42404a4e44
The option "--clear-ino-cache" is not really that suitable for "btrfs check" group. Let's move it to "btrfs rescue" group to fix those small hiccups, just like the existing "btrfs rescue fix-device-size" command. For now, "btrfs check --clear-ino-cache" would still work, with one extra warning referring to "btrfs rescue clear-ino-cache". This is mostly to reduce the surprise, and keep script users (I doubt if there is any though) happy for now. In the next or two releases, we would fully remove the support in "btrfs check" group. Another small change is, in the documents, we refer to the feature as "inode map", which doesn't match with the mount option documents. Since we're here, unify them to "inode cache" feature. Issue: #669 Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
131 lines
4.3 KiB
ReStructuredText
131 lines
4.3 KiB
ReStructuredText
btrfs-rescue(8)
|
|
===============
|
|
|
|
SYNOPSIS
|
|
--------
|
|
|
|
**btrfs rescue** <subcommand> <args>
|
|
|
|
DESCRIPTION
|
|
-----------
|
|
|
|
:command:`btrfs rescue` is used to try to recover a damaged btrfs filesystem.
|
|
|
|
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 :command:`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.
|
|
|
|
.. code-block:: none
|
|
|
|
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:
|
|
|
|
.. code-block:: none
|
|
|
|
WARNING: CPU: 3 PID: 439 at fs/btrfs/ctree.h:1559 btrfs_update_device+0x1c5/0x1d0 [btrfs]
|
|
|
|
clear-ino-cache <device>
|
|
Remove leftover items pertaining to the deprecated `inode cache` feature.
|
|
|
|
The `inode cache` feature (enabled by mount option "inode_cache") has been
|
|
completely removed in 5.11 kernel.
|
|
|
|
clear-uuid-tree <device>
|
|
Clear UUID tree, so that kernel can re-generate it at next read-write
|
|
mount.
|
|
|
|
Since kernel v4.16 there are more sanity check performed, and sometimes
|
|
non-critical trees like UUID tree can cause problems and reject the mount.
|
|
In such case, clearing UUID tree may make the filesystem to be mountable again
|
|
without much risk as it's built from other trees.
|
|
|
|
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 stack traces 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 :command:`zero-log` is needed according to the kernel
|
|
backtrace:
|
|
|
|
.. code-block:: none
|
|
|
|
? 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 :command:`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*.
|
|
|
|
EXIT STATUS
|
|
-----------
|
|
|
|
**btrfs rescue** returns a zero exit status if it succeeds. Non zero is
|
|
returned in case of failure.
|
|
|
|
AVAILABILITY
|
|
------------
|
|
|
|
**btrfs** is part of btrfs-progs. Please refer to the documentation at
|
|
`https://btrfs.readthedocs.io <https://btrfs.readthedocs.io>`_.
|
|
|
|
SEE ALSO
|
|
--------
|
|
|
|
:doc:`btrfs-check`,
|
|
:doc:`btrfs-scrub`,
|
|
:doc:`mkfs.btrfs`
|