20 Sep, 2021
2 commits
-
Attempt to mount 9p file system as root gives the following kernel panic:
9pnet_virtio: no channels available for device root
Kernel panic - not syncing: VFS: Unable to mount root "root" (9p), err=-2
CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.15.0-rc1+ #127
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
Call Trace:
dump_stack_lvl+0x45/0x59
panic+0x1e2/0x44b
? __warn_printk+0xf3/0xf3
? free_unref_page+0x2d4/0x4a0
? trace_hardirqs_on+0x32/0x120
? free_unref_page+0x2d4/0x4a0
mount_root+0x189/0x1e0
prepare_namespace+0x136/0x165
kernel_init_freeable+0x3b8/0x3cb
? rest_init+0x2e0/0x2e0
kernel_init+0x19/0x130
ret_from_fork+0x1f/0x30
Kernel Offset: disabled
---[ end Kernel panic - not syncing: VFS: Unable to mount root "root" (9p), err=-2 ]---QEMU command line:
"qemu-system-x86_64 -append root=/dev/root rw rootfstype=9p rootflags=trans=virtio ..."This error is because root_device_name is truncated in prepare_namespace() from
being "/dev/root" to be "root" prior to call to mount_nodev_root().As a solution, don't treat errors in mount_nodev_root() as errors that
require panics and allow failback to the mount flow that existed before
patch citied in Fixes tag.Fixes: f9259be6a9e7 ("init: allow mounting arbitrary non-blockdevice filesystems as root")
Signed-off-by: Leon Romanovsky
Reviewed-by: Christoph Hellwig
Signed-off-by: Al Viro -
split_fs_names() currently takes comma separate list of filesystems
and converts it into individual filesystem strings. Pleaces these
strings in the input buffer passed by caller and returns number of
strings.If caller manages to pass input string bigger than buffer, then we
can write beyond the buffer. Or if string just fits buffer, we will
still write beyond the buffer as we append a '\0' byte at the end.Pass size of input buffer to split_fs_names() and put enough checks
in place so such buffer overrun possibilities do not occur.This patch does few things.
- Add a parameter "size" to split_fs_names(). This specifies size
of input buffer.- Use strlcpy() (instead of strcpy()) so that we can't go beyond
buffer size. If input string "names" is larger than passed in
buffer, input string will be truncated to fit in buffer.- Stop appending extra '\0' character at the end and avoid one
possibility of going beyond the input buffer size.- Do not use extra loop to count number of strings.
- Previously if one passed "rootfstype=foo,,bar", split_fs_names()
will return only 1 string "foo" (and "bar" will be truncated
due to extra ,). After this patch, now split_fs_names() will
return 3 strings ("foo", zero-sized-string, and "bar").Callers of split_fs_names() have been modified to check for
zero sized string and skip to next one.Reported-by: xu xin
Signed-off-by: Vivek Goyal
Reviewed-by: Jan Kara
Signed-off-by: Al Viro
10 Sep, 2021
1 commit
-
Pull root filesystem type handling updates from Al Viro:
"Teach init/do_mounts.c to handle non-block filesystems, hopefully
preventing even more special-cased kludges (such as root=/dev/nfs,
etc)"* 'work.init' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs: simplify get_filesystem_list / get_all_fs_names
init: allow mounting arbitrary non-blockdevice filesystems as root
init: split get_fs_names
24 Aug, 2021
1 commit
-
This might have been a neat debug aid when the extended dev_t was
added, but that time is long gone.Signed-off-by: Christoph Hellwig
Link: https://lore.kernel.org/r/20210824075216.1179406-3-hch@lst.de
Signed-off-by: Jens Axboe
23 Aug, 2021
3 commits
-
Just output the '\0' separate list of supported file systems for block
devices directly rather than going through a pointless round of string
manipulation.Based on an earlier patch from Al Viro .
Vivek:
Modified list_bdev_fs_names() and split_fs_names() to return number of
null terminted strings to caller. Callers now use that information to
loop through all the strings instead of relying on one extra null char
being present at the end.Signed-off-by: Christoph Hellwig
Signed-off-by: Vivek Goyal
Signed-off-by: Al Viro -
Currently the only non-blockdevice filesystems that can be used as the
initial root filesystem are NFS and CIFS, which use the magic
"root=/dev/nfs" and "root=/dev/cifs" syntax that requires the root
device file system details to come from filesystem specific kernel
command line options.Add a little bit of new code that allows to just pass arbitrary
string mount options to any non-blockdevice filesystems so that it can
be mounted as the root file system.For example a virtiofs root file system can be mounted using the
following syntax:"root=myfs rootfstype=virtiofs rw"
Based on an earlier patch from Vivek Goyal .
Signed-off-by: Christoph Hellwig
Signed-off-by: Al Viro -
Split get_fs_names into one function that splits up the command line
argument, and one that gets the list of all registered file systems.Signed-off-by: Christoph Hellwig
Signed-off-by: Al Viro
01 Jun, 2021
1 commit
-
Add a helper to find the dev_t for a disk + partno tuple.
Signed-off-by: Christoph Hellwig
Reviewed-by: Ming Lei
Link: https://lore.kernel.org/r/20210525061301.2242282-8-hch@lst.de
Signed-off-by: Jens Axboe
02 Dec, 2020
6 commits
-
Instead of having two structures that represent each block device with
different life time rules, merge them into a single one. This also
greatly simplifies the reference counting rules, as we can use the inode
reference count as the main reference count for the new struct
block_device, with the device model reference front ending it for device
model interaction.Signed-off-by: Christoph Hellwig
Reviewed-by: Jan Kara
Reviewed-by: Hannes Reinecke
Signed-off-by: Jens Axboe -
Just use the bd_partno field in struct block_device everywhere.
Signed-off-by: Christoph Hellwig
Reviewed-by: Jan Kara
Reviewed-by: Hannes Reinecke
Signed-off-by: Jens Axboe -
Move the partition_meta_info to struct block_device in preparation for
killing struct hd_struct.Signed-off-by: Christoph Hellwig
Reviewed-by: Jan Kara
Reviewed-by: Hannes Reinecke
Signed-off-by: Jens Axboe -
Avoid a totally pointless goto label, and use the same style of
comparism for both helpers.Signed-off-by: Christoph Hellwig
Reviewed-by: Greg Kroah-Hartman
Reviewed-by: Jan Kara
Reviewed-by: Hannes Reinecke
Reviewed-by: Johannes Thumshirn
Acked-by: Tejun Heo
Signed-off-by: Jens Axboe -
The code in devt_from_partuuid is very convoluted. Refactor a bit by
sanitizing the goto and variable name usage.Signed-off-by: Christoph Hellwig
Reviewed-by: Greg Kroah-Hartman
Reviewed-by: Jan Kara
Reviewed-by: Hannes Reinecke
Acked-by: Tejun Heo
Signed-off-by: Jens Axboe -
Split each case into a self-contained helper, and move the block
dependent code entirely under the pre-existing #ifdef CONFIG_BLOCK.
This allows to remove the blk_lookup_devt stub in genhd.h.Signed-off-by: Christoph Hellwig
Reviewed-by: Greg Kroah-Hartman
Reviewed-by: Jan Kara
Reviewed-by: Hannes Reinecke
Reviewed-by: Johannes Thumshirn
Acked-by: Tejun Heo
Signed-off-by: Jens Axboe
31 Jul, 2020
3 commits
-
Add a simple helper to chroot with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_chroot.Signed-off-by: Christoph Hellwig
-
Add a simple helper to chdir with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_chdir.Signed-off-by: Christoph Hellwig
-
Like do_mount, but takes a kernel pointer for the destination path.
Switch over the mounts in the init code and devtmpfs to it, which
just happen to work due to the implicit set_fs(KERNEL_DS) during early
init right now.Signed-off-by: Christoph Hellwig
30 Jul, 2020
1 commit
-
Remove the special handling for multiple floppies in the initrd code.
No one should be using floppies for booting these days. (famous last
words..)Includes a spelling fix from Colin Ian King .
Signed-off-by: Christoph Hellwig
Acked-by: Linus Torvalds
16 Jul, 2020
1 commit
-
Just like the NFS and CIFS root code this better lives with the
driver it is tightly integrated with.Signed-off-by: Christoph Hellwig
Acked-by: Song Liu
Acked-by: Linus Torvalds
24 Mar, 2020
1 commit
-
There is no good reason for __bdevname to exist. Just open code
printing the string in the callers. For three of them the format
string can be trivially merged into existing printk statements,
and in init/do_mounts.c we can at least do the scnprintf once at
the start of the function, and unconditional of CONFIG_BLOCK to
make the output for tiny configfs a little more helpful.Acked-by: Theodore Ts'o # for ext4
Signed-off-by: Christoph Hellwig
Signed-off-by: Jens Axboe
17 Dec, 2019
1 commit
-
The "trivial conversion" in commit cccaa5e33525 ("init: use do_mount()
instead of ksys_mount()") was totally broken, since it didn't handle the
case of a NULL mount data pointer. And while I had "tested" it (and
presumably Dominik had too) that bug was hidden by me having options.Cc: Dominik Brodowski
Cc: Arnd Bergmann
Reported-by: Ondřej Jirman
Reported-by: Guenter Roeck
Reported-by: Naresh Kamboju
Reported-and-tested-by: Borislav Petkov
Tested-by: Chris Clayton
Tested-by: Eric Biggers
Tested-by: Geert Uytterhoeven
Tested-by: Guido Günther
Signed-off-by: Linus Torvalds
12 Dec, 2019
2 commits
-
In prepare_namespace(), do_mount() can be used instead of ksys_mount()
as the first and third argument are const strings in the kernel, the
second and fourth argument are passed through anyway, and the fifth
argument is NULL.In do_mount_root(), ksys_mount() is called with the first and third
argument being already kernelspace strings, which do not need to be
copied over from userspace to kernelspace (again). The second and
fourth arguments are passed through to do_mount() anyway. The fifth
argument, while already residing in kernelspace, needs to be put into
a page of its own. Then, do_mount() can be used instead of
ksys_mount().Once this is done, there are no in-kernel users to ksys_mount() left,
which can therefore be removed.Signed-off-by: Dominik Brodowski
-
In devtmpfs, do_mount() can be called directly instead of complex wrapping
by ksys_mount():
- the first and third arguments are const strings in the kernel,
and do not need to be copied over from userspace;
- the fifth argument is NULL, and therefore no page needs to be
copied over from userspace;
- the second and fourth argument are passed through anyway.Signed-off-by: Dominik Brodowski
03 Oct, 2019
1 commit
-
Add a new virtual device named /dev/cifs (0xfe) to tell the kernel to
mount the root file system over the network by using SMB protocol.cifs_root_data() will be responsible to retrieve the parsed
information of the new command-line option (cifsroot=) and then call
do_mount_root() with the appropriate mount options for cifs.ko.Signed-off-by: Paulo Alcantara (SUSE)
Signed-off-by: David S. Miller
13 Sep, 2019
1 commit
-
Convert the ramfs, shmem, tmpfs, devtmpfs and rootfs filesystems to the new
internal mount API as the old one will be obsoleted and removed. This
allows greater flexibility in communication of mount parameters between
userspace, the VFS and the filesystem.See Documentation/filesystems/mount_api.txt for more information.
Note that tmpfs is slightly tricky as it can contain embedded commas, so it
can't be trivially split up using strsep() to break on commas in
generic_parse_monolithic(). Instead, tmpfs has to supply its own generic
parser.However, if tmpfs changes, then devtmpfs and rootfs, which are wrappers
around tmpfs or ramfs, must change too - and thus so must ramfs, so these
had to be converted also.[AV: rewritten]
Signed-off-by: David Howells
cc: Hugh Dickins
cc: linux-mm@kvack.org
Signed-off-by: Al Viro
06 Sep, 2019
2 commits
-
... have callers use shmem_mount()
Signed-off-by: Al Viro
-
all users should just call ramfs_mount()
Signed-off-by: Al Viro
20 Jul, 2019
1 commit
-
Pull vfs mount updates from Al Viro:
"The first part of mount updates.Convert filesystems to use the new mount API"
* 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
mnt_init(): call shmem_init() unconditionally
constify ksys_mount() string arguments
don't bother with registering rootfs
init_rootfs(): don't bother with init_ramfs_fs()
vfs: Convert smackfs to use the new mount API
vfs: Convert selinuxfs to use the new mount API
vfs: Convert securityfs to use the new mount API
vfs: Convert apparmorfs to use the new mount API
vfs: Convert openpromfs to use the new mount API
vfs: Convert xenfs to use the new mount API
vfs: Convert gadgetfs to use the new mount API
vfs: Convert oprofilefs to use the new mount API
vfs: Convert ibmasmfs to use the new mount API
vfs: Convert qib_fs/ipathfs to use the new mount API
vfs: Convert efivarfs to use the new mount API
vfs: Convert configfs to use the new mount API
vfs: Convert binfmt_misc to use the new mount API
convenience helper: get_tree_single()
convenience helper get_tree_nodev()
vfs: Kill sget_userns()
...
05 Jul, 2019
3 commits
-
No point having two call sites (earlier in init_rootfs() from
mnt_init() in case we are going to use shmem-style rootfs,
later from do_basic_setup() unconditionally), along with the
logics in shmem_init() itself to make the second call a no-op...Signed-off-by: Al Viro
-
init_mount_tree() can get to rootfs_fs_type directly and that simplifies
a lot of things. We don't need to register it, we don't need to look
it up *and* we don't need to bother with preventing subsequent userland
mounts. That's the way we should've done that from the very beginning.There is a user-visible change, namely the disappearance of "rootfs"
from /proc/filesystems. Note that it's been unmountable all along
and it didn't show up in /proc/mounts; however, it *is* a user-visible
change and theoretically some script might've been using its presence
in /proc/filesystems to tell 2.4.11+ from earlier kernels.*IF* any complaints about behaviour change do show up, we could fake
it in /proc/filesystems. I very much doubt we'll have to, though.Signed-off-by: Al Viro
-
the only thing done by the latter is making ramfs visible
to mount(2); we don't need it there - rootfs is separate
and, in fact, made visible to mount(2) in the same init_rootfs().Signed-off-by: Al Viro
21 May, 2019
1 commit
-
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 fileThese 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
21 Dec, 2018
1 commit
-
Only the mount namespace code that implements mount(2) should be using the
MS_* flags. Suppress them inside the kernel unless uapi/linux/mount.h is
included.Signed-off-by: David Howells
Signed-off-by: Al Viro
Reviewed-by: David Howells
31 Oct, 2018
1 commit
-
Support referencing the root partition label from GPT as argument
to the root= option on the kernel command line in analogy to
referencing the partition uuid as root=PARTUUID=.Specifying the partition label instead of the uuid is often much
easier, e.g. in embedded environments when there is an
A/B rootfs partition scheme for interruptible firmware updates
(i.e. rootfsA/ rootfsB).The partition label can be queried with the blkid command.
Link: http://lkml.kernel.org/r/20180822060904.828E510665E@pc-niv.weinmann.com
Signed-off-by: Nikolaus Voss
Reviewed-by: Andrew Morton
Cc: Dominik Brodowski
Cc: Sasha Levin
Cc: Al Viro
Cc: Jens Axboe
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
23 Aug, 2018
1 commit
-
Sparse checking used to be disabled on init/do_mounts.c and a few related
files because "Many of the syscalls used in this file expect some of the
arguments to be __user pointers not __kernel pointers".However since 28128c61e ("kconfig.h: Include compiler types to avoid
missed struct attributes") the checks are, in fact, not disabled anymore
because of the more early include of "linux/compiler_types.h"So remove the now ineffective #undefery that was done to disable these
warnings, as well as the associated comment.Link: http://lkml.kernel.org/r/20180617115355.53799-1-luc.vanoostenryck@gmail.com
Signed-off-by: Luc Van Oostenryck
Cc: Dominik Brodowski
Cc: Al Viro
Cc: Kees Cook
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
03 Apr, 2018
5 commits
-
Using this helper allows us to avoid the in-kernel calls to the
sys_read() syscall. The ksys_ prefix denotes that this function
is meant as a drop-in replacement for the syscall. In particular, it
uses the same calling convention as sys_read().This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.netCc: Alexander Viro
Signed-off-by: Dominik Brodowski -
Using this helper allows us to avoid the in-kernel calls to the
sys_ioctl() syscall. The ksys_ prefix denotes that this function
is meant as a drop-in replacement for the syscall. In particular, it
uses the same calling convention as sys_ioctl().After careful review, at least some of these calls could be converted
to do_vfs_ioctl() in future.This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.netCc: Alexander Viro
Signed-off-by: Dominik Brodowski -
Using this wrapper allows us to avoid the in-kernel calls to the
sys_open() syscall. The ksys_ prefix denotes that this function is meant
as a drop-in replacement for the syscall. In particular, it uses the
same calling convention as sys_open().This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.netCc: Al Viro
Cc: Andrew Morton
Signed-off-by: Dominik Brodowski -
Using the ksys_close() wrapper allows us to get rid of in-kernel calls
to the sys_close() syscall. The ksys_ prefix denotes that this function
is meant as a drop-in replacement for the syscall. In particular, it
uses the same calling convention as sys_close(), with one subtle
difference:The few places which checked the return value did not care about the return
value re-writing in sys_close(), so simply use a wrapper around
__close_fd().This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.netCc: Al Viro
Cc: Andrew Morton
Signed-off-by: Dominik Brodowski -
Using this helper allows us to avoid the in-kernel calls to the sys_chdir()
syscall. The ksys_ prefix denotes that this function is meant as a drop-in
replacement for the syscall. In particular, it uses the same calling
convention as sys_chdir().This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.netCc: Al Viro
Cc: Andrew Morton
Signed-off-by: Dominik Brodowski