From f73be4480a5dd104a77e3ef84d7dcc80b834e593 Mon Sep 17 00:00:00 2001
From: David Teigland <teigland@redhat.com>
Date: Tue, 2 Nov 2021 15:42:26 -0500
Subject: [PATCH 06/54] 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.
---
lib/commands/toolcontext.c | 24 ++-
lib/filters/filter-sysfs.c | 296 +++----------------------------------
2 files changed, 32 insertions(+), 288 deletions(-)
diff --git a/lib/commands/toolcontext.c b/lib/commands/toolcontext.c
index 1b7170de1..a0c78ddd6 100644
--- a/lib/commands/toolcontext.c
+++ b/lib/commands/toolcontext.c
@@ -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");
diff --git a/lib/filters/filter-sysfs.c b/lib/filters/filter-sysfs.c
index 32ac324dd..672211057 100644
--- a/lib/filters/filter-sysfs.c
+++ b/lib/filters/filter-sysfs.c
@@ -17,288 +17,49 @@
#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)
+static int _accept_p(struct cmd_context *cmd, struct dev_filter *f, struct device *dev, const char *use_filter_name)
{
+ char path[PATH_MAX];
+ const char *sysfs_dir;
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;
-}
+ dev->filtered_flags &= ~DEV_FILTERED_SYSFS;
-static int _set_lookup(struct dev_set *ds, dev_t dev)
-{
- unsigned h = _hash_dev(dev);
- struct entry *e;
+ /*
+ * 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;
- for (e = ds->slots[h]; e; e = e->next)
- if (e->dev == dev)
+ 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;
-
- 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 (lstat(path, &info)) {
+ log_debug_devs("%s: Skipping (sysfs)", dev_name(dev));
+ dev->filtered_flags |= DEV_FILTERED_SYSFS;
+ return 0;
}
}
- 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;
-
- dev->filtered_flags &= ~DEV_FILTERED_SYSFS;
-
- if (!ds->initialised)
- _init_devs(ds);
-
- /* Pass through if initialisation failed */
- if (ds->initialised != 1)
- 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;
- }
-
return 1;
}
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;
}
--
2.34.3