Zygo Blaxell 2f3165ecf1 btrfs: don't force mounts to wait for cleaner_kthread to delete one or more subvolumes ... During a mount, we start the cleaner kthread first because the transaction kthread wants to wake up the cleaner kthread. We start the transaction kthread next because everything in btrfs wants transactions. We do reloc recovery in the thread that was doing the original mount call once the transaction kthread is running. This means that the cleaner kthread could already be running when reloc recovery happens (e.g. if a snapshot delete was started before a crash). Relocation does not play well with the cleaner kthread, so a mutex was added in commit 5f3164813b "Btrfs: fix race between balance recovery and root deletion" to prevent both from being active at the same time. If the cleaner kthread is already holding the mutex by the time we get to btrfs_recover_relocation, the mount will be blocked until at least one deleted subvolume is cleaned (possibly more if the mount process doesn't get the lock right away). During this time (which could be an arbitrarily long time on a large/slow filesystem), the mount process is stuck and the filesystem is unnecessarily inaccessible. Fix this by locking cleaner_mutex before we start cleaner_kthread, and unlocking the mutex after mount no longer requires it. This ensures that the mounting process will not be blocked by the cleaner kthread. The cleaner kthread is already prepared for mutex contention and will just go to sleep until the mutex is available. Signed-off-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>		2016-05-06 15:22:49 +02:00
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btrfs	btrfs: don't force mounts to wait for cleaner_kthread to delete one or more subvolumes	2016-05-06 15:22:49 +02:00
cachefiles
ceph
cifs
coda
configfs
cramfs
crypto
debugfs
devpts
dlm
ecryptfs
efivarfs
efs
exofs
exportfs
ext2
ext4
f2fs
fat
freevxfs
fscache
fuse
gfs2
hfs
hfsplus
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hpfs
hugetlbfs
isofs
jbd2
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jfs
kernfs
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aio.c
anon_inodes.c
attr.c
bad_inode.c
binfmt_aout.c
binfmt_elf_fdpic.c
binfmt_elf.c
binfmt_em86.c
binfmt_flat.c
binfmt_misc.c
binfmt_script.c
block_dev.c
buffer.c
char_dev.c
compat_binfmt_elf.c
compat_ioctl.c
compat.c
coredump.c
dax.c
dcache.c
dcookies.c
direct-io.c
drop_caches.c
eventfd.c
eventpoll.c
exec.c
fcntl.c
fhandle.c
file_table.c
file.c
filesystems.c
fs_pin.c
fs_struct.c
fs-writeback.c
inode.c
internal.h
ioctl.c
Kconfig
Kconfig.binfmt
libfs.c
locks.c
Makefile
mbcache.c
mount.h
mpage.c
namei.c
namespace.c
no-block.c
nsfs.c
open.c
pipe.c
pnode.c
pnode.h
posix_acl.c
proc_namespace.c
read_write.c
readdir.c
select.c
seq_file.c
signalfd.c
splice.c
stack.c
stat.c
statfs.c
super.c
sync.c
timerfd.c
userfaultfd.c
utimes.c
xattr.c