As of now commands mentioned below (with in [..]) are calling call register-device
ioctl BTRFS_IOC_SCAN_DEV for all the devices in the system.
Some issues with it:
BTRFS_IOC_SCAN_DEV: ioctl is a write operation, we don't want command like
btrfs-debug-tree threads to do that..
eg:
----
$ cat /proc/fs/btrfs/devlist | egrep fsid | wc -l
0
$ btrfs-debug-tree /dev/sde (num_device > 1)
$ cat /proc/fs/btrfs/devlist | egrep fsid | wc -l
5
----
btrfs_scan_fs_devices() ends up calling this ioctl only when num_device > 1.
That's inconsistency with in feature/bug.
We don't have to register _all_ the btrfs devices (again) in the system
without user consent.
Why its inconsistent:
function btrfs_scan_fs_devices() calls btrfs_scan_lblkid only when
num_devices is > 1, which in turn calls BTRFS_IOC_SCAN_DEV ioctl, if
conditions are met.
But main issue is we have too many consumers of btrfs_scan_fs_devices()
the names below with in [] is the cli leading to this function.
open_ctree_broken() [btrfs-find-root]
recover_prepare() [btrfs rescue super-recover]
__open_ctree_fd
(updates always except when flag OPEN_CTREE_RECOVER_SUPER is set and
flag OPEN_CTREE_RECOVER_SUPER is set only by 'btrfs rescue super-
recover' but still this thread sneaks through the open_ctree function
to call register-device-ioctl as show below).
open_ctree_fs_info
[btrfs-debug-tree]
[btrfs-image -r]
[btrfs check]
open_fs
[btrfs restore]
open_ctree
[calc-size]
[btrfs-corrupt-block]
[btrfs-image] (create)
[btrfs-map-logical]
[btrfs-select-super]
[btrfstune]
[btrfs-zero-log]
[tester]
[mkfs]
[quick-test.c]
[btrfs label set unmounted]
[btrfs get label unmounted]
[btrfs rescue super-recover]
open_ctree_fd
[btrfs-convert]
Fix:
In an effort to make register-device consistent, all calls to
btrfs_scan_fs_devices() will have 5th parameter set to 0. that means
we don't need 5th parameter at all. And with this function not calling
the register ioctl at all, finally we will have following two cli to call
the ioctl BTRFS_IOC_SCAN_DEV.
btrfs dev scan and
mkfs.btrfs
Threads needing to update kernel about a device would have to use
btrfs_register_one_device() separately.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
super-recover collects btrfs devices infomation using existed
functions scan_one_devices().
Problem is fs_devices is freed twice in close_ctree() and
free_recover_superblock() for super correction path.
Fix this problem by checking whether fs_devices memory
have been freed before we free it.
Cc: Eric Sandeen <sandeen@redhat.com>
Cc: Chris Murphy <lists@colorremedies.com>
Acked-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Wang Shilong <wangshilong1991@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Btrfs-progs superblock checksum check is somewhat too restricted for
super-recover, since current btrfs-progs will only read the 1st
superblock and if you need super-recover the 1st superblock is
possibly already damaged.
The fix is introducing super_recover parameter for
btrfs_read_dev_super() and callers to allow scan backup superblocks if
needed.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Fix corporate name for copyright.
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
So I needed to add a flag to not try to read block groups when doing
--init-extent-tree since we could hang there, but that meant adding a whole
other 0/1 type flag to open_ctree_fs_info. So instead I've converted it all
over to using a flags setting and added the flag that I needed. This has been
tested with xfstests and make test. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Until now if one of device's first superblock is corrupt,btrfs will
fail to mount. Luckily, btrfs have at least two superblocks for
every disk.
In theory, if silent corrupting happens when we are writting superblocks
into disk, we must hold at least one good superblock.
One side effect is that user must gurantee that the disk must be
a btrfs disk. Otherwise, this tool may destroy other fs.(This is also
reason why btrfs only use first superblock in every disk to mount)
This little program will try to correct bad superblocks from
good superblocks with max generation.
There will be five kinds of return values:
0: all supers are valid, no need to recover
1: usage or syntax error
2: recover all bad superblocks successfully
3: fail to recover bad superblocks
4: abort to recover bad superblocks
Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Anand Jain