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Commit Graph

162 Commits

Author SHA1 Message Date
David Teigland
6ae22125c6 vgcfgrestore: use lvmetad disabled state
Previously, vgcfgrestore would attempt to vg_remove the
existing VG from lvmetad and then vg_update to add the
restored VG.  But, if there was a failure in the command
or with vg_update, the lvmetad cache would be left incorrect.
Now, disable lvmetad before the restore begins, and then
rescan to populate lvmetad from disk after restore has
written the new VG to disk.
2016-06-20 11:19:49 -05:00
David Teigland
ed6ffc7a34 lvmetad: handle update failures
If a command gets stuck during an lvmetad update, lvmetad
will cancel that update after the timeout.  The next command
to check the lvmetad will see that lvmetad needs to be
populated because lvmetad will return token of "none" after
a timed out update (same as when lvmetad is not populated
at all after starting.)

If a command gets an error during an lvmetad update, it
will now just quit and leave its updating token in place.
That update will be cancelled after the timeout.
2016-06-07 10:17:00 -05:00
David Teigland
851ccfccaf lvmetad: remove disabled case for "scan error"
Failures while populating lvmetad will be handling
differently in a subsequent commit.
2016-06-07 10:17:00 -05:00
David Teigland
e0c22df5c4 lvmetad: remove old thread locking
The old thread locking is very fine grained and complex,
and appears to have no concurrency advantage.
2016-05-16 14:38:25 -05:00
David Teigland
9f72a52302 lvmetad: add request level thread locking
Use an rwlock for requests that read/write cache state.
Use a mutex for requests that read/write global info.
2016-05-16 14:38:04 -05:00
David Teigland
b1ea27b1e2 lvmetad: disable if device scan fails
If a command begins repopulating the lvmetad cache,
and fails part way through, it should set the disabled
state in lvmetad so other commands don't use bad data.
If a subsequent scan succeeds, the disabled state is
cleared.
2016-05-06 09:00:00 -05:00
David Teigland
3d2fbfe243 lvmetad: set disabled flag when duplicate PVs are seen
When duplicate PVs are detected, set the disabled
flag so that commands will disable use of lvmetad.

This duplicate detection is done by lvmetad itself
when it's told about a single new PV with a PVID
that matches an existing PV on another device.
(This is different from the case where the command
is scanning all devices and detects the duplicate.)

Remove the "altdev" logic that attempted to keep
track of multiple devices for a single PV.  It
is no longer used since lvmetad is disabled in
this case.
2016-05-06 08:59:59 -05:00
David Teigland
593900b795 lvmetad: use defines for disabled reason strings 2016-04-19 11:45:24 -05:00
David Teigland
a4ef8fa25e lvmetad: add disabled state
A global flag in lvmetad indicates it has been disabled.
Other flags indicate the reason it was disabled.
These flags can be queried using get_global_info.

The lvmetactl debugging utility can set and clear the
disabled flag in lvmetad.  Nothing else sets the
disabled flag yet.

Commands will check these flags after connecting to
lvmetad.  If the disabled flag is set, the command
will not use the lvmetad cache, but revert to disk
scanning.

To test this feature:

$ lvmetactl get_global_info
response = "OK"
global_invalid = 0
global_disable = 0
disable_reason = "none"
token = "filter:3041577944"

$ vgs
(should report VGs from lvmetad)

$ lvmetactl set_global_disable 1

$ lvmetactl get_global_info
response = "OK"
global_invalid = 0
global_disable = 1
disable_reason = "DIRECT"
token = "filter:3041577944"

$ vgs
  WARNING: Not using lvmetad because the disable flag was set directly.
(should report VGs without contacting lvmetad)

$ lvmetactl set_global_disable 0

$ vgs
(should report VGs from lvmetad)
2016-04-19 09:41:18 -05:00
David Teigland
56c68b3476 lvmetad: preemptively check and rescan in commands
Move checking the lvmetad state, and the possible rescan,
out of lvmetad_send() to the start of the command.

Previously, the token mismatch and rescan would occur
within lvmetad_send() for some other request.  Now,
the token mismatch is detected earlier, so the
rescan can be done before the main command is in
progress.  Rescanning deep within the processing of
another command will disturb the lvmcache state of
that other command.

A rescan already exists at the start of the command
for the case where foreign VGs are going to be read.
This same rescan is now also performed when there is
an lvmetad token mismatch (from a changed global_filter).

The commands pvscan/vgscan/lvscan/vgimport are excluded
from this preemptive checking/rescanning for lvmetad
because they want to do rescanning themselves explicitly.

If rescanning devices fails, then lvmetad has not been
correctly repopulated and should not be used, so make
the command revert to not using lvmetad.
2016-04-13 14:05:42 -05:00
Zdenek Kabelac
fcbef05aae doc: change fsf address
Hmm rpmlint suggest fsf is using a different address these days,
so lets keep it up-to-date
2016-01-21 12:11:37 +01:00
David Teigland
931fede81b hash: change name of new lookup function 2015-11-17 11:59:44 -06:00
David Teigland
485d2ca945 lvmetad: different style for hash functions
In lookup, return a count of entries with the
same key rather than the value from a second
entry with the same key.

Using some slightly different names.
2015-11-17 10:27:16 -06:00
David Teigland
d42cedae58 lvmetad: add error explaining duplicate VG names
When a VG name lookup fails because the name matches
multiple VGs, return an explanatory error.
2015-11-16 16:25:49 -06:00
David Teigland
7d1c9e1d5a lvmetad: fix some error logging
For some errors old_meta may not be set, so
check before logging it.
2015-11-16 15:13:26 -06:00
David Teigland
68c386cce7 lvmetad: use lookup_withval in another location
Simply use lookup_withval right away rather than doing a
standard lookup, checking for the wrong mapping, then
repeating with lookup_withval to get the right mapping.
2015-11-16 15:13:22 -06:00
David Teigland
4a984cabc4 lvmetad: remove unneeded FIXME
This case is now handled correctly.
2015-11-16 13:44:57 -06:00
David Teigland
d9295410e9 lvmetad: change the new hash to take data len
If the data len is passed into the hash table
and saved there, then the hash table internals
do not need to assume that the data value is
a string at any point.
2015-11-13 16:54:22 -06:00
David Teigland
46193f4a59 lvmetad: handle duplicate VG names
New hash table functions are added that allow for
multiple entries with the same key.  Use of the
vgname_to_vgid hash table is converted to these
new functions since there are multiple entries
in vgname_to_vgid that have the same key (vgname).

When multiple VGs with the same name exist, commands
that reference only a VG name will fail saying the
VG could not be found (that error message could be
improved.)  Any command that works with the select
option can access one of the VGs with -S vg_uuid=X.
vgrename is a special case that allows the first VG
name arg to be replaced by a uuid, which also works.

(The existing hash table implementation is not well
suited for handling this case, but it works ok with
the new extensions.  Changing lvmetad to use its own
custom hash tables may be preferable at some point.)
2015-11-13 14:56:35 -06:00
David Teigland
43777b551d lvmetad: tail chasing to shut up coverity 2015-11-12 09:35:41 -06:00
David Teigland
cd937efa77 lvmetad: change recent cleanups
with better alternatives.
2015-11-09 12:18:43 -06:00
Zdenek Kabelac
c2d5cfbdb8 cleanup: use _ for local function 2015-11-09 17:04:10 +01:00
Zdenek Kabelac
0b5a75c9af lvmetad: restore use of FMTd64
daemon_reply_simple() eats just 64bit numbers - so make it explicit.
2015-11-09 14:02:27 +01:00
Zdenek Kabelac
5aae8de776 lvmetad: maintain seqno as int
Keep seqno as 32bit value.
Also use '_' prefix for local _update_metadata.
2015-11-09 12:21:17 +01:00
Zdenek Kabelac
99def8f439 lvmetad: check for pointers not NULL
Check for  arg_vgid_lookup and arg_name_lookup not being NULL.
Drop checking arg_vgid and arg_name for NULL since they
are already dereference earlier - thus mostly must be NOT NULL.

(If that would be possible larger rework of this function would be
required).
2015-11-09 10:19:19 +01:00
Zdenek Kabelac
f66fe2c444 lvmetad: require meta_lookup
Coverity: do not call update_pvid_to_vgid() with
meta_lookup == NULL since it is dereferencing it.
2015-11-09 10:19:19 +01:00
Zdenek Kabelac
91bde0f4a1 lvmetad: check for allocation fail
Coverity: missing check for root != NULL as this pointer is
later dereferenced in add_last_node().
2015-11-09 10:19:19 +01:00
David Teigland
4e6377f5ba lvmetad: refactor and document
update_metadata and pv_found update the cached metadata;
these are both reworked to improve the code, organize it
by each possible state and transition, make it much more
clear what's changing, add more error checking and
handling, and add comments.

The state and content of the cache (hash tables) does not
change (apart from some things that didn't work before),
and the communication to/from commands does not change.
The implementation and organization of the code making
the state changes does change significantly.

One detail related to the content of the cache does change:
different hash tables do not reference the same memory any more;
the target values in each hash table are allocated and freed
individually.
2015-11-03 13:18:27 -06:00
David Teigland
73e679f33f man: document possible lvmetad -l values
In the man page and the lvmetad help output.
2015-10-21 13:36:57 -05:00
Ondrej Kozina
f67a52677b lvmetad: add optional timeout option 2015-10-20 15:45:14 +02:00
Alasdair G Kergon
fb12308416 style: Standardise some error paths. 2015-09-05 23:56:30 +01:00
David Teigland
f0b3e05add lvmetad: also accept vg name for set_vg_info
set_vg_info previously accepted only vg uuid,
now accept both vg uuid and vg name.  If the
uuid is provided, it's used just as before,
but if the uuid is not provided, or if it's
not found, then fall back to using the vg
name if that is provided.
2015-08-28 14:36:48 -05:00
Peter Rajnoha
10d27998b3 coverity: missing return value checks 2015-07-09 15:15:15 +02:00
Peter Rajnoha
023cf21848 coverity: fix possible invalid dereferences
lib/format1/import-export.c:167: var_deref_op: Dereferencing null pointer "vg->lvm1_system_id"
lib/cache/lvmetad.c:1023: var_deref_op: Dereferencing null pointer "this"
daemons/lvmlockd/lvmlockd-core.c:2659: check_after_deref: Null-checking "act" suggests that it may be null, but it has already been dereferenced on all paths leading to the check
/daemons/lvmetad/lvmetad-core.c:1024: check_after_deref: Null-checking "pvmeta" suggests that it may be null, but it has already been dereferenced on all paths leading to the check
2015-07-09 12:07:41 +02:00
Alasdair G Kergon
dfe3eb12d0 include: Standardise around new tool.h. 2015-07-06 17:30:18 +01:00
David Teigland
bf77f71711 lvmetad: add invalidation method
Add the ability to invalidate global or individual VG metadata.
The invalid state is returned to lvm commands along with the metadata.
This allows lvm commands to detect stale metadata from the cache and
reread the latest metadata from disk (in a subsequent patch.)

These changes do not change the protocol or compatibility between
lvm commands and lvmetad.

Global information
------------------

Global information refers to metadata that is not isolated
to a single VG , e.g. the list of vg names, or the list of pvs.

When an external system, e.g. a locking system, detects that global
information has been changed from another host (e.g. a new vg has been
created) it sends lvmetad the message: set_global_info: global_invalid=1.
lvmetad sets the global invalid flag to indicate that its cached data is
stale.

When lvm commands request information from lvmetad, lvmetad returns the
cached information, along with an additional top-level config node called
"global_invalid".  This new info tells the lvm command that the cached
information is stale.

When an lvm command sees global_invalid from lvmated, it knows it should
rescan devices and update lvmetad with the latest information.  When this
is complete, it sends lvmetad the message: set_global_info:
global_invalid=0, and lvmetad clears the global invalid flag.  Further lvm
commands will use the lvmetad cache until it is invalidated again.

The most common commands that cause global invalidation are vgcreate and
vgextend.  These are uncommon compared to commands that report global
information, e.g. vgs.  So, the percentage of lvmetad replies containing
global_invalid should be very small.

VG information
--------------

VG information refers to metadata that is isolated to a single VG,
e.g. an LV or the size of an LV.

When an external system determines that VG information has been changed
from another host (e.g. an lvcreate or lvresize), it sends lvmetad the
message: set_vg_info: uuid=X version=N.  X is the VG uuid, and N is the
latest VG seqno that was written.  lvmetad checks the seqno of its cached
VG, and if the version from the message is newer, it sets an invalid flag
for the cached VG.  The invalid flag, along with the newer seqno are saved
in a new vg_info struct.

When lvm commands request VG metadata from lvmetad, lvmetad includes the
invalid flag along with the VG metadata.  The lvm command checks for this
flag, and rereads the VG from disk if set.  The VG read from disk is sent
to lvmetad.  lvmetad sees that the seqno in the new version matches the
seqno from the last set_vg_info message, and clears the vg invalid flag.
Further lvm commands will use the VG metadata from lvmetad until it is
next invalidated.
2015-06-23 16:36:33 -05:00
David Teigland
fd1376ebef libdaemon: move compare_config to lib
so it can be used elsewhere.
2015-06-17 13:07:52 -05:00
Petr Rockai
4f91ad64c3 lvmetad: Make it possible to clear the outdated PVs list for a VG. 2015-06-10 16:18:57 +02:00
Zdenek Kabelac
d1531ab26d cleanup: gcc warn fix, don't hide pvs() 2015-05-27 11:10:43 +02:00
Petr Rockai
55f3369692 lvmetad: Provide entire pvmeta sections for outdated_pvs. 2015-05-20 19:46:14 +02:00
Petr Rockai
1562cd7320 lvmetad: Attach an outdated_pvs list to vg_lookup replies. 2015-05-20 19:46:13 +02:00
Petr Rockai
da1527d65d lvmetad: Clear the vgid_to_outdated_pvs hash on shutdown. 2015-05-20 19:46:13 +02:00
Petr Rockai
925268794f lvmetad: Maintain info about outdated PVs. 2015-05-20 19:46:13 +02:00
Zdenek Kabelac
923902013c lvmetad: drop unused vars
Squash some unused vars introduced in some previous commit.s
2015-04-29 15:09:58 +02:00
Petr Rockai
4946c64092 lvmetad: Avoid duplicate entries in the list of alternate devices. 2015-04-29 13:23:23 +02:00
Petr Rockai
a1dd61459c lvmetad: Track alternate devices for PVs.
There are two reasons for this: first, this allows the client side to notice
that some PV has multiple devices associated with it and print appropriate
warnings. Second, if a duplicate device pops up and disappears, after this
change the original connection between the PV and device is not lost.
2015-04-14 20:18:27 +02:00
Zdenek Kabelac
f12e3da639 cleanup: gcc warnings 2014-11-10 22:05:49 +01:00
Zdenek Kabelac
3fda296da6 cleanup: lvmetad use dm_hash_iterator
Simplify code with the use of dm_hash_iterator
2014-03-26 14:11:37 +01:00
Petr Rockai
551b6b7998 lvmetad: Fix pvmeta_old_{pvid,dev} logic when they are the same. 2014-03-14 10:09:16 +01:00
Marian Csontos
67c539f346 lvmetad: Fix previous commit
"%d" in buffer_append_vf is 64 bit wide. Using just `int` for the
variable will fetch more from va_list than intended and shifting
remaining arguments resulting in errors like:

    Internal error: Bad format string at '#orphan'
2014-03-14 08:09:37 +01:00