kernel/linux.git/init/do_mounts.c, branch v6.19.11

Merge tag 'pull-persistency' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2025-12-05T22:36:21+00:00

Pull persistent dentry infrastructure and conversion from Al Viro: "Some filesystems use a kinda-sorta controlled dentry refcount leak to pin dentries of created objects in dcache (and undo it when removing those). A reference is grabbed and not released, but it's not actually _stored_ anywhere. That works, but it's hard to follow and verify; among other things, we have no way to tell _which_ of the increments is intended to be an unpaired one. Worse, on removal we need to decide whether the reference had already been dropped, which can be non-trivial if that removal is on umount and we need to figure out if this dentry is pinned due to e.g. unlink() not done. Usually that is handled by using kill_litter_super() as ->kill_sb(), but there are open-coded special cases of the same (consider e.g. /proc/self). Things get simpler if we introduce a new dentry flag (DCACHE_PERSISTENT) marking those "leaked" dentries. Having it set claims responsibility for +1 in refcount. The end result this series is aiming for: - get these unbalanced dget() and dput() replaced with new primitives that would, in addition to adjusting refcount, set and clear persistency flag. - instead of having kill_litter_super() mess with removing the remaining "leaked" references (e.g. for all tmpfs files that hadn't been removed prior to umount), have the regular shrink_dcache_for_umount() strip DCACHE_PERSISTENT of all dentries, dropping the corresponding reference if it had been set. After that kill_litter_super() becomes an equivalent of kill_anon_super(). Doing that in a single step is not feasible - it would affect too many places in too many filesystems. It has to be split into a series. This work has really started early in 2024; quite a few preliminary pieces have already gone into mainline. This chunk is finally getting to the meat of that stuff - infrastructure and most of the conversions to it. Some pieces are still sitting in the local branches, but the bulk of that stuff is here" * tag 'pull-persistency' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (54 commits) d_make_discardable(): warn if given a non-persistent dentry kill securityfs_recursive_remove() convert securityfs get rid of kill_litter_super() convert rust_binderfs convert nfsctl convert rpc_pipefs convert hypfs hypfs: swich hypfs_create_u64() to returning int hypfs: switch hypfs_create_str() to returning int hypfs: don't pin dentries twice convert gadgetfs gadgetfs: switch to simple_remove_by_name() convert functionfs functionfs: switch to simple_remove_by_name() functionfs: fix the open/removal races functionfs: need to cancel ->reset_work in ->kill_sb() functionfs: don't bother with ffs->ref in ffs_data_{opened,closed}() functionfs: don't abuse ffs_data_closed() on fs shutdown convert selinuxfs ...

convert ramfs and tmpfs

2025-11-16T06:35:02+00:00

Quite a bit is already done by infrastructure changes (simple_link(), simple_unlink()) - all that is left is replacing d_instantiate() + pinning dget() (in ->symlink() and ->mknod()) with d_make_persistent(), and, in case of shmem, using simple_unlink() and simple_link() in ->unlink() and ->link() resp., instead of open-coding those there. Since d_make_persistent() accepts (and hashes) unhashed ones, shmem situation gets simpler - we no longer care whether ->lookup() has hashed the sucker. With that done, we don't need kill_litter_super() for these filesystems anymore - by the umount time all remaining dentries will be marked persistent and kill_litter_super() will boil down to call of kill_anon_super(). The same goes for devtmpfs and rootfs - they are handled by ramfs or by shmem, depending upon config. NB: strictly speaking, both devtmpfs and rootfs ought to use ramfs_kill_sb() if they end up using ramfs; that's a separate story and the only impact of "just use kill_{litter,anon}_super()" is that we fail to free their sb->s_fs_info... on reboot. That's orthogonal to the changes in this series - kill_litter_super() is identical to kill_anon_super() for those at this point. Signed-off-by: Al Viro

init: Replace simple_strtoul() with kstrtouint() in root_delay_setup()

2025-11-05T11:49:38+00:00

Replace deprecated simple_strtoul() with kstrtouint() for better error handling and input validation. Return 0 on parsing failure to indicate invalid parameter, maintaining existing behavior for valid inputs. The simple_strtoul() function is deprecated in favor of kstrtoint() family functions which provide better error handling and are recommended for new code and replacements. Signed-off-by: Kaushlendra Kumar Link: https://patch.msgid.link/20251103080627.1844645-1-kaushlendra.kumar@intel.com Reviewed-by: Jan Kara Signed-off-by: Christian Brauner

init: replace deprecated strncpy with strscpy_pad

2024-04-30T17:34:29+00:00

strncpy() is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces. data_page wants to be NUL-terminated and NUL-padded, use strscpy_pad to provide both of these. data_page no longer awkwardly relies on init_mount to perform its NUL-termination, although that sanity check is left unchanged. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2] Link: https://github.com/KSPP/linux/issues/90 Cc: Signed-off-by: Justin Stitt Reviewed-by: Kees Cook Link: https://lore.kernel.org/r/20240402-strncpy-init-do_mounts-c-v1-1-e16d7bc20974@google.com Signed-off-by: Kees Cook

init: flush async file closing

2024-02-08T17:41:03+00:00

When unpacking the initramfs or when mounting block devices we need to ensure that any delayed fput() finished to prevent spurious errors. The init process can be a proper kernel thread or a user mode helper. In the latter case PF_KTHREAD isn't set. So we need to do both flush_delayed_work() and task_work_run(). Since we'll port block device opening and closing to regular file open and closing we need to ensure the same as for the initramfs. So just make that a little helper. Tested-by: Marek Szyprowski Tested-by: Srikanth Aithal Link: https://lore.kernel.org/r/CA+G9fYttTwsbFuVq10igbSvP5xC6bf_XijM=mpUqrJV=uvUirQ@mail.gmail.com Signed-off-by: Christian Brauner

rootfs: Fix support for rootfstype= when root= is given

2023-12-07T01:29:21+00:00

Documentation/filesystems/ramfs-rootfs-initramfs.rst states: If CONFIG_TMPFS is enabled, rootfs will use tmpfs instead of ramfs by default. To force ramfs, add "rootfstype=ramfs" to the kernel command line. This currently does not work when root= is provided since then saved_root_name contains a string and rootfstype= is ignored. Therefore, ramfs is currently always chosen when root= is provided. The current behavior for rootfs's filesystem is: root= | rootfstype= | chosen rootfs filesystem ------------+-------------+-------------------------- unspecified | unspecified | tmpfs unspecified | tmpfs | tmpfs unspecified | ramfs | ramfs provided | ignored | ramfs rootfstype= should be respected regardless whether root= is given, as shown below: root= | rootfstype= | chosen rootfs filesystem ------------+-------------+-------------------------- unspecified | unspecified | tmpfs (as before) unspecified | tmpfs | tmpfs (as before) unspecified | ramfs | ramfs (as before) provided | unspecified | ramfs (compatibility with before) provided | tmpfs | tmpfs (new) provided | ramfs | ramfs (new) This table represents the new behavior. Fixes: 6e19eded3684 ("initmpfs: use initramfs if rootfstype= or root= specified") Cc: Signed-off-by: Rob Landley Link: https://lore.kernel.org/lkml/8244c75f-445e-b15b-9dbf-266e7ca666e2@landley.net/ Reviewed-and-Tested-by: Mimi Zohar Signed-off-by: Stefan Berger Link: https://lore.kernel.org/r/20231120011248.396012-1-stefanb@linux.ibm.com Signed-off-by: Greg Kroah-Hartman

init/mount: print pretty name of root device when panics

2023-10-19T09:02:46+00:00

Given a wrong root device, current log may not give the pretty name which is useful to locate root cause. For example, there are 2 blk devs in a VM, /dev/vda which has 2 partitials /dev/vda1 and /dev/vda2 and /dev/vdb which is blank. /dev/vda2 is the right root dev. When set "root=/dev/vdb", we get error log: [ 0.635575] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(254,16) It's not straightforward to find out the root cause as there is lack of the root devive name therefore hard for people to get those info from the device number, in the example, (254,16). It is more comprehensive way to hint the root cause if pretty name is given here, like: [ 0.559887] Kernel panic - not syncing: VFS: Unable to mount root fs on "/dev/vdb" or unknown-block(254,16) Signed-off-by: Jianyong Wu Message-Id: <20230907091025.3436878-1-jianyong.wu@arm.com> Signed-off-by: Christian Brauner

init: Add support for rootwait timeout parameter

2023-08-15T09:34:23+00:00

Add an optional timeout arg to 'rootwait' as the maximum time in seconds to wait for the root device to show up before attempting forced mount of the root filesystem. Use case: In case of device mapper usage for the rootfs (e.g. root=/dev/dm-0), if the mapper is not able to create the virtual block for any reason (wrong arguments, bad dm-verity signature, etc), the `rootwait` param causes the kernel to wait forever. It may however be desirable to only wait for a given time and then panic (force mount) to cause device reset. This gives the bootloader a chance to detect the problem and to take some measures, such as marking the booted partition as bad (for A/B case) or entering a recovery mode. In success case, mounting happens as soon as the root device is ready, unlike the existing 'rootdelay' parameter which performs an unconditional pause. Signed-off-by: Loic Poulain Message-Id: <20230813082349.513386-1-loic.poulain@linaro.org> Signed-off-by: Christian Brauner

Merge tag 'mm-nonmm-stable-2023-06-24-19-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-06-28T17:59:38+00:00

Pull non-mm updates from Andrew Morton: - Arnd Bergmann has fixed a bunch of -Wmissing-prototypes in top-level directories - Douglas Anderson has added a new "buddy" mode to the hardlockup detector. It permits the detector to work on architectures which cannot provide the required interrupts, by having CPUs periodically perform checks on other CPUs - Zhen Lei has enhanced kexec's ability to support two crash regions - Petr Mladek has done a lot of cleanup on the hard lockup detector's Kconfig entries - And the usual bunch of singleton patches in various places * tag 'mm-nonmm-stable-2023-06-24-19-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (72 commits) kernel/time/posix-stubs.c: remove duplicated include ocfs2: remove redundant assignment to variable bit_off watchdog/hardlockup: fix typo in config HARDLOCKUP_DETECTOR_PREFER_BUDDY powerpc: move arch_trigger_cpumask_backtrace from nmi.h to irq.h devres: show which resource was invalid in __devm_ioremap_resource() watchdog/hardlockup: define HARDLOCKUP_DETECTOR_ARCH watchdog/sparc64: define HARDLOCKUP_DETECTOR_SPARC64 watchdog/hardlockup: make HAVE_NMI_WATCHDOG sparc64-specific watchdog/hardlockup: declare arch_touch_nmi_watchdog() only in linux/nmi.h watchdog/hardlockup: make the config checks more straightforward watchdog/hardlockup: sort hardlockup detector related config values a logical way watchdog/hardlockup: move SMP barriers from common code to buddy code watchdog/buddy: simplify the dependency for HARDLOCKUP_DETECTOR_PREFER_BUDDY watchdog/buddy: don't copy the cpumask in watchdog_next_cpu() watchdog/buddy: cleanup how watchdog_buddy_check_hardlockup() is called watchdog/hardlockup: remove softlockup comment in touch_nmi_watchdog() watchdog/hardlockup: in watchdog_hardlockup_check() use cpumask_copy() watchdog/hardlockup: don't use raw_cpu_ptr() in watchdog_hardlockup_kick() watchdog/hardlockup: HAVE_NMI_WATCHDOG must implement watchdog_hardlockup_probe() watchdog/hardlockup: keep kernel.nmi_watchdog sysctl as 0444 if probe fails ...

Merge tag 'for-6.5/block-2023-06-23' of git://git.kernel.dk/linux

2023-06-26T19:47:20+00:00

Pull block updates from Jens Axboe: - NVMe pull request via Keith: - Various cleanups all around (Irvin, Chaitanya, Christophe) - Better struct packing (Christophe JAILLET) - Reduce controller error logs for optional commands (Keith) - Support for >=64KiB block sizes (Daniel Gomez) - Fabrics fixes and code organization (Max, Chaitanya, Daniel Wagner) - bcache updates via Coly: - Fix a race at init time (Mingzhe Zou) - Misc fixes and cleanups (Andrea, Thomas, Zheng, Ye) - use page pinning in the block layer for dio (David) - convert old block dio code to page pinning (David, Christoph) - cleanups for pktcdvd (Andy) - cleanups for rnbd (Guoqing) - use the unchecked __bio_add_page() for the initial single page additions (Johannes) - fix overflows in the Amiga partition handling code (Michael) - improve mq-deadline zoned device support (Bart) - keep passthrough requests out of the IO schedulers (Christoph, Ming) - improve support for flush requests, making them less special to deal with (Christoph) - add bdev holder ops and shutdown methods (Christoph) - fix the name_to_dev_t() situation and use cases (Christoph) - decouple the block open flags from fmode_t (Christoph) - ublk updates and cleanups, including adding user copy support (Ming) - BFQ sanity checking (Bart) - convert brd from radix to xarray (Pankaj) - constify various structures (Thomas, Ivan) - more fine grained persistent reservation ioctl capability checks (Jingbo) - misc fixes and cleanups (Arnd, Azeem, Demi, Ed, Hengqi, Hou, Jan, Jordy, Li, Min, Yu, Zhong, Waiman) * tag 'for-6.5/block-2023-06-23' of git://git.kernel.dk/linux: (266 commits) scsi/sg: don't grab scsi host module reference ext4: Fix warning in blkdev_put() block: don't return -EINVAL for not found names in devt_from_devname cdrom: Fix spectre-v1 gadget block: Improve kernel-doc headers blk-mq: don't insert passthrough request into sw queue bsg: make bsg_class a static const structure ublk: make ublk_chr_class a static const structure aoe: make aoe_class a static const structure block/rnbd: make all 'class' structures const block: fix the exclusive open mask in disk_scan_partitions block: add overflow checks for Amiga partition support block: change all __u32 annotations to __be32 in affs_hardblocks.h block: fix signed int overflow in Amiga partition support block: add capacity validation in bdev_add_partition() block: fine-granular CAP_SYS_ADMIN for Persistent Reservation block: disallow Persistent Reservation on partitions reiserfs: fix blkdev_put() warning from release_journal_dev() block: fix wrong mode for blkdev_get_by_dev() from disk_scan_partitions() block: document the holder argument to blkdev_get_by_path ...