows in bcmgenet driver, from Doug Berger. 14) Allow to dump cgroup id and filter by it in inet_diag code, from Dmitry Yakunin. 15) Add infrastructure to export netlink attribute policies to userspace, from Johannes Berg. 16) Several optimizations to sch_fq scheduler, from Eric Dumazet. 17) Fallback to the default qdisc if qdisc init fails because otherwise a packet scheduler init failure will make a device inoperative. From Jesper Dangaard Brouer. 18) Several RISCV bpf jit optimizations, from Luke Nelson. 19) Correct the return type of the ->ndo_start_xmit() method in several drivers, it's netdev_tx_t but many drivers were using 'int'. From Yunjian Wang. 20) Add an ethtool interface for PHY master/slave config, from Oleksij Rempel. 21) Add BPF iterators, from Yonghang Song. 22) Add cable test infrastructure, including ethool interfaces, from Andrew Lunn. Marvell PHY driver is the first to support this facility. 23) Remove zero-length arrays all over, from Gustavo A. R. Silva. 24) Calculate and maintain an explicit frame size in XDP, from Jesper Dangaard Brouer. 25) Add CAP_BPF, from Alexei Starovoitov. 26) Support terse dumps in the packet scheduler, from Vlad Buslov. 27) Support XDP_TX bulking in dpaa2 driver, from Ioana Ciornei. 28) Add devm_register_netdev(), from Bartosz Golaszewski. 29) Minimize qdisc resets, from Cong Wang. 30) Get rid of kernel_getsockopt and kernel_setsockopt in order to eliminate set_fs/get_fs calls. From Christoph Hellwig. * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2517 commits) selftests: net: ip_defrag: ignore EPERM net_failover: fixed rollback in net_failover_open() Revert "tipc: Fix potential tipc_aead refcnt leak in tipc_crypto_rcv" Revert "tipc: Fix potential tipc_node refcnt leak in tipc_rcv" vmxnet3: allow rx flow hash ops only when rss is enabled hinic: add set_channels ethtool_ops support selftests/bpf: Add a default $(CXX) value tools/bpf: Don't use $(COMPILE.c) bpf, selftests: Use bpf_probe_read_kernel s390/bpf: Use bcr 0,%0 as tail call nop filler s390/bpf: Maintain 8-byte stack alignment selftests/bpf: Fix verifier test selftests/bpf: Fix sample_cnt shared between two threads bpf, selftests: Adapt cls_redirect to call csum_level helper bpf: Add csum_level helper for fixing up csum levels bpf: Fix up bpf_skb_adjust_room helper's skb csum setting sfc: add missing annotation for efx_ef10_try_update_nic_stats_vf() crypto/chtls: IPv6 support for inline TLS Crypto/chcr: Fixes a coccinile check error Crypto/chcr: Fixes compilations warnings ...
2020-06-02vfs: track per-sb writeback errors and report them to syncfsJeff Layton1-0/+1
Patch series "vfs: have syncfs() return error when there are writeback errors", v6. Currently, syncfs does not return errors when one of the inodes fails to be written back. It will return errors based on the legacy AS_EIO and AS_ENOSPC flags when syncing out the block device fails, but that's not particularly helpful for filesystems that aren't backed by a blockdev. It's also possible for a stray sync to lose those errors. The basic idea in this set is to track writeback errors at the superblock level, so that we can quickly and easily check whether something bad happened without having to fsync each file individually. syncfs is then changed to reliably report writeback errors after they occur, much in the same fashion as fsync does now. This patch (of 2): Usually we suggest that applications call fsync when they want to ensure that all data written to the file has made it to the backing store, but that can be inefficient when there are a lot of open files. Calling syncfs on the filesystem can be more efficient in some situations, but the error reporting doesn't currently work the way most people expect. If a single inode on a filesystem reports a writeback error, syncfs won't necessarily return an error. syncfs only returns an error if __sync_blockdev fails, and on some filesystems that's a no-op. It would be better if syncfs reported an error if there were any writeback failures. Then applications could call syncfs to see if there are any errors on any open files, and could then call fsync on all of the other descriptors to figure out which one failed. This patch adds a new errseq_t to struct super_block, and has mapping_set_error also record writeback errors there. To report those errors, we also need to keep an errseq_t in struct file to act as a cursor. This patch adds a dedicated field for that purpose, which slots nicely into 4 bytes of padding at the end of struct file on x86_64. An earlier version of this patch used an O_PATH file descriptor to cue the kernel that the open file should track the superblock error and not the inode's writeback error. I think that API is just too weird though. This is simpler and should make syncfs error reporting "just work" even if someone is multiplexing fsync and syncfs on the same fds. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Andres Freund <andres@anarazel.de> Cc: Matthew Wilcox <willy@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: David Howells <dhowells@redhat.com> Link: http://lkml.kernel.org/r/20200428135155.19223-1-jlayton@kernel.org Link: http://lkml.kernel.org/r/20200428135155.19223-2-jlayton@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-27sysctl: pass kernel pointers to ->proc_handlerChristoph Hellwig1-2/+2
Instead of having all the sysctl handlers deal with user pointers, which is rather hairy in terms of the BPF interaction, copy the input to and from userspace in common code. This also means that the strings are always NUL-terminated by the common code, making the API a little bit safer. As most handler just pass through the data to one of the common handlers a lot of the changes are mechnical. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-08-19vfs: Export flush_delayed_fput for use by knfsd.Trond Myklebust1-0/+1
Allow knfsd to flush the delayed fput list so that it can ensure the cached struct file is closed before it is unlinked. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2019-05-21treewide: Add SPDX license identifier for missed filesThomas Gleixner1-0/+1
Add SPDX license identifiers to all files which: - Have no license information of any form - Have EXPORT_.*_SYMBOL_GPL inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-21vfs: syscall: Add open_tree(2) to reference or clone a mountAl Viro1-3/+6
open_tree(dfd, pathname, flags) Returns an O_PATH-opened file descriptor or an error. dfd and pathname specify the location to open, in usual fashion (see e.g. fstatat(2)). flags should be an OR of some of the following: * AT_PATH_EMPTY, AT_NO_AUTOMOUNT, AT_SYMLINK_NOFOLLOW - same meanings as usual * OPEN_TREE_CLOEXEC - make the resulting descriptor close-on-exec * OPEN_TREE_CLONE or OPEN_TREE_CLONE | AT_RECURSIVE - instead of opening the location in question, create a detached mount tree matching the subtree rooted at location specified by dfd/pathname. With AT_RECURSIVE the entire subtree is cloned, without it - only the part within in the mount containing the location in question. In other words, the same as mount --rbind or mount --bind would've taken. The detached tree will be dissolved on the final close of obtained file. Creation of such detached trees requires the same capabilities as doing mount --bind. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> cc: linux-api@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-02-28fs: add fget_many() and fput_many()Jens Axboe1-2/+7
Some uses cases repeatedly get and put references to the same file, but the only exposed interface is doing these one at the time. As each of these entail an atomic inc or dec on a shared structure, that cost can add up. Add fget_many(), which works just like fget(), except it takes an argument for how many references to get on the file. Ditto fput_many(), which can drop an arbitrary number of references to a file. Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-28mm: convert totalram_pages and totalhigh_pages variables to atomicArun KS1-1/+1
totalram_pages and totalhigh_pages are made static inline function. Main motivation was that managed_page_count_lock handling was complicating things. It was discussed in length here, https://lore.kernel.org/patchwork/patch/995739/#1181785 So it seemes better to remove the lock and convert variables to atomic, with preventing poteintial store-to-read tearing as a bonus. [akpm@linux-foundation.org: coding style fixes] Link: http://lkml.kernel.org/r/1542090790-21750-4-git-send-email-arunks@codeaurora.org Signed-off-by: Arun KS <arunks@codeaurora.org> Suggested-by: Michal Hocko <mhocko@suse.com> Suggested-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28mm: reference totalram_pages and managed_pages once per functionArun KS1-3/+4
Patch series "mm: convert totalram_pages, totalhigh_pages and managed pages to atomic", v5. This series converts totalram_pages, totalhigh_pages and zone->managed_pages to atomic variables. totalram_pages, zone->managed_pages and totalhigh_pages updates are protected by managed_page_count_lock, but readers never care about it. Convert these variables to atomic to avoid readers potentially seeing a store tear. Main motivation was that managed_page_count_lock handling was complicating things. It was discussed in length here, https://lore.kernel.org/patchwork/patch/995739/#1181785 It seemes better to remove the lock and convert variables to atomic. With the change, preventing poteintial store-to-read tearing comes as a bonus. This patch (of 4): This is in preparation to a later patch which converts totalram_pages and zone->managed_pages to atomic variables. Please note that re-reading the value might lead to a different value and as such it could lead to unexpected behavior. There are no known bugs as a result of the current code but it is better to prevent from them in principle. Link: http://lkml.kernel.org/r/1542090790-21750-2-git-send-email-arunks@codeaurora.org Signed-off-by: Arun KS <arunks@codeaurora.org> Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22Merge tag 'ovl-update-4.19' of ↵Linus Torvalds1-21/+48
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull overlayfs updates from Miklos Szeredi: "This contains two new features: - Stack file operations: this allows removal of several hacks from the VFS, proper interaction of read-only open files with copy-up, possibility to implement fs modifying ioctls properly, and others. - Metadata only copy-up: when file is on lower layer and only metadata is modified (except size) then only copy up the metadata and continue to use the data from the lower file" * tag 'ovl-update-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (66 commits) ovl: Enable metadata only feature ovl: Do not do metacopy only for ioctl modifying file attr ovl: Do not do metadata only copy-up for truncate operation ovl: add helper to force data copy-up ovl: Check redirect on index as well ovl: Set redirect on upper inode when it is linked ovl: Set redirect on metacopy files upon rename ovl: Do not set dentry type ORIGIN for broken hardlinks ovl: Add an inode flag OVL_CONST_INO ovl: Treat metacopy dentries as type OVL_PATH_MERGE ovl: Check redirects for metacopy files ovl: Move some dir related ovl_lookup_single() code in else block ovl: Do not expose metacopy only dentry from d_real() ovl: Open file with data except for the case of fsync ovl: Add helper ovl_inode_realdata() ovl: Store lower data inode in ovl_inode ovl: Fix ovl_getattr() to get number of blocks from lower ovl: Add helper ovl_dentry_lowerdata() to get lower data dentry ovl: Copy up meta inode data from lowest data inode ovl: Modify ovl_lookup() and friends to lookup metacopy dentry ...
2018-07-18vfs: make open_with_fake_path() not contribute to nr_filesMiklos Szeredi1-21/+48
Stacking file operations in overlay will store an extra open file for each overlay file opened. The overhead is just that of "struct file" which is about 256bytes, because overlay already pins an extra dentry and inode when the file is open, which add up to a much larger overhead. For fear of breaking working setups, don't start accounting the extra file. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-07-12make alloc_file() staticAl Viro1-2/+1
Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>