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lvm uses a bcache block size of 128K. A bcache block
at the end of the metadata area will overlap the PEs
from which LVs are allocated. How much depends on
alignments. When lvm reads and writes one of these
bcache blocks to update VG metadata, it can also be
reading and writing PEs that belong to an LV.
If these overlapping PEs are being written to by the
LV user (e.g. filesystem) at the same time that lvm
is modifying VG metadata in the overlapping bcache
block, then the user's updates to the PEs can be lost.
This patch is a quick hack to prevent lvm from writing
past the end of the metadata area.
This is the number of concurrent async io requests that
the scan layer will submit to the bcache layer. There
will be an open fd for each of these, so it is best to
keep this well below the default limit for max open files
(1024), otherwise lvm may get EMFILE from open(2) when
there are around 1024 devices to scan on the system.
When lvm2 command is executed in test mode, discard ioctl is skipped.
This may cause even data-loose in case, issuing discard for released
areas was enabled and user 'tested' lvreduce.
udev creates a train wreck of events if we open devices
with RDWR. Until we can fix/disable/scrap udev, work around
this by opening RDONLY and then closing/reopening RDWR when
a write is needed. This invalidates the bcache blocks for
the device before writing so it can trigger unnecessary
rereading.
The md filter can operate in two native modes:
- normal: reads only the start of each device
- full: reads both the start and end of each device
md 1.0 devices place the superblock at the end of the device,
so components of this version will only be identified and
excluded when lvm uses the full md filter.
Previously, the full md filter was only used in commands
that could write to the device. Now, the full md filter
is also applied when there is an md 1.0 device present
on the system. This means the 'pvs' command can avoid
displaying md 1.0 components (at the cost of doubling
the i/o to every device on the system.)
(The md filter can operate in a third mode, using udev,
but this is disabled by default because there have been
problems with reliability of the info returned from udev.)
Remove the io error message from bcache.c since it is not
very useful without the device path.
Make the io error messages from dev_read_bytes/dev_write_bytes
more user friendly.
We have been warning about duplicate devices (and disabling lvmetad)
immediately when the dup was detected (during label_scan). Move the
warnings (and the disabling) to happen later, after label_scan is
finished.
This lets us avoid an unwanted warning message about duplicates
in the special case were md components are eliminated during the
duplicate device resolution.
The device-mapper directory now holds a copy of libdm source. At
the moment this code is identical to libdm. Over time code will
migrate out to appropriate places (see doc/refactoring.txt).
The libdm directory still exists, and contains the source for the
libdevmapper shared library, which we will continue to ship (though
not neccessarily update).
All code using libdm should now use the version in device-mapper.
As we start refactoring the code to break dependencies (see doc/refactoring.txt),
I want us to use full paths in the includes (eg, #include "base/data-struct/list.h").
This makes it more obvious when we're breaking abstraction boundaries, eg, including a file in
metadata/ from base/
md devices using an older superblock version have
superblocks at the end of the md device. For commands
that skip reading the end of devices during filtering,
the md component devs will be scanned, and will appear
as duplicate PVs to the original md device. Remove
these md components from the list of unused duplicate
devices, so they are treated as if they had been
ignored during filtering. This avoids the restrictions
that are placed on using PVs with duplicates.
All these functions are now used as utilities,
e.g. for ioctl (not for io), and need to
open/close the device each time they are called.
(Many of the opens can probably be eliminated by
just using the bcache fd for the ioctl.)
Filters are still applied before any device reading or
the label scan, but any filter checks that want to read
the device are skipped and the device is flagged.
After bcache is populated, but before lvm looks for
devices (i.e. before label scan), the filters are
reapplied to the devices that were flagged above.
The filters will then find the data they need in
bcache.
bcache_invalidate() now returns a bool to indicate success. If fails
if the block is currently held, or the block is dirty and writeback
fails.
Added a bunch of unit tests for the invalidate functions.
Fixed some bugs to do with invalidating errored blocks.
The error handling code wasn't working, but it
appears that just removing it is what we need.
The doesn't really need any different behavior
related to bcache blocks on an io error, it just
wants to know if there was an error.
Create a new dev->bcache_fd that the scanning code owns
and is in charge of opening/closing. This prevents other
parts of lvm code (which do various open/close) from
interfering with the bcache fd. A number of dev_open
and dev_close are removed from the reading path since
the read path now uses the bcache.
With that in place, open(O_EXCL) for pvcreate/pvremove
can then be fixed. That wouldn't work previously because
of other open fds.
New label_scan function populates bcache for each device
on the system.
The two read paths are updated to get data from bcache.
The bcache is not yet used for writing. bcache blocks
for a device are invalidated when the device is written.
With these read errors it's useful to know the reason.
Also avoid to log error just once so we know exactly
how many times we did failing read.
On the other hand reduce repeated log_error() on code 'backtrace'
path and change severity of message to just log_debug() so the
actual read error is printed once for one read.
Actually the removed code is necessary - since not all writes are
getting alligned buffer - older compilers seems to be not able
to create 4K aligned buffers on stack - this the aligning code still
need to be present for write path.
If the data being requested is present in last_[extra_]devbuf,
return that directly instead of reading it from disk again.
Typical LVM2 access patterns request data within two adjacent 4k blocks
so we eliminate some read() system calls by always reading at least 8k.
Callers that read larger amounts of data now get a pointer to read-only
data directly without copying it through an intermediate buffer. This
data is owned by the device layer so the callers no longer free it.
If it obtains the data, it passes it into the supplied callback function
and returns 1. Otherwise the callback receives failed = 1.
Updated config_file_read_fd to use this and similarly return the data
via a callback fn of its own.
Rename dev_read() to dev_read_buf() - the function that reads data
into a supplied buffer.
Introduce a new dev_read() that allocates the buffer it returns and
switch the important users over to this. No caller may change the
returned data. (For now, callers are responsible for freeing it after
use, but later the device layer will take full ownership.)
dev_read_buf() should only be used for tiny buffers or unimportant code
(such as the old disk formats).
The creation of wrapped around metadata - where the start of metadata is
written up to the end of the buffer and the remainder follows back at
the start of the buffer - is now restricted to cases where writing the
metadata in one piece wouldn't fit. This shouldn't happen in 'normal'
usage so let's begin treating the code for this as a special case that
can be ignored when optimising 'normal' cases.
Mark the first metadata area on each text format PV as MDA_PRIMARY.
Pass this information down to the device layer so that when
there are two metadata areas on a block device, we can easily
distinguish two independent streams of I/O.
Introduce enum dev_io_reason to categorise block device I/O
in debug messages so it's obvious what it is for.
DEV_IO_SIGNATURES /* Scanning device signatures */
DEV_IO_LABEL /* LVM PV disk label */
DEV_IO_MDA_HEADER /* Text format metadata area header */
DEV_IO_MDA_CONTENT /* Text format metadata area content */
DEV_IO_FMT1 /* Original LVM1 metadata format */
DEV_IO_POOL /* Pool metadata format */
DEV_IO_LV /* Content written to an LV */
DEV_IO_LOG /* Logging messages */
- Use 'lvmcache' consistently instead of 'metadata cache'
- Always use 5 characters for source line number
- Remember to convert uuids into printable form
- Use <no name> rather than (null) when VG has no name.
Replaced the confusing device error message "not found (or ignored by
filtering)" by either "not found" or "excluded by a filter".
(Later we should be able to say which filter.)
Left the the liblvm code paths alone.
Older udev versions (udev < v165), don't have the official
udev_device_get_is_initialized function available to query for
device initialization state in udev database. Also, devices don't
have USEC_INITIALIZED udev db variable set - this is bound to the
udev_device_get_is_initialized fn functionality.
In this case, check for "DEVLINKS" variable instead - all block devices
have at least one symlink set for the node (the "/dev/block/<major:minor>".
This symlink is set by default basic udev rules provided by udev directly.
We'll use this as an alternative for the check that initial udev
processing for a device has already finished.
Treat loop device created with 'losetup -P' as regular
partitioned device - so if it has partition table,
prevent its usage in commands like 'pvcreate'.
Before 'pvcreate /dev/loop0' could have erased and formated as PV,
after this patch, device is filtered out and cannot be used.
When not obtaining device from udev, we are doing deep devdir scan,
and at the same time we try to insert everything what /sys/dev/block
knows about. However in case lvm2 is configured to use nonstardard
devdir this way it will see (and scan) devices from a real system.
lvm2 test suite is using its own test devdir with its
own device nodes. To avoid touching real /dev devices, validate
the device node exist in give dir and do not insert such device
into a cache.
With obtain list from udev this patch has no effect
(the normal user path).
We have _insert_dirs() for udev and non-udev compilation.
Compiling without udev missed to call dev_cache_index_devs().
Move the call after _insert_dirs() call so both compilation
gets it.
/sys/dev/block is available since kernel version 2.2.26 (~ 2008):
https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-dev
The VGID/LVID indexing code relies on this feature so skip indexing
if it's not available to avoid error messages about inability to open
/sys/dev/block directory.
We're not going to provide fallback code to read the /sys/block/
instead in this case as that's not that efficient - it needs extra
reads for getting major:minor and reading partitions would also
pose further reads and that's not worth it.
If obtain_device_list_from_udev=0, LVM can make use of persistent .cache
file. This cache file contains only devices which underwent filters in
previous LVM command run. But we need to iterate over all block devices
to create the VGID/LVID index completely for the device mismatch check
to be complete as well.
This patch iterates over block devices found in sysfs to generate the
VGID/LVID index in dev cache if obtain_device_list_from_udev=0
(if obtain_device_list_from_udev=1, we always read complete list of
block devices from udev and we ignore .cache file so we don't need
to look in sysfs for the complete list).
For the case when we print device name associated with struct device
that was not found in /dev, but in sysfs, for example when printing
devices where LV device mismatch is found.
It's correct to have a DM device that has no DM UUID assigned
so no need to issue error message in this case. Also, if the
device doesn't have DM UUID, it's also clear it's not an LVM LV
(...when looking for VGID/LVID while creating VGID/LVID indices
in dev cache).
For example:
$ dmsetup create test --table "0 1 linear /dev/sda 0"
And there's no PV in the system.
Before this patch (spurious error message issued):
$ pvs
_get_sysfs_value: /sys/dev/block/253:2/dm/uuid: no value
With this patch applied (no spurious error message):
$ pvs
If we're using persistent .cache file, we're reading this file instead
of traversing the /dev content. Fix missing indexing by VGID and LVID
here - hook this into persistent_filter_load where we populate device
cache from persistent .cache file instead of scanning /dev.
For example, inducing situation in which we warn about different device
actually used than what LVM thinks should be used based on metadata:
$ lsblk -s /dev/vg/lvol0
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
vg-lvol0 253:4 0 124M 0 lvm
`-loop1 7:1 0 128M 0 loop
$ lvmconfig --type diff
global {
use_lvmetad=0
}
devices {
obtain_device_list_from_udev=0
}
(obtain_device_list_from_udev=0 also means the persistent .cache file is used)
Before this patch - pvs is fine as it does the dev scan, but lvs relies
on persistent .cache file and it misses the VGID/LVID indices to check
and warn about incorrect devices used:
$ pvs
Found duplicate PV B9gXTHkIdEIiMVwcOoT2LX3Ywh4YIHgR: using /dev/loop0 not /dev/loop1
Using duplicate PV /dev/loop0 without holders, ignoring /dev/loop1
WARNING: Device mismatch detected for vg/lvol0 which is accessing /dev/loop1 instead of /dev/loop0.
PV VG Fmt Attr PSize PFree
/dev/loop0 vg lvm2 a-- 124.00m 0
$ lvs
Found duplicate PV B9gXTHkIdEIiMVwcOoT2LX3Ywh4YIHgR: using /dev/loop0 not /dev/loop1
Using duplicate PV /dev/loop0 without holders, ignoring /dev/loop1
LV VG Attr LSize
lvol0 vg -wi-a----- 124.00m
With this patch applied - both pvs and lvs is fine - the indices are
always created correctly (lvs just an example here, other LVM commands
that rely on persistent .cache file are fixed with this patch too):
$ pvs
Found duplicate PV B9gXTHkIdEIiMVwcOoT2LX3Ywh4YIHgR: using /dev/loop0 not /dev/loop1
Using duplicate PV /dev/loop0 without holders, ignoring /dev/loop1
WARNING: Device mismatch detected for vg/lvol0 which is accessing /dev/loop1 instead of /dev/loop0.
PV VG Fmt Attr PSize PFree
/dev/loop0 vg lvm2 a-- 124.00m 0
$ lvs
Found duplicate PV B9gXTHkIdEIiMVwcOoT2LX3Ywh4YIHgR: using /dev/loop0 not /dev/loop1
Using duplicate PV /dev/loop0 without holders, ignoring /dev/loop1
WARNING: Device mismatch detected for vg/lvol0 which is accessing /dev/loop1 instead of /dev/loop0.
LV VG Attr LSize
lvol0 vg -wi-a----- 124.00m
It's possible that while a device is already referenced in sysfs, the node
is not yet in /dev directory.
This may happen in some rare cases right after LVs get created - we sync
with udev (or alternatively we create /dev content ourselves) while VG
lock is held. However, dev scan is done without VG lock so devices may
already be in sysfs, but /dev may not be updated yet if we call LVM command
right after LV creation (so the fact that fs_unlock is done within VG
lock is not usable here much). This is not a problem with devtmpfs as
there's at least kernel name for device in /dev as soon as the sysfs
item exists, but we still support environments without devtmpfs or
where different directory for dev nodes is used (e.g. our test suite).
This patch covers these situations by tracking such devices in
_cache.sysfs_only_names helper hash for the vgid/lvid check to work still.
This also resolves commit 6129d2e64d
which was then reverted by commit 109b7e2095
due to performance issues it may have brought (...and it didn't resolve
the problem fully anyway).
UUID for LV is either "LVM-<vg_uuid><lv_uuid>" or "LVM-<vg_uuid><lv_uuid>-<suffix>".
The code before just checked the length of the UUID based on the first
template, not the variant with suffix - so LVs with this suffix were not
processed properly.
For example a thin pool LV (as an example of an LV that contains
sub LVs where UUIDs have suffixes):
[0] fedora/~ # lsblk -s /dev/vg/lvol1
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
vg-lvol1 253:8 0 4M 0 lvm
`-vg-pool-tpool 253:6 0 116M 0 lvm
|-vg-pool_tmeta 253:2 0 4M 0 lvm
| `-sda 8:0 0 128M 0 disk
`-vg-pool_tdata 253:3 0 116M 0 lvm
`-sda 8:0 0 128M 0 disk
Before this patch (spurious warning message about device mismatch):
[0] fedora/~ # pvs
WARNING: Device mismatch detected for vg/lvol1 which is accessing /dev/mapper/vg-pool-tpool instead of (null).
PV VG Fmt Attr PSize PFree
/dev/sda vg lvm2 a-- 124.00m 0
With this patch applied (no spurious warning message about device mismatch):
[0] fedora/~ # pvs
PV VG Fmt Attr PSize PFree
/dev/sda vg lvm2 a-- 124.00m 0
Check if the value we read from sysfs is not blank and replace the '\n'
at the end only when needed ('\n' should usually be there for sysfs values,
but better check this).
It's possible for an LVM LV to use a device during activation which
then differs from device which LVM assumes based on metadata later on.
For example, such device mismatch can occur if LVM doesn't have
complete view of devices during activation or if filters are
misbehaving or they're incorrectly set during activation.
This patch adds code that can detect this mismatch by creating
VG UUID and LV UUID index while scanning devices for device cache.
The VG UUID index maps VG UUID to a device list. Each device in the
list has a device layered above as a holder which is an LVM LV device
and for which we know the VG UUID (and similarly for LV UUID index).
We can acquire VG and LV UUID by reading /sys/block/<dm_dev_name>/dm/uuid.
So these indices represent the actual state of PV device use in
the system by LVs and then we compare that to what LVM assumes
based on metadata.
For example:
[0] fedora/~ # lsblk /dev/sdq /dev/sdr /dev/sds /dev/sdt
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sdq 65:0 0 104M 0 disk
|-vg-lvol0 253:2 0 200M 0 lvm
`-mpath_dev1 253:3 0 104M 0 mpath
sdr 65:16 0 104M 0 disk
`-mpath_dev1 253:3 0 104M 0 mpath
sds 65:32 0 104M 0 disk
|-vg-lvol0 253:2 0 200M 0 lvm
`-mpath_dev2 253:4 0 104M 0 mpath
sdt 65:48 0 104M 0 disk
`-mpath_dev2 253:4 0 104M 0 mpath
In this case the vg-lvol0 is mapped onto sdq and sds becauset this is
what was available and seen during activation. Then later on, sdr and
sdt appeared and mpath devices were created out of sdq+sdr (mpath_dev1)
and sds+sdt (mpath_dev2). Now, LVM assumes (correctly) that mpath_dev1
and mpath_dev2 are the PVs that should be used, not the mpath
components (sdq/sdr, sds/sdt).
[0] fedora/~ # pvs
Found duplicate PV xSUix1GJ2SK82ACFuKzFLAQi8xMfFxnO: using /dev/mapper/mpath_dev1 not /dev/sdq
Using duplicate PV /dev/mapper/mpath_dev1 from subsystem DM, replacing /dev/sdq
Found duplicate PV MvHyMVabtSqr33AbkUrobq1LjP8oiTRm: using /dev/mapper/mpath_dev2 not /dev/sds
Using duplicate PV /dev/mapper/mpath_dev2 from subsystem DM, ignoring /dev/sds
WARNING: Device mismatch detected for vg/lvol0 which is accessing /dev/sdq, /dev/sds instead of /dev/mapper/mpath_dev1, /dev/mapper/mpath_dev2.
PV VG Fmt Attr PSize PFree
/dev/mapper/mpath_dev1 vg lvm2 a-- 100.00m 0
/dev/mapper/mpath_dev2 vg lvm2 a-- 100.00m 0
Recent kernel (4.4) start to report values smaller then sector size
(but in reporting size for SSD which support data zeroing on discard).
For now log warning and assume it really means 1 sector.
Addressing RHBZ:
https://bugzilla.redhat.com/show_bug.cgi?id=1313377
Non-dm devices have ID_PART_TABLE_TYPE variable exported in
udev db from blkid scan for *both* whole devices and partitions.
We used ID_PART_ENTRY_DISK in addition to decide whether this
is the whole device or partition and then we filtered out only
whole devices where the partition table really is.
However, ID_PART_ENTRY_DISK was added in blkid 2.20 so we need
to use a different set of variables to decide on whole devices
and partitions on systems where older blkid is still used.
Now, we use ID_PART_TABLE_TYPE to detect that there's something
related to partitioning with this device and we use DEVTYPE variable
instead to decide between whole device (DEVTYPE="disk") and partition
(DEVTYPE="partition").
For dm devices it's simpler, we have ID_PART_TABLE_TYPE variable\
set in udev db for whole devices. It's not set for partitions,
hence we don't need more variable in addition to make the decision
on whole device vs. partition (dm devices do not have regular
partitions, hence DEVTYPE can't be used anyway, it's always set
to "disk" for whole disks and partitions).
Add "size" and "size_seqno" to struct device to cache device's size
and also to control its lifetime - the cached value is valid as long
as the global _dev_size_seqno is equal to the device's size_seqno,
otherwise we need to get the size again and cache the new value.
This patch also adds new dev_size_seqno_inc() fn for the appropriate
parts of the code to increment current global value of _dev_size_seqno
and hence to cause all currently cached values for device sizes to
be invalidated.
The device size is now cached because we're planning to reuse this
information for further checks and we want to avoid checking it more
than necessary to save resources.
Before commit c1f246fedf,
_get_all_devices() did a full device scan before
get_vgnameids() was called. The full scan in
_get_all_devices() is from calling dev_iter_create(f, 1).
The '1' arg forces a full scan.
By doing a full scan in _get_all_devices(), new devices
were added to dev-cache before get_vgnameids() began
scanning labels. So, labels would be read from new devices.
(e.g. by the first 'pvs' command after the new device appeared.)
After that commit, _get_all_devices() was called
after get_vgnameids() was finished scanning labels.
So, new devices would be missed while scanning labels.
When _get_all_devices() saw the new devices (after
labels were scanned), those devices were added to
the .cache file. This meant that the second 'pvs'
command would see the devices because they would be
in .cache.
Now, the full device scan is factored out of
_get_all_devices() and called by itself at the
start of the command so that new devices will
be known before get_vgnameids() scans labels.
The udev_device_get_is_initialized is available since libudev version
165. Older versions are still used somewhere (e.g. RHEL6). So better
check for this fn and use it only if it's available.
Udev db records are marked as not initialized (incomplete) on timeout.
Issue an error message whenever LVM finds such records so users are
aware that something's going wrong with udev db.
This is important in case we use devices/external_device_info_source="udev"
where udev database records are used to do various filtering decisions.
For example:
udev log of timed out worker:
Nov 11 13:02:25 raw.virt systemd-udevd[607]: seq 1997 '/devices/virtual/block/dm-2' is taking a long time
Nov 11 13:04:25 raw.virt systemd-udevd[607]: seq 1997 '/devices/virtual/block/dm-2' killed
Nov 11 13:04:25 raw.virt systemd-udevd[607]: worker [11221] terminated by signal 9 (Killed)
Nov 11 13:04:25 raw.virt systemd-udevd[607]: worker [11221] failed while handling '/devices/virtual/block/dm-2'
...
LVM also issues error message visibly if incomplete udev db record is found,
devices/external_device_info_source="udev" is set:
$ pvs
Udev database has incomplete information about device /dev/dm-2.
Failed to get external handle for device /dev/dm-2 [udev].
...
Doing 'stat' checking first and later opening is racy.
And since we do not really care about any 'status' info
here and we read 'sysfs' here - just drop whole 'stat()'
call and directly handle error from failing 'fopen()'.
The former patch(dab3ebce4c) is a little bit strict. For example, it is
OK to create PV on unpartitioned DASD devices with LDL formatted. So
after lvm version containing the patch, LVs created on those devices
could not be found.
Signed-off-by: Lidong Zhong <lzhong@suse.com>
Some signatures are spread around the disk in several copies, mainly for
backup. Make libblkid to detect these extra copies - there was missing
"blkid_probe_step_back" fn call after successful wipe of previous signature
copy.
An example with FAT table which has copies:
$ mkfs.vfat /dev/sda1
Before this patch:
$ pvcreate /dev/sda1
WARNING: vfat signature detected on /dev/sda1 at offset 54. Wipe it? [y/n]: y
Wiping vfat signature on /dev/sda1.
Physical volume "/dev/sda1" successfully created
With this patch applied:
$ pvcreate /dev/sda1
WARNING: vfat signature detected on /dev/sda1 at offset 54. Wipe it? [y/n]: y
Wiping vfat signature on /dev/sda1.
WARNING: vfat signature detected on /dev/sda1 at offset 0. Wipe it? [y/n]: y
Wiping vfat signature on /dev/sda1.
WARNING: vfat signature detected on /dev/sda1 at offset 510. Wipe it? [y/n]: y
Wiping vfat signature on /dev/sda1.
Physical volume "/dev/sda1" successfully created
As part of fix that came with cf700151eb,
I forgot to add the check whether the result of stat was successful or
not. This bug caused uninitialized buffer to be used for entries
from .cache file which are no longer valid.
This bug may have caused these uninitialized values to be used further,
for example (see the unreal (2567,590944) representing major:minor
pair):
$ pvs
/dev/abc: stat failed: No such file or directory
Path /dev/abc no longer valid for device(2567,590944)
PV VG Fmt Attr PSize PFree
/dev/mapper/test lvm2 --- 104.00m 104.00m
/dev/vda2 rhel lvm2 a-- 9.51g 0
This is a regression introduced by commit
6c0e44d5a2 which changed
the way dev_cache_get fn works - before this patch, when a
device was not found, it fired a full rescan to correct the
cache. However, the change coming with that commit missed
this full_rescan call, causing the lvmcache to still contain
info about PVs which should be filtered now.
Such situation may have happened by coincidence of using
old persistent cache (/etc/lvm/cache/.cache) which does not
reflect the actual state anymore, a device name/symlink which
now points to a device which should be filtered and a fact we
keep info about usable DM devices in .cache no matter what
the filter setting is.
This bug could be hidden though by changes introduced in
commit f1a000a477 as it
calls full_rescan earlier before this problem is hit.
But we need to fix this anyway for the dev_cache_get
to be correct if we happen to use the same code path
again somewhere sometime.
For example, simple reproducer was (before commit
1a000a477558e157532d5f2cd2f9c9139d4f87c):
- /dev/sda contains a PV header with UUID y5PzRD-RBAv-7sBx-V3SP-vDmy-DeSq-GUh65M
- lvm.conf: filter = [ "r|.*|" ]
- rm -f .cache (to start with clean state)
- dmsetup create test --table "0 8388608 linear /dev/sda 0" (8388608 is
just the size of the /dev/sda device I use in the reproducer)
- pvs (this will create .cache file which contains
"/dev/disk/by-id/lvm-pv-uuid-y5PzRD-RBAv-7sBx-V3SP-vDmy-DeSq-GUh65M"
as well as "/dev/mapper/test" and the target node "/dev/dm-1" - all the
usable DM mappings (and their symlinks) get into the .cache file even
though the filter "is set to "ignore all" - we do this - so far it's OK)
- dmsetup remove test (so we end up with /dev/disk/by-id/lvm-pv-uuid-...
pointing to the /dev/sda now since it's the underlying device
containing the actual PV header)
- now calling "pvs" with such .cache file and we get:
$ pvs
PV VG Fmt Attr PSize PFree
/dev/disk/by-id/lvm-pv-uuid-y5PzRD-RBAv-7sBx-V3SP-vDmy-DeSq-GUh65M vg lvm2 a-- 4.00g 0
Even though we have set filter = [ "r|.*|" ] in the lvm.conf file!
Comply with the rules we have for log_error and log_warn...
$ pvcreate /dev/sda1
Failed to get offset of the xfs_external_log signature on /dev/sda1.
1 existing signature left on the device.
Aborting pvcreate on /dev/sda1.
$ pvcreate /dev/sda1 --force
WARNING: Failed to get offset of the xfs_external_log signature on /dev/sda1.
Physical volume "/dev/sda1" successfully created
libblkid may return the list of signatures found, but it may not
provide offset and size for each signature detected. This may
happen in case signatures are mixed up or there are more, possibly
overlapping, signatures found.
Make lvm commands pass if such situation happens and we're using
--force (or any stronger force method).
For example:
$ pvcreate /dev/sda1
Failed to get offset of the xfs_external_log signature on /dev/sda1.
1 existing signature left on the device.
Aborting pvcreate on /dev/sda1.
$ pvcreate --force /dev/sda1
Failed to get offset of the xfs_external_log signature on /dev/sda1.
Physical volume "/dev/sda1" successfully created
Replace misleading "not found" in the log message when
devices/preferred_names is set to empty array:
Really not found:
device/dev-cache.c:689 devices/preferred_names not found in config: using built-in preferences
Found, but empty:
config/config.c:1431 Setting devices/preferred_names to preferred_names = [ ]
device/dev-cache.c:689 devices/preferred_names is empty: using built-in preferences
Example:
/dev/loop0 and /dev/loop1 are duplicates,
created by copying one backing file to the
other.
'identity /dev/loopX' creates an identity
mapping for loopX named idmloopX, which
adds a duplicate for the named device.
The duplicate selection code for lvmetad is
incomplete, and lvmetad is disabled for this
example.
[~]# losetup -f loopfile0
[~]# pvs
PV VG Fmt Attr PSize PFree
/dev/loop0 foo lvm2 a-- 308.00m 296.00m
[~]# losetup -f loopfile1
[~]# pvs
Found duplicate PV LnSOEqzEYED3RvIOa5PZP2s7uyuBLmAV: using /dev/loop1 not /dev/loop0
Using duplicate PV /dev/loop1 which is more recent, replacing /dev/loop0
PV VG Fmt Attr PSize PFree
/dev/loop1 foo lvm2 a-- 308.00m 308.00m
[~]# ./identity /dev/loop0
[~]# pvs
Found duplicate PV LnSOEqzEYED3RvIOa5PZP2s7uyuBLmAV: using /dev/loop1 not /dev/loop0
Using duplicate PV /dev/loop1 without holders, replacing /dev/loop0
Found duplicate PV LnSOEqzEYED3RvIOa5PZP2s7uyuBLmAV: using /dev/mapper/idmloop0 not /dev/loop1
Using duplicate PV /dev/mapper/idmloop0 from subsystem DM, replacing /dev/loop1
PV VG Fmt Attr PSize PFree
/dev/mapper/idmloop0 foo lvm2 a-- 308.00m 296.00m
[~]# ./identity /dev/loop1
[~]# pvs
WARNING: duplicate PV LnSOEqzEYED3RvIOa5PZP2s7uyuBLmAV is being used from both devices /dev/loop0 and /dev/loop1
Found duplicate PV LnSOEqzEYED3RvIOa5PZP2s7uyuBLmAV: using /dev/loop1 not /dev/loop0
Using duplicate PV /dev/loop1 which is more recent, replacing /dev/loop0
Found duplicate PV LnSOEqzEYED3RvIOa5PZP2s7uyuBLmAV: using /dev/mapper/idmloop0 not /dev/loop1
Using duplicate PV /dev/mapper/idmloop0 from subsystem DM, replacing /dev/loop1
Found duplicate PV LnSOEqzEYED3RvIOa5PZP2s7uyuBLmAV: using /dev/mapper/idmloop1 not /dev/mapper/idmloop0
Using duplicate PV /dev/mapper/idmloop1 which is more recent, replacing /dev/mapper/idmloop0
PV VG Fmt Attr PSize PFree
/dev/mapper/idmloop1 foo lvm2 a-- 308.00m 308.00m
When pvscan --cache --major --minor command is issued from
udev REMOVE event, it basically resulted into a whole device
scan since the device was missing. So avoid such scan
and first check via /sysfs (when available) if such device actually
exists.
Dop unused value assignments.
Unknown is detected via other combination
(!linear && !striped).
Also change the log_error() message into a warning,
since the function is not really returning error,
but still keep the INTERNAL_ERROR.
Ret value is always set later.
We exclude some signatures from being wiped when using blkid wiping.
These are signatures which we simply overwrite. For example, the
LVM2_member signature which denotes a PV - if we call pvcreate on
existing PV, we just overwrite the PV header, no need to wipe it.
Previously, we counted such signatures as if they were wiped
and they were counted in the final number of wiped signatures
that _wipe_known_signatures_with_blkid fn returned in the "wiped"
output arg. Then the code checking this output arg could be
mislead that wiping happened while no wiping took place in real
and we could fire some code uselessly based on this information
(e.g. refreshing filters/rescanning - see also
commit 6b4066585f).
Before, we refreshed filters and we did full rescan of devices if
we passed through wiping (wipe_known_signatures fn call). However,
this fn returns success even if no signatures were found and so
nothing was wiped. In this case, it's not necessary to do the
filter refresh/rescan of devices as nothing changed clearly.
This patch exports number of wiped signatures from all the
wiping functions below. The caller (_pvcreate_check) then checks
whether any wiping was done at all and if not, no refresh/rescan
is done, saving some time and resources.
Partitioned devices are marked in udev db as:
ID_PART_TABLE="<partition table type name>"
and at the same time they are *not* marked with:
ID_PART_ENTRY_DISK="<parent disk major:minor>"
Where partition table type name is dos/gpt/... But checking the presence
of this variable is enough for LVM here - it just needs to know whether
there's a partition table or not, not interested in the actual type.
The same applies for parent disk major:minor.
Normally, if there are partitions defined on top of device-mapper
device, there should be a device-mapper device created for each
partiton on top of the old one and once the underlying DM device
is used by another devices (partition mappings in this case),
it can't be used as a PV anymore.
However, sometimes, it may happen the partition mappings are
missing - either the partitioning tool is not creating them if
it does not contain full support for device-mapper devices or
the mappings were removed.
Better safe than sorry - check for partition header on DM devs
and filter them out as unsuitable for PVs in case the check is
positive. Whatever the user is doing, let's do our best to prevent
unwanted corruption (...by running pvcreate on top of such device
that would corrupt the partition header).
The code in dev_iter_create assumes that if a filter can be wiped, doing so will
always trigger a call to _full_scan. This is not true for composite filters
though, since they can always be wiped in principle, but there is no way to know
that a component filter inside will exist that actually triggers the scan.
Avoid playing with +1.
PATH_MAX code needs probably more thinking anyway, since
there is no MAX path in Linux - user may easily create path
with 64kB chars - so 4kB buffer is surelly not enough for
such dirs.
Note:
http://insanecoding.blogspot.cz/2007/11/pathmax-simply-isnt.html
The list of strings is used quite frequently and we'd like to reuse
this simple structure for report selection support too. Make it part
of libdevmapper for general reuse throughout the code.
This also simplifies the LVM code a bit since we don't need to
include and manage lvm-types.h anymore (the string list was the
only structure defined there).
When lvm2 command works with clvmd and uses locking in wrong way,
it may 'leak' certain file descriptors in opened (incorrect) state.
dev_cache_exit then destroys memory pool of cached devices, while
_open_devices list in dev-io.c was still referencing them if they
were still opened.
Patch properly calls _close() function to 'self-heal' from this
invalid state, but it will report internal error (so execution
with abort_on_internal_error causes immediate death). On the
normal 'execution', error is only reported, but memory state is
corrected, and linked list is not referencing devices from
released mempool.
For crash see: https://bugzilla.redhat.com/show_bug.cgi?id=1073886
Smallest supported size for swap device is 40KB, however current
test skipped devices smaller then 4096 sectors (2MB).
Since page is in bytes, convert it to sectors before comparing
with device size (in sectors).
The libblkid can detect DM_snapshot_cow signature and when creating
new LVs with blkid wiping used (allocation/use_blkid_wiping=1 lvm.conf
setting and --wipe y used at the same time - which it is by default).
Do not issue any prompts about this signature when new LV is created
and just wipe it right away without asking questions. Still keep the
log in verbose mode though.
We need both offset and length when trying to wipe detected signatures.
The libblkid can fail so it's good to have an error message issued for
this state instead of being silent (libblkid does not issue any error
messages here). We just issued "stack" here before but that was not
quite useful if some error occurs...
If there is no define for BLKPBSZGET - we have hard time how to
decrypt physical block size - we can't use here block_size,
since this is usually 4k while we need to use 512b.
FIXME: find some better way, until that enforce value 512.
Eventually we could also try to put in:
+#ifndef BLKPBSZGET
+# define BLKPBSZGET _IO(0x12,123)
+#endif
but this will still not work well on old kernels.
When the device is inserted in dev_name_confirmed() stat() is
called twice as _insert() has it's own stat() call.
Extend _insert() parameter with struct stat* - which could be used
if it has been just obtained. When NULL is passed code is
doing its own stat() call as before.
If we're calling pvcreate on a device that already has a PV label,
the blkid detects the existing PV and then we consider it for wiping
before we continue creating the new PV label and we issue a warning
with a prompt whether such old PV label should be removed. We don't
do this with native signature detection code. Let's make it consistent
with old behaviour.
But still keep this "PV" (identified as "LVM1_member" or "LVM2_member"
by blkid) detection when creating new LVs to avoid unexpected PV label
appeareance inside LV.
This is actually the wipefs functionailty as a matter of fact
(wipefs uses the same libblkid calls).
libblkid is more rich when it comes to detecting various
signatures, including filesystems and users can better
decide what to erase and what should be kept.
The code is shared for both pvcreate (where wiping is necessary
to complete the pvcreate operation) and lvcreate where it's up
to the user to decide.
The verbose output contains a bit more information about the
signature like LABEL and UUID.
For example:
raw/~ # lvcreate -L16m vg
WARNING: linux_raid_member signature detected on /dev/vg/lvol0 at offset 4096. Wipe it? [y/n]
or more verbose one:
raw/~ # lvcreate -L16m vg -v
...
Found existing signature on /dev/vg/lvol0 at offset 4096: LABEL="raw.virt:0" UUID="da6af139-8403-5d06-b8c4-13f6f24b73b1" TYPE="linux_raid_member" USAGE="raid"
WARNING: linux_raid_member signature detected on /dev/vg/lvol0 at offset 4096. Wipe it? [y/n]
The verbose output is the same output as found in blkid.
The wipe_known_signatures fn now wraps the _wipe_signature fn that is called
for each known signature (currently md, swap and luks). This patch makes the
code more readable, not repeating the same sequence when used anywhere in the
code. We're going to reuse this code later...
Put common printf() case into a function and use
the string with text format as direct arg to make
the compile time validation of args easier and
code shorter.
Switch log_error() to log_warn(), since 'return 0'
doesn't cause any failure here.
Split out the partitioned device filter that needs to open the device
and move the multipath filter in front of it.
When a device is multipathed, sending I/O to the underlying paths may
cause problems, the most obvious being I/O errors visible to lvm if a
path is down.
Revert the incorrect <backtrace> messages added when a device doesn't
pass a filter.
Log each filter initialisation to show sequence.
Avoid duplicate 'Using $device' debug messages.
