linux/block/bdev.c, branch v6.8

Merge tag 'vfs-6.8.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2024-01-08T18:43:51Z

Pull vfs super updates from Christian Brauner: "This contains the super work for this cycle including the long-awaited series by Jan to make it possible to prevent writing to mounted block devices: - Writing to mounted devices is dangerous and can lead to filesystem corruption as well as crashes. Furthermore syzbot comes with more and more involved examples how to corrupt block device under a mounted filesystem leading to kernel crashes and reports we can do nothing about. Add tracking of writers to each block device and a kernel cmdline argument which controls whether other writeable opens to block devices open with BLK_OPEN_RESTRICT_WRITES flag are allowed. Note that this effectively only prevents modification of the particular block device's page cache by other writers. The actual device content can still be modified by other means - e.g. by issuing direct scsi commands, by doing writes through devices lower in the storage stack (e.g. in case loop devices, DM, or MD are involved) etc. But blocking direct modifications of the block device page cache is enough to give filesystems a chance to perform data validation when loading data from the underlying storage and thus prevent kernel crashes. Syzbot can use this cmdline argument option to avoid uninteresting crashes. Also users whose userspace setup does not need writing to mounted block devices can set this option for hardening. We expect that this will be interesting to quite a few workloads. Btrfs is currently opted out of this because they still haven't merged patches we require for this to work from three kernel releases ago. - Reimplement block device freezing and thawing as holder operations on the block device. This allows us to extend block device freezing to all devices associated with a superblock and not just the main device. It also allows us to remove get_active_super() and thus another function that scans the global list of superblocks. Freezing via additional block devices only works if the filesystem chooses to use @fs_holder_ops for these additional devices as well. That currently only includes ext4 and xfs. Earlier releases switched get_tree_bdev() and mount_bdev() to use @fs_holder_ops. The remaining nilfs2 open-coded version of mount_bdev() has been converted to rely on @fs_holder_ops as well. So block device freezing for the main block device will continue to work as before. There should be no regressions in functionality. The only special case is btrfs where block device freezing for the main block device never worked because sb->s_bdev isn't set. Block device freezing for btrfs can be fixed once they can switch to @fs_holder_ops but that can happen whenever they're ready" * tag 'vfs-6.8.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (27 commits) block: Fix a memory leak in bdev_open_by_dev() super: don't bother with WARN_ON_ONCE() super: massage wait event mechanism ext4: Block writes to journal device xfs: Block writes to log device fs: Block writes to mounted block devices btrfs: Do not restrict writes to btrfs devices block: Add config option to not allow writing to mounted devices block: Remove blkdev_get_by_*() functions bcachefs: Convert to bdev_open_by_path() fs: handle freezing from multiple devices fs: remove dead check nilfs2: simplify device handling fs: streamline thaw_super_locked ext4: simplify device handling xfs: simplify device handling fs: simplify setup_bdev_super() calls blkdev: comment fs_holder_ops porting: document block device freeze and thaw changes fs: remove unused helper ...

block: Fix a memory leak in bdev_open_by_dev()

2023-12-28T10:48:17Z

If we early exit here, 'handle' needs to be freed, or some memory leaks. Fixes: ed5cc702d311 ("block: Add config option to not allow writing to mounted devices") Signed-off-by: Christophe JAILLET Link: https://lore.kernel.org/r/8eaec334781e695810aaa383b55de00ca4ab1352.1703439383.git.christophe.jaillet@wanadoo.fr Reviewed-by: Christoph Hellwig Reviewed-by: Jens Axboe Signed-off-by: Christian Brauner

block: update the stable_writes flag in bdev_add

2023-11-20T14:05:18Z

Propagate the per-queue stable_write flags into each bdev inode in bdev_add. This makes sure devices that require stable writes have it set for I/O on the block device node as well. Note that this doesn't cover the case of a flag changing on a live device yet. We should handle that as well, but I plan to cover it as part of a more general rework of how changing runtime paramters on block devices works. Fixes: 1cb039f3dc16 ("bdi: replace BDI_CAP_STABLE_WRITES with a queue and a sb flag") Reported-by: Ilya Dryomov Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20231025141020.192413-3-hch@lst.de Tested-by: Ilya Dryomov Reviewed-by: Darrick J. Wong Signed-off-by: Christian Brauner

block: Add config option to not allow writing to mounted devices

2023-11-18T13:59:25Z

Writing to mounted devices is dangerous and can lead to filesystem corruption as well as crashes. Furthermore syzbot comes with more and more involved examples how to corrupt block device under a mounted filesystem leading to kernel crashes and reports we can do nothing about. Add tracking of writers to each block device and a kernel cmdline argument which controls whether other writeable opens to block devices open with BLK_OPEN_RESTRICT_WRITES flag are allowed. We will make filesystems use this flag for used devices. Note that this effectively only prevents modification of the particular block device's page cache by other writers. The actual device content can still be modified by other means - e.g. by issuing direct scsi commands, by doing writes through devices lower in the storage stack (e.g. in case loop devices, DM, or MD are involved) etc. But blocking direct modifications of the block device page cache is enough to give filesystems a chance to perform data validation when loading data from the underlying storage and thus prevent kernel crashes. Syzbot can use this cmdline argument option to avoid uninteresting crashes. Also users whose userspace setup does not need writing to mounted block devices can set this option for hardening. Link: https://lore.kernel.org/all/60788e5d-5c7c-1142-e554-c21d709acfd9@linaro.org Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20231101174325.10596-3-jack@suse.cz Reviewed-by: Jens Axboe Signed-off-by: Christian Brauner

block: Remove blkdev_get_by_*() functions

2023-11-18T13:59:25Z

blkdev_get_by_*() and blkdev_put() functions are now unused. Remove them. Acked-by: Christoph Hellwig Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20231101174325.10596-2-jack@suse.cz Reviewed-by: Christian Brauner Reviewed-by: Jens Axboe Signed-off-by: Christian Brauner

bdev: implement freeze and thaw holder operations

2023-11-18T13:59:23Z

The old method of implementing block device freeze and thaw operations required us to rely on get_active_super() to walk the list of all superblocks on the system to find any superblock that might use the block device. This is wasteful and not very pleasant overall. Now that we can finally go straight from block device to owning superblock things become way simpler. Link: https://lore.kernel.org/r/20231024-vfs-super-freeze-v2-5-599c19f4faac@kernel.org Reviewed-by: Darrick J. Wong Reviewed-by: Jan Kara Signed-off-by: Christian Brauner

bdev: surface the error from sync_blockdev()

2023-11-18T13:59:23Z

When freeze_super() is called, sync_filesystem() will be called which calls sync_blockdev() and already surfaces any errors. Do the same for block devices that aren't owned by a superblock and also for filesystems that don't call sync_blockdev() internally but implicitly rely on bdev_freeze() to do it. Link: https://lore.kernel.org/r/20231024-vfs-super-freeze-v2-3-599c19f4faac@kernel.org Reviewed-by: Darrick J. Wong Reviewed-by: Jan Kara Signed-off-by: Christian Brauner

bdev: rename freeze and thaw helpers

2023-11-18T13:59:23Z

We have bdev_mark_dead() etc and we're going to move block device freezing to holder ops in the next patch. Make the naming consistent: * freeze_bdev() -> bdev_freeze() * thaw_bdev() -> bdev_thaw() Also document the return code. Link: https://lore.kernel.org/r/20231024-vfs-super-freeze-v2-2-599c19f4faac@kernel.org Reviewed-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Reviewed-by: Jan Kara Signed-off-by: Christian Brauner

Merge tag 'mm-nonmm-stable-2023-11-02-14-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-11-03T06:53:31Z

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 ...

block: move bdev_mark_dead out of disk_check_media_change

2023-10-28T11:29:23Z

disk_check_media_change is mostly called from ->open where it makes little sense to mark the file system on the device as dead, as we are just opening it. So instead of calling bdev_mark_dead from disk_check_media_change move it into the few callers that are not in an open instance. This avoid calling into bdev_mark_dead and thus taking s_umount with open_mutex held. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20231017184823.1383356-4-hch@lst.de Reviewed-by: Ming Lei Reviewed-by: Christian Brauner Reviewed-by: Jan Kara Reviewed-by: Jens Axboe Signed-off-by: Christian Brauner