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mirror of git://sourceware.org/git/lvm2.git synced 2024-11-11 23:22:05 +03:00

filter-sysfs: skip when device id is set

When a device id is set for a device, using an idtype other
than devname, it means that sysfs has been used with the device
to match the device id.  So, checking for a sysfs entry for the
device in filter-sysfs is redundant.  For any other cases not
covered by this (e.g. devname ids), have filter-sysfs simply
stat /sys/dev/block/major:minor to test if the device exists
in sysfs.

The extensive processing done by filter-sysfs init is removed.
It was taking an immense amount of time with many devices, e.g.
. 1024 PVs in 520 VGs
. 520 concurrent vgchange -ay <vgname> commands
. vgchange scans only PVs in the named VG (based on pvs_online
  files from a pending patch)

A large number of the vgchange commands were taking over 1 min,
and nearly half of that time was used by filter-sysfs init.
With this patch, the vgchange commands take about half the time.
This commit is contained in:
David Teigland 2021-11-02 15:42:26 -05:00
parent 5d0964d127
commit b5b0369e4d
2 changed files with 34 additions and 290 deletions

View File

@ -1143,19 +1143,6 @@ static struct dev_filter *_init_filter_chain(struct cmd_context *cmd)
* Update MAX_FILTERS definition above when adding new filters.
*/
/*
* sysfs filter. Only available on 2.6 kernels. Non-critical.
* Listed first because it's very efficient at eliminating
* unavailable devices.
*
* TODO: I suspect that using the lvm_type and device_id
* filters before this one may be more efficient.
*/
if (find_config_tree_bool(cmd, devices_sysfs_scan_CFG, NULL)) {
if ((filters[nr_filt] = sysfs_filter_create()))
nr_filt++;
}
/* internal filter used by command processing. */
if (!(filters[nr_filt] = internal_filter_create())) {
log_error("Failed to create internal device filter");
@ -1195,6 +1182,17 @@ static struct dev_filter *_init_filter_chain(struct cmd_context *cmd)
}
nr_filt++;
/*
* sysfs filter. Only available on 2.6 kernels. Non-critical.
* Eliminates unavailable devices.
* TODO: this may be unnecessary now with device ids
* (currently not used for devs match to device id using syfs)
*/
if (find_config_tree_bool(cmd, devices_sysfs_scan_CFG, NULL)) {
if ((filters[nr_filt] = sysfs_filter_create()))
nr_filt++;
}
/* usable device filter. Required. */
if (!(filters[nr_filt] = usable_filter_create(cmd, cmd->dev_types, FILTER_MODE_NO_LVMETAD))) {
log_error("Failed to create usabled device filter");

View File

@ -17,266 +17,34 @@
#ifdef __linux__
#include <sys/sysmacros.h>
#include <dirent.h>
static int _locate_sysfs_blocks(const char *sysfs_dir, char *path, size_t len,
unsigned *sysfs_depth)
{
struct stat info;
unsigned i;
static const struct dir_class {
const char path[32];
int depth;
} classes[] = {
/*
* unified classification directory for all kernel subsystems
*
* /sys/subsystem/block/devices
* |-- sda -> ../../../devices/pci0000:00/0000:00:1f.2/host0/target0:0:0/0:0:0:0/block/sda
* |-- sda1 -> ../../../devices/pci0000:00/0000:00:1f.2/host0/target0:0:0/0:0:0:0/block/sda/sda1
* `-- sr0 -> ../../../devices/pci0000:00/0000:00:1f.2/host1/target1:0:0/1:0:0:0/block/sr0
*
*/
{ "subsystem/block/devices", 0 },
/*
* block subsystem as a class
*
* /sys/class/block
* |-- sda -> ../../devices/pci0000:00/0000:00:1f.2/host0/target0:0:0/0:0:0:0/block/sda
* |-- sda1 -> ../../devices/pci0000:00/0000:00:1f.2/host0/target0:0:0/0:0:0:0/block/sda/sda1
* `-- sr0 -> ../../devices/pci0000:00/0000:00:1f.2/host1/target1:0:0/1:0:0:0/block/sr0
*
*/
{ "class/block", 0 },
/*
* old block subsystem layout with nested directories
*
* /sys/block/
* |-- sda
* | |-- capability
* | |-- dev
* ...
* | |-- sda1
* | | |-- dev
* ...
* |
* `-- sr0
* |-- capability
* |-- dev
* ...
*
*/
{ "block", 1 }
};
for (i = 0; i < DM_ARRAY_SIZE(classes); ++i)
if ((dm_snprintf(path, len, "%s%s", sysfs_dir, classes[i].path) >= 0) &&
(stat(path, &info) == 0)) {
*sysfs_depth = classes[i].depth;
return 1;
}
return 0;
}
/*----------------------------------------------------------------
* We need to store a set of dev_t.
*--------------------------------------------------------------*/
struct entry {
struct entry *next;
dev_t dev;
};
#define SET_BUCKETS 64
struct dev_set {
struct dm_pool *mem;
const char *sys_block;
unsigned sysfs_depth;
int initialised;
struct entry *slots[SET_BUCKETS];
};
static struct dev_set *_dev_set_create(struct dm_pool *mem,
const char *sys_block,
unsigned sysfs_depth)
{
struct dev_set *ds;
if (!(ds = dm_pool_zalloc(mem, sizeof(*ds))))
return NULL;
ds->mem = mem;
if (!(ds->sys_block = dm_pool_strdup(mem, sys_block)))
return NULL;
ds->sysfs_depth = sysfs_depth;
ds->initialised = 0;
return ds;
}
static unsigned _hash_dev(dev_t dev)
{
return (major(dev) ^ minor(dev)) & (SET_BUCKETS - 1);
}
/*
* Doesn't check that the set already contains dev.
*/
static int _set_insert(struct dev_set *ds, dev_t dev)
{
struct entry *e;
unsigned h = _hash_dev(dev);
if (!(e = dm_pool_alloc(ds->mem, sizeof(*e))))
return 0;
e->next = ds->slots[h];
e->dev = dev;
ds->slots[h] = e;
return 1;
}
static int _set_lookup(struct dev_set *ds, dev_t dev)
{
unsigned h = _hash_dev(dev);
struct entry *e;
for (e = ds->slots[h]; e; e = e->next)
if (e->dev == dev)
return 1;
return 0;
}
/*----------------------------------------------------------------
* filter methods
*--------------------------------------------------------------*/
static int _parse_dev(const char *file, FILE *fp, dev_t *result)
{
unsigned major, minor;
char buffer[64];
if (!fgets(buffer, sizeof(buffer), fp)) {
log_error("Empty sysfs device file: %s", file);
return 0;
}
if (sscanf(buffer, "%u:%u", &major, &minor) != 2) {
log_error("Incorrect format for sysfs device file: %s.", file);
return 0;
}
*result = makedev(major, minor);
return 1;
}
static int _read_dev(const char *file, dev_t *result)
{
int r;
FILE *fp;
if (!(fp = fopen(file, "r"))) {
log_sys_error("fopen", file);
return 0;
}
r = _parse_dev(file, fp, result);
if (fclose(fp))
log_sys_error("fclose", file);
return r;
}
/*
* Recurse through sysfs directories, inserting any devs found.
*/
static int _read_devs(struct dev_set *ds, const char *dir, unsigned sysfs_depth)
{
struct dirent *d;
DIR *dr;
struct stat info;
char path[PATH_MAX];
char file[PATH_MAX];
dev_t dev = { 0 };
int r = 1;
if (!(dr = opendir(dir))) {
log_sys_error("opendir", dir);
return 0;
}
while ((d = readdir(dr))) {
if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
continue;
if (dm_snprintf(path, sizeof(path), "%s/%s", dir,
d->d_name) < 0) {
log_warn("WARNING: sysfs path name too long: %s in %s.",
d->d_name, dir);
continue;
}
/* devices have a "dev" file */
if (dm_snprintf(file, sizeof(file), "%s/dev", path) < 0) {
log_warn("WARNING: sysfs path name too long: %s in %s.",
d->d_name, dir);
continue;
}
if (!stat(file, &info)) {
/* recurse if we found a device and expect subdirs */
if (sysfs_depth)
_read_devs(ds, path, sysfs_depth - 1);
/* add the device we have found */
if (_read_dev(file, &dev))
_set_insert(ds, dev);
}
}
if (closedir(dr))
log_sys_debug("closedir", dir);
return r;
}
static int _init_devs(struct dev_set *ds)
{
if (!_read_devs(ds, ds->sys_block, ds->sysfs_depth)) {
ds->initialised = -1;
return 0;
}
ds->initialised = 1;
return 1;
}
static int _accept_p(struct cmd_context *cmd, struct dev_filter *f, struct device *dev, const char *use_filter_name)
{
struct dev_set *ds = (struct dev_set *) f->private;
char path[PATH_MAX];
const char *sysfs_dir;
struct stat info;
dev->filtered_flags &= ~DEV_FILTERED_SYSFS;
if (!ds->initialised)
_init_devs(ds);
/* Pass through if initialisation failed */
if (ds->initialised != 1)
/*
* Any kind of device id other than devname has been set
* using sysfs so we know that sysfs info exists for dev.
*/
if (dev->id && dev->id->idtype && (dev->id->idtype != DEV_ID_TYPE_DEVNAME))
return 1;
if (!_set_lookup(ds, dev->dev)) {
log_debug_devs("%s: Skipping (sysfs)", dev_name(dev));
dev->filtered_flags |= DEV_FILTERED_SYSFS;
return 0;
sysfs_dir = dm_sysfs_dir();
if (sysfs_dir && *sysfs_dir) {
if (dm_snprintf(path, sizeof(path), "%sdev/block/%d:%d",
sysfs_dir, (int)MAJOR(dev->dev), (int)MINOR(dev->dev)) < 0) {
log_debug("failed to create sysfs path");
return 1;
}
if (lstat(path, &info)) {
log_debug_devs("%s: Skipping (sysfs)", dev_name(dev));
dev->filtered_flags |= DEV_FILTERED_SYSFS;
return 0;
}
}
return 1;
@ -284,21 +52,14 @@ static int _accept_p(struct cmd_context *cmd, struct dev_filter *f, struct devic
static void _destroy(struct dev_filter *f)
{
struct dev_set *ds = (struct dev_set *) f->private;
if (f->use_count)
log_error(INTERNAL_ERROR "Destroying sysfs filter while in use %u times.", f->use_count);
dm_pool_destroy(ds->mem);
free(f);
}
struct dev_filter *sysfs_filter_create(void)
{
const char *sysfs_dir = dm_sysfs_dir();
char sys_block[PATH_MAX];
unsigned sysfs_depth;
struct dm_pool *mem;
struct dev_set *ds;
struct dev_filter *f;
if (!*sysfs_dir) {
@ -306,26 +67,12 @@ struct dev_filter *sysfs_filter_create(void)
return NULL;
}
if (!_locate_sysfs_blocks(sysfs_dir, sys_block, sizeof(sys_block), &sysfs_depth))
return NULL;
if (!(mem = dm_pool_create("sysfs", 256))) {
log_error("sysfs pool creation failed");
return NULL;
}
if (!(ds = _dev_set_create(mem, sys_block, sysfs_depth))) {
log_error("sysfs dev_set creation failed");
goto bad;
}
if (!(f = dm_pool_zalloc(mem, sizeof(*f))))
if (!(f = zalloc(sizeof(*f))))
goto_bad;
f->passes_filter = _accept_p;
f->destroy = _destroy;
f->use_count = 0;
f->private = ds;
f->name = "sysfs";
log_debug_devs("Sysfs filter initialised.");
@ -333,7 +80,6 @@ struct dev_filter *sysfs_filter_create(void)
return f;
bad:
dm_pool_destroy(mem);
return NULL;
}