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Code Releases Activity

lvmcache: remove lvmcache_update_vg_from_write

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After a vg_write, this function was used to attempt to
make lvmcache data match the new state written to disk.
It was not updated correctly in a many or most cases,
and the resulting lvmcache is not actually used after
vg_write, making the update unnecessary.
This commit is contained in:
David Teigland 2022-01-12 16:46:26 -06:00
parent 5e428d22d9
commit cb798ee1c1
3 changed files with 0 additions and 52 deletions
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44
lib/cache/lvmcache.c vendored
View File

@ -2239,50 +2239,6 @@ int lvmcache_update_vgname_and_id(struct cmd_context *cmd, struct lvmcache_info
return 1;
}
/*
* FIXME: quit trying to mirror changes that a command is making into lvmcache.
*
* First, it's complicated and hard to ensure it's done correctly in every case
* (it would be much easier and safer to just toss out what's in lvmcache and
* reread the info to recreate it from scratch instead of trying to make sure
* every possible discrete state change is correct.)
*
* Second, it's unnecessary if commands just use the vg they are modifying
* rather than also trying to get info from lvmcache. The lvmcache state
* should be populated by label_scan, used to perform vg_read's, and then
* ignored (or dropped so it can't be used).
*
* lvmcache info is already used very little after a command begins its
* operation. The code that's supposed to keep the lvmcache in sync with
* changes being made to disk could be half wrong and we wouldn't know it.
* That creates a landmine for someone who might try to use a bit of it that
* isn't being updated correctly.
*/
int lvmcache_update_vg_from_write(struct volume_group *vg)
{
char vgid[ID_LEN + 1] __attribute__((aligned(8))) = { 0 };
struct pv_list *pvl;
struct lvmcache_info *info;
struct lvmcache_vgsummary vgsummary = {
.vgname = vg->name,
.vgstatus = vg->status,
.system_id = vg->system_id,
.lock_type = vg->lock_type
};
memcpy(vgid, &vg->id, ID_LEN);
memcpy(vgsummary.vgid, vgid, ID_LEN);
dm_list_iterate_items(pvl, &vg->pvs) {
if ((info = lvmcache_info_from_pv_id(&pvl->pv->id, pvl->pv->dev, 0)) &&
!lvmcache_update_vgname_and_id(vg->cmd, info, &vgsummary))
return_0;
}
return 1;
}
/*
* The lvmcache representation of a VG after label_scan can be incorrect
* because the label_scan does not use the full VG metadata to construct

1
lib/cache/lvmcache.h vendored
View File

@ -84,7 +84,6 @@ void lvmcache_del_dev(struct device *dev);
int lvmcache_update_vgname_and_id(struct cmd_context *cmd, struct lvmcache_info *info,
struct lvmcache_vgsummary *vgsummary);
int lvmcache_update_vg_from_read(struct volume_group *vg, unsigned precommitted);
int lvmcache_update_vg_from_write(struct volume_group *vg);
void lvmcache_lock_vgname(const char *vgname, int read_only);
void lvmcache_unlock_vgname(const char *vgname);

7
lib/metadata/metadata.c
View File

@ -3102,7 +3102,6 @@ static int _vg_commit_mdas(struct volume_group *vg)
DM_LIST_INIT(ignored);
int failed = 0;
int good = 0;
int cache_updated = 0;
/* Rearrange the metadata_areas_in_use so ignored mdas come first. */
dm_list_iterate_items_safe(mda, tmda, &vg->fid->metadata_areas_in_use)
@ -3123,12 +3122,6 @@ static int _vg_commit_mdas(struct volume_group *vg)
failed = 1;
} else
good++;
/* Update cache first time we succeed */
if (!failed && !cache_updated) {
lvmcache_update_vg_from_write(vg);
cache_updated = 1;
}
}
if (good)
return 1;