Commit Graph

83 Commits

Author SHA1 Message Date
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
Tsutomu Itoh
c55248003c btrfs-progs: setting of time to the root directory
This patch adds the setting of time to the root directory to the
mkfs.btrfs command.
As a result, the time of the mount point not correctly displayed
comes to be displayed correctly.

[before]
 # mkfs.btrfs /dev/sdd10
 # mount /dev/sdd10 /test1
 # ls -ld /test1
 dr-xr-xr-x 1 root root 0 Jan  1  1970 /test1

[after]
 # date
 Tue Nov 16 18:06:05 JST 2010
 # mkfs.btrfs /dev/sdd10
 # mount /dev/sdd10 /test1
 # ls -ld /test1
 dr-xr-xr-x 1 root root 0 Nov 16 18:06 /test1

Thanks,
Tsutomu

Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Hugo Mills <hugo@carfax.org.uk>
2011-10-25 09:18:32 -04:00
Christoph Hellwig
43a06f07c7 btrfs-progs: add discard support to mkfs
Discard the whole device before starting to create the filesystem structures.
Modelled after similar support in mkfs.xfs.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-10-25 09:18:32 -04:00
Goffredo Baroncelli
e8f47cf068 Add the "btrfs filesystem label" command
Hi all,

this patch adds the command "btrfs filesystem label" to change (or show) the
label of a filesystem.
This patch is a subset of the one written previously by Morey Roof. I
included the user space part only. So it is possible only to change/show a
label of a *single device* and *unounted* filesystem.

The reason of excluding the kernel space part, is to simplify the patch in
order to speed the check and then the merging of the patch itself. In fact I
have to point out that in the past there was almost three attempts to propose
this patch, without success neither complaints.

Chris, let me know how you want to proceed. I know that you are very busy,
and you prefer to work to stabilize btrfs instead adding new feature. But I
think that changing a label is a *essential* feature for a filesystem
managing tool. Think about a mount by LABEL.

To show a label

$ btrfs filesystem label <device>

To set a label

$ btrfs filesystem label <device> <newlabel>

Please guys, give a look to the source.
Comments are welcome.

You can pull the source from the branch "label" of the repository
http://cassiopea.homelinux.net/git/btrfs-progs-unstable.git

Regards
G.Baroncelli

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-10-25 09:18:31 -04:00
Josef Bacik
b8802ae3fa Btrfs-progs: add support for mixed data+metadata block groups
So alot of crazy people (I'm looking at you Meego) want to use btrfs on phones
and such with small devices.  Unfortunately the way we split out metadata/data
chunks it makes space usage inefficient for volumes that are smaller than
1gigabyte.  So add a -M option for mixing metadata+data, and default to this
mixed mode if the filesystem is less than or equal to 1 gigabyte.  I've tested
this with xfstests on a 100mb filesystem and everything is a-ok.

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-10-25 09:18:31 -04:00
Josef Bacik
e2a6859d93 Btrfs-progs: update super fields for space cache
This patch updates the super field to add the cache_generation member.  It also
makes us set it to -1 on mkfs so any new filesystem will get the space cache
stuff turned on.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-10-25 09:18:31 -04:00
Goffredo Baroncelli
17cf679fb3 Improve error handling in the btrfs command
Hi Chris,

below is enclosed a trivial patch, which has the aim to improve the error
reporting of the "btrfs" command.

You can pull from

	http://cassiopea.homelinux.net/git/btrfs-progs-unstable.git

branch

	strerror

I changed every printf("some-error") to something like:

	e = errno;
	fprintf(stderr, "ERROR: .... - %s", strerror(e));

so:

1) all the error are reported to standard error
2) At the end of the message is printed the error as returned by the system.

The change is quite simple, I replaced every printf("some-error") to the line
above. I don't touched anything other.
I also integrated a missing "printf" on the basis of the Ben patch.

This patch leads the btrfs command to be more "user friendly" :-)

Regards
G.Baroncelli

 btrfs-list.c |   40 ++++++++++++++++++++++--------
 btrfs_cmds.c |   77 ++++++++++++++++++++++++++++++++++++++++-----------------
 utils.c      |    6 ++++
 3 files changed, 89 insertions(+), 34 deletions(-)

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-10-25 09:18:31 -04:00
Goldwyn Rodrigues
eb5418933f Btrfs-progs utils Informative errors
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-10-25 09:18:31 -04:00
Eduardo Silva
16261f09c4 Btrfs-progs use safe string manipulation functions
Signed-off-by: Eduardo Silva <eduardo.silva@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-10-25 09:18:31 -04:00
Andi Drebes
09559bfe7b multidevice support for check_mounted
Check_mount() should also work with multi device filesystems.
This patch adds checks that allow to detect if a file is a device
file used by a mounted single or multi device btrfs or if it is a
regular file used by a loopback device that is part of a mounted
single or multi device btrfs.

The single device checks also work for non-btrfs filesystems.
This might be helpful to prevent users from running btrfs programs
(e.g. mkfs.btrfs) accidentally on a filesystem used somewhere else.

Signed-off-by: Andi Drebes <lists-receive@programmierforen.de>
2010-09-23 20:26:49 -04:00
Chris Mason
95d3f20b51 Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.

The new back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer by
searching the tree. The shortcoming of the new back ref is that it only works
for pointers in tree blocks referenced by their owner trees.

This is mostly a problem for snapshots, where resolving one of these fuzzy back
references would be O(number_of_snapshots) and quite slow.  The solution used
here is to use the fuzzy back references in the common case where a given tree
block is only referenced by one root, and use the full back references when
multiple roots have a reference
2009-06-08 13:30:36 -04:00