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Code Releases Activity

filter: enhance mpath detection

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Internal detection of SCSI device being in-use by DM mpath has been
performed several times for each component device - this could be
eventually racy - so instead when we do remember  1st. checked result
for device being mpath and use it consistenly over the filter runtime.
This commit is contained in:
Zdenek Kabelac 2019-03-13 13:02:09 +01:00
parent 1eeb2fa3f6
commit dc6dea4033
2 changed files with 67 additions and 12 deletions
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1
WHATS_NEW
View File

@ -1,5 +1,6 @@
Version 2.03.02 -
===================================
Query mpath device only once per command for its state.
Use device INFO instead of STATUS when checking for mpath device uuid.
Change default io_memory_size from 4 to 8 MiB.
Add config setting io_memory_size to set bcache size.

78
lib/filters/filter-mpath.c
View File

@ -27,6 +27,14 @@
#define MPATH_PREFIX "mpath-"
struct mpath_priv {
struct dm_pool *mem;
struct dev_filter f;
struct dev_types *dt;
struct dm_hash_table *hash;
};
static const char *_get_sysfs_name(struct device *dev)
{
const char *name;
@ -174,7 +182,8 @@ static int _udev_dev_is_mpath(struct device *dev)
static int _native_dev_is_mpath(struct dev_filter *f, struct device *dev)
{
struct dev_types *dt = (struct dev_types *) f->private;
struct mpath_priv *mp = (struct mpath_priv *) f->private;
struct dev_types *dt = mp->dt;
const char *part_name, *name;
struct stat info;
char path[PATH_MAX], parent_name[PATH_MAX];
@ -182,6 +191,7 @@ static int _native_dev_is_mpath(struct dev_filter *f, struct device *dev)
int major = MAJOR(dev->dev);
int minor = MINOR(dev->dev);
dev_t primary_dev;
long look;
/* Limit this filter only to SCSI devices */
if (!major_is_scsi_device(dt, MAJOR(dev->dev)))
@ -228,7 +238,22 @@ static int _native_dev_is_mpath(struct dev_filter *f, struct device *dev)
if (major != dt->device_mapper_major)
return 0;
return lvm_dm_prefix_check(major, minor, MPATH_PREFIX);
/* Avoid repeated detection of multipath device and use first checked result */
look = (long) dm_hash_lookup_binary(mp->hash, &minor, sizeof(minor));
if (look > 0) {
log_debug_devs("%s(%u:%u): already checked as %sbeing mpath.",
parent_name, major, minor, (look > 1) ? "" : "not ");
return (look > 1) ? 0 : 1;
}
if (lvm_dm_prefix_check(major, minor, MPATH_PREFIX)) {
(void) dm_hash_insert_binary(mp->hash, &minor, sizeof(minor), (void*)2);
return 1;
}
(void) dm_hash_insert_binary(mp->hash, &minor, sizeof(minor), (void*)1);
return 0;
}
static int _dev_is_mpath(struct dev_filter *f, struct device *dev)
@ -263,36 +288,65 @@ static int _ignore_mpath(struct cmd_context *cmd, struct dev_filter *f, struct d
static void _destroy(struct dev_filter *f)
{
struct mpath_priv *mp = (struct mpath_priv*) f->private;
if (f->use_count)
log_error(INTERNAL_ERROR "Destroying mpath filter while in use %u times.", f->use_count);
free(f);
dm_hash_destroy(mp->hash);
dm_pool_destroy(mp->mem);
}
struct dev_filter *mpath_filter_create(struct dev_types *dt)
{
const char *sysfs_dir = dm_sysfs_dir();
struct dev_filter *f;
struct dm_pool *mem;
struct mpath_priv *mp;
struct dm_hash_table *hash;
if (!*sysfs_dir) {
log_verbose("No proc filesystem found: skipping multipath filter");
return NULL;
}
if (!(f = zalloc(sizeof(*f)))) {
log_error("mpath filter allocation failed");
if (!(hash = dm_hash_create(128))) {
log_error("mpath hash table creation failed.");
return NULL;
}
f->passes_filter = _ignore_mpath;
f->destroy = _destroy;
f->use_count = 0;
f->private = dt;
f->name = "mpath";
if (!(mem = dm_pool_create("mpath", 256))) {
log_error("mpath pool creation failed.");
dm_hash_destroy(hash);
return NULL;
}
if (!(mp = dm_pool_zalloc(mem, sizeof(*mp)))) {
log_error("mpath filter allocation failed.");
goto bad;
}
if (!(mp = dm_pool_zalloc(mem, sizeof(*mp)))) {
log_error("mpath filter allocation failed.");
goto bad;
}
mp->f.passes_filter = _ignore_mpath;
mp->f.destroy = _destroy;
mp->f.use_count = 0;
mp->f.private = mp;
mp->f.name = "mpath";
mp->mem = mem;
mp->dt = dt;
mp->hash = hash;
log_debug_devs("mpath filter initialised.");
return f;
return &mp->f;
bad:
dm_pool_destroy(mem);
dm_hash_destroy(hash);
return NULL;
}
#else