Hey Linus,
/* Summary */
Last cycle we changed opening of block devices in [1]. Now opening a
block device would return a bdev_handle. This allowed us to implement
support for restricting and forbidding writes to mounted block devices.
It was accompanied by converting and adding helpers to operate on
bdev_handles instead of plain block devices.
That was already a good step forward but ultimately it isn't necessary
to have special purpose helpers for opening block devices internally
that return a bdev_handle.
Fundamentally, opening a block device internally should just be
equivalent to opening files. So with this pull request all internal
opens of block devices return files just as a userspace open would.
Instead of introducing a separate indirection into bdev_open_by_*() via
struct bdev_handle bdev_file_open_by_*() is made to just return
a struct file. Opening and closing a block device just becomes
equivalent to opening and closing a file.
This all works well because internally we already have a pseudo fs for
block devices and so opening block devices is simple. There's a few
places where we needed to be careful such as during boot when the kernel
is supposed to mount the rootfs directly without init doing it. Here we
need to take care to ensure that we flush out any asynchronous file
close. That's what we already do for opening, unpacking, and closing the
initramfs. So nothing new here.
The equivalence of opening and closing block devices to regular files is
a win in and of itself. But it also has various other advantages. We can
remove struct bdev_handle completely. Various low-level helpers are now
private to the block layer. Other helpers were simply removable
completely.
A follow-up series that is already reviewed build on this and makes it
possible to remove bdev->bd_inode and allows various clean ups of the
buffer head code as well. All places where we stashed a bdev_handle now
just stash a file and use simple accessors to get to the actual block
device which was already the case for bdev_handle.
Link: 3f6984e7301f ("Merge tag 'vfs-6.8.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs") [1]
/* Testing */
clang: Debian clang version 16.0.6 (19)
gcc: (Debian 13.2.0-7) 13.2.0
All patches are based on v6.8-rc1 and have been sitting in linux-next.
No build failures or warnings were observed.
This series has been in -next for a very long time and it held up in
xfstests and in blktests so far.
/* Conflicts */
Merge conflicts with other trees
================================
[1] linux-next: manual merge of the block tree with the vfs-brauner tree
https://lore.kernel.org/linux-next/20240206124852.6183d0f7@xxxxxxxxxxxxxxxx
Full transparency: I had intended to coordinate this merge with Jens
to minimize the conflict but I just remembered the merge conflict
right now as I went through all the conflicts I had written down.
[2] linux-next: manual merge of the vfs-brauner tree with the bcachefs tree
https://lore.kernel.org/linux-next/20240213100455.07e181c8@xxxxxxxxxxxxxxxx
[3] linux-next: manual merge of the vfs-brauner tree with the bcachefs tree
https://lore.kernel.org/linux-next/20240215100517.027fd255@xxxxxxxxxxxxxxxx
[4] linux-next: manual merge of the vfs-brauner tree with the bcachefs tree
https://lore.kernel.org/linux-next/20240226111257.2784c310@xxxxxxxxxxxxxxxx
[5] linux-next: manual merge of the vfs-brauner tree with the xfs tree
https://lore.kernel.org/linux-next/20240227102827.313113cd@xxxxxxxxxxxxxxxx
[6] linux-next: manual merge of the vfs-brauner tree with the f2fs tree
https://lore.kernel.org/linux-next/20240229104140.2927da29@xxxxxxxxxxxxxxxx
Merge conflicts with mainline
=============================
[1] There's a merge conflict with bcachefs that can be resolved as follows:
diff --cc fs/bcachefs/super-io.c
index 36988add581f,ce8cf2d91f84..000000000000
--- a/fs/bcachefs/super-io.c
+++ b/fs/bcachefs/super-io.c
@@@ -715,11 -715,11 +715,11 @@@ retry
opt_set(*opts, nochanges, true);
}
- if (IS_ERR(sb->bdev_handle)) {
- ret = PTR_ERR(sb->bdev_handle);
+ if (IS_ERR(sb->s_bdev_file)) {
+ ret = PTR_ERR(sb->s_bdev_file);
- goto out;
+ goto err;
}
- sb->bdev = sb->bdev_handle->bdev;
+ sb->bdev = file_bdev(sb->s_bdev_file);
ret = bch2_sb_realloc(sb, 0);
if (ret) {
The following changes since commit 6613476e225e090cc9aad49be7fa504e290dd33d:
Linux 6.8-rc1 (2024-01-21 14:11:32 -0800)
are available in the Git repository at:
git@xxxxxxxxxxxxxxxxxxx:pub/scm/linux/kernel/git/vfs/vfs tags/vfs-6.9.super
for you to fetch changes up to 40ebc18b991bdb867bc693a4ac1b5d7db44838f3:
Merge series 'Open block devices as files' of https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-0-adbd023e19cc@xxxxxxxxxx (2024-02-25 12:05:28 +0100)
Please consider pulling these changes from the signed vfs-6.9.super tag.
Thanks!
Christian
----------------------------------------------------------------
vfs-6.9.super
----------------------------------------------------------------
Christian Brauner (36):
init: flush async file closing
file: prepare for new helper
file: add alloc_file_pseudo_noaccount()
bdev: open block device as files
block/ioctl: port blkdev_bszset() to file
block/genhd: port disk_scan_partitions() to file
md: port block device access to file
swap: port block device usage to file
power: port block device access to file
xfs: port block device access to files
drbd: port block device access to file
pktcdvd: port block device access to file
rnbd: port block device access to file
xen: port block device access to file
zram: port block device access to file
bcache: port block device access to files
block2mtd: port device access to files
nvme: port block device access to file
s390: port block device access to file
target: port block device access to file
bcachefs: port block device access to file
btrfs: port device access to file
erofs: port device access to file
ext4: port block device access to file
f2fs: port block device access to files
jfs: port block device access to file
nfs: port block device access to files
ocfs2: port block device access to file
reiserfs: port block device access to file
bdev: remove bdev_open_by_path()
bdev: make bdev_{release, open_by_dev}() private to block layer
bdev: make struct bdev_handle private to the block layer
bdev: remove bdev pointer from struct bdev_handle
block: don't rely on BLK_OPEN_RESTRICT_WRITES when yielding write access
block: remove bdev_handle completely
Merge series 'Open block devices as files' of https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-0-adbd023e19cc@xxxxxxxxxx
block/bdev.c | 252 ++++++++++++++++++++++--------------
block/blk.h | 4 +
block/fops.c | 46 +++----
block/genhd.c | 12 +-
block/ioctl.c | 9 +-
drivers/block/drbd/drbd_int.h | 4 +-
drivers/block/drbd/drbd_nl.c | 58 ++++-----
drivers/block/pktcdvd.c | 68 +++++-----
drivers/block/rnbd/rnbd-srv.c | 28 ++--
drivers/block/rnbd/rnbd-srv.h | 2 +-
drivers/block/xen-blkback/blkback.c | 4 +-
drivers/block/xen-blkback/common.h | 4 +-
drivers/block/xen-blkback/xenbus.c | 37 +++---
drivers/block/zram/zram_drv.c | 26 ++--
drivers/block/zram/zram_drv.h | 2 +-
drivers/md/bcache/bcache.h | 4 +-
drivers/md/bcache/super.c | 74 +++++------
drivers/md/dm.c | 23 ++--
drivers/md/md.c | 12 +-
drivers/md/md.h | 2 +-
drivers/mtd/devices/block2mtd.c | 46 +++----
drivers/nvme/target/io-cmd-bdev.c | 16 +--
drivers/nvme/target/nvmet.h | 2 +-
drivers/s390/block/dasd.c | 10 +-
drivers/s390/block/dasd_genhd.c | 36 +++---
drivers/s390/block/dasd_int.h | 2 +-
drivers/s390/block/dasd_ioctl.c | 2 +-
drivers/target/target_core_iblock.c | 18 +--
drivers/target/target_core_iblock.h | 2 +-
drivers/target/target_core_pscsi.c | 22 ++--
drivers/target/target_core_pscsi.h | 2 +-
fs/bcachefs/super-io.c | 20 +--
fs/bcachefs/super_types.h | 2 +-
fs/btrfs/dev-replace.c | 14 +-
fs/btrfs/ioctl.c | 16 +--
fs/btrfs/volumes.c | 92 ++++++-------
fs/btrfs/volumes.h | 4 +-
fs/cramfs/inode.c | 2 +-
fs/erofs/data.c | 6 +-
fs/erofs/internal.h | 2 +-
fs/erofs/super.c | 16 +--
fs/ext4/ext4.h | 2 +-
fs/ext4/fsmap.c | 8 +-
fs/ext4/super.c | 52 ++++----
fs/f2fs/f2fs.h | 2 +-
fs/f2fs/super.c | 12 +-
fs/file_table.c | 83 +++++++++---
fs/jfs/jfs_logmgr.c | 26 ++--
fs/jfs/jfs_logmgr.h | 2 +-
fs/jfs/jfs_mount.c | 2 +-
fs/nfs/blocklayout/blocklayout.h | 2 +-
fs/nfs/blocklayout/dev.c | 68 +++++-----
fs/ocfs2/cluster/heartbeat.c | 32 ++---
fs/reiserfs/journal.c | 38 +++---
fs/reiserfs/procfs.c | 2 +-
fs/reiserfs/reiserfs.h | 8 +-
fs/romfs/super.c | 2 +-
fs/super.c | 18 +--
fs/xfs/xfs_buf.c | 10 +-
fs/xfs/xfs_buf.h | 4 +-
fs/xfs/xfs_super.c | 44 +++----
include/linux/blkdev.h | 13 +-
include/linux/device-mapper.h | 2 +-
include/linux/file.h | 2 +
include/linux/fs.h | 4 +-
include/linux/pktcdvd.h | 4 +-
include/linux/swap.h | 2 +-
init/do_mounts.c | 3 +
init/do_mounts.h | 9 ++
init/initramfs.c | 6 +-
kernel/power/swap.c | 28 ++--
mm/swapfile.c | 22 ++--
72 files changed, 812 insertions(+), 703 deletions(-)
