kernel/linux.git/fs/devpts, branch v6.6.132

Merge tag 'v6.6-vfs.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2023-08-28T17:17:14+00:00

Pull misc vfs updates from Christian Brauner: "This contains the usual miscellaneous features, cleanups, and fixes for vfs and individual filesystems. Features: - Block mode changes on symlinks and rectify our broken semantics - Report file modifications via fsnotify() for splice - Allow specifying an explicit timeout for the "rootwait" kernel command line option. This allows to timeout and reboot instead of always waiting indefinitely for the root device to show up - Use synchronous fput for the close system call Cleanups: - Get rid of open-coded lockdep workarounds for async io submitters and replace it all with a single consolidated helper - Simplify epoll allocation helper - Convert simple_write_begin and simple_write_end to use a folio - Convert page_cache_pipe_buf_confirm() to use a folio - Simplify __range_close to avoid pointless locking - Disable per-cpu buffer head cache for isolated cpus - Port ecryptfs to kmap_local_page() api - Remove redundant initialization of pointer buf in pipe code - Unexport the d_genocide() function which is only used within core vfs - Replace printk(KERN_ERR) and WARN_ON() with WARN() Fixes: - Fix various kernel-doc issues - Fix refcount underflow for eventfds when used as EFD_SEMAPHORE - Fix a mainly theoretical issue in devpts - Check the return value of __getblk() in reiserfs - Fix a racy assert in i_readcount_dec - Fix integer conversion issues in various functions - Fix LSM security context handling during automounts that prevented NFS superblock sharing" * tag 'v6.6-vfs.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (39 commits) cachefiles: use kiocb_{start,end}_write() helpers ovl: use kiocb_{start,end}_write() helpers aio: use kiocb_{start,end}_write() helpers io_uring: use kiocb_{start,end}_write() helpers fs: create kiocb_{start,end}_write() helpers fs: add kerneldoc to file_{start,end}_write() helpers io_uring: rename kiocb_end_write() local helper splice: Convert page_cache_pipe_buf_confirm() to use a folio libfs: Convert simple_write_begin and simple_write_end to use a folio fs/dcache: Replace printk and WARN_ON by WARN fs/pipe: remove redundant initialization of pointer buf fs: Fix kernel-doc warnings devpts: Fix kernel-doc warnings doc: idmappings: fix an error and rephrase a paragraph init: Add support for rootwait timeout parameter vfs: fix up the assert in i_readcount_dec fs: Fix one kernel-doc comment docs: filesystems: idmappings: clarify from where idmappings are taken fs/buffer.c: disable per-CPU buffer_head cache for isolated CPUs vfs, security: Fix automount superblock LSM init problem, preventing NFS sb sharing ...

devpts: Fix kernel-doc warnings

2023-08-19T10:11:10+00:00

This documentation has bit-rotted over time. Signed-off-by: "Matthew Wilcox (Oracle)" Message-Id: <20230818201003.2720257-1-willy@infradead.org> Signed-off-by: Christian Brauner

devpts: convert to ctime accessor functions

2023-07-13T08:28:06+00:00

In later patches, we're going to change how the inode's ctime field is used. Switch to using accessor functions instead of raw accesses of inode->i_ctime. Signed-off-by: Jeff Layton Reviewed-by: Jan Kara Message-Id: <20230705190309.579783-33-jlayton@kernel.org> Signed-off-by: Christian Brauner

devpts: simplify two-level sysctl registration for pty_kern_table

2023-03-13T11:36:34+00:00

There is no need to declare two tables to just create directories, this can be easily be done with a prefix path with register_sysctl(). Simplify this registration. Signed-off-by: Luis Chamberlain Signed-off-by: Christian Brauner (Microsoft)

fsnotify: fix fsnotify hooks in pseudo filesystems

2022-01-24T13:17:02+00:00

Commit 49246466a989 ("fsnotify: move fsnotify_nameremove() hook out of d_delete()") moved the fsnotify delete hook before d_delete() so fsnotify will have access to a positive dentry. This allowed a race where opening the deleted file via cached dentry is now possible after receiving the IN_DELETE event. To fix the regression in pseudo filesystems, convert d_delete() calls to d_drop() (see commit 46c46f8df9aa ("devpts_pty_kill(): don't bother with d_delete()") and move the fsnotify hook after d_drop(). Add a missing fsnotify_unlink() hook in nfsdfs that was found during the audit of fsnotify hooks in pseudo filesystems. Note that the fsnotify hooks in simple_recursive_removal() follow d_invalidate(), so they require no change. Link: https://lore.kernel.org/r/20220120215305.282577-2-amir73il@gmail.com Reported-by: Ivan Delalande Link: https://lore.kernel.org/linux-fsdevel/YeNyzoDM5hP5LtGW@visor/ Fixes: 49246466a989 ("fsnotify: move fsnotify_nameremove() hook out of d_delete()") Cc: stable@vger.kernel.org # v5.3+ Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara

devpts_pty_kill(): don't bother with d_delete()

2019-09-03T13:30:56+00:00

we are not retaining dentries there anyway (simple_dentry_operations), so d_delete()+dput() == d_drop()+dput() Signed-off-by: Al Viro

devpts: call fsnotify_unlink() hook

2019-06-20T12:46:34+00:00

This will allow generating fsnotify delete events after the fsnotify_nameremove() hook is removed from d_delete(). Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 83

2019-05-24T15:37:52+00:00

Based on 1 normalized pattern(s): this file is part of the linux kernel and is made available under the terms of the gnu general public license version 2 or at your option any later version incorporated herein by reference extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 18 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Richard Fontana Reviewed-by: Allison Randal Reviewed-by: Armijn Hemel Reviewed-by: Kate Stewart Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520075211.321157221@linutronix.de Signed-off-by: Greg Kroah-Hartman

treewide: Add SPDX license identifier - Makefile/Kconfig

2019-05-21T08:50:46+00:00

Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form 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 Signed-off-by: Greg Kroah-Hartman

fs/devpts: always delete dcache dentry-s in dput()

2019-01-24T18:38:30+00:00

d_delete only unhashes an entry if it is reached with dentry->d_lockref.count != 1. Prior to commit 8ead9dd54716 ("devpts: more pty driver interface cleanups"), d_delete was called on a dentry from devpts_pty_kill with two references held, which would trigger the unhashing, and the subsequent dputs would release it. Commit 8ead9dd54716 reworked devpts_pty_kill to stop acquiring the second reference from d_find_alias, and the d_delete call left the dentries still on the hashed list without actually ever being dropped from dcache before explicit cleanup. This causes the number of negative dentries for devpts to pile up, and an `ls /dev/pts` invocation can take seconds to return. Provide always_delete_dentry() from simple_dentry_operations as .d_delete for devpts, to make the dentry be dropped from dcache. Without this cleanup, the number of dentries in /dev/pts/ can be grown arbitrarily as: `python -c 'import pty; pty.spawn(["ls", "/dev/pts"])'` A systemtap probe on dcache_readdir to count d_subdirs shows this count to increase with each pty spawn invocation above: probe kernel.function("dcache_readdir") { subdirs = &@cast($file->f_path->dentry, "dentry")->d_subdirs; p = subdirs; p = @cast(p, "list_head")->next; i = 0 while (p != subdirs) { p = @cast(p, "list_head")->next; i = i+1; } printf("number of dentries: %d\n", i); } Fixes: 8ead9dd54716 ("devpts: more pty driver interface cleanups") Signed-off-by: Varad Gautam Reported-by: Zheng Wang Reported-by: Brandon Schwartz Root-caused-by: Maximilian Heyne Root-caused-by: Nicolas Pernas Maradei CC: David Woodhouse CC: Maximilian Heyne CC: Stefan Nuernberger CC: Amit Shah CC: Linus Torvalds CC: Greg Kroah-Hartman CC: Al Viro CC: Christian Brauner CC: Eric W. Biederman CC: Matthew Wilcox CC: Eric Biggers CC: # 4.9+ Signed-off-by: Al Viro