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Commit Graph

244 Commits

Author SHA1 Message Date
Zdenek Kabelac
bc1bc4cffc debug: drop stack from regular code flow 2021-03-15 11:13:24 +01:00
Zdenek Kabelac
75037bee5d debug: more tracing
Check result of device_ids_write() and at least provide stack;
2021-03-10 01:27:13 +01:00
Zdenek Kabelac
ca12dae32b hints: keep strings aligned in structure
Preffer aligned string access.
2021-03-08 15:33:15 +01:00
Zdenek Kabelac
00531186fc label: check only with active device for rescan
When 'lv_info()' is called with &info structure,
the presence of node has to be checked from this structure.
Without this we were needlesly trying to look out 0:0 device.
2021-03-02 22:54:40 +01:00
David Teigland
83fe6e720f device usage based on devices file
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
2021-02-23 16:43:32 -06:00
David Teigland
c94d78f068 scan: wipe filters when dropping scanned data
Fix clearing persistent filter state when clearing all
the state from a label_scan.

label_scan reads devs and saves info in bcache, lvmcache,
and in the persistent filter.  In some uncommon cases, an
lvm command wants to clear all info from a prior label_scan,
and repeat label_scan from scratch.  In these cases, info
in lvmcache, bcache and the persistent filter all need to
be cleared before repeating label_scan.

By missing the persistent filter wiping, outdated persistent
filter info, from a prior label_scan, could cause lvm to
incorrectly filter devices that change between polling intervals.
(i.e. if the device changes in such a way that the filtering
results change.)

A case where lvm wants to do multiple label_scans is a
polling command (like lvconvert --merge), when lvmpolld
has been disabled, so that the command itself needs to
to do repeated polling checks.
2021-02-10 15:34:45 -06:00
Zdenek Kabelac
a383586177 label: avoid rescaning unusable DM devices 2021-02-10 15:39:03 +01:00
David Teigland
87ee401eea md component detection changes
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.
2021-02-05 16:23:51 -06:00
David Teigland
2ec29d0677 label_scan: fix missing free of filtered_devs
missing free of devl entries on filtered_devs list in
commit 2c9bb67604
2021-01-18 16:26:02 -06:00
David Teigland
2c31939827 pvcreate: clean up opening and filtering of args
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
2020-10-26 11:13:27 -05:00
David Teigland
a7f195b7e8 add label_scan_devs_cached
label_scan_devs without invalidating data first
for cases where the caller wants to use any
bcache data they have already read.
2020-10-21 16:24:16 -05:00
David Teigland
677f829e54 add label_read_pvid
To read the lvm headers and set dev->pvid if the
device is a PV.  Difference from label_scan_ functions
is this does not read any vg metadata or add any info
to lvmcache.
2020-10-21 16:24:16 -05:00
David Teigland
c7311d4722 lvmcache: rename label_read label_scan_dev
for consistent naming with other similar functions
2020-10-21 16:24:16 -05:00
David Teigland
2c9bb67604 scanning: improve filtering control
Filtering in label_scan was controlled indirectly by
the fact that bcache was not yet set up when label_scan
first ran.  The result is that filters that needed data
would not run and would return -EAGAIN, which would
result in the dev flag FILTER_AFTER_SCAN being set.
After the dev header was read for checking the label,
filters would be rechecked because of FILTER_AFTER_SCAN.
All filters would be checked this time because bcache
was now set up, and the filters needing data would
largely use data already scanned for reading the label.
This design worked but is hard to adjust for future
cases where bcache is already set up.

Replace this method (based on setting up bcache, or not)
with a new cmd flag filter_nodata_only.  When this flag
is set filters that need data will not run.  This allows
the same label_scan behavior when bcache has been set up.
There are no expected changes in behavior.
2020-10-21 16:24:16 -05:00
Zdenek Kabelac
117fc64e6e debug: no backtrace
As the path already printed verbose message drop backtrace.
2020-10-02 21:04:16 +02:00
David Teigland
da14cf68cb scanning: keep open an lvm device with scanning problem
The command may want to update it.
2020-09-28 13:25:57 -05:00
David Teigland
890c7ef451 devices: fix reopen for unopened device
If there's a request to reopen rw a device that's not
open, then just call the normal open function.
2020-09-28 13:25:57 -05:00
David Teigland
1404e5ee61 metadata: open rw fd before closing ro fd
lvm opens devices readonly to scan them, but
needs to open then readwrite to update the metadata.
Previously, the ro fd was closed before the rw fd
was opened, leaving a small gap where the dev was
not held open, and during which the dev could
possibly change which storage it referred to.

With the bcache_change_fd() interface, lvm opens a
rw fd on a device to be written, tells bcache to
change to the new rw fd, and closes the ro fd.

. open dev ro
. read dev with the ro fd (label_scan)
. lock vg (ex for writing)
. open dev rw
. close ro fd
. rescan dev to check if the metadata changed
  between the scan and the lock
. if the metadata did change, reread in full
. write the metadata
2020-09-18 15:10:11 -05:00
David Teigland
1570e76233 bcache: use indirection table for fd
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.
2020-09-18 15:10:11 -05:00
David Teigland
46f43589d0 hints: enhance debug messages 2020-09-16 15:01:10 -05:00
David Teigland
491eb25832 label: cleanup set_byte error exit 2020-09-16 13:54:16 -05:00
David Teigland
37bcd7ce84 Revert "label: use formaters FMTu64 and FMTsize_t"
This reverts commit d0ccb2521b.
2020-09-16 13:47:06 -05:00
Zdenek Kabelac
d0ccb2521b label: use formaters FMTu64 and FMTsize_t
Produces code without casts to differntly signed types
and also shortens and enhances readbility.
2020-09-15 23:07:06 +02:00
Zdenek Kabelac
7bcc994776 label: deduplicate dev_set_bytes
As dev_write_zeros() is same as dev_set_bytes() reused the code
directly.
2020-09-15 22:52:25 +02:00
Zdenek Kabelac
7b08133844 label: code deduplication 2020-09-15 22:52:25 +02:00
Zdenek Kabelac
6d344b4ac0 hints: enhance debug with log_sys_debug 2020-09-15 22:52:25 +02:00
David Teigland
8b9028bbe7 hints: remove warning when clearing hint file
When the hint file cannot be accessed, silently
ignore hints, like other instances do.
2020-09-02 14:06:46 -05:00
Zdenek Kabelac
a481f42630 cov: always initialized values
Make sure values are initialized for all possible paths.
2020-09-01 17:57:50 +02:00
Zdenek Kabelac
85e2c7e14d cov: explicitely ignore function result 2020-09-01 17:57:50 +02:00
Zdenek Kabelac
1705b439b1 cov: always sure we end with '0'
Use easier dm_strncpy().
2020-09-01 17:57:50 +02:00
Zdenek Kabelac
fd96f1014b gcc: zero-sized array to fexlible array C99
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.
2020-09-01 17:57:50 +02:00
Zdenek Kabelac
19e9c88faf gcc: do not use return with void function
Follow C norm and do not use 'return' in void function to call other
functions.
2020-08-28 21:43:03 +02:00
Zdenek Kabelac
ee0cb17608 gcc: use apropriate type for reading and printing values 2020-08-28 21:43:03 +02:00
Zdenek Kabelac
cca2a652d1 cov: avoid double call of free_hints() on error path
Since we 'free_hints()' on return error path from call of
_read_hint_file(), avoid calling it twice in the middle of
error path process.
2020-06-24 15:01:03 +02:00
David Teigland
5c095400de hints: free hint structs on exit
and free on a couple error paths.
2020-05-13 17:20:16 -05:00
David Teigland
2f29765e7f devs: add some checks for a dev with no path name
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.
2020-05-13 16:26:26 -05:00
David Teigland
cc4051eec0 pass cmd struct through more functions
no functional change
2020-04-21 10:58:05 -05:00
David Teigland
f50e7ce76c hints: free hint list in error exit path 2020-03-03 12:25:34 -06:00
Zdenek Kabelac
de43527f94 cov: unused header file removal
cov: unused header removed
Also ensure library header file with config settings goes first.
Move inclusion of format-text.h into layout.h
2020-02-04 17:22:06 +01:00
David Teigland
94076245df scan: add simple scan to find a pvid 2019-11-27 11:13:47 -06:00
David Teigland
56a295f78c bcache: add invalidate_bytes function 2019-11-26 16:52:28 -06:00
David Teigland
7ea71a9eb9 Revert "hints: rewrite function"
This reverts commit 70fb31b5d6.
2019-11-14 12:15:05 -06:00
David Teigland
31a862a6be Revert "debug: enhance debug messages"
This reverts commit e92d3bd1f7.
2019-11-14 12:11:53 -06:00
Zdenek Kabelac
e92d3bd1f7 debug: enhance debug messages 2019-11-14 18:06:42 +01:00
Zdenek Kabelac
14e01d6316 hints: drop unneeded memset
strncpy will zero buffer itself.
2019-11-14 18:06:42 +01:00
Zdenek Kabelac
1760b96368 hints: no need to check for NULL before free
free() itself checks for NULL.
2019-11-14 18:06:42 +01:00
Zdenek Kabelac
61a483a654 hints: check for _touch_hints
Exit when !_touch_hints().
2019-11-14 18:06:42 +01:00
Zdenek Kabelac
c38be06531 hints: fix mem leaking buffers 2019-11-14 18:06:42 +01:00
Zdenek Kabelac
1349a52626 hints: validate allocation result 2019-11-14 18:06:42 +01:00
Zdenek Kabelac
219fe72359 hints: validate sscanf results 2019-11-14 18:06:42 +01:00