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Commit Graph

8 Commits

Author SHA1 Message Date
Zdenek Kabelac
bb20fac4ab libdm: maintain binary interface for new FEATURE flag
Older library version was not detecting unknown 'feature' bits
and could let start target without needed option.

New versioned symbol now checks for supported feature bits.
_Base version keeps accepting only previously known features and
mask/ignores unknown bits.

NB: if the older binary passed in 'random' bits, it will not get
metadata2 by chance. New linked binary get new validation function.
Library user is required to not pass 'trash' for unsupported bits,
as such calls will be rejected.
2017-03-10 19:33:01 +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
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
Zdenek Kabelac
9ef820a2a5 libdm: dm_tree_node_size_changed recognizes reduction
Add more functionality to size_changed function.
While 'existing' API only detected  0 for
unchanged,  and !0 for changed,
new improved API will also detected if the
size has only went bigger - or there was
size reduction.

Function work for the whole dm-tree - so
no change is size is always 0.
only size extension  1.
and if some size reduction is there - returns -1.

This result can be used for better evaluation
whether we need to flush before suspend.
2015-10-25 21:05:15 +01:00
Bryn M. Reeves
82a27a85b5 macros: fix default symbol export control
Fix the version export macros to make it possible to export two
different DM_* versions of a symbol: currently it is only possible for a
DM_* symbol to override a symbol in Base. Attempting to export two
symbols at different DM_* version levels (e.g. DM_1_02_104 and
DM_1_02_106) leads to a linker error due to a duplicate symbol
definition.

This is because the DM_EXPORTED_SYMBOL macro makes each exported symbol
the default (@@VERSION):

       __asm__(".symver " #func "_v" #ver ", " #func "@@DM_" #ver )

Fix the macro to use a single '@' for a symbols exported in multiple
versions and rename the macros to DM_EXPORT_*:

  DM_EXPORT_SYMBOL(func,ver)
  DM_EXPORT_SYMBOL_BASE(func,ver)

For functions that have multiple implementations these macros control
symbol export and versioning.

Function definitions that exist in only one version never need to use
these macros.

Backwards compatible implementations must include a version tag of
the form "_v1_02_104" as a suffix to the function name and use the
macro DM_EXPORT_SYMBOL to export the function and bind it to the
specified version string.

Since versioning is only available when compiling with GCC the entire
compatibility version should be enclosed in '#if defined(__GNUC__)',
for example:

  int dm_foo(int bar)
  {
    return bar;
  }

  #if defined(__GNUC__)
  // Backward compatible dm_foo() version 1.02.104
  int dm_foo_v1_02_104(void);
  int dm_foo_v1_02_104(void)
  {
    return 0;
  }
  DM_EXPORT_SYMBOL(dm_foo,1_02_104)
  #endif

A prototype for the compatibility version is required as these
functions must not be declared static.

The DM_EXPORT_SYMBOL_BASE macro is only used to export the base
versions of library symbols prior to the introduction of symbol
versioning: it must never be used for new symbols.
2015-08-24 20:03:21 +01:00
Zdenek Kabelac
797c18d543 libdm: new dm_task_get_info with internal_suspend
Introduce new implmentation of dm_task_get_info() function
with support for reading internal_suspend.
.
This time it is done in a 'versioned' way.

We keep the old fashion dm_task_get_info(Base) to implement
the old behavior of 1.02.95 libdm code.

libdm version 1.02.96 introduced 'macro' wrapper
dm_task_get_info_with_deferred_remove with new implementation
of dm_task_get_info() - we cannot do anything else then to
provide compatible version of this symbol.

Now in version 1.02.97 we add new versioned implementation of
dm_task_get_info(DM_1_02_97) symbol.

This has the effect that i.e. rpm build will finaly resolve proper
dependency on a new symbol - so it will be no longer possible,
to build a new binary and use old library
(rpm -q --provides will show libdevmapper.so.1.02(DM_1_02_97)(64bit))

Also the history is now tracked. If a new function is added (or
reimplemented), it needs to be placed in proper file,
so it could be exported with right versioning symbol.
File .exported_symbols.Base should and any existing older DM
should be treated as read-only after a release.

Also - only libdm has been currently enhanced with versioned .Base
file, as soon as other libs (liblvm, libdevmapper-event) needs changes
they should also get their exported symbol files - meanwhile
make.tmpl handles both cases.
2015-05-15 16:48:22 +02:00