восстановить поврежденную файловую систему btrfs (Recover a damaged btrfs filesystem)
Имя (Name)
btrfs-rescue - Recover a damaged btrfs filesystem
Синопсис (Synopsis)
btrfs rescue <subcommand> <args>
Описание (Description)
btrfs rescue is used to try to recover a damaged btrfs
filesystem.
Подкоманда (Subcommand)
chunk-recover [options] <device>
Recover the chunk tree by scanning the devices
Options
-y
assume an answer of yes to all questions.
-h
help.
-v
(deprecated) alias for global -v option
Note
Since chunk-recover will scan the whole device, it will be
VERY slow especially executed on a large device.
fix-device-size <device>
fix device size and super block total bytes values that are
do not match
Kernel 4.11 starts to check the device size more strictly and
this might mismatch the stored value of total bytes. See the
exact error message below. Newer kernel will refuse to mount
the filesystem where the values do not match. This error is
not fatal and can be fixed. This command will fix the device
size values if possible.
BTRFS error (device sdb): super_total_bytes 92017859088384 mismatch with fs_devices total_rw_bytes 92017859094528
The mismatch may also exhibit as a kernel warning:
WARNING: CPU: 3 PID: 439 at fs/btrfs/ctree.h:1559 btrfs_update_device+0x1c5/0x1d0 [btrfs]
super-recover [options] <device>
Recover bad superblocks from good copies.
Options
-y
assume an answer of yes to all questions.
-v
(deprecated) alias for global -v option
zero-log <device>
clear the filesystem log tree
This command will clear the filesystem log tree. This may fix
a specific set of problem when the filesystem mount fails due
to the log replay. See below for sample stacktraces that may
show up in system log.
The common case where this happens was fixed a long time ago,
so it is unlikely that you will see this particular problem,
but the command is kept around.
Note
clearing the log may lead to loss of changes that were
made since the last transaction commit. This may be up to
30 seconds (default commit period) or less if the commit
was implied by other filesystem activity.
One can determine whether zero-log is needed according to the
kernel backtrace:
? replay_one_dir_item+0xb5/0xb5 [btrfs]
? walk_log_tree+0x9c/0x19d [btrfs]
? btrfs_read_fs_root_no_radix+0x169/0x1a1 [btrfs]
? btrfs_recover_log_trees+0x195/0x29c [btrfs]
? replay_one_dir_item+0xb5/0xb5 [btrfs]
? btree_read_extent_buffer_pages+0x76/0xbc [btrfs]
? open_ctree+0xff6/0x132c [btrfs]
If the errors are like above, then zero-log should be used to
clear the log and the filesystem may be mounted normally
again. The keywords to look for are open_ctree which says
that it's during mount and function names that contain
replay, recover or log_tree.
Статус выхода (Exit)
btrfs rescue returns a zero exit status if it succeeds. Non zero
is returned in case of failure.
Доступность (Availability)
btrfs is part of btrfs-progs. Please refer to the btrfs wiki
http://btrfs.wiki.kernel.org
Смотри также (See also)
mkfs.btrfs(8), btrfs-scrub(8), btrfs-check(8)
