[lvm-devel] master - vgsplit: simplify vg creation
David Teigland
teigland at sourceware.org
Mon Jun 10 15:40:02 UTC 2019
Gitweb: https://sourceware.org/git/?p=lvm2.git;a=commitdiff;h=550536474f2b2ad3ac58f1f91aa2325022df53b9
Commit: 550536474f2b2ad3ac58f1f91aa2325022df53b9
Parent: 5036244ce87f3854c7d6b14ab754f43eceaf24eb
Author: David Teigland <teigland at redhat.com>
AuthorDate: Fri Jun 7 14:30:03 2019 -0500
Committer: David Teigland <teigland at redhat.com>
CommitterDate: Mon Jun 10 10:38:32 2019 -0500
vgsplit: simplify vg creation
The way that this command now uses the global lock
followed by a label scan, it can simply check if the
new VG name exists, and if not lock it and create it.
---
lib/metadata/metadata.c | 62 +---------------------
tools/vgsplit.c | 133 ++++++++++-------------------------------------
2 files changed, 29 insertions(+), 166 deletions(-)
diff --git a/lib/metadata/metadata.c b/lib/metadata/metadata.c
index e0a5114..aceac5a 100644
--- a/lib/metadata/metadata.c
+++ b/lib/metadata/metadata.c
@@ -985,29 +985,6 @@ int vg_has_unknown_segments(const struct volume_group *vg)
return 0;
}
-struct volume_group *vg_lock_and_create(struct cmd_context *cmd, const char *vg_name, int *exists)
-{
- uint32_t rc;
- struct volume_group *vg;
-
- if (!validate_name(vg_name)) {
- log_error("Invalid vg name %s", vg_name);
- return NULL;
- }
-
- rc = vg_lock_newname(cmd, vg_name);
- if (rc == FAILED_EXIST)
- *exists = 1;
- if (rc != SUCCESS)
- return NULL;
-
- vg = vg_create(cmd, vg_name);
- if (!vg)
- unlock_vg(cmd, NULL, vg_name);
-
- return vg;
-}
-
/*
* Create a VG with default parameters.
*/
@@ -3265,7 +3242,7 @@ static int _vg_read_orphan_pv(struct lvmcache_info *info, void *baton)
/* Make orphan PVs look like a VG. */
struct volume_group *vg_read_orphans(struct cmd_context *cmd, const char *orphan_vgname)
{
- const struct format_type *fmt;
+ const struct format_type *fmt = cmd->fmt;
struct lvmcache_vginfo *vginfo;
struct volume_group *vg = NULL;
struct _vg_read_orphan_baton baton;
@@ -3277,9 +3254,6 @@ struct volume_group *vg_read_orphans(struct cmd_context *cmd, const char *orphan
if (!(vginfo = lvmcache_vginfo_from_vgname(orphan_vgname, NULL)))
return_NULL;
- if (!(fmt = lvmcache_fmt_from_vgname(cmd, orphan_vgname, NULL, 0)))
- return_NULL;
-
vg = fmt->orphan_vg;
dm_list_iterate_items_safe(pvl, tpvl, &vg->pvs)
@@ -3973,40 +3947,6 @@ uint32_t vg_read_error(struct volume_group *vg_handle)
return SUCCESS;
}
-/*
- * Lock a vgname and/or check for existence.
- * Takes a WRITE lock on the vgname before scanning.
- * If scanning fails or vgname found, release the lock.
- * NOTE: If you find the return codes confusing, you might think of this
- * function as similar to an open() call with O_CREAT and O_EXCL flags
- * (open returns fail with -EEXIST if file already exists).
- *
- * Returns:
- * FAILED_LOCKING - Cannot lock name
- * FAILED_EXIST - VG name already exists - cannot reserve
- * SUCCESS - VG name does not exist in system and WRITE lock held
- */
-uint32_t vg_lock_newname(struct cmd_context *cmd, const char *vgname)
-{
- if (!lock_vol(cmd, vgname, LCK_VG_WRITE, NULL))
- return FAILED_LOCKING;
-
- /* Find the vgname in the cache */
- /* If it's not there we must do full scan to be completely sure */
- if (!lvmcache_fmt_from_vgname(cmd, vgname, NULL, 1)) {
- lvmcache_label_scan(cmd);
- if (!lvmcache_fmt_from_vgname(cmd, vgname, NULL, 1)) {
- lvmcache_label_scan(cmd);
- if (!lvmcache_fmt_from_vgname(cmd, vgname, NULL, 0))
- return SUCCESS; /* vgname not found after scanning */
- }
- }
-
- /* Found vgname so cannot reserve. */
- unlock_vg(cmd, NULL, vgname);
- return FAILED_EXIST;
-}
-
struct format_instance *alloc_fid(const struct format_type *fmt,
const struct format_instance_ctx *fic)
{
diff --git a/tools/vgsplit.c b/tools/vgsplit.c
index abf7013..61cb13b 100644
--- a/tools/vgsplit.c
+++ b/tools/vgsplit.c
@@ -446,80 +446,6 @@ static int _move_cache(struct volume_group *vg_from,
}
/*
- * Create or open the destination of the vgsplit operation.
- * Returns
- * - non-NULL: VG handle w/VG lock held
- * - NULL: no VG lock held
- */
-static struct volume_group *_vgsplit_to(struct cmd_context *cmd,
- const char *vg_name_to,
- int *existing_vg)
-{
- struct volume_group *vg_to = NULL;
- int exists = 0;
-
- log_verbose("Checking for new volume group \"%s\"", vg_name_to);
- /*
- * First try to create a new VG. If we cannot create it,
- * and we get FAILED_EXIST (we will not be holding a lock),
- * a VG must already exist with this name. We then try to
- * read the existing VG - the vgsplit will be into an existing VG.
- *
- * Otherwise, if the lock was successful, it must be the case that
- * we obtained a WRITE lock and could not find the vgname in the
- * system. Thus, the split will be into a new VG.
- */
- vg_to = vg_lock_and_create(cmd, vg_name_to, &exists);
- if (!vg_to && !exists) {
- log_error("Can't get lock for %s", vg_name_to);
- release_vg(vg_to);
- return NULL;
- }
- if (!vg_to && exists) {
- *existing_vg = 1;
- release_vg(vg_to);
- vg_to = vg_read_for_update(cmd, vg_name_to, NULL, 0, 0);
-
- if (vg_read_error(vg_to)) {
- release_vg(vg_to);
- return_NULL;
- }
-
- } else if (vg_read_error(vg_to) == SUCCESS) {
- *existing_vg = 0;
- }
- return vg_to;
-}
-
-/*
- * Open the source of the vgsplit operation.
- * Returns
- * - non-NULL: VG handle w/VG lock held
- * - NULL: no VG lock held
- */
-static struct volume_group *_vgsplit_from(struct cmd_context *cmd,
- const char *vg_name_from)
-{
- struct volume_group *vg_from;
-
- log_verbose("Checking for volume group \"%s\"", vg_name_from);
-
- vg_from = vg_read_for_update(cmd, vg_name_from, NULL, 0, 0);
- if (vg_read_error(vg_from)) {
- release_vg(vg_from);
- return NULL;
- }
-
- if (vg_is_shared(vg_from)) {
- log_error("vgsplit not allowed for lock_type %s", vg_from->lock_type);
- unlock_and_release_vg(cmd, vg_from, vg_name_from);
- return NULL;
- }
-
- return vg_from;
-}
-
-/*
* Has the user given an option related to a new vg as the split destination?
*/
static int _new_vg_option_specified(struct cmd_context *cmd)
@@ -537,11 +463,11 @@ int vgsplit(struct cmd_context *cmd, int argc, char **argv)
struct vgcreate_params vp_def;
const char *vg_name_from, *vg_name_to;
struct volume_group *vg_to = NULL, *vg_from = NULL;
+ struct lvmcache_vginfo *vginfo_to;
int opt;
int existing_vg = 0;
int r = ECMD_FAILED;
const char *lv_name;
- int lock_vg_from_first = 1;
if ((arg_is_set(cmd, name_ARG) + argc) < 3) {
log_error("Existing VG, new VG and either physical volumes "
@@ -577,47 +503,44 @@ int vgsplit(struct cmd_context *cmd, int argc, char **argv)
lvmcache_label_scan(cmd);
- if (strcmp(vg_name_to, vg_name_from) < 0)
- lock_vg_from_first = 0;
-
- if (lock_vg_from_first) {
- if (!(vg_from = _vgsplit_from(cmd, vg_name_from)))
- return_ECMD_FAILED;
- /*
- * Set metadata format of original VG.
- * NOTE: We must set the format before calling vg_lock_and_create()
- * since vg_lock_and_create() calls the per-format constructor.
- */
- cmd->fmt = vg_from->fid->fmt;
-
- if (!(vg_to = _vgsplit_to(cmd, vg_name_to, &existing_vg))) {
- unlock_and_release_vg(cmd, vg_from, vg_name_from);
- return_ECMD_FAILED;
+ if (!(vginfo_to = lvmcache_vginfo_from_vgname(vg_name_to, NULL))) {
+ if (!validate_name(vg_name_to)) {
+ log_error("Invalid vg name %s.", vg_name_to);
+ return ECMD_FAILED;
}
- } else {
- if (!(vg_to = _vgsplit_to(cmd, vg_name_to, &existing_vg)))
- return_ECMD_FAILED;
- if (!(vg_from = _vgsplit_from(cmd, vg_name_from))) {
- unlock_and_release_vg(cmd, vg_to, vg_name_to);
- return_ECMD_FAILED;
+ if (!lock_vol(cmd, vg_name_to, LCK_VG_WRITE, NULL)) {
+ log_error("Failed to lock new VG name %s.", vg_name_to);
+ return ECMD_FAILED;
}
- if (cmd->fmt != vg_from->fid->fmt) {
- /* In this case we don't know the vg_from->fid->fmt */
- log_error("Unable to set new VG metadata type based on "
- "source VG format - use -M option.");
- goto bad;
+ if (!(vg_to = vg_create(cmd, vg_name_to))) {
+ log_error("Failed to create new VG %s.", vg_name_to);
+ unlock_vg(cmd, NULL, vg_name_to);
+ return ECMD_FAILED;
+ }
+ } else {
+ if (!(vg_to = vg_read_for_update(cmd, vg_name_to, NULL, 0, 0))) {
+ log_error("Failed to read VG %s.", vg_name_to);
+ return ECMD_FAILED;
}
+ existing_vg = 1;
}
+ if (!(vg_from = vg_read_for_update(cmd, vg_name_from, NULL, 0, 0))) {
+ log_error("Failed to read VG %s.", vg_name_to);
+ unlock_and_release_vg(cmd, vg_to, vg_name_to);
+ return ECMD_FAILED;
+ }
+
+ cmd->fmt = vg_from->fid->fmt;
+
if (existing_vg) {
if (_new_vg_option_specified(cmd)) {
- log_error("Volume group \"%s\" exists, but new VG "
- "option specified", vg_name_to);
+ log_error("Volume group \"%s\" exists, but new VG option specified", vg_name_to);
goto bad;
}
- if (!vgs_are_compatible(cmd, vg_from,vg_to))
+ if (!vgs_are_compatible(cmd, vg_from, vg_to))
goto_bad;
} else {
if (!vgcreate_params_set_defaults(cmd, &vp_def, vg_from)) {
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