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lib: reduce parsing in vgname_from_mda

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Use similar logic as with text_vg_import_fd() and avoid repeated
parsing of same mda and its config tree for vgname_from_mda().

Remember last parsed vgname, vgid and creation_host in labeller
structure and if the  metadata have the same size and checksum,
return this stored info.

TODO: The reuse of labeller struct is not ideal, some lvmcache API for
this functionality would be nicer.
This commit is contained in:
Zdenek Kabelac 2015-03-06 10:24:26 +01:00
parent 7e7411966a
commit a9b28a4f21
7 changed files with 62 additions and 23 deletions
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1
WHATS_NEW
View File

@ -1,5 +1,6 @@
Version 2.02.118 -
=================================
Reduce number of VG metadata parsing when looking for vgname on a PV.
Avoid reparsing same metadata when reading same metadata from multiple PVs.
Save extra device open/close when scanning device for size.
Fix seg_monitor field to report status also for mirrors and thick snapshots.

21
lib/format_text/format-text.c
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@ -1124,14 +1124,14 @@ static int _scan_file(const struct format_type *fmt, const char *vgname)
}
const char *vgname_from_mda(const struct format_type *fmt,
struct mda_header *mdah,
struct device_area *dev_area, struct id *vgid,
struct mda_header *mdah, struct device_area *dev_area,
uint32_t *mda_checksum, size_t *mda_size,
const char *vgname, struct id *vgid,
uint64_t *vgstatus, char **creation_host,
uint64_t *mda_free_sectors)
{
struct raw_locn *rlocn;
uint32_t wrap = 0;
const char *vgname = NULL;
unsigned int len = 0;
char buf[NAME_LEN + 1] __attribute__((aligned(8)));
char uuid[64] __attribute__((aligned(8)));
@ -1182,6 +1182,10 @@ const char *vgname_from_mda(const struct format_type *fmt,
return NULL;
}
/* Check if it could be the same VG */
if ((rlocn->checksum != *mda_checksum) || (rlocn->size != *mda_size))
vgname = NULL; /* nope, reset to NULL */
/* FIXME 64-bit */
if (!(vgname = text_vgname_import(fmt, dev_area->dev,
(off_t) (dev_area->start +
@ -1190,6 +1194,7 @@ const char *vgname_from_mda(const struct format_type *fmt,
(off_t) (dev_area->start +
MDA_HEADER_SIZE),
wrap, calc_crc, rlocn->checksum,
vgname,
vgid, vgstatus, creation_host)))
return_NULL;
@ -1217,6 +1222,9 @@ const char *vgname_from_mda(const struct format_type *fmt,
*mda_free_sectors = ((buffer_size - 2 * current_usage) / 2) >> SECTOR_SHIFT;
}
*mda_checksum = rlocn->checksum;
*mda_size = rlocn->size;
return vgname;
}
@ -1230,6 +1238,8 @@ static int _scan_raw(const struct format_type *fmt, const char *vgname __attribu
struct id vgid;
uint64_t vgstatus;
struct mda_header *mdah;
uint32_t mda_checksum = 0;
size_t mda_size = 0;
raw_list = &((struct mda_lists *) fmt->private)->raws;
@ -1249,8 +1259,11 @@ static int _scan_raw(const struct format_type *fmt, const char *vgname __attribu
goto close_dev;
}
/* TODO: caching as in vgname_from_mda() (trigger this code?) */
if ((scanned_vgname = vgname_from_mda(fmt, mdah,
&rl->dev_area, &vgid, &vgstatus,
&rl->dev_area,
&mda_checksum, &mda_size, NULL,
&vgid, &vgstatus,
NULL, NULL))) {
vg = _vg_read_raw_area(&fid, scanned_vgname, &rl->dev_area, 0, 0);
if (vg)

1
lib/format_text/import-export.h
View File

@ -82,6 +82,7 @@ const char *text_vgname_import(const struct format_type *fmt,
off_t offset, uint32_t size,
off_t offset2, uint32_t size2,
checksum_fn_t checksum_fn, uint32_t checksum,
const char *vgname,
struct id *vgid, uint64_t *vgstatus,
char **creation_host);

13
lib/format_text/import.c
View File

@ -32,17 +32,22 @@ static void _init_text_import(void)
_text_import_initialised = 1;
}
/*
* Find out vgname on a given device.
* If the checksum and metadata size is matching the vgname discovered in last read
* (multi PVs VG) could be passed back and it may skip parsing of such metadata.
*/
const char *text_vgname_import(const struct format_type *fmt,
struct device *dev,
off_t offset, uint32_t size,
off_t offset2, uint32_t size2,
checksum_fn_t checksum_fn, uint32_t checksum,
const char *vgname,
struct id *vgid, uint64_t *vgstatus,
char **creation_host)
{
struct dm_config_tree *cft;
struct text_vg_version_ops **vsn;
const char *vgname = NULL;
_init_text_import();
@ -51,11 +56,15 @@ const char *text_vgname_import(const struct format_type *fmt,
if ((!dev && !config_file_read(cft)) ||
(dev && !config_file_read_fd(cft, dev, offset, size,
offset2, size2, checksum_fn, checksum, 0))) {
offset2, size2, checksum_fn, checksum,
(vgname != NULL)))) {
log_error("Couldn't read volume group metadata.");
goto out;
}
if (vgname)
goto out; /* Everything is matching from the last call */
/*
* Find a set of version functions that can read this file
*/

4
lib/format_text/layout.h
View File

@ -100,7 +100,9 @@ struct mda_context {
const char *vgname_from_mda(const struct format_type *fmt,
struct mda_header *mdah,
struct device_area *dev_area, struct id *vgid,
struct device_area *dev_area,
uint32_t *mda_checksum, size_t *mda_size,
const char *vgname, struct id *vgid,
uint64_t *vgstatus, char **creation_host,
uint64_t *mda_free_sectors);

25
lib/format_text/text_label.c
View File

@ -319,10 +319,14 @@ static int _update_mda(struct metadata_area *mda, void *baton)
const struct format_type *fmt = p->label->labeller->fmt;
struct mda_context *mdac = (struct mda_context *) mda->metadata_locn;
struct mda_header *mdah;
const char *vgname = NULL;
struct id vgid;
uint64_t vgstatus;
char *creation_host;
struct labeller *l = p->label->labeller;
/*
* Using the labeller struct to preserve info about
* the last parsed vgname, vgid, creation host
*
* TODO: make lvmcache smarter and move this cache logic there
*/
if (!dev_open_readonly(mdac->area.dev)) {
mda_set_ignored(mda, 1);
@ -346,17 +350,18 @@ static int _update_mda(struct metadata_area *mda, void *baton)
return 1;
}
if ((vgname = vgname_from_mda(fmt, mdah,
&mdac->area,
&vgid, &vgstatus, &creation_host,
if ((l->vgname = vgname_from_mda(fmt, mdah, &mdac->area,
&l->mda_checksum, &l->mda_size, l->vgname,
&l->vgid, &l->vgstatus, &l->creation_host,
&mdac->free_sectors)) &&
!lvmcache_update_vgname_and_id(p->info, vgname,
(char *) &vgid, vgstatus,
creation_host)) {
!lvmcache_update_vgname_and_id(p->info, l->vgname,
(char *) &l->vgid, l->vgstatus,
l->creation_host)) {
if (!dev_close(mdac->area.dev))
stack;
return_0;
}
close_dev:
if (!dev_close(mdac->area.dev))
stack;

8
lib/label/label.h
View File

@ -89,6 +89,14 @@ struct label_ops {
struct labeller {
struct label_ops *ops;
const struct format_type *fmt;
/* Caching info */
const char *vgname;
struct id vgid;
uint64_t vgstatus;
char *creation_host;
uint32_t mda_checksum;
size_t mda_size;
};
int label_init(void);