To survive fuzz filesystem images, we need various validation checks to
make btrfsck detect any invalid value inside chunks including those in
sys_array.
Note that these checks may not be sufficient to cover all corner cases,
we may need to add more later.
This also refractor previous various checks into a helper function so
that we can add more checks into it in the future.
Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Reported-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The message
"warning devid %llu not found already\n",
does not seem to be too useful, it appears during several commands and
sometimes repeatedly.
Signed-off-by: David Sterba <dsterba@suse.com>
Since open_ctree_fs_info() now may return a fs_info even without any
roots, modify functions like read_tree_block() to operate with such
fs_info.
This provides the basis for btrfs-find-root to operate on chunk tree
with corrupted fs.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
[ coding style adjustments, unified declarations ]
Signed-off-by: David Sterba <dsterba@suse.com>
There is a small bug from 2011, where btrfs_next_bg (formally
btrfs_next_metadata) function will always skip the first chunk.
That's OK for that time, as there is always 3 empty temporary chunks.
But now, we may ended up with only one metadata or system chunk, with
empty chunk auto-remove from kernel or new mkfs.btrfs.
So fix it by checking the initial value so btrfs_next_bg() will return
the first chunk if its *logical parameter is 0.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Enhance chunk validation:
1) Num_stripes
We already have such check but it's only in super block sys chunk
array.
Now check all on-disk chunks.
2) Chunk logical
It should be aligned to sector size.
This behavior should be *DOUBLE CHECKED* for 64K sector size like
PPC64 or AArch64.
Maybe we can found some hidden bugs.
3) Chunk length
Same as chunk logical, should be aligned to sector size.
4) Stripe length
It should be power of 2.
5) Chunk type
Any bit out of TYPE_MAS | PROFILE_MASK is invalid.
With all these much restrict rules, several fuzzed image reported in
mail list should no longer cause btrfsck error.
Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We can handle the special case of num_stripes == 0 directly inside
btrfs_read_sys_array. The BUG_ON in btrfs_chunk_item_size is there to
catch other unhandled cases where we fail to validate external data,
like in btrfs-show-super.
Signed-off-by: David Sterba <dsterba@suse.com>
Port of kernel commit e3540eab29e1b2260bc4b9b3979a49a00e3e3af8
Verify that the sys_array has enough bytes to read the next item.
Signed-off-by: David Sterba <dsterba@suse.com>
Port of kernel commit 1ffb22cf8c322bbfea6b35fe23d025841b49fede
There's a pointer to buffer, integer offset and offset passed as
pointer, try to find matching names for them.
Signed-off-by: David Sterba <dsterba@suse.com>
There are some sanity checks missing on both sides, kernel/userspace.
Preparation to port the missing changes.
Sync code with parent of kernel commit
1ffb22cf8c322bbfea6b35fe23d025841b49fede ("btrfs: cleanup, rename a few
variables in btrfs_read_sys_array")
This effectively reverts progs commit
be96777126 ("btrfs-progs: Cleanup unneeded
extra variant in btrfs_read_sys_array") so we can apply more of the
kernel patches.
Signed-off-by: David Sterba <dsterba@suse.com>
Add support to search chunk root, as we only need to search tree roots
in system chunk, which should be very easy to add, just iterate in
system chunks.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
[ renamed to btrfs_next_bg_* ]
Signed-off-by: David Sterba <dsterba@suse.com>
This patch is generated from a coccinelle semantic patch:
identifier t;
expression e;
statement s;
@@
-t = malloc(e);
+t = calloc(1, e);
(
if (!t) s
|
if (t == NULL) s
|
)
-memset(t, 0, e);
Signed-off-by: Silvio Fricke <silvio.fricke@gmail.com>
[squashed patches into one]
Signed-off-by: David Sterba <dsterba@suse.com>
If there is more than one fs_devices in fs_uuids list (like mkfs.btrfs
does), we need close them all before exit. Add a helper for that.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This bug is found by making break point after change_fsid_prepare() and
then kill the unfinished change, then try to restore the unfinished fsid
change.
If fsid change is canceled, open_ctree will still fail even with
IGNORE_FSID_MIMATCH open ctree flag, since it can't find device with
mismatched fsid, making it unable to restoring.
Now add ignore_fsid_mismatch judgment in btrfs_find_device() to fix the
bug and allow later restore to work as expected.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
For DUP profile, the num_stripes should be 2 not 1.
This causes btrfs offline tool fails on valid image.
Also, num_stripes check is too restrict for btrfsck self test,
as there is some image in degraded mode, so modify it to allow degraded
chunk.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Adds extra check when reading a chunk item:
1) Check chunk type.
Don't allow any unsupported type/profile bit.
2) Check num_stripes
Any chunk item should contain at least one stripe.
For system chunk, the chunk item size(calculated by btrfs_stripe size *
(num_stripes - 1) + btrfs_chunk size) should not exceed
BTRFS_SYSTEM_CHUNK_SIZE(2048).
For normal chunk, the chunk item size(calculated) should match the chunk
item size.
3) Check num_stripes/sub_stripes against chunk profile.
Num_stripes/sub_stripes must meet its lower limit for its chunk profile.
Reported-by: Lukas Lueg <lukas.lueg@gmail.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
glibc 2.10+ (5+ years old) enables all the desired features:
_XOPEN_SOURCE 700, __XOPEN2K8, POSIX_C_SOURCE, DEFAULT_SOURCE; with a
single _GNU_SOURCE define in the makefile alone. For portability to
other libc implementations (e.g. dietlibc) _XOPEN_SOURCE=700 is also
defined.
This also resolves Debian bug report filed by Michael Tautschnig -
"Inconsistent use of _XOPEN_SOURCE results in conflicting
declarations". Whilst I was not able to reproduce the results, the
reported fact is that _XOPEN_SOURCE set to 500 in one set of files
(e.g. cmds-filesystem.c) generates/defines different struct stat from
other files (cmds-replace.c).
This patch thus cleans up all feature defines, and sets them at a
consistent level.
Bug-Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=747969
Signed-off-by: Dimitri John Ledkov <dimitri.j.ledkov@intel.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Run fstests: btrfs/012 will fail with message:
unable to do rollback
It is because the rollback function checks sequentially each piece of space
to map to a certain block group. If some piece doesn't, rollback refuses to continue.
After kernel commit:
commit 47ab2a6c689913db23ccae38349714edf8365e0a
Btrfs: remove empty block groups automatically
Empty block groups are removed, so there are possible gaps:
|--block group 1--| |--block group 2--|
^
|
gap
So the piece of space of the gap belongs to a removed empty block group,
and rollback should detect this case, and feel free to continue.
Signed-off-by: Gui Hecheng <guihc.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
The @search_cache_extent() only returns the next cache_extent or NULL,
it will never return the previous cache_extent.
So just remove the dead condition for previous cache_extent handle.
Signed-off-by: Gui Hecheng <guihc.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
*Note*
this handles the problem under umounted state, the similar problem
under mounted state is already fixed by Anand.
Steps to reproduce:
# mkfs.btrfs -f /dev/sda1
# btrfstune -S 1 /dev/sda1
# mount /dev/sda1 /mnt
# btrfs dev add /dev/sda2 /mnt
# umount /mnt <== (umounted)
# btrfs fi show /dev/sda2
result:
Label: none uuid: XXXXXXXXXXXXXXXXXX
Total devices 2 FS bytes used 368.00KiB
devid 2 size 9.31GiB used 1.25GiB path /dev/sda2
*** Some devices missing
Btrfs v3.16-67-g69f54ea-dirty
It is because @btrfs_scan_lblkid() won't establish mappinig
between the seed and sprout devices. So seeding devices are missing.
We could use @open_ctree_* to detect all seed/sprout mappings
for each fs scanned after @btrfs_scan_lblkid().
sth worthes mention:
o If there are multi-level of seeds, all devices in them will be shown
in the ascending order of @devid
o If device replace is execed on a sprout fs with a device in a seed fs,
the replaced device still exist in the seed fs together with
the replacing device in the sprout fs, so we only keep the latest device
with the newest generation
Signed-off-by: Gui Hecheng <guihc.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Steps to reproduce:
# mkfs.btrfs -f /dev/sda[1-2]
# btrfstune -S 1 /dev/sda1
# mount /dev/sda /mnt
# btrfs dev add /dev/sda3 /mnt
# umount /mnt
# mkfs.ext4 /dev/sda1 // kill seed dev
# mkfs.ext4 /dev/sda2 // kill seed dev
# btrfs-debug-tree /dev/sda3 <== BUG_ON
Output msg:
volumes.c:1824: btrfs_read_chunk_tree: Assertion `ret` failed.
btrfs-debug-tree[0x41cb36]
btrfs-debug-tree(btrfs_read_chunk_tree+0x3ca)
btrfs-debug-tree(btrfs_setup_chunk_tree_and_device_map
btrfs-debug-tree[0x40f695]
btrfs-debug-tree(open_ctree_fs_info+0x86)
btrfs-debug-tree(main+0x12d)
/lib64/libc.so.6(__libc_start_main+0xf5)
btrfs-debug-tree[0x4062e9]
This BUG_ON complains about a failed @read_one_dev() call when
@open_seed_devices() failed to find the seed @fs_devices object
for a dev_item in chunk tree.
In this case, just insert a "shadow" @fs_devices with the fsid in
dev_item shall make no harm since no other tools will try to
make use of the stuff that the "shadow" @fs_devices possesses
after its creation.
After apply this commit, btrfs-debug-tree will report unable
to open the device.
Signed-off-by: Gui Hecheng <guihc.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Asserting is no fun, we may be able to recover from this error in certain cases
(like btrfs-image and btrfsck). Just do what the kernel does and spit out an
error and return that there is only 1 copy. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Recently we merge a memory leak fix, which fails xfstests/btrfs/012,
the cause is that it only frees @fs_devices but leaves it on the global
fs_uuid list, which cause a 'Segmentation fault' over running command
btrfs-convert. This fixes the problem.
Signed-off-by: Liu Bo <bo.li.liu@oracle.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>
When a struct btrfs_fs_devices was being torn down by
btrfs_close_devices(), there was an invalidated pointer in the global
list fs_uuids which still pointed to it; if a device was closed and
then reopened (which btrfs-convert does), freed memory would be
accessed.
This was found using ThreadSanitizer (pretty much doing what
AddressSanitizer would, but not exiting after the first failure).
To reproduce, build with -fsanitize=thread and run 'make test'.
Representative output is below.
This change makes the current tests TSan-clean.
WARNING: ThreadSanitizer: heap-use-after-free (pid=29161)
Read of size 8 at 0x7d180000eee0 by main thread:
#0 memcmp ??:0
#1 find_fsid .../volumes.c:81
#2 device_list_add .../volumes.c:95
#3 btrfs_scan_one_device .../volumes.c:259
#4 btrfs_scan_fs_devices .../disk-io.c:1002
#5 __open_ctree_fd .../disk-io.c:1090
#6 open_ctree_fd .../disk-io.c:1191
#7 do_convert .../btrfs-convert.c:2317
#8 main .../btrfs-convert.c:2745
Previous write of size 8 at 0x7d180000eee0 by main thread:
#0 free ??:0
#1 btrfs_close_devices .../volumes.c:191
#2 close_ctree .../disk-io.c:1401
#3 do_convert .../btrfs-convert.c:2300
#4 main .../btrfs-convert.c:2745
Location is heap block of size 96 at 0x7d180000eee0 allocated by main thread:
#0 calloc ??:0 (exe+0x00000002acc6)
#1 device_list_add .../volumes.c:97
#2 btrfs_scan_one_device .../volumes.c:259
#3 btrfs_scan_fs_devices .../disk-io.c:1002
#4 __open_ctree_fd .../disk-io.c:1090
#5 open_ctree_fd .../disk-io.c:1191
#6 do_convert .../btrfs-convert.c:2256
#7 main .../btrfs-convert.c:2745
Signed-off-by: Adam Buchbinder <abuchbinder@google.com>
Reviewed-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
For RAID0,5,6,10,
For system chunk, there shouldn't be too many stripes to
make a btrfs_chunk that exceeds BTRFS_SYSTEM_CHUNK_ARRAY_SIZE
For data/meta chunk, there shouldn't be too many stripes to
make a btrfs_chunk that exceeds a leaf.
Signed-off-by: Gui Hecheng <guihc.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
For system chunk array,
We copy a "disk_key" and an chunk item each time,
so there should be enough space to hold both of them,
not only the chunk item.
Signed-off-by: Gui Hecheng <guihc.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Valgrind reports memleak in btrfs_scan_one_device() about allocating
btrfs_device but on btrfs_close_devices() they are not reclaimed.
Although not a bug since after btrfs_close_devices() btrfs will exit so
memory will be reclaimed by system anyway, it's better to fix it anyway.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
this patch will make btrfsck operations to open disk in exclusive mode,
so that mount will fail when btrfsck is running
Signed-off-by: Anand Jain <Anand.Jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
free(3) already checks the pointer for NULL, no need to do it
on your own. This patch make the change globally.
Signed-off-by: Gui Hecheng <guihc.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
When reading block groups we will searching it's corresponding chunk, however, at this
time, some chunks has not been built(data chunks raid0/raid10/raid56), don't bug_on here,
we will try to rebuild these chunks later.
Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
I found that mkfs.btrfs aborts when assigned multi volumes contain
a small volume:
# parted /dev/sdf p
Model: LSI MegaRAID SAS RMB (scsi)
Disk /dev/sdf: 72.8GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Number Start End Size Type File system Flags
1 32.3kB 72.4GB 72.4GB primary
2 72.4GB 72.8GB 461MB primary
# ./mkfs.btrfs -f /dev/sdf1 /dev/sdf2
:
SMALL VOLUME: forcing mixed metadata/data groups
adding device /dev/sdf2 id 2
mkfs.btrfs: volumes.c:852: btrfs_alloc_chunk: Assertion `!(ret)' failed.
Aborted (core dumped)
This failure of btrfs_alloc_chunk was caused by following steps:
1) since there is only small space in the small device, mkfs was
going to allocate a chunk from free space as much as available.
So mkfs called btrfs_alloc_chunk with
size = device->total_bytes - device->used_bytes.
2) (According to the comment in source code, to avoid overwriting
superblock,) btrfs_alloc_chunk starts taking chunks at an offset
of 1MB. It means that the layout of a disk will be like:
[[1MB at beginning for sb][allocated chunks]* ... free space ... ]
and you can see that the available free space for allocation is:
avail = device->total_bytes - device->used_bytes - 1MB.
3) Therefore there is only free space 1MB less than requested. damn.
>From further investigations I also found that this issue is easily
reproduced by using -A, --alloc-start option:
# truncate --size=1G testfile
# ./mkfs.btrfs -A900M -f testfile
:
mkfs.btrfs: volumes.c:852: btrfs_alloc_chunk: Assertion `!(ret)' failed.
Aborted (core dumped)
In this case there is only 100MB for allocation but btrfs_alloc_chunk
was going to allocate more than the 100MB.
The root cause of both of above troubles is a same simple bug:
btrfs_chunk_alloc does not calculate available bytes properly even
though it researches how many devices have enough room to have a
chunk to be allocated.
So this patch introduces new function btrfs_device_avail_bytes()
which returns available bytes for allocation in specified device.
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
sparse hates variable length array definitions on the stack:
btrfs-show-super.c:155:21: warning: Variable length array is used.
And it's right to. They're a fragile construct that doesn't handle bad
input well at all.
Signed-off-by: Zach Brown <zab@redhat.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
This fixes all the instances of warnings that symbols declared in blocks
shadow symbols with the same name in surrounding scopes:
cmds-device.c:341:22: warning: symbol 'path' shadows an earlier one
cmds-device.c:285:14: originally declared here
I just renamed or removed the risky shadow symbols instead of pulling
their blocks out into functions.
Signed-off-by: Zach Brown <zab@redhat.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
In files copied from the kernel, mark many functions as static,
and remove any resulting dead code.
Some functions are left unmarked if they aren't static in the
kernel tree.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Port of commit b3b4aa7 to userspace.
parameter tree root it's not used since commit
5f39d397dfbe140a14edecd4e73c34ce23c4f9ee ("Btrfs: Create extent_buffer
interface for large blocksizes")
This gets userspace a tad closer to kernelspace by removing
this unused parameter that was all over the codebase...
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
If the chunk tree search failed in volumes.c:btrfs_read_chunk_tree()
return immediately, rather than looping and use the invalid contents
of the path structure, causing weird errors/crash at run time.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
After reading all device items from the chunk tree, don't
exit the loop and then navigate down the tree again to find
the chunk items. Instead just read all device items and
chunk items with a single tree search. This is possible
because all device items are found before any chunk item in
the chunks tree.
This is a port of the corresponding kernel patch to keep both
kernel and btrfs-progs identical:
https://patchwork.kernel.org/patch/2835529/
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
When allocating a btrfs_device structure, device_list_add()
in volumes.c was not checking if the call to duplicate the
label string succeeded or not.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
The btrfs_read_sys_array function uses 3 variants to read data from
super block.
But the three variants are related to each other, so the patch removes
unneeded extra variants and make code a little simpler.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Some codes still use the cpu_to_lexx instead of the
BTRFS_SETGET_STACK_FUNCS declared in ctree.h.
Also added some BTRFS_SETGET_STACK_FUNCS for btrfs_header and
btrfs_super.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
div_factor has been implemented for two times, cleanup it.
And I move them into a independent file named math.h because they are
common math functions.
[Eric Sandeen: port kernel commit 3fed40c to userspace]
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
If a device could not be opened in volumes.c:read_one_dev(), a
btrfs_device instance was allocated and added to the list of
devices of the fs - however this device instance had its fd,
name and label fields not initialized. This is problematic in
disk-io.c:close_all_devices() as it tried to sync, fadvise and
close the (invalid) fd of the device, and kfree() its name and
label, which pointed to random memory locations.
Thread 1 (Thread 0x7f0a3d2d1740 (LWP 23585)):
#0 __GI___libc_free (mem=0xa5a5a5a5a5a5a5a5) at malloc.c:2970
#1 0x000000000042054b in close_all_devices (fs_info=0x1e92bf0) at disk-io.c:1276
#2 0x0000000000421dcd in close_ctree (root=<optimized out>) at disk-io.c:1336
#3 0x0000000000418cfa in cmd_check (argc=<optimized out>, argv=<optimized out>) at cmds-check.c:4171
#4 0x0000000000403ed4 in main (argc=2, argv=0x7fff9a583d28) at btrfs.c:295
v2: Added Liu Bo's review mention.
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
This adds a 'btrfs-image -m' option, which let us restore an image that
is built from a btrfs of multiple disks onto several disks altogether.
This aims to address the following case,
$ mkfs.btrfs -m raid0 sda sdb
$ btrfs-image sda image.file
$ btrfs-image -r image.file sdc
---------
so we can only restore metadata onto sdc, and another thing is we can
only mount sdc with degraded mode as we don't provide informations of
another disk. And, it's built as RAID0 and we have only one disk,
so after mount sdc we'll get into readonly mode.
This is just annoying for people(like me) who're trying to restore image
but turn to find they cannot make it work.
So this'll make your life easier, just tap
$ btrfs-image -m image.file sdc sdd
---------
then you get everything about metadata done, the same offset with that of
the originals(of course, you need offer enough disk size, at least the disk
size of the original disks).
Besides, this also works with raid5 and raid6 metadata image.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
