[lvm-devel] main - filter-mpath: work with nvme devices
David Teigland
teigland at sourceware.org
Tue Feb 2 19:01:40 UTC 2021
Gitweb: https://sourceware.org/git/?p=lvm2.git;a=commitdiff;h=bee9f4efdd8195f383f026290b741314cdc42439
Commit: bee9f4efdd8195f383f026290b741314cdc42439
Parent: 48dfc388f7bde964d8e4d6816f27de858c984fb3
Author: David Teigland <teigland at redhat.com>
AuthorDate: Thu Dec 3 10:48:21 2020 -0600
Committer: David Teigland <teigland at redhat.com>
CommitterDate: Tue Feb 2 13:01:20 2021 -0600
filter-mpath: work with nvme devices
Recognize when a device is nvme, and apply filter-mpath to
nvme devices in addition to scsi devices.
---
lib/device/dev-type.c | 81 +++++++++++++++++++----
lib/device/dev-type.h | 2 +
lib/device/device.h | 1 +
lib/filters/filter-mpath.c | 156 ++++++++++++++++++++++++++++++---------------
4 files changed, 177 insertions(+), 63 deletions(-)
diff --git a/lib/device/dev-type.c b/lib/device/dev-type.c
index 896821de8..379afa89c 100644
--- a/lib/device/dev-type.c
+++ b/lib/device/dev-type.c
@@ -21,6 +21,7 @@
#include "lib/metadata/metadata.h"
#include "lib/device/bcache.h"
#include "lib/label/label.h"
+#include "lib/commands/toolcontext.h"
#ifdef BLKID_WIPING_SUPPORT
#include <blkid.h>
@@ -67,6 +68,31 @@ int dev_is_pmem(struct device *dev)
return is_pmem ? 1 : 0;
}
+/*
+ * An nvme device has major number 259 (BLKEXT), minor number <minor>,
+ * and reading /sys/dev/block/259:<minor>/device/dev shows a character
+ * device cmajor:cminor where cmajor matches the major number of the
+ * nvme character device entry in /proc/devices. Checking all of that
+ * is excessive and unnecessary compared to just comparing /dev/name*.
+ */
+
+int dev_is_nvme(struct dev_types *dt, struct device *dev)
+{
+ struct dm_str_list *strl;
+
+ if (dev->flags & DEV_IS_NVME)
+ return 1;
+
+ dm_list_iterate_items(strl, &dev->aliases) {
+ if (!strncmp(strl->str, "/dev/nvme", 9)) {
+ log_debug("Found nvme device %s", dev_name(dev));
+ dev->flags |= DEV_IS_NVME;
+ return 1;
+ }
+ }
+ return 0;
+}
+
int dev_is_lv(struct device *dev)
{
FILE *fp;
@@ -302,6 +328,9 @@ int dev_subsystem_part_major(struct dev_types *dt, struct device *dev)
const char *dev_subsystem_name(struct dev_types *dt, struct device *dev)
{
+ if (dev->flags & DEV_IS_NVME)
+ return "NVME";
+
if (MAJOR(dev->dev) == dt->device_mapper_major)
return "DM";
@@ -348,7 +377,6 @@ int major_is_scsi_device(struct dev_types *dt, int major)
return (dt->dev_type_array[major].flags & PARTITION_SCSI_DEVICE) ? 1 : 0;
}
-
static int _loop_is_with_partscan(struct device *dev)
{
FILE *fp;
@@ -398,6 +426,28 @@ struct partition {
uint32_t nr_sects;
} __attribute__((packed));
+static int _has_sys_partition(struct device *dev)
+{
+ char path[PATH_MAX];
+ struct stat info;
+ int major = (int) MAJOR(dev->dev);
+ int minor = (int) MINOR(dev->dev);
+
+ /* check if dev is a partition */
+ if (dm_snprintf(path, sizeof(path), "%s/dev/block/%d:%d/partition",
+ dm_sysfs_dir(), major, minor) < 0) {
+ log_error("dm_snprintf partition failed");
+ return 0;
+ }
+
+ if (stat(path, &info) == -1) {
+ if (errno != ENOENT)
+ log_sys_error("stat", path);
+ return 0;
+ }
+ return 1;
+}
+
static int _is_partitionable(struct dev_types *dt, struct device *dev)
{
int parts = major_max_partitions(dt, MAJOR(dev->dev));
@@ -414,6 +464,13 @@ static int _is_partitionable(struct dev_types *dt, struct device *dev)
_loop_is_with_partscan(dev))
return 1;
+ if (dev_is_nvme(dt, dev)) {
+ /* If this dev is already a partition then it's not partitionable. */
+ if (_has_sys_partition(dev))
+ return 0;
+ return 1;
+ }
+
if ((parts <= 1) || (MINOR(dev->dev) % parts))
return 0;
@@ -557,10 +614,17 @@ int dev_get_primary_dev(struct dev_types *dt, struct device *dev, dev_t *result)
char path[PATH_MAX];
char temp_path[PATH_MAX];
char buffer[64];
- struct stat info;
FILE *fp = NULL;
int parts, residue, size, ret = 0;
+ /*
+ * /dev/nvme devs don't use the major:minor numbering like
+ * block dev types that have their own major number, so
+ * the calculation based on minor number doesn't work.
+ */
+ if (dev_is_nvme(dt, dev))
+ goto sys_partition;
+
/*
* Try to get the primary dev out of the
* list of known device types first.
@@ -576,23 +640,14 @@ int dev_get_primary_dev(struct dev_types *dt, struct device *dev, dev_t *result)
goto out;
}
+ sys_partition:
/*
* If we can't get the primary dev out of the list of known device
* types, try to look at sysfs directly then. This is more complex
* way and it also requires certain sysfs layout to be present
* which might not be there in old kernels!
*/
-
- /* check if dev is a partition */
- if (dm_snprintf(path, sizeof(path), "%s/dev/block/%d:%d/partition",
- sysfs_dir, major, minor) < 0) {
- log_error("dm_snprintf partition failed");
- goto out;
- }
-
- if (stat(path, &info) == -1) {
- if (errno != ENOENT)
- log_sys_error("stat", path);
+ if (!_has_sys_partition(dev)) {
*result = dev->dev;
ret = 1;
goto out; /* dev is not a partition! */
diff --git a/lib/device/dev-type.h b/lib/device/dev-type.h
index fdf7791cf..8b94b7997 100644
--- a/lib/device/dev-type.h
+++ b/lib/device/dev-type.h
@@ -95,6 +95,8 @@ int dev_is_rotational(struct dev_types *dt, struct device *dev);
int dev_is_pmem(struct device *dev);
+int dev_is_nvme(struct dev_types *dt, struct device *dev);
+
int dev_is_lv(struct device *dev);
int get_fs_block_size(struct device *dev, uint32_t *fs_block_size);
diff --git a/lib/device/device.h b/lib/device/device.h
index a58bff8e3..816db3166 100644
--- a/lib/device/device.h
+++ b/lib/device/device.h
@@ -38,6 +38,7 @@
#define DEV_SCAN_FOUND_LABEL 0x00010000 /* label scan read dev and found label */
#define DEV_IS_MD_COMPONENT 0x00020000 /* device is an md component */
#define DEV_UDEV_INFO_MISSING 0x00040000 /* we have no udev info for this device */
+#define DEV_IS_NVME 0x00080000 /* set if dev is nvme */
/*
* Support for external device info.
diff --git a/lib/filters/filter-mpath.c b/lib/filters/filter-mpath.c
index 889a2dd96..853a2c569 100644
--- a/lib/filters/filter-mpath.c
+++ b/lib/filters/filter-mpath.c
@@ -16,6 +16,7 @@
#include "lib/misc/lib.h"
#include "lib/filters/filter.h"
#include "lib/activate/activate.h"
+#include "lib/commands/toolcontext.h"
#ifdef UDEV_SYNC_SUPPORT
#include <libudev.h>
#include "lib/device/dev-ext-udev-constants.h"
@@ -27,7 +28,6 @@
#define MPATH_PREFIX "mpath-"
-
struct mpath_priv {
struct dm_pool *mem;
struct dev_filter f;
@@ -35,6 +35,9 @@ struct mpath_priv {
struct dm_hash_table *hash;
};
+/*
+ * given "/dev/foo" return "foo"
+ */
static const char *_get_sysfs_name(struct device *dev)
{
const char *name;
@@ -53,6 +56,11 @@ static const char *_get_sysfs_name(struct device *dev)
return name;
}
+/*
+ * given major:minor
+ * readlink translates /sys/dev/block/major:minor to /sys/.../foo
+ * from /sys/.../foo return "foo"
+ */
static const char *_get_sysfs_name_by_devt(const char *sysfs_dir, dev_t devno,
char *buf, size_t buf_size)
{
@@ -102,27 +110,28 @@ static int _get_sysfs_string(const char *path, char *buffer, int max_size)
return r;
}
-static int _get_sysfs_get_major_minor(const char *sysfs_dir, const char *kname, int *major, int *minor)
+static int _get_sysfs_dm_mpath(struct dev_types *dt, const char *sysfs_dir, const char *holder_name)
{
- char path[PATH_MAX], buffer[64];
+ char path[PATH_MAX];
+ char buffer[128];
- if (dm_snprintf(path, sizeof(path), "%sblock/%s/dev", sysfs_dir, kname) < 0) {
+ if (dm_snprintf(path, sizeof(path), "%sblock/%s/dm/uuid", sysfs_dir, holder_name) < 0) {
log_error("Sysfs path string is too long.");
return 0;
}
+ buffer[0] = '\0';
+
if (!_get_sysfs_string(path, buffer, sizeof(buffer)))
return_0;
- if (sscanf(buffer, "%d:%d", major, minor) != 2) {
- log_error("Failed to parse major minor from %s", buffer);
- return 0;
- }
+ if (!strncmp(buffer, MPATH_PREFIX, 6))
+ return 1;
- return 1;
+ return 0;
}
-static int _get_parent_mpath(const char *dir, char *name, int max_size)
+static int _get_holder_name(const char *dir, char *name, int max_size)
{
struct dirent *d;
DIR *dr;
@@ -155,7 +164,7 @@ static int _get_parent_mpath(const char *dir, char *name, int max_size)
}
#ifdef UDEV_SYNC_SUPPORT
-static int _udev_dev_is_mpath(struct device *dev)
+static int _udev_dev_is_mpath_component(struct device *dev)
{
const char *value;
struct dev_ext *ext;
@@ -174,95 +183,148 @@ static int _udev_dev_is_mpath(struct device *dev)
return 0;
}
#else
-static int _udev_dev_is_mpath(struct device *dev)
+static int _udev_dev_is_mpath_component(struct device *dev)
{
return 0;
}
#endif
-static int _native_dev_is_mpath(struct dev_filter *f, struct device *dev)
+static int _native_dev_is_mpath_component(struct cmd_context *cmd, struct dev_filter *f, struct device *dev)
{
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];
+ const char *part_name;
+ const char *name; /* e.g. "sda" for "/dev/sda" */
+ char link_path[PATH_MAX]; /* some obscure, unpredictable sysfs path */
+ char holders_path[PATH_MAX]; /* e.g. "/sys/block/sda/holders/" */
+ char dm_dev_path[PATH_MAX]; /* e.g. "/dev/dm-1" */
+ char holder_name[128] = { 0 }; /* e.g. "dm-1" */
const char *sysfs_dir = dm_sysfs_dir();
- int major = MAJOR(dev->dev);
- int minor = MINOR(dev->dev);
+ int dev_major = MAJOR(dev->dev);
+ int dev_minor = MINOR(dev->dev);
+ int dm_dev_major;
+ int dm_dev_minor;
+ struct stat info;
dev_t primary_dev;
long look;
- /* Limit this filter only to SCSI devices */
- if (!major_is_scsi_device(dt, MAJOR(dev->dev)))
+ /* Limit this filter to SCSI or NVME devices */
+ if (!major_is_scsi_device(dt, dev_major) && !dev_is_nvme(dt, dev))
return 0;
switch (dev_get_primary_dev(dt, dev, &primary_dev)) {
+
case 2: /* The dev is partition. */
part_name = dev_name(dev); /* name of original dev for log_debug msg */
- if (!(name = _get_sysfs_name_by_devt(sysfs_dir, primary_dev, parent_name, sizeof(parent_name))))
+
+ /* gets "foo" for "/dev/foo" where "/dev/foo" comes from major:minor */
+ if (!(name = _get_sysfs_name_by_devt(sysfs_dir, primary_dev, link_path, sizeof(link_path))))
return_0;
+
log_debug_devs("%s: Device is a partition, using primary "
"device %s for mpath component detection",
part_name, name);
break;
+
case 1: /* The dev is already a primary dev. Just continue with the dev. */
+
+ /* gets "foo" for "/dev/foo" */
if (!(name = _get_sysfs_name(dev)))
return_0;
break;
+
default: /* 0, error. */
- log_warn("Failed to get primary device for %d:%d.", major, minor);
+ log_warn("Failed to get primary device for %d:%d.", dev_major, dev_minor);
return 0;
}
- if (dm_snprintf(path, sizeof(path), "%sblock/%s/holders", sysfs_dir, name) < 0) {
+ if (dm_snprintf(holders_path, sizeof(holders_path), "%sblock/%s/holders", sysfs_dir, name) < 0) {
log_warn("Sysfs path to check mpath is too long.");
return 0;
}
/* also will filter out partitions */
- if (stat(path, &info))
+ if (stat(holders_path, &info))
return 0;
if (!S_ISDIR(info.st_mode)) {
- log_warn("Path %s is not a directory.", path);
+ log_warn("Path %s is not a directory.", holders_path);
return 0;
}
- if (!_get_parent_mpath(path, parent_name, sizeof(parent_name)))
+ /*
+ * If holders dir contains an entry such as "dm-1", then this sets
+ * holder_name to "dm-1".
+ *
+ * If holders dir is empty, return 0 (this is generally where
+ * devs that are not mpath components return.)
+ */
+ if (!_get_holder_name(holders_path, holder_name, sizeof(holder_name)))
return 0;
- if (!_get_sysfs_get_major_minor(sysfs_dir, parent_name, &major, &minor))
- return_0;
+ if (dm_snprintf(dm_dev_path, sizeof(dm_dev_path), "%s/%s", cmd->dev_dir, holder_name) < 0) {
+ log_warn("dm device path to check mpath is too long.");
+ return 0;
+ }
- if (major != dt->device_mapper_major)
+ /*
+ * stat "/dev/dm-1" which is the holder of the dev we're checking
+ * dm_dev_major:dm_dev_minor come from stat("/dev/dm-1")
+ */
+ if (stat(dm_dev_path, &info)) {
+ log_debug("filter-mpath %s holder %s stat result %d",
+ dev_name(dev), dm_dev_path, errno);
return 0;
+ }
+ dm_dev_major = (int)MAJOR(info.st_rdev);
+ dm_dev_minor = (int)MINOR(info.st_rdev);
+
+ if (dm_dev_major != dt->device_mapper_major) {
+ log_debug_devs("filter-mpath %s holder %s %d:%d does not have dm major",
+ dev_name(dev), dm_dev_path, dm_dev_major, dm_dev_minor);
+ return 0;
+ }
- /* Avoid repeated detection of multipath device and use first checked result */
- look = (long) dm_hash_lookup_binary(mp->hash, &minor, sizeof(minor));
+ /*
+ * Save the result of checking that "/dev/dm-1" is an mpath device
+ * to avoid repeating it for each path component.
+ * The minor number of "/dev/dm-1" is added to the hash table with
+ * const value 2 meaning that dm minor 1 (for /dev/dm-1) is a multipath dev
+ * and const value 1 meaning that dm minor 1 is not a multipath dev.
+ */
+ look = (long) dm_hash_lookup_binary(mp->hash, &dm_dev_minor, sizeof(dm_dev_minor));
if (look > 0) {
- log_debug_devs("%s(%u:%u): already checked as %sbeing mpath.",
- parent_name, major, minor, (look > 1) ? "" : "not ");
+ log_debug_devs("filter-mpath %s holder %s %u:%u already checked as %sbeing mpath.",
+ dev_name(dev), holder_name, dm_dev_major, dm_dev_minor, (look > 1) ? "" : "not ");
return (look > 1) ? 1 : 0;
}
- if (lvm_dm_prefix_check(major, minor, MPATH_PREFIX)) {
- (void) dm_hash_insert_binary(mp->hash, &minor, sizeof(minor), (void*)2);
+ /*
+ * Returns 1 if /sys/block/<holder_name>/dm/uuid indicates that
+ * <holder_name> is a dm device with dm uuid prefix mpath-.
+ * When true, <holder_name> will be something like "dm-1".
+ *
+ * (Is a hash table worth it to avoid reading one sysfs file?)
+ */
+ if (_get_sysfs_dm_mpath(dt, sysfs_dir, holder_name)) {
+ log_debug_devs("filter-mpath %s holder %s %u:%u ignore mpath component",
+ dev_name(dev), holder_name, dm_dev_major, dm_dev_minor);
+ (void) dm_hash_insert_binary(mp->hash, &dm_dev_minor, sizeof(dm_dev_minor), (void*)2);
return 1;
}
- (void) dm_hash_insert_binary(mp->hash, &minor, sizeof(minor), (void*)1);
+ (void) dm_hash_insert_binary(mp->hash, &dm_dev_minor, sizeof(dm_dev_minor), (void*)1);
return 0;
}
-static int _dev_is_mpath(struct dev_filter *f, struct device *dev)
+static int _dev_is_mpath_component(struct cmd_context *cmd, struct dev_filter *f, struct device *dev)
{
if (dev->ext.src == DEV_EXT_NONE)
- return _native_dev_is_mpath(f, dev);
+ return _native_dev_is_mpath_component(cmd, f, dev);
if (dev->ext.src == DEV_EXT_UDEV)
- return _udev_dev_is_mpath(dev);
+ return _udev_dev_is_mpath_component(dev);
log_error(INTERNAL_ERROR "Missing hook for mpath recognition "
"using external device info source %s", dev_ext_name(dev));
@@ -272,11 +334,11 @@ static int _dev_is_mpath(struct dev_filter *f, struct device *dev)
#define MSG_SKIPPING "%s: Skipping mpath component device"
-static int _ignore_mpath(struct cmd_context *cmd, struct dev_filter *f, struct device *dev, const char *use_filter_name)
+static int _ignore_mpath_component(struct cmd_context *cmd, struct dev_filter *f, struct device *dev, const char *use_filter_name)
{
dev->filtered_flags &= ~DEV_FILTERED_MPATH_COMPONENT;
- if (_dev_is_mpath(f, dev) == 1) {
+ if (_dev_is_mpath_component(cmd, f, dev) == 1) {
if (dev->ext.src == DEV_EXT_NONE)
log_debug_devs(MSG_SKIPPING, dev_name(dev));
else
@@ -303,8 +365,8 @@ static void _destroy(struct dev_filter *f)
struct dev_filter *mpath_filter_create(struct dev_types *dt)
{
const char *sysfs_dir = dm_sysfs_dir();
- struct dm_pool *mem;
struct mpath_priv *mp;
+ struct dm_pool *mem;
struct dm_hash_table *hash;
if (!*sysfs_dir) {
@@ -328,19 +390,13 @@ struct dev_filter *mpath_filter_create(struct dev_types *dt)
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.passes_filter = _ignore_mpath_component;
mp->f.destroy = _destroy;
mp->f.use_count = 0;
mp->f.private = mp;
mp->f.name = "mpath";
-
- mp->mem = mem;
mp->dt = dt;
+ mp->mem = mem;
mp->hash = hash;
log_debug_devs("mpath filter initialised.");
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