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312c89fbca
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Misono, Tomohiro 312c89fbca btrfs: cleanup btrfs_mount() using btrfs_mount_root() 
Cleanup btrfs_mount() by using btrfs_mount_root(). This avoids getting
btrfs_mount() called twice in mount path.

Old btrfs_mount() will do:
0. VFS layer calls vfs_kern_mount() with registered file_system_type
   (for btrfs, btrfs_fs_type). btrfs_mount() is called on the way.
1. btrfs_parse_early_options() parses "subvolid=" mount option and set the
   value to subvol_objectid. Otherwise, subvol_objectid has the initial
   value of 0
2. check subvol_objectid is 5 or not. Assume this time id is not 5, then
   btrfs_mount() returns by calling mount_subvol()
3. In mount_subvol(), original mount options are modified to contain
   "subvolid=0" in setup_root_args(). Then, vfs_kern_mount() is called with
   btrfs_fs_type and new options
4. btrfs_mount() is called again
5. btrfs_parse_early_options() parses "subvolid=0" and set 5 (instead of 0)
   to subvol_objectid
6. check subvol_objectid is 5 or not. This time id is 5 and mount_subvol()
   is not called. btrfs_mount() finishes mounting a root
7. (in mount_subvol()) with using a return vale of vfs_kern_mount(), it
   calls mount_subtree()
8. return subvolume's dentry

Reusing the same file_system_type (and btrfs_mount()) for vfs_kern_mount()
is the cause of complication.

Instead, new btrfs_mount() will do:
1. parse subvol id related options for later use in mount_subvol()
2. mount device's root by calling vfs_kern_mount() with
   btrfs_root_fs_type, which is not registered to VFS by
   register_filesystem(). As a result, btrfs_mount_root() is called
3. return by calling mount_subvol()

The code of 2. is moved from the first part of mount_subvol().

The semantics of device holder changes from btrfs_fs_type to
btrfs_root_fs_type and has to be used in all contexts. Otherwise we'd
get wrong results when mount and dev scan would not check the same
thing. (this has been found indendently and the fix is folded into this
patch)

Signed-off-by: Tomohiro Misono <misono.tomohiro@jp.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ fold the btrfs_control_ioctl fixup, extend the comment ]
Signed-off-by: David Sterba <dsterba@suse.com>
2018-01-22 16:08:18 +01:00
..
9p Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
adfs Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
affs Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
afs afs: Fix missing error handling in afs_write_end() 2018-01-02 10:02:19 +00:00
autofs4 autofs: fix careless error in recent commit 2017-12-14 16:00:48 -08:00
befs Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
bfs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
btrfs btrfs: cleanup btrfs_mount() using btrfs_mount_root() 2018-01-22 16:08:18 +01:00
cachefiles mm: remove __GFP_COLD 2017-11-15 18:21:06 -08:00
ceph ceph: drop negative child dentries before try pruning inode's alias 2017-12-08 11:07:12 +01:00
cifs CIFS: don't log STATUS_NOT_FOUND errors for DFS 2017-12-06 12:48:01 -06:00
coda Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
configfs configfs: make ci_type field, some pointers and function arguments const 2017-10-19 16:15:16 +02:00
cramfs cramfs: fix MTD dependency 2017-12-17 12:20:58 -08:00
crypto fscrypt: lots of cleanups, mostly courtesy by Eric Biggers 2017-11-14 11:35:15 -08:00
debugfs debugfs: Remove redundant license text 2017-11-07 20:25:03 +01:00
devpts
dlm A couple of configfs cleanups: 2017-11-14 14:44:04 -08:00
ecryptfs Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
efivarfs
efs Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
exofs Merge branch 'for-4.14/block' of git://git.kernel.dk/linux-block 2017-09-07 11:59:42 -07:00
exportfs
ext2 Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
ext4 ext4: fix crash when a directory's i_size is too small 2017-12-11 15:00:57 -05:00
f2fs Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
fat fs/fat/inode.c: fix sb_rdonly() change 2017-11-29 18:40:43 -08:00
freevxfs Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
fscache AFS development 2017-11-16 11:41:22 -08:00
fuse Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
gfs2 Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
hfs Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
hfsplus Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
hostfs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
hpfs hpfs: don't bother with the i_version counter or f_version 2017-12-10 12:58:18 -08:00
hugetlbfs fs/hugetlbfs/inode.c: change put_page/unlock_page order in hugetlbfs_fallocate() 2017-11-29 18:40:43 -08:00
isofs Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
jbd2 libnvdimm for 4.15 2017-11-17 09:51:57 -08:00
jffs2 Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
jfs Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
kernfs Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
lockd nlm_shutdown_hosts_net() cleanup 2017-11-27 16:45:11 -05:00
minix Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
ncpfs Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
nfs NFS client fixes for Linux 4.15-rc4 2017-12-16 13:12:53 -08:00
nfs_common lockd: fix "list_add double add" caused by legacy signal interface 2017-11-27 16:45:11 -05:00
nfsd kernel: make groups_sort calling a responsibility group_info allocators 2017-12-14 16:00:49 -08:00
nilfs2 Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
nls License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
notify Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
ntfs Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
ocfs2 Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
omfs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
openpromfs Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
orangefs Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
overlayfs ovl: fix overlay: warning prefix 2017-12-14 11:14:52 +01:00
proc proc: fix coredump vs read /proc/*/stat race 2018-01-19 10:09:41 -08:00
pstore treewide: Switch DEFINE_TIMER callbacks to struct timer_list * 2017-11-21 15:57:05 -08:00
qnx4 Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
qnx6 Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
quota quota: Check for register_shrinker() failure. 2017-11-29 16:46:48 +01:00
ramfs mm: make pagevec_lookup() update index 2017-09-06 17:27:26 -07:00
reiserfs Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2017-11-30 18:38:47 -05:00
romfs Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
squashfs Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
sysfs Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
sysv Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
tracefs
ubifs Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
udf Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
ufs Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
xfs Changes since last update: 2018-01-05 12:59:32 -08:00
aio.c Merge branch 'misc.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-11-17 11:54:55 -08:00
anon_inodes.c
attr.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
bad_inode.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
binfmt_aout.c fs: fix kernel_read prototype 2017-09-04 19:05:15 -04:00
binfmt_elf_fdpic.c Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-11-17 12:54:01 -08:00
binfmt_elf.c Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm 2017-11-16 12:50:35 -08:00
binfmt_em86.c
binfmt_flat.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
binfmt_misc.c fs/binfmt_misc.c: node could be NULL when evicting inode 2017-10-13 16:18:33 -07:00
binfmt_script.c exec: load_script: kill the onstack interp[BINPRM_BUF_SIZE] array 2017-10-03 17:54:25 -07:00
block_dev.c Merge branch 'for-4.15/block' of git://git.kernel.dk/linux-block 2017-11-14 15:32:19 -08:00
buffer.c mm, pagevec: remove cold parameter for pagevecs 2017-11-15 18:21:06 -08:00
char_dev.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
compat_binfmt_elf.c
compat_ioctl.c Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-11-17 12:54:01 -08:00
compat.c
coredump.c Merge branch 'misc.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-11-17 11:54:55 -08:00
dax.c Revert "mm: replace p??_write with pte_access_permitted in fault + gup paths" 2017-12-15 18:53:22 -08:00
dcache.c kmemcheck: remove annotations 2017-11-15 18:21:04 -08:00
dcookies.c
direct-io.c Merge branch 'for-4.15/block' of git://git.kernel.dk/linux-block 2017-11-14 15:32:19 -08:00
drop_caches.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
eventfd.c
eventpoll.c Merge branch 'akpm' (patches from Andrew) 2017-11-17 16:56:17 -08:00
exec.c exec: Weaken dumpability for secureexec 2018-01-03 10:13:36 -08:00
fcntl.c fcntl: don't cap l_start and l_end values for F_GETLK64 in compat syscall 2017-11-15 08:08:36 -05:00
fhandle.c Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-11-17 12:54:01 -08:00
file_table.c fs, mm: account filp cache to kmemcg 2017-11-15 18:21:04 -08:00
file.c Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-11-17 12:54:01 -08:00
filesystems.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs_pin.c Merge branch 'linus' into locking/core, to resolve conflicts 2017-11-07 10:32:44 +01:00
fs_struct.c
fs-writeback.c Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
inode.c Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
internal.h fs: expose do_unlinkat for built-in callers 2017-11-10 08:48:46 -05:00
ioctl.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
iomap.c Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-11-17 12:08:18 -08:00
Kconfig
Kconfig.binfmt ARM: enable elf_fdpic on systems with an MMU 2017-09-10 19:31:46 -04:00
libfs.c Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
locks.c Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mbcache.c fs/mbcache.c: make count_objects() more robust 2017-11-29 18:40:43 -08:00
mount.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mpage.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
namei.c autofs: revert "autofs: fix AT_NO_AUTOMOUNT not being honored" 2017-11-29 18:40:43 -08:00
namespace.c VFS: Handle lazytime in do_mount() 2017-12-09 20:16:33 -05:00
no-block.c
nsfs.c Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
open.c ovl: don't allow writing ioctl on lower layer 2017-09-05 12:53:12 +02:00
pipe.c pipe: add proc_dopipe_max_size() to safely assign pipe_max_size 2017-11-17 16:10:03 -08:00
pnode.c
pnode.h
posix_acl.c
proc_namespace.c Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
read_write.c Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-11-17 12:08:18 -08:00
readdir.c Merge branch 'linus' into locking/core, to resolve conflicts 2017-11-07 10:32:44 +01:00
select.c Merge branch 'misc.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-11-17 11:54:55 -08:00
seq_file.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
signalfd.c Merge branch 'misc.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-11-17 11:54:55 -08:00
splice.c locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE() 2017-10-25 11:01:08 +02:00
stack.c
stat.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
statfs.c Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
super.c sget(): handle failures of register_shrinker() 2017-12-18 15:05:07 -05:00
sync.c Merge branch 'for-4.15/block' of git://git.kernel.dk/linux-block 2017-11-14 15:32:19 -08:00
timerfd.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
userfaultfd.c userfaultfd: clear the vma->vm_userfaultfd_ctx if UFFD_EVENT_FORK fails 2018-01-04 16:45:09 -08:00
utimes.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xattr.c lsm: fix smack_inode_removexattr and xattr_getsecurity memleak 2017-10-04 18:03:15 +11:00