Merge tag 'vfs-6.14-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull misc vfs updates from Christian Brauner:
"Features:

- Support caching symlink lengths in inodes

Merge tag 'vfs-6.14-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull misc vfs updates from Christian Brauner:
"Features:

- Support caching symlink lengths in inodes

The size is stored in a new union utilizing the same space as
i_devices, thus avoiding growing the struct or taking up any more
space

When utilized it dodges strlen() in vfs_readlink(), giving about
1.5% speed up when issuing readlink on /initrd.img on ext4

- Add RWF_DONTCACHE iocb and FOP_DONTCACHE file_operations flag

If a file system supports uncached buffered IO, it may set
FOP_DONTCACHE and enable support for RWF_DONTCACHE.

If RWF_DONTCACHE is attempted without the file system supporting
it, it'll get errored with -EOPNOTSUPP

- Enable VBOXGUEST and VBOXSF_FS on ARM64

Now that VirtualBox is able to run as a host on arm64 (e.g. the
Apple M3 processors) we can enable VBOXSF_FS (and in turn
VBOXGUEST) for this architecture.

Tested with various runs of bonnie++ and dbench on an Apple MacBook
Pro with the latest Virtualbox 7.1.4 r165100 installed

Cleanups:

- Delay sysctl_nr_open check in expand_files()

- Use kernel-doc includes in fiemap docbook

- Use page->private instead of page->index in watch_queue

- Use a consume fence in mnt_idmap() as it's heavily used in
link_path_walk()

- Replace magic number 7 with ARRAY_SIZE() in fc_log

- Sort out a stale comment about races between fd alloc and dup2()

- Fix return type of do_mount() from long to int

- Various cosmetic cleanups for the lockref code

Fixes:

- Annotate spinning as unlikely() in __read_seqcount_begin

The annotation already used to be there, but got lost in commit
52ac39e5db51 ("seqlock: seqcount_t: Implement all read APIs as
statement expressions")

- Fix proc_handler for sysctl_nr_open

- Flush delayed work in delayed fput()

- Fix grammar and spelling in propagate_umount()

- Fix ESP not readable during coredump

In /proc/PID/stat, there is the kstkesp field which is the stack
pointer of a thread. While the thread is active, this field reads
zero. But during a coredump, it should have a valid value

However, at the moment, kstkesp is zero even during coredump

- Don't wake up the writer if the pipe is still full

- Fix unbalanced user_access_end() in select code"

* tag 'vfs-6.14-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (28 commits)
gfs2: use lockref_init for qd_lockref
erofs: use lockref_init for pcl->lockref
dcache: use lockref_init for d_lockref
lockref: add a lockref_init helper
lockref: drop superfluous externs
lockref: use bool for false/true returns
lockref: improve the lockref_get_not_zero description
lockref: remove lockref_put_not_zero
fs: Fix return type of do_mount() from long to int
select: Fix unbalanced user_access_end()
vbox: Enable VBOXGUEST and VBOXSF_FS on ARM64
pipe_read: don't wake up the writer if the pipe is still full
selftests: coredump: Add stackdump test
fs/proc: do_task_stat: Fix ESP not readable during coredump
fs: add RWF_DONTCACHE iocb and FOP_DONTCACHE file_operations flag
fs: sort out a stale comment about races between fd alloc and dup2
fs: Fix grammar and spelling in propagate_umount()
fs: fc_log replace magic number 7 with ARRAY_SIZE()
fs: use a consume fence in mnt_idmap()
file: flush delayed work in delayed fput()
...

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Merge patch series "fix reading ESP during coredump"

Nam Cao <namcao@linutronix.de> says:

In /proc/PID/stat, there is the kstkesp field which is the stack pointer of
a thread. While the thread is a

Merge patch series "fix reading ESP during coredump"

Nam Cao <namcao@linutronix.de> says:

In /proc/PID/stat, there is the kstkesp field which is the stack pointer of
a thread. While the thread is active, this field reads zero. But during a
coredump, it should have a valid value.

However, at the moment, kstkesp is zero even during coredump.

The first commit fixes this problem, and the second commit adds a selftest
to detect if this problem appears again in the future.

* patches from https://lore.kernel.org/r/cover.1735805772.git.namcao@linutronix.de:
selftests: coredump: Add stackdump test
fs/proc: do_task_stat: Fix ESP not readable during coredump

Link: https://lore.kernel.org/r/cover.1735805772.git.namcao@linutronix.de
Signed-off-by: Christian Brauner <brauner@kernel.org>

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selftests: coredump: Add stackdump test

Add a test which checks that the kstkesp field in /proc/pid/stat can be
read for all threads of a coredumping process.

For full details including the motivat

selftests: coredump: Add stackdump test

Add a test which checks that the kstkesp field in /proc/pid/stat can be
read for all threads of a coredumping process.

For full details including the motivation for this test and how it works,
see the README file added by this commit.

Reviewed-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/r/50e737b6576208566d14efcf1934fe840de6b1f4.1735805772.git.namcao@linutronix.de
Signed-off-by: Christian Brauner <brauner@kernel.org>

show more ...