Commit Graph

93 Commits

Author SHA1 Message Date
Anand Jain
b3a9a3c94a btrfs-progs: get_label_mounted to return label instead of print
This would help to reuse the function

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-08-09 14:32:37 +02:00
Anand Jain
5333445574 btrfs-progs: congregate dev scan
the dev scan to find btrfs is performed at two locations
all most the same way one at filesystem show and another
at device scan. They both follow the same steps. This
patch does not alter anything except that it brings these
two same logic into the function scan_for_btrfs so that
we can play tweaking it.

the patch which recommends to use /dev/mapper
will also need it

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-08-09 14:32:36 +02:00
Anand Jain
65ed88d472 btrfs-progs: btrfs_scan_for_fsid doesn't need all the arguments
btrfs_scan_for_fsid uses only one argument run_ioctl out of 3
so remove the rest two of them

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-08-09 14:32:36 +02:00
Wang Shilong
c125b7cf43 Btrfs-progs: fix closing of opendir()
valgrind complains open_file_or_dir() causes a memory leak.That is because
if we open a directoy by opendir(), and then we should call closedir()
to free memory.

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>
2013-08-09 14:32:36 +02:00
David Sterba
76f0b7e187 btrfs-progs: use IEC units for sizes
As implemented now, we use 1024 based units but reporting 1000 based,
let's finally fix that and add optional unit bases later.

Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-08-09 14:32:35 +02:00
Filipe David Borba Manana
2e9adfb909 Btrfs-progs: return error on write failure in make_btrfs()
Instead of aborting with a BUG_ON() statement, return a
negated errno code. Also updated mkfs and convert tools
to print a nicer error message when make_btrfs() returns
an error.

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>
2013-08-09 14:32:33 +02:00
Filipe David Borba Manana
80bab0f18c Btrfs-progs: add missing write check for mkfs
Assert that the writes of the device and chunk tree
roots succeed. This verification is currently done
for all other tree roots, however it was missing for
those 2 trees.

Would these tree root writes fail, but all others succeed,
it would lead to a corrupted/incomplete btrfs filesystem,
or, more likely some weird failure later on in mkfs.btrfs
inside open_ctree().

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>
2013-08-09 14:32:33 +02:00
Zach Brown
876e3f9380 btrfs-progs: per-thread, per-call pretty buffer
We don't need callers to manage string storage for each pretty_sizes()
call.  We can use a macro to have per-thread and per-call static storage
so that pretty_sizes() can be used as many times as needed in printf()
arguments without requiring a bunch of supporting variables.

This lets us have a natural interface at the cost of requiring __thread
and TLS from gcc and a small amount of static storage.  This seems
better than the current code or doing something with illegible format
specifier macros.

Signed-off-by: Zach Brown <zab@redhat.com>
Acked-by: Wang Shilong <wangs.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-08-09 14:32:33 +02:00
Qu Wenruo
6c10240e4e btrfs-progs: Cleanup for using BTRFS_SETGET_STACK instead of raw convert
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>
2013-08-09 14:32:32 +02:00
Anand Jain
617efb6bb8 btrfs-progs: mkfs seg fault for wrong free
With commit
        87c09f7 Btrfs-progs: fix memory leaks on cleanup

mkfs on multiple dev is ending with segfault at
close_all_devices() during kfree(device->name)

because mkfs calls btrfs_add_to_fsid, which does not initialize
name when dev is added to the list.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-05-02 22:30:02 -04:00
Anand Jain
4b3c9136be btrfs-progs: mkfs should first check all disks before writing to a disk
In the cases where one of the disk is not suitable for
btrfs, then we would fail the mkfs, however we determine
that after we have written btrfs to the preceding disks.
At this time if user changes mind for not to use btrfs
will left with no choice.

So this patch will check if all the provided disks are
suitable for the btrfs at once before proceeding to
create btrfs on a disk.

Further this patch also removed duplicate code to check
device suitability for the btrfs.

Next, there is an existing bug about the -r mkfs option,
which this patch would carry forward most of it.
Ref:
[PATCH 2/2, RFC] btrfs-progs: overhaul mkfs.btrfs -r option

Signed-off-by: Anand Jain <anand.jain@oracle.com>

to merg prev

Signed-off-by: Anand Jain <anand.jain@oracle.com>
2013-04-23 18:56:20 +02:00
Anand Jain
486e7ca4cd btrfs-progs: delete unused function get_mountpt
and get_btrfs_mount has replaced it

Signed-off-by: Anand Jain <anand.jain@oracle.com>
2013-04-23 18:56:19 +02:00
Josef Bacik
d6f7e3da0d Btrfs-progs: make btrfs-image restore with a valid chunk tree V2
Previously btrfs-image would set a METADUMP flag and would make one big system
chunk to cover the entire file system in the super in order to get around the
unpleasant business of having to adjust the chunk tree.  This meant that you
could use the progs stuff on a restored file system, which is great for testing
btrfsck and other such things.  But we want to be able to run the tree log
replay on a file system that is not able to run the tree log replay.  So in
order to do this we need to fixup the super's chunk array and the chunk tree
itself.  This is pretty easy since we restore using the logical offsets of the
metadata, so we just have to set the chunk items to have 1 stripe and have the
stripes point at the primary device and then use the logical offset of the chunk
as the physical offset.  With this patch I can restore a file system image that
had a tree log and mount the file system and have the log be replayed
successfully.  This patch also gives you the -o option in case you want the old
restore way, in the case where we want to make sure the system chunks as they
were given to us are correct.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-04-09 18:43:24 +02:00
Anand Jain
44a33d0d14 btrfs-progs: print errno string when /dev/btrfs-control open fails
Of recently and intermittently I am seeing open fail
for /dev/btrfs-control (btrfs is loaded), and there are no
dmesg errors, this may not be a complete help in digging
this issue but something which is necessary.
Thanks

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
2013-03-14 23:43:04 +01:00
Eric Sandeen
7a355379ea btrfs-progs: rework get_fs_info to remove side effects
get_fs_info() has been silently switching from a device to a mounted
path as needed; the caller's filehandle was unexpectedly closed &
reopened outside the caller's scope.  Not so great.

The callers do want "fdmnt" to be the filehandle for the mount point
in all cases, though - the various ioctls act on this (not on an fd
for the device).  But switching it in the local scope of get_fs_info
is incorrect; it just so happens that *usually* the fd number is
unchanged.

So - use the new helpers to detect when an argument is a block
device, and open the the mounted path more obviously / explicitly
for ioctl use, storing the filehandle in fdmnt.

Then, in get_fs_info, ignore the fd completely, and use the path on
the argument to determine if the caller wanted to act on just that
device, or on all devices for the filesystem.

Affects those commands which are documented to accept either
a block device or a path:

* btrfs device stats
* btrfs replace start
* btrfs scrub start
* btrfs scrub status

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
2013-03-12 17:07:40 +01:00
Eric Sandeen
10e00b0764 btrfs-progs: three new device/path helpers
Add 3 new helpers:

* is_block_device(), to test if a path is a block device.
* get_btrfs_mount(), to get the mountpoint of a device,
  if mounted.
* open_path_or_dev_mnt(path), to open either the pathname
  or, if it's a mounted btrfs dev, the mountpoint.  Useful
  for some commands which can take either type of arg.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
2013-03-12 16:44:40 +01:00
Eric Sandeen
5bc34c6602 btrfs-progs: close fd on return from label get/set functions
Somehow missed these 2 in the last round.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
2013-03-12 16:34:41 +01:00
David Sterba
dd21bc16ad btrfs-progs: separate super_copy out of fs_info
Allocate fs_info::super_copy dynamically of full BTRFS_SUPER_INFO_SIZE
and use it directly for saving superblock to disk.

This fixes incorrect superblock checksum after mkfs.

Signed-off-by: David Sterba <dsterba@suse.cz>
2013-03-10 16:12:21 +01:00
Eric Sandeen
1b18ff60b1 btrfs-progs: check for null string in parse_size
Because it's better than a segfault if it's called improperly,
and it makes static checkers happier.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
2013-03-10 15:54:49 +01:00
Anand Jain
ec68ca2202 btrfs-progs: from troubleshooting point of view messages must be unique
-----
cmds-device.c:                  fprintf(stderr, "ERROR: unable to scan the device '%s' - %s\n",
utils.c:                fprintf(stderr, "ERROR: unable to scan the device '%s' - %s\n",
-----

Signed-off-by: Anand Jain <anand.jain@oracle.com>
2013-03-03 17:34:33 +01:00
Anand Jain
57ca339bf4 Btrfs-progs: add correct indentation
A trivial fix, corrects the indentation.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
2013-02-27 16:47:26 +01:00
Jeff Liu
efbbbc88cb btrfs-progs: move btrfslabel.[c|h] stuff to utils.[c|h]
Clean btrfslabel.[c|h] out of the source tree and move those related
functions to utils.[c|h].

CC: Gene Czarcinski <gene@czarc.net>
Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
2013-02-26 19:27:22 +01:00
Jeff Liu
63a44771a4 btrfs-progs: refactor check_label()
Refactor check_label().

- Make it be static at first, this is a preparation step since we'll remove
btrfslabel.[c|h] and move those functions from there to utils.[c|h], we can
do pre-checking against the input label string with it.
- Fix the label length check up from BTRFS_LABEL_SIZE to BTRFS_LABEL_SIZE - 1.
- Kill the check of label contains an invalid character, see below commits for detail:
  79e0e445fc
  btrfs-progs: kill check for /'s in labels.

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
CC: David Sterba <dsterba@suse.cz>
CC: Gene Czarcinski <gene@czarc.net>
2013-02-26 19:24:14 +01:00
Tsutomu Itoh
d065d63057 Btrfs-progs: check out if the swap device
Currently, the following commands succeed.

 # cat /proc/swaps
 Filename                                Type            Size    Used    Priority
 /dev/sda3                               partition       8388604 0       -1
 /dev/sdc8                               partition       9765884 0       -2
 # mkfs.btrfs /dev/sdc8

 WARNING! - Btrfs v0.20-rc1-165-g82ac345 IS EXPERIMENTAL
 WARNING! - see http://btrfs.wiki.kernel.org before using

 fs created label (null) on /dev/sdc8
         nodesize 4096 leafsize 4096 sectorsize 4096 size 9.31GB
 Btrfs v0.20-rc1-165-g82ac345
 # btrfs fi sh /dev/sdc8
 Label: none  uuid: fc0bdbd0-7eed-460f-b4e9-131273b66df2
         Total devices 1 FS bytes used 28.00KB
         devid    1 size 9.31GB used 989.62MB path /dev/sdc8

 Btrfs v0.20-rc1-165-g82ac345
 #

But we should check out the swap device. Fixed it.

Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
2013-02-19 11:15:30 +01:00
Eric Sandeen
a8cb2d03dd Btrfs-progs print more informative error when we fail to open a device
print more informative error when we fail to open a device

If open() fails, we should let the user know why it failed.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Gene Czarcinski <gene@czarc.net>
2013-02-06 23:09:02 +01:00
Eric Sandeen
bcb2b73358 btrfs-progs: simplify ioctl name copy and null termination
In the places where we copy a string into the name
member of btrfs_ioctl_vol_args or btrfs_ioctl_vol_args_v2,
we use strncopy (to not overflow the name array) and then
set the last position to the null character.

Howver, in both cases the arrays are defined with:

        char name[MAX+1];

hence the last array position is name[MAX].

In most cases, we now insert the null at name[MAX-1]
which deprives us of one useful character.

Even the above isn't consistent through the code, so
make some helper code to make it simple, i.e.
strncpy_null(dest, src) which automatically does the
right thing based on the size of dest.

Thanks to Zach Brown for the macro suggestion.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
2013-02-05 16:09:41 -08:00
Zach Brown
de763395fb btrfs-progs: fix overflow in btrfs_scan_one_dir()
btrfs_scan_one_dir() can overflow an arbitrarily small 256 byte buffer
with an arbitrarily slightly larger 1024 byte buffer as it remembers the
path of a dir to later descend.

Make these buffers the same size to stop the overflow and chose PATH_MAX
for that size so that it won't fail on legitimately bonkers paths.

Signed-off-by: Zach Brown <zab@redhat.com>
2013-02-05 16:09:39 -08:00
Zach Brown
aaf682ac2e btrfs-progs: array indexes must be < ARRAY_SIZE()
It looks like the usual kernel idiom of "< ARRAY_SIZE()" was
accidentally negated as ">" instead of ">=".

Signed-off-by: Zach Brown <zab@redhat.com>
2013-02-05 16:09:39 -08:00
Zach Brown
52162700bb btrfs-progs: treat super.magic as an le64
The super block magic is a le64 whose value looks like an unterminated
string in memory.  The lack of null termination leads to clumsy use of
string functions and causes static analysis tools to warn that the
string will be unterminated.

So let's just treat it as the le64 that it is.  Endian wrappers are used
on the constant so that they're compiled into run-time constants.

Signed-off-by: Zach Brown <zab@redhat.com>
2013-02-05 16:09:32 -08:00
Stefan Behrens
7a69dc4eec Btrfs-progs: make two utility functions globally available
Two convenient utility functions that have so far been local to scrub are
moved to utils.c.
They will be used in the device stats code in a following commit.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
2013-01-30 00:40:35 +01:00
Anand Jain
46e3b8087b Btrfs-progs: move open_file_or_dir() to utils.c
The definition of the function open_file_or_dir() is moved from common.c
to utils.c in order to be able to share some common code between scrub
and the device stats in the following step. That common code uses
open_file_or_dir(). Since open_file_or_dir() makes use of the function
dirfd(3), the required XOPEN version was raised from 6 to 7.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Original-Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
2013-01-30 00:40:35 +01:00
Nirbheek Chauhan
abdb0ced01 Btrfs-progs: fix resolving of loop devices
The LOOP_GET_STATUS ioctl truncates filenames to 64 characters. We should get
the backing file for a given loop device from /sys/. This is how losetup does it
as well.

Signed-off-by: Nirbheek Chauhan <nirbheek.chauhan@collabora.co.uk>
Signed-off-by: Gene Czarcinski <gene@czarc.net>
Tested-By: Hector Oron <hector.oron@collabora.co.uk>
2013-01-21 18:28:00 +01:00
Goffredo Baroncelli
681813b797 Ignore the error ENXIO and ENOMEDIUM during a devs scan
Ignore the error ENXIO (device don't exists) and ENOMEDIUM (
No medium found -> like a cd tray empty) in the function
btrfs_scan_one_dir.
This avoids spurios errors due to an empty CD or a block device node
without a device (which is frequent in a static /dev).

Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it>
2013-01-18 18:25:50 +01:00
Kenji Okimoto
6e0e6c5e63 btrfs-progs: plug memory leaks in btrfs_scan_one_dir() reported by cppcheck.
[utils.c:983]: (error) Memory leak: fullpath

Signed-off-by: Kenji Okimoto <okimoto@clear-code.com>
2013-01-17 18:27:55 +01:00
Goffredo Baroncelli
9495b4d228 parse_size(): add new suffixes
Add new suffixes in parse_size() function. New suffixes are: T as
terabyte, P as petabyte, E as exabyte. Note these units are
multiply of 2 .

Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it>
2013-01-17 18:27:54 +01:00
Goffredo Baroncelli
6318867602 parse_size(): replace atoll() with strtoull()
Replace the function atoll with strtoull(); Check that the suffix for the
parse_size() input is of only one character.

Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it>
2013-01-17 18:27:54 +01:00
Goffredo Baroncelli
8f76aee6bc Move parse_size() to utils.[hc]
Move the function from cmds-filesystem.c and mkfs.c to utils.c

Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it>
2013-01-17 18:27:54 +01:00
Goffredo Baroncelli
29db8b12cd pretty_sizes() returns incorrect values
pretty_sizes() returns incorrect values if the argument is < 1024.

pretty_sizes(0) -> 0.00		OK
pretty_sizes(102) -> 0.10	WRONG
pretty_sizes(1023) -> 1.00	WRONG
pretty_sizes(1024) -> 1.00KB	OK

Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-10-04 16:26:33 -04:00
Josef Bacik
605e806166 Btrfs-progs: only enforce a maximum size if we specify one
My patch

04609add88

introduced a regression where if you mkfs'ed a group of disks with different
sizes it limited the disks to the size of the first one that is specified.
This was not the intent of my patch, I only want it to limit the size based
on the -b option, so I've reworked the code to pass in a max block count and
that fixes the issue.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-10-02 13:02:48 +02:00
David Sterba
17e6d421a9 btrfs-progs: mkfs: create root directory with 755 permissions
That's what all other mkfs do and there's no reason for 0555.

Signed-off-by: David Sterba <dsterba@suse.cz>
2012-10-02 13:02:39 +02:00
David Sterba
8935d84361 btrfs-progs: mkfs: add option to skip trim
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-07-06 10:11:10 -04:00
Josef Bacik
04609add88 btrfs-progs: enforce block count on all devices in mkfs
I had a test that creates a 7gig raid1 device but it was ending up wonky
because the second device that gets added is the full size of the disk
instead of the limited size.  So enforce the limited size on all disks
passed in at mkfs time, otherwise our threshold calculations end up wonky
when doing chunk allocations.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
2012-07-03 16:27:46 -04:00
Jim Meyering
54e345b5c2 avoid several strncpy-induced buffer overruns
* restore.c (main): Ensure strncpy-copied dir_name is NUL-terminated.
* btrfsctl.c (main): Likewise, for a command-line argument.
* utils.c (multiple functions): Likewise.
* btrfs-list.c (add_root): Likewise.
* btrfslabel.c (change_label_unmounted): Likewise.
* cmds-device.c (cmd_add_dev, cmd_rm_dev, cmd_scan_dev): Likewise.
* cmds-filesystem.c (cmd_resize): Likewise.
* cmds-subvolume.c (cmd_subvol_create, cmd_subvol_delete, cmd_snapshot):
Likewise.

Reviewed-by: Josef Bacik <josef@redhat.com>
2012-06-05 19:56:20 +01:00
Jim Meyering
0195702a09 btrfs_scan_one_dir: avoid use-after-free on error path
If we iterate the "goto again" loop, we've called "closedir(dirp)",
yet at the top of the loop, upon malloc failure we "goto fail",
where we test dirp and if non-NULL, call closedir(dirp) again.
* utils.c (btrfs_scan_one_dir): Clear "dirp" after closedir to avoid
use-after-free upon failed fullpath = malloc(...

Signed-off-by: Jim Meyering <meyering@redhat.com>
2012-06-05 19:56:20 +01:00
Chris Mason
8f01235dd8 Scan /dev/md and device mapper devices last
When we're using multipath or raid0, it is possible
that btrfs dev scan will find one of the component devices
instead of the proper virtual device the kernel creates.

We want to make sure the kernel scans the virtual devices last,
since it always remembers the last device it finds with a given fsid.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-02-22 10:59:55 -05:00
Chris Mason
32eff71182 Btrfs: use /proc/partitions scanning for btrfs_scan_for_fsid
btrfs_scan_for_fsid is used by open_ctree and by mkfs when it is
checking for mounted devices.  It currently scans all of /dev,
which is rarely the right answer.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-02-21 15:35:13 -05:00
Chris Mason
ba1aa28496 btrfs-progs: fixup is_mounted checks
/proc/mounts contains device names that don't exist,
we end up erroring out because we're not able to stat
the device (that doesn't exist).

Fix this by allowing the mkfs when the target device doesn't exist.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-10-27 16:23:14 -04:00
Goffredo Baroncelli
0dbd99fb3e Scan the devices listed in /proc/partitions
During the commands:
	- btrfs filesystem show
	- btrfs device scan
the devices "scanned" are extracted from /proc/partitions. This
should avoid to scan devices not suitable for a btrfs filesystem like cdrom
and floppy or to scan not existant devices.
The old behavior (scan all the block devices under /dev) may be
forced passing the "--all-devices" switch.
2011-10-25 09:19:00 -04:00
Jan Schmidt
828f2b30df btrfs-progs: added check_mounted_where
new version of check_mounted() returning more information gathered while
searching. check_mounted() is now a wrapper for check_mounted_where(). the
new version is needed by scrub.c

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Hugo Mills <hugo@carfax.org.uk>
2011-10-25 09:18:59 -04:00
Jan Schmidt
42f9568bfd mkfs should initialize unused fields properly
we discovered speed setting is (probably unintentionally) initialized to 1 in make_btrfs(), while being initialized to 0 in btrfs_add_to_fsid(). initialization in make_btrfs() is due to reuse of buf after pwrite() without clearing it. consequently, code like

 	btrfs_set_extent_generation(buf, extent_item, 1);

writes to the same location in buf where speed will be placed, later. It may be a good idea to clear buf after each pwrite(), though leaving the struct btrfs_header intact.

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Hugo Mills <hugo@carfax.org.uk>
2011-10-25 09:18:32 -04:00