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The LVM devices file lists devices that lvm can use. The default
file is /etc/lvm/devices/system.devices, and the lvmdevices(8)
command is used to add or remove device entries. If the file
does not exist, or if lvm.conf includes use_devicesfile=0, then
lvm will not use a devices file. When the devices file is in use,
the regex filter is not used, and the filter settings in lvm.conf
or on the command line are ignored.
LVM records devices in the devices file using hardware-specific
IDs, such as the WWID, and attempts to use subsystem-specific
IDs for virtual device types. These device IDs are also written
in the VG metadata. When no hardware or virtual ID is available,
lvm falls back using the unstable device name as the device ID.
When devnames are used, lvm performs extra scanning to find
devices if their devname changes, e.g. after reboot.
When proper device IDs are used, an lvm command will not look
at devices outside the devices file, but when devnames are used
as a fallback, lvm will scan devices outside the devices file
to locate PVs on renamed devices. A config setting
search_for_devnames can be used to control the scanning for
renamed devname entries.
Related to the devices file, the new command option
--devices <devnames> allows a list of devices to be specified for
the command to use, overriding the devices file. The listed
devices act as a sort of devices file in terms of limiting which
devices lvm will see and use. Devices that are not listed will
appear to be missing to the lvm command.
Multiple devices files can be kept in /etc/lvm/devices, which
allows lvm to be used with different sets of devices, e.g.
system devices do not need to be exposed to a specific application,
and the application can use lvm on its own set of devices that are
not exposed to the system. The option --devicesfile <filename> is
used to select the devices file to use with the command. Without
the option set, the default system devices file is used.
Setting --devicesfile "" causes lvm to not use a devices file.
An existing, empty devices file means lvm will see no devices.
The new command vgimportdevices adds PVs from a VG to the devices
file and updates the VG metadata to include the device IDs.
vgimportdevices -a will import all VGs into the system devices file.
LVM commands run by dmeventd not use a devices file by default,
and will look at all devices on the system. A devices file can
be created for dmeventd (/etc/lvm/devices/dmeventd.devices) If
this file exists, lvm commands run by dmeventd will use it.
Internal implementaion:
- device_ids_read - read the devices file
. add struct dev_use (du) to cmd->use_devices for each devices file entry
- dev_cache_scan - get /dev entries
. add struct device (dev) to dev_cache for each device on the system
- device_ids_match - match devices file entries to /dev entries
. match each du on cmd->use_devices to a dev in dev_cache, using device ID
. on match, set du->dev, dev->id, dev->flags MATCHED_USE_ID
- label_scan - read lvm headers and metadata from devices
. filters are applied, those that do not need data from the device
. filter-deviceid skips devs without MATCHED_USE_ID, i.e.
skips /dev entries that are not listed in the devices file
. read lvm label from dev
. filters are applied, those that use data from the device
. read lvm metadata from dev
. add info/vginfo structs for PVs/VGs (info is "lvmcache")
- device_ids_find_renamed_devs - handle devices with unstable devname ID
where devname changed
. this step only needed when devs do not have proper device IDs,
and their dev names change, e.g. after reboot sdb becomes sdc.
. detect incorrect match because PVID in the devices file entry
does not match the PVID found when the device was read above
. undo incorrect match between du and dev above
. search system devices for new location of PVID
. update devices file with new devnames for PVIDs on renamed devices
. label_scan the renamed devs
- continue with command processing
User use 'lvconvert -Zn --type vdo-pool' to convert an existing
vdo formated volume and skip lvm2 internal formating.
This however requires user is passing proper matching parameters.
For them user can use --profile|--metadataprofile option whos
support has been also enhanced.
TODO: add support to read values directly from formated volume.
When converting an existing LV to thin-pool,
user may now pass also '--errorwhenfull' option
like with 'lvcreate'.
Also recalculate chunksize when performace profile is
used with conversion (again matching lvcreate).
Adds missing flagging for uncropped metadata sizes.
In past we had this control with use_lvmetad check for
pvscan --cache -aay
Howerer this got lost with lvmetad removal commit:
117160b27e
When user sets lvm.conf global/event_activation=0
pvscan service will no longer auto activate any LVs on appeared PVs.
Move extra md component detection into the label scan phase.
It had been in set_pv_devices which was deep within the vg_read
phase, which wasn't a good place (better to detect that earlier.)
Now that pv metadata info is available in the scan phase, the pv
details (size and device_hint) can be used for extra md checking.
Use the device_hint from the pv metadata to trigger a full md
component check if the device_hint begins with /dev/md.
Stop triggering full md component checks based on missing
udev info for a dev.
Changes to tests to reflect that the code is now detecting
md components in some test case that it wasn't before.
A cachevol can be forcibly detached when it's missing devices.
Also allow this if it's damaged/invalid and unrepairable.
This would be needed to recover data from the origin LV after
a cachevol is lost or damaged beyond repair.
In cases where lvconvert does not detect a fs block size on the
device, it falls back to choosing a writecache block size based
on the device's LBS and PBS (tries to match those.)
If the user specifies a writecache block size on the command
line (--cachesettings block_size=4096|512), lvconvert currently
fails and reports an error if the user-specified value does not
match the value lvconvert would have chosen based on LBS and PBS.
The purpose of allowing a user-specified value on the command line
is to override what lvconvert would otherwise do, so change this
to just print a warning that the user value does not match the
value that would be chosen based on the LBS/PBS, and then take
the user-specified value as the writecache block size.
Use update_pool_metadata_min_max() which is shared with
thin-pool metadata min-max updating.
Gives improved messages when converting volumes to metadata.
Initial support for thin-pool used slightly smaller max size 15.81GiB
for thin-pool metadata. However the real limit later settled at 15.88GiB
(difference is ~64MiB - 16448 4K blocks).
lvm2 could not simply increase the size as it has been using hard cropping
of the loaded metadata device to avoid warnings printing warning of kernel
when the size was bigger (i.e. due to bigger extent_size).
This patch adds the new lvm.conf configurable setting:
allocation/thin_pool_crop_metadata
which defaults to 0 -> no crop of metadata beyond 15.81GiB.
Only user with these sizes of metadata will be affected.
Without cropping lvm2 now limits metadata allocation size to 15.88GiB.
Any space beyond is currently not used by thin-pool target.
Even if i.e. bigger LV is used for metadata via lvconvert,
or allocated bigger because of to large extent size.
With cropping enabled (=1) lvm2 preserves the old limitation
15.81GiB and should allow to work in the evironement with
older lvm2 tools (i.e. older distribution).
Thin-pool metadata with size bigger then 15.81G is now using CROP_METADATA
flag within lvm2 metadata, so older lvm2 recognizes an
incompatible thin-pool and cannot activate such pool!
Users should use uncropped version as it is not suffering
from various issues between thin_repair results and allocated
metadata LV as thin_repair limit is 15.88GiB
Users should use cropping only when really needed!
Patch also better handles resize of thin-pool metadata and prevents resize
beoyond usable size 15.88GiB. Resize beyond 15.81GiB automatically
switches pool to no-crop version. Even with existing bigger thin-pool
metadata command 'lvextend -l+1 vg/pool_tmeta' does the change.
Patch gives better controls 'coverted' metadata LV and
reports less confusing message during conversion.
Patch set also moves the code for updating min/max into pool_manip.c
for better sharing with cache_pool code.
When detaching writecache, make the first stage send a message
to dm-writecache to set the cleaner option. This is instead of
reloading the dm table with the cleaner option set. Reloading
the table causes udev to process/probe the dm dev, which gets
stalled because of the writeback activity, and the stalled udev
in turn stalls the lvconvert command when it tries to sync with
udev events.
When getting writecache status we do not need to get
open_count or read_head info, which can cause extra steps.
Read buffersize - 1 so the last byte is always 0.
Simplify init of 0 buffers.
Check snprintf result for error and report internal error as it could
happen only via bad compile parameters.
Fix the two-step writecache detach in commit c32d7fed4f.
In the case of uncache, the cachevol is removed after
detaching the writecache. When the detach is finished
in the second step, the remove must wait until then.
filters needing io weren't being run because bcache
wasn't set up. Read the first 4k of the device
before doing filtering or reading ondisk structs to
reduce reads.
It's possible for a machine with a non-4k page size
to create a PV with an mda_header at an offset other
than 4k. Fix pvck --dump to work with these other
mda offsets. pvck --repair will write a new first
mda at 4096 but lvm with other page sizes will work
with this.
The args for pvcreate/pvremove (and vgcreate/vgextend
when applicable) were not efficiently opened, scanned,
and filtered. This change reorganizes the opening
and filtering in the following steps:
- label scan and filter all devs
. open ro
. standard label scan at the start of command
- label scan and filter dev args
. open ro
. uses full md component check
. typically the first scan and filter of pvcreate devs
- close and reopen dev args
. open rw and excl
- repeat label scan and filter dev args
. using reopened rw excl fd
- wipe and write new headers
. using reopened rw excl fd
Since 'kilobytes' could be seen in 2 way - SI as '1000',
while all programmers sees it as '1024' - switch to
commonly acceptted KiB, MiB....
Resolves RHBZ 1496255.
Restructure the pvscan code, and add new temporary files
that list pvids in a VG, used for processing PVs that
have no metadata.
The new temp files, in /run/lvm/pvs_lookup/<vgname>, allow a
proper pvscan --cache to be done on PVs that have no metadata.
pvscan --cache <dev> is only supposed to read <dev>, but when
<dev> has no metadata, this had not been possible. The
command had to fall back to scanning all devices to read all
VG metadata to get the list of all PVIDs needed to check for
a complete VG. Now, the temp file can be used in place of
reading metadata from all PVs on the system.
cmd context has 'threaded' value that used be set
by clvmd - and allowed proper memory locking management.
Reuse same bit for dmeventd.
Since dmeventd is using 300KiB stack per thread,
we will ignore any user settings for allocation/reserved_stack
until some better solution is find.
This avoids crashing of dmevend when user changes this value
and because in most cases lvm2 should work ok with 64K stack
size, this change should not cause any problems.
When detaching a writecache, use the cleaner setting
by default to writeback data prior to suspending the
lv to detach the writecache. This avoids potentially
blocking for a long period with the device suspended.
Detaching a writecache first sets the cleaner option, waits
for a short period of time (less than a second), and checks
if the writecache has quickly become clean. If so, the
writecache is detached immediately. This optimizes the case
where little writeback is needed.
If the writecache does not quickly become clean, then the
detach command leaves the writecache attached with the
cleaner option set. This leaves the LV in the same state
as if the user had set the cleaner option directly with
lvchange --cachesettings cleaner=1 LV.
After leaving the LV with the cleaner option set, the
detach command will wait and watch the writeback progress,
and will finally detach the writecache when the writeback
is finished. The detach command does not need to wait
during the writeback phase, and can be canceled, in which
case the LV will remain with the writecache attached and
the cleaner option set. When the user runs the detach
command again it will complete the detach.
To detach a writecache directly, without using the cleaner
step (which has been the approach previously), add the
option --cachesettings cleaner=0 to the detach command.
Reorganize checking the device args for pvcreate/pvremove
to prepare for future changes. There should be no change
in behavior. Stop the inverted use of process_each_pv,
which pulled in a lot of unnecessary processing, and call
the check functions on each device directly.
LVM2 is distributed under GPLv2 only. The readline library changed its
license long ago to GPLv3. Given that those licenses are incompatible
and you follow the FSF in their interpretation that dynamically linking
creates a derivative work, distributing LVM2 linked against a current
readline version might be legally problematic.
Add support for the BSD licensed editline library as an alternative for
readline.
Link: https://thrysoee.dk/editline
There's a bug when lvpoll attempts to write new hints,
related to the fact that lvpoll does not follow the same
scanning process as standard commands.
Fix by disabling the use of hints in lvpoll. We may want
to renable hints in lvpoll in a way that they can be used,
if valid, but not updated if they don't exist or are invalid.
Add a "device index" (di) for each device, and use this
in the bcache api to the rest of lvm. This replaces the
file descriptor (fd) in the api. The rest of lvm uses
new functions bcache_set_fd(), bcache_clear_fd(), and
bcache_change_fd() to control which fd bcache uses for
io to a particular device.
. lvm opens a dev and gets and fd.
fd = open(dev);
. lvm passes fd to the bcache layer and gets a di
to use in the bcache api for the dev.
di = bcache_set_fd(fd);
. lvm uses bcache functions, passing di for the dev.
bcache_write_bytes(di, ...), etc.
. bcache translates di to fd to do io.
. lvm closes the device and clears the di/fd bcache state.
close(fd);
bcache_clear_fd(di);
In the bcache layer, a di-to-fd translation table
(int *_fd_table) is added. When bcache needs to
perform io on a di, it uses _fd_table[di].
In the following commit, lvm will make use of the new
bcache_change_fd() function to change the fd that
bcache uses for the dev, without dropping cached blocks.
Cow may not be a COW type, the return value of origin_from_cow(cow) may be NULL.
Reported-by: Wu Guanghao <wuguanghao3@huawei.com>
Reported-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Cow may not be a snapshot type, the return value of origin_from_cow(cow) may be NULL
Signed-off-by: Wu Guanghao <wuguanghao3@huawei.com>
Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
LV may not be a snapshot type, the return value of find_snapshot(lv) may be NULL.
Here, we will call stack if LV is not a snapshot type.
Signed-off-by: Wu Guanghao <wuguanghao3@huawei.com>
Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
The return value of top_level_lv_name() may be NULL, so we should
check return value of top_level_lv_name before calling
strcmp(lv->name, top_level_lv_name(vg, lv_name)).
Signed-off-by: Wu Guanghao <wuguanghao3@huawei.com>
Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Use '0' for error and '1' as success.
Also drop INTERNAL_ERROR from path - as this error
is ATM used for invalid devices.
(i.e. test lvconvert-raid1-split-trackchanges.sh)
Since we declare dev_name in lib/device/device.h
and pvs in commands.h
rename local dev_name to device_name
and pvs to pvs_list to prevent shadowing warning.
m
Switch remaining zero sized struct to flexible arrays to be C99
complient.
These simple rules should apply:
- The incomplete array type must be the last element within the structure.
- There cannot be an array of structures that contain a flexible array member.
- Structures that contain a flexible array member cannot be used as a member of another structure.
- The structure must contain at least one named member in addition to the flexible array member.
Although some of the code pieces should be still improved.
Allow the optional '--type raid1' to be included in the lvconvert
command when adding or removing raid images with integrity.
It does not change the meaning of the command (specifying a type
that matches the current type is redundant but generally allowed.)
When converting volume to pool LV use also wiping of other signatures.
For writecache & pool conversion support --yet and --force
to bypass prompting for signature wiping.
For writecache drop unneded zero_sectors.
Note: currently we have lvconvert doing convertion and prompting
for confirmation of conversion - and then again wipe_lv() prompts
for removing i.e. filesystem signature - we should unify this
prompting into 1 message - althought the 'filesystem' discovery
needs active volume - while the 1st. conversion prompt can
work without active converted volume.
To create a new cache or writecache LV with a single command:
lvcreate --type cache|writecache
-n Name -L Size --cachedevice PVfast VG [PVslow ...]
- A new main linear|striped LV is created as usual, using the
specified -n Name and -L Size, and using the optionally
specified PVslow devices.
- Then, a new cachevol LV is created internally, using PVfast
specified by the cachedevice option.
- Then, the cachevol is attached to the main LV, converting the
main LV to type cache|writecache.
Include --cachesize Size to specify the size of cache|writecache
to create from the specified --cachedevice PVs, otherwise the
entire cachedevice PV is used. The --cachedevice option can be
repeated to create the cache from multiple devices, or the
cachedevice option can contain a tag name specifying a set of PVs
to allocate the cache from.
To create a new cache or writecache LV with a single command
using an existing cachevol LV:
lvcreate --type cache|writecache
-n Name -L Size --cachevol LVfast VG [PVslow ...]
- A new main linear|striped LV is created as usual, using the
specified -n Name and -L Size, and using the optionally
specified PVslow devices.
- Then, the cachevol LVfast is attached to the main LV, converting
the main LV to type cache|writecache.
In cases where more advanced types (for the main LV or cachevol LV)
are needed, they should be created independently and then combined
with lvconvert.
Example
-------
user creates a new VG with one slow device and one fast device:
$ vgcreate vg /dev/slow1 /dev/fast1
user creates a new 8G main LV on /dev/slow1 that uses all of
/dev/fast1 as a writecache:
$ lvcreate --type writecache --cachedevice /dev/fast1
-n main -L 8G vg /dev/slow1
Example
-------
user creates a new VG with two slow devs and two fast devs:
$ vgcreate vg /dev/slow1 /dev/slow2 /dev/fast1 /dev/fast2
user creates a new 8G main LV on /dev/slow1 and /dev/slow2
that uses all of /dev/fast1 and /dev/fast2 as a writecache:
$ lvcreate --type writecache --cachedevice /dev/fast1 --cachedevice /dev/fast2
-n main -L 8G vg /dev/slow1 /dev/slow2
Example
-------
A user has several slow devices and several fast devices in their VG,
the slow devs have tag @slow, the fast devs have tag @fast.
user creates a new 8G main LV on the slow devs with a
2G writecache on the fast devs:
$ lvcreate --type writecache -n main -L 8G
--cachedevice @fast --cachesize 2G vg @slow
To add a cache or writecache to a main LV with a single command:
lvconvert --type cache|writecache --cachedevice /dev/ssd vg/main
A cachevol LV will be allocated from the specified cache device,
then attached to the main LV. Include --cachesize to specify the
size of cachevol to create, otherwise the entire cachedevice is
used. The cachedevice option can be repeated to create a cachevol
from multiple devices.
Example
-------
A user has an existing main LV that they want to speed up
using a new ssd.
user adds the new ssd to the VG:
$ vgextend vg /dev/ssd
user attaches the new ssd their main LV:
$ lvconvert --type writecache --cachedevice /dev/ssd vg/main
Example
-------
A user has two existing main LVs that they want to speed up
with a new ssd.
user adds the new 16G ssd to the VG:
$ vgextend vg /dev/ssd
user attaches some of the new ssd to the first main LV,
using half of the space:
$ lvconvert --type writecache --cachedevice /dev/ssd
--cachesize 8G vg/main1
user attaches some of the new ssd to the second main LV,
using the other half of the space:
$ lvconvert --type writecache --cachedevice /dev/ssd
--cachesize 8G vg/main2
Example
-------
A user has an existing main LV that they want to speed up using
two new ssds.
user adds the new two ssds the VG:
$ vgextend vg /dev/ssd1
$ vgextend vg /dev/ssd2
user attaches both ssds their main LV:
$ lvconvert --type writecache
--cachedevice /dev/ssd1 --cachedevice /dev/ssd2 vg/main
Use libblkid to detect sector/block size of the fs on the LV.
Use this to choose a compatible writecache block size.
Enable attaching writecache to an active LV.
When lvconvert is used to remove raid images, we can
skip calling lv_add_integrity_to_raid(), which finds
nothing to do, but the the blocksize validation would
be called unnecessarily and trigger spurious errors.
pvck --dump headers reads the metadata text area
to compute the text metadata checksum to compare
with the mda_header checksum.
The new header_only will skip reading the metadata
text and not validate the mda_header checksum.
dm-integrity stores checksums of the data written to an
LV, and returns an error if data read from the LV does
not match the previously saved checksum. When used on
raid images, dm-raid will correct the error by reading
the block from another image, and the device user sees
no error. The integrity metadata (checksums) are stored
on an internal LV allocated by lvm for each linear image.
The internal LV is allocated on the same PV as the image.
Create a raid LV with an integrity layer over each
raid image (for raid levels 1,4,5,6,10):
lvcreate --type raidN --raidintegrity y [options]
Add an integrity layer to images of an existing raid LV:
lvconvert --raidintegrity y LV
Remove the integrity layer from images of a raid LV:
lvconvert --raidintegrity n LV
Settings
Use --raidintegritymode journal|bitmap (journal is default)
to configure the method used by dm-integrity to ensure
crash consistency.
Initialization
When integrity is added to an LV, the kernel needs to
initialize the integrity metadata/checksums for all blocks
in the LV. The data corruption checking performed by
dm-integrity will only operate on areas of the LV that
are already initialized. The progress of integrity
initialization is reported by the "syncpercent" LV
reporting field (and under the Cpy%Sync lvs column.)
Example: create a raid1 LV with integrity:
$ lvcreate --type raid1 -m1 --raidintegrity y -n rr -L1G foo
Creating integrity metadata LV rr_rimage_0_imeta with size 12.00 MiB.
Logical volume "rr_rimage_0_imeta" created.
Creating integrity metadata LV rr_rimage_1_imeta with size 12.00 MiB.
Logical volume "rr_rimage_1_imeta" created.
Logical volume "rr" created.
$ lvs -a foo
LV VG Attr LSize Origin Cpy%Sync
rr foo rwi-a-r--- 1.00g 4.93
[rr_rimage_0] foo gwi-aor--- 1.00g [rr_rimage_0_iorig] 41.02
[rr_rimage_0_imeta] foo ewi-ao---- 12.00m
[rr_rimage_0_iorig] foo -wi-ao---- 1.00g
[rr_rimage_1] foo gwi-aor--- 1.00g [rr_rimage_1_iorig] 39.45
[rr_rimage_1_imeta] foo ewi-ao---- 12.00m
[rr_rimage_1_iorig] foo -wi-ao---- 1.00g
[rr_rmeta_0] foo ewi-aor--- 4.00m
[rr_rmeta_1] foo ewi-aor--- 4.00m
lvm2 supports thin-pool to be later used by other tools doing
virtual volumes themself (i.e. docker) - in this case we
shall not validate transaction Id - is this is used by
other tools and lvm2 keeps value 0 - so the transationId
validation need to be skipped in this case.
Prevent attaching writecache to an active LV until
we can determine the block size of the fs on the LV,
and use that to enforce an appropriate writecache
block size. Changing the block size under a mounted
fs can cause panic/corruption.
Currently the error messages are not clear. This very easy to
guide user to execute "--removemissing --force", it is dangerous
and will make the LVs to be destroied.
Signed-off-by: Zhao Heming <heming.zhao@suse.com>
Since VDO is also pool, the old if() case missed to know about this,
and executed unnecesserily initialization of cache pool variables.
This was usually harmless when using 'smaller' sizes of VDO pools,
but for big VDO pool size, we were reporting senseless messages
about big cache chunk sizes.
To write a new/repaired pv_header and label_header:
pvck --repairtype pv_header --file <file> <device>
This uses the metadata input file to find the PV UUID,
device size, and data offset.
To write new/repaired metadata text and mda_header:
pvck --repairtype metadata --file <file> <device>
This requires a good pv_header which points to one or two
metadata areas. Any metadata areas referenced by the
pv_header are updated with the specified metadata and
a new mda_header. "--settings mda_num=1|2" can be used
to select one mda to repair.
To combine all header and metadata repairs:
pvck --repair --file <file> <device>
It's best to use a raw metadata file as input, that was
extracted from another PV in the same VG (or from another
metadata area on the same PV.) pvck will also accept a
metadata backup file, but that will produce metadata that
is not identical to other metadata copies on other PVs
and other areas. So, when using a backup file, consider
using it to update metadata on all PVs/areas.
To get a raw metadata file to use for the repair, see
pvck --dump metadata|metadata_search.
List all instances of metadata from the metadata area:
pvck --dump metadata_search <device>
Save one instance of metadata at the given offset to
the specified file (this file can be used for repair):
pvck --dump metadata_search --file <file>
--settings "metadata_offset=<off>" <device>
using --settings:
mda_offset=<offset> mda_size=<size> can be used
in place of the offset/size that normally come
from headers.
metadata_offset=<offset> prints/saves one instance
of metadata text at the given offset, in
metadata_all or metadata_search.
This reverts commit 7474440d3b.
lvs can use the scanning optimization again since it has
been changed in:
"scanning: optimize by checking text offset and checksum"
The kernel MD runtime requires region size to be larger than stripe size
on striped raid layouts, thus the dm-raid target's constructor rejects
such request.
This causes e.g. an 'lvcreate --type raid10 -i3 -I4096 -R2048 -n lv vg' to fail.
Avoid failing late in the kernel by enforcing region size to be
larger or equal to stripe size.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1698225
When pvcreate/pvremove prompt the user, they first release
the global lock, then acquire it again after the prompt,
to avoid blocking other commands while waiting for a user
response. This release/reacquire changes the locking
order with respect to the hints flock (and potentially other
locks). So, to avoid deadlock, use a nonblocking request
when reacquiring the global lock.
The scanning optimization can produce warnings from
'lvs' when run concurrently with commands modifying LVs,
so disable the optimization until it can be improved.
Without the scanning optimization, lvs will always
read all PVs twice:
1. read metadata from all PVs, saving it in memory
2. for each VG
3. lock VG
4. reread metadata from all PVs in VG, replacing metadata
saved from step 1
5. run command on VG
6. unlock VG
The optimization would usually cause step 4 to be skipped,
and PVs would be read only once.
Running the command in step 5 using metadata that was not
read under the VG lock is usually fine, except for the
fact that lvs attempts to validate the metadata by comparing
it to current dm state. If other commands are modifying dm
state while lvs is running, lvs may see differences between
metadata from step 1 and dm state checked during step 5,
and print warnings.
(A better fix may be to detect the concurrent change and
fall back to rereading metadata in step 4 only when needed.)
Since we check for NULL pointers earlier we need
to be consistent across function - since the NULL
would applies across whole function.
When dropping 'mda' check - we are actually
already dereferencing it before - so it can't
be NULL at that places (and it's validated
before entering _read_mda_header_and_metadata).
When a cachevol LV is attached, have the LV keep it's lock
allocated. The lock on the cachevol won't be used while
it's attached. When the cachevol is split a new lock does
not need to be allocated. (Applies to cachevol usage by
both dm-cache and dm-writecache.)
When a user includes "--type foo" in a command, only
look at command definitions with matching type, as
opposed to using matching/mismatching --type as a
vote for/against a given command def. This means a
command with --type foo will prioritize a command def
with --type foo over other command defs that have
more matching options but an unmatching type. This
makes it more likely that a closely matching command
def will be recommended.
When LV gets cached and uses cache-pool - such cache-pool
will now get _cpool suffix automatically.
Thus 'Pool' column for cached LV will now show either _cvol
or _cpool LV.
Improve the implementation of extracting all text metadata
copies from the metadata area. Use this for the existing
metadata_all dump option.
Add a new metadata_search dump option which does not use
lvm headers to find metadata, but looks in standard
locations. This is useful if headers are damaged and
can't be used to locate metadata.
Adding '-v' to metadata_all or metadata_search will add
the description and creation_time to the printed list of
metadata instances that are found.
Before 'archive()' is called, lvm2 must not touch/modify metadata.
So move setting CACHE_VOL related flags past this point.
Also make sure reading of cache segtype always restores this
flag properly (even if compatible flag would be lost).
When an LV is used as a writecache cachevol, give
it the LV name a _cvol suffix. Remove the suffix
when the cachevol is detached, restoring the
original LV name.
A cachevol LV had the CACHE_VOL status flag in metadata,
and the cache LV using it had no new flag. This caused
problems if the new metadata was used by an old version
of lvm. An old version of lvm would have two problems
processing the new metadata:
. The old lvm would return an error when reading the VG
metadata when it saw the unknown CACHE_VOL status flag.
. The old lvm would return an error when reading the VG
metadata because it would not find an expected cache pool
attached to the cache LV (since the cache LV had a
cachevol attached instead.)
Change the use of flags:
. Change the CACHE_VOL flag to be a COMPATIBLE flag (instead
of a STATUS flag) so that old versions will not fail when
they see it.
. When a cache LV is using a cachevol, the cache LV gets
a new SEGTYPE flag CACHE_USES_CACHEVOL. This flag is
appended to the segtype name, so that old lvm versions
will fail to use the LV because of an unknown segtype,
as opposed to failing to read the VG.
Instead of using 'noflush' option, switch cache_mode into WRITETHROUGH
which does not require flushing, when user confirmed he does not
want flushing for WRITEBACK (because of (partially) missing caching PV)
For wiping we activate and clear 'regular' devices,
since in case of whole process interuption (i.e. kill -9)
we leave metadata & DM table and workable state all the time.
vgck --updatemetadata would write the same correct
metadata to good mdas, and then to bad mdas, but the
sequence of vg_write/vg_commit calls betwen good and
bad mdas could cause a different description field to
be generated for good/bad mdas. (The description field
describing the command was recently included in the
ondisk copy of the metadata text.)
When the PV device names in the VG metadata do not match the
current PV device names seen on the system, do not use the
optimized activation function (that avoids extra device scanning.)
When the device names do not match, it's a clue that there could
be duplicate PVs, in which case we want to scan all devicess to
find any duplicates and stop the activation if found.
This does not prevent autoactivating a VG from the incorrect
duplicate PV, because the incorrect duplicate may appear by itself
first. At that point its duplicate PV does not exist to be seen.
(A future enhancement could use the WWID to strengthen this
detection.)
- use internal CACHE_VOL flag on cachevol LV
- add suffixes to dm uuids for internal LVs
- display appropriate letters in the LV attr field
- display writecache's cachevol in lvs output
. For dm-cache in writethrough, always allow splitcache,
whether the cache is missing PVs or not.
. For dm-cache in writeback, if the cache is missing PVs,
allow splitcache with force and yes.
. For dm-writecache, if the cache is missing PVs,
allow splitcache with force and yes.
Enhance 'activation' experience for VDO pool to more closely match
what happens for thin-pools where we do use a 'fake' LV to keep pool
running even when no thinLVs are active. This gives user a choice
whether he want to keep thin-pool running (wihout possibly lenghty
activation/deactivation process)
As we do plan to support multple VDO LVs to be mapped into a single VDO,
we want to give user same experience and 'use-patter' as with thin-pools.
This patch gives option to activate VDO pool only without activating
VDO LV.
Also due to 'fake' layering LV we can protect usage of VDO pool from
command like 'mkfs' which do require exlusive access to the volume,
which is no longer possible.
Note: VDO pool contains 1024 initial sectors as 'empty' header - such
header is also exposed in layered LV (as read-only LV).
For blkid we are indentified as LV with UUID suffix - thus private DM
device of lvm2 - so we do not need to store any extra info in this
header space (aka zero is good enough).
When pvscan is used to activate a VG via an
asynchronous service (i.e. lvm2-pvscan), there
is no requirement that the command wait for
udev to create device nodes before returning.
It's possible that waiting for udev is slow
enough to cause the service running the command
to time out. So, allow the --noudevsync option
to be given to pvscan to skip waiting for udev.
(This commit is not changing the lvm2-pvscan
service itself to use --noudevsync.)
Still unknown is whether there are any complex
LV activation cases in which lvm itself requires
access to a device node, in which case the udev
wait could be needed by lvm itself.
(When running an activation command directly
from the command line, it's generally expected
that the activated LVs are ready to use when
the command is finished, so lvm waits for
udev to finish creating the dev nodes.)
When an online PV completed a VG, the standard
activation functions were used to activate the VG.
These functions use a full scan of all devs.
When many pvscans are run during startup and need
to activate many VGs, scanning all devs from all
the pvscans can take a long time.
Optimize VG activation in pvscan to scan only the
devs in the VG being activated. This makes use of
the online file info that was used to determine
the VG was complete.
The downside of this approach is that pvscan activation
will not detect duplicate PVs and block activation,
where a normal activation command (which scans all
devices) would.
New udev in rawhide seems to be 'dropping' udev rule operations for devices
that are no longer existing - while this is 'probably' a bug - it's
revealing moments in lvm2 that likely should not run in a single
transaction and we should wait for a cookie before submitting more work.
TODO: it seem more 'error' paths should always include synchronization
before starting deactivating 'just activated' devices.
We should probably figure out some 'automatic' solution for this instead
of placing sync_local_dev_name() all over the place...
Between 'resume' and 'remove' we need to wait for udev to synchronize,
otherwise udev may 'skip' resume event processing if the udev node
is already gone.
Usually md components are eliminated in label scan and/or
duplicate resolution, but they could sometimes get into
the vg_read stage, where set_pv_devices compares the
device to the PV.
If set_pv_devices runs an md component check and finds
one, vg_read should eliminate the components.
In set_pv_devices, run an md component check always
if the PV is smaller than the device (this is not
very common.) If the PV is larger than the device,
(more common), do the component check when the config
setting is "auto" (the default).
Avoid having PVs with different logical block sizes in the same VG.
This prevents LVs from having mixed block sizes, which can produce
file system errors.
The new config setting devices/allow_mixed_block_sizes (default 0)
can be changed to 1 to return to the unrestricted mode.
