There'd been several issues around struct block_device::bd_inode.
It points to coallocated inode and it's unpleasant in several respects.
We definitely need stuff that sits in that sucker, but we need a sane
set of primitives for accessing those.
I've a branch that does, among other things, have ->bd_inode eliminated;
see #bd_inode or #bdev (identical resulting trees) in viro/vfs.git for
the current state of that thing. The problem is to do it with sane
topology, though.
First, a summary of ->bd_inode users:
* most of them want the address_space of block device, which is
currently found as ->bd_inode->i_mapping, either directly or with minor
massage. I've added ->bd_mapping for that.
* there are several places where gendisk and partition code
wants to unhash or drop the coallocated inode. Exposure is similar to
add_bdev(); I went for a couple of extra primitives with the same
visibility (bdev_unhash() and bdev_drop()).
* there are users in block/bdev.c, where we know how block_device
and associated inode are allocated; there we can easily get ->bd_inode
value via container_of(). A couple of existing inline helpers can simply
move there (disk_live() and block_size(); neither is used on hot paths,
so the cost of call is not an issue).
* there are places that implemented an equivalent of bdev_nr_bytes()
by reading ->i_size of associated inode. Might as well use bdev_nr_bytes()
and be done with that.
* 2 oddballs - nilfs_attach_log_writer() and dasd_format(). Both
want the associated inode. I'm somewhat suspicious about the former
(looks like it might be a layering violation) and there's definitely
quite a few things wrong about the latter. Neither is on the fast
path; I went for ->bd_mapping->host, admittedly unidiomatic there.
* there's some outright dead code.
And that's it. The main problem is keeping topology sane. A part of
that had been in vfs/vfs.git#vfs.super, and the things would be easier
if we could replace that pile.
#work.bd_inode is the variant keeping vfs.super as-is; identical tree
with saner topology is in #work.bdev and IMO it makes a lot more sense.
#work.bdev starts at #work.set_blocksize (as posted); what follows is
* cleanups, dead code elimination and adding missing primitives
7 commits, all but the last one reordered from current vfs.super;
some of that from me, some from Yu Kuai. The tip of that is #work.bd_inode-0
* merge-in of invariant branch with 2 erofs patches (#misc.erofs,
as posted and acked by erofs maintainer)
* After that merge we have ->bd_mapping introduction and conversions,
handling of ->bd_inode users in block/bdev.c, followed by nilfs and s390
oddballs handling and finally removal of now-unused ->bd_inode.
That's #work.bd_inode-1. Several of those are close to ones currently
in vfs.super.
* merge with #work.bd_flags-2 (as posted).
Please, review. Individual patches (on #work.bd_inode-{0,1}; #misc.erofs
and work.{set_blocksize,bd_flags-2} had been already posted) in followups.
I think the series makes more sense in this form; the downside is that
it replaces the current vfs/vfs.git#vfs.super, but AFAICS nothings other
than vfs.all pulls from that, so it's not too drastic.
Overall shortlog:
Al Viro (34):
erofs: switch erofs_bread() to passing offset instead of block number
erofs_buf: store address_space instead of inode
bcache_register(): don't bother with set_blocksize()
pktcdvd: sort set_blocksize() calls out
swapon(2)/swapoff(2): don't bother with block size
swapon(2): open swap with O_EXCL
zram: don't bother with reopening - just use O_EXCL for open
swsusp: don't bother with setting block size
btrfs_get_bdev_and_sb(): call set_blocksize() only for exclusive opens
set_blocksize(): switch to passing struct file *
make set_blocksize() fail unless block device is opened exclusive
Use bdev_is_paritition() instead of open-coding it
wrapper for access to ->bd_partno
bdev: infrastructure for flags
bdev: move ->bd_read_only to ->__bd_flags
bdev: move ->bd_write_holder into ->__bd_flags
bdev: move ->bd_has_subit_bio to ->__bd_flags
bdev: move ->bd_ro_warned to ->__bd_flags
bdev: move ->bd_make_it_fail to ->__bd_flags
blkdev_write_iter(): saner way to get inode and bdev
dm-vdo: use bdev_nr_bytes(bdev) instead of i_size_read(bdev->bd_inode)
missing helpers: bdev_unhash(), bdev_drop()
Merge branch 'misc.erofs' into work.bdev
block_device: add a pointer to struct address_space (page cache of bdev)
use ->bd_mapping instead of ->bd_inode->i_mapping
grow_dev_folio(): we only want ->bd_inode->i_mapping there
blk_ioctl_{discard,zeroout}(): we only want ->bd_inode->i_mapping here...
fs/buffer.c: massage the remaining users of ->bd_inode to ->bd_mapping
gfs2: more obvious initializations of mapping->host
block/bdev.c: use the knowledge of inode/bdev coallocation
nilfs_attach_log_writer(): use ->bd_mapping->host instead of ->bd_inode
dasd_format(): killing the last remaining user of ->bd_inode
RIP ->bd_inode
Merge branch 'work.bd_flags-2' into work.bdev
Yu Kuai (4):
ext4: remove block_device_ejected()
bcachefs: remove dead function bdev_sectors()
block2mtd: prevent direct access of bd_inode
block: move two helpers into bdev.c
Diffstat:
Documentation/filesystems/porting.rst | 7 +++
block/bdev.c | 97 +++++++++++++++++++++++-----------
block/blk-core.c | 17 +++---
block/blk-mq.c | 2 +-
block/blk-zoned.c | 4 +-
block/blk.h | 2 +
block/early-lookup.c | 2 +-
block/fops.c | 4 +-
block/genhd.c | 23 ++++----
block/ioctl.c | 40 +++++++-------
block/partitions/core.c | 20 +++----
drivers/block/pktcdvd.c | 7 +--
drivers/block/zram/zram_drv.c | 29 +++-------
drivers/block/zram/zram_drv.h | 2 +-
drivers/md/bcache/super.c | 6 +--
drivers/md/dm-vdo/dm-vdo-target.c | 4 +-
drivers/md/dm-vdo/indexer/io-factory.c | 2 +-
drivers/mtd/devices/block2mtd.c | 6 ++-
drivers/s390/block/dasd_ioctl.c | 2 +-
drivers/scsi/scsicam.c | 2 +-
fs/bcachefs/util.h | 5 --
fs/btrfs/dev-replace.c | 2 +-
fs/btrfs/disk-io.c | 6 +--
fs/btrfs/volumes.c | 15 +++---
fs/btrfs/zoned.c | 2 +-
fs/buffer.c | 26 ++++-----
fs/cramfs/inode.c | 2 +-
fs/erofs/data.c | 12 ++---
fs/erofs/dir.c | 4 +-
fs/erofs/internal.h | 4 +-
fs/erofs/namei.c | 6 +--
fs/erofs/super.c | 8 +--
fs/erofs/xattr.c | 37 +++++--------
fs/erofs/zdata.c | 6 +--
fs/ext4/dir.c | 2 +-
fs/ext4/ext4_jbd2.c | 2 +-
fs/ext4/super.c | 26 ++-------
fs/gfs2/glock.c | 2 +-
fs/gfs2/ops_fstype.c | 2 +-
fs/jbd2/journal.c | 2 +-
fs/nilfs2/segment.c | 2 +-
fs/reiserfs/journal.c | 5 +-
fs/xfs/xfs_buf.c | 2 +-
include/linux/blk_types.h | 19 +++----
include/linux/blkdev.h | 40 +++++++++-----
include/linux/buffer_head.h | 4 +-
include/linux/jbd2.h | 4 +-
include/linux/part_stat.h | 2 +-
include/linux/swap.h | 2 -
kernel/power/swap.c | 7 +--
lib/vsprintf.c | 4 +-
mm/swapfile.c | 29 +---------
52 files changed, 275 insertions(+), 294 deletions(-)
