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Since lvm2 normally block signals during protected
phase where it does not want to be interrupted.
Support interruptible processing when allowed
in section between sigint_allow() ... sigint_restore())
and let the 'io_getenvents()' finish with EINTR.
When bcache tries to write data to a faulty device,
it may get out of caching blocks and then just busy-loops
on a CPU - so this check protects this by checking
if there is already max_io (~64) errored blocks.
Call _wait_all() which does check whether there is still
some pending IO before sleep. Otherwise it may happen
our submitted IO operations have been already dispatched
and this call then endlessly waits for IO which are all done.
This can be reproduced when device returns quickly errors
on write requests.
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.
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.
When initiated larger write request, it may have happened, bcache
got out of free chunks - fix the loop, that is supposed to wait
until next free chunk becomes avain available.
It's possible for a dev-cache entry to remain after all
paths for it have been removed, and other parts of the
code expect that a dev always has a name. A better fix
may be to remove a device from dev-cache after all paths
to it have been removed.
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
Do this at two levels, although one would be enough to
fix the problem seen recently:
- Ignore any reported sector size other than 512 of 4096.
If either sector size (physical or logical) is reported
as 512, then use 512. If neither are reported as 512,
and one or the other is reported as 4096, then use 4096.
If neither is reported as either 512 or 4096, then use 512.
- When rounding up a limited write in bcache to be a multiple
of the sector size, check that the resulting write size is
not larger than the bcache block itself. (This shouldn't
happen if the sector size is 512 or 4096.)
An active md device with an end superblock causes lvm to
enable full md component detection. This was being done
within the filter loop instead of before, so the full
filtering of some devs could be missed.
Also incorporate the recently added config setting that
controls the md component detection.
If udev info is missing for a device, (which would indicate
if it's an MD component), then do an end-of-device read to
check if a PV is an MD component. (This is skipped when
using hints since we already know devs in hints are good.)
A new config setting md_component_checks can be used to
disable the additional end-of-device MD checks, or to
always enable end-of-device MD checks.
When both hints and udev info are disabled/unavailable,
the end of PVs will now be scanned by default. If md
devices with end-of-device superblocks are not being
used, the extra I/O overhead can be avoided by setting
md_component_checks="start".
udev_dev_is_md_component and udev_dev_is_mpath_component
are not used for obtaining the device list, but they still
use libudev for device info. When there are problems with
udev, these functions can get stuck. So, use the existing
obtain_device_list_from_udev config setting to also control
whether these "is component" functions are used, which gives
us a way to avoid using libudev entirely when it's causing
problems.
Save the list of PVs in /run/lvm/hints. These hints
are used to reduce scanning in a number of commands
to only the PVs on the system, or only the PVs in a
requested VG (rather than all devices on the system.)
Ensure configure.h is always 1st. included header.
Maybe we could eventually introduce gcc -include option, but for now
this better uses dependency tracking.
Also move _REENTRANT and _GNU_SOURCE into configure.h so it
doesn't need to be present in various source files.
This ensures consistent compilation of headers like stdio.h since
it may produce different declaration.
commit de28637
scan: use full md filter when md 1.0 devices are present
missed the fact that md superblock version 0.90 also puts
metadata at the end of the device, so the full md filter
needs to be used when either 0.90 or 1.0 is present.
fix lseek error check
fix read/write error checks
handle zero return from read and write
don't return an error for short io
fix partial read/write loop
io_setup() for aio may fail if a system has reached the
aio request limit. In this case, fall back to using
sync io. Also, lvm use of aio can be disabled entirely
with config setting global/use_aio=0.
The system limit for aio requests can be seen from
/proc/sys/fs/aio-max-nr
The current usage of aio requests can be seen from
/proc/sys/fs/aio-nr
The system limit for aio requests can be increased by
setting fs.aio-max-nr using sysctl.
Also add last-byte limit to the sync io code.
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!
