[lvm-devel] [PATCH 1/9] Fix snapshot segment import to not use duplicate segments & replace.
Milan Broz
mbroz at redhat.com
Wed May 13 15:23:22 UTC 2009
The snapshot segment (snapshotX) is created twice
during the text metadata segment processing.
This can cause temporary violation of max_lv count.
Simplify the code, snapshot segment is properly initialized
in init_snapshot_seg function now and do not need to be replaced
by vg_add_snapshot call.
The vg_add_snapshot() is now usefull only for adding new
snapshot and it shares the same initialization function.
The snapshot name is always generated, name paramater can be
removed from function call.
Signed-off-by: Milan Broz <mbroz at redhat.com>
---
lib/format1/import-export.c | 2 +-
lib/format_text/import_vsn1.c | 10 -------
lib/metadata/metadata-exported.h | 6 +++-
lib/metadata/snapshot_manip.c | 55 ++++++++++++++++++++------------------
lib/snapshot/snapshot.c | 6 +---
tools/lvconvert.c | 3 +-
tools/lvcreate.c | 2 +-
7 files changed, 37 insertions(+), 47 deletions(-)
diff --git a/lib/format1/import-export.c b/lib/format1/import-export.c
index a950f9a..5d2e86a 100644
--- a/lib/format1/import-export.c
+++ b/lib/format1/import-export.c
@@ -616,7 +616,7 @@ int import_snapshots(struct dm_pool *mem __attribute((unused)), struct volume_gr
continue;
/* insert the snapshot */
- if (!vg_add_snapshot(NULL, org, cow, NULL,
+ if (!vg_add_snapshot(org, cow, NULL,
org->le_count,
lvd->lv_chunk_size)) {
log_err("Couldn't add snapshot.");
diff --git a/lib/format_text/import_vsn1.c b/lib/format_text/import_vsn1.c
index 0bb9843..a9748aa 100644
--- a/lib/format_text/import_vsn1.c
+++ b/lib/format_text/import_vsn1.c
@@ -603,16 +603,6 @@ static int _read_lvsegs(struct format_instance *fid __attribute((unused)),
lv->size = (uint64_t) lv->le_count * (uint64_t) vg->extent_size;
- /*
- * FIXME We now have 2 LVs for each snapshot. The real one was
- * created by vg_add_snapshot from the segment text_import.
- */
- if (lv->status & SNAPSHOT) {
- vg->lv_count--;
- dm_list_del(&lvl->list);
- return 1;
- }
-
lv->minor = -1;
if ((lv->status & FIXED_MINOR) &&
!_read_int32(lvn, "minor", &lv->minor)) {
diff --git a/lib/metadata/metadata-exported.h b/lib/metadata/metadata-exported.h
index 9bd3389..6c32ab4 100644
--- a/lib/metadata/metadata-exported.h
+++ b/lib/metadata/metadata-exported.h
@@ -545,8 +545,10 @@ struct lv_segment *find_cow(const struct logical_volume *lv);
/* Given a cow LV, return its origin */
struct logical_volume *origin_from_cow(const struct logical_volume *lv);
-int vg_add_snapshot(const char *name,
- struct logical_volume *origin, struct logical_volume *cow,
+void init_snapshot_seg(struct lv_segment *seg, struct logical_volume *origin,
+ struct logical_volume *cow, uint32_t chunk_size);
+
+int vg_add_snapshot(struct logical_volume *origin, struct logical_volume *cow,
union lvid *lvid, uint32_t extent_count,
uint32_t chunk_size);
diff --git a/lib/metadata/snapshot_manip.c b/lib/metadata/snapshot_manip.c
index 6aa29a0..9364b4f 100644
--- a/lib/metadata/snapshot_manip.c
+++ b/lib/metadata/snapshot_manip.c
@@ -62,7 +62,31 @@ struct logical_volume *origin_from_cow(const struct logical_volume *lv)
return lv->snapshot->origin;
}
-int vg_add_snapshot(const char *name, struct logical_volume *origin,
+void init_snapshot_seg(struct lv_segment *seg, struct logical_volume *origin,
+ struct logical_volume *cow, uint32_t chunk_size)
+{
+ seg->chunk_size = chunk_size;
+ seg->origin = origin;
+ seg->cow = cow;
+
+ // FIXME: direct count manipulation to be removed later
+ cow->status &= ~VISIBLE_LV;
+ cow->vg->lv_count--;
+ cow->snapshot = seg;
+
+ origin->origin_count++;
+ origin->vg->lv_count--;
+
+ /* FIXME Assumes an invisible origin belongs to a sparse device */
+ if (!lv_is_visible(origin))
+ origin->status |= VIRTUAL_ORIGIN;
+
+ seg->lv->status |= (SNAPSHOT | VIRTUAL);
+
+ dm_list_add(&origin->snapshot_segs, &seg->origin_list);
+}
+
+int vg_add_snapshot(struct logical_volume *origin,
struct logical_volume *cow, union lvid *lvid,
uint32_t extent_count, uint32_t chunk_size)
{
@@ -82,39 +106,18 @@ int vg_add_snapshot(const char *name, struct logical_volume *origin,
return 0;
}
- /*
- * Set origin lv count in advance to prevent fail because
- * of temporary violation of LV limits.
- */
- origin->vg->lv_count--;
-
- if (!(snap = lv_create_empty(name ? name : "snapshot%d",
+ if (!(snap = lv_create_empty("snapshot%d",
lvid, LVM_READ | LVM_WRITE | VISIBLE_LV,
- ALLOC_INHERIT, 1, origin->vg))) {
- origin->vg->lv_count++;
+ ALLOC_INHERIT, 1, origin->vg)))
return_0;
- }
snap->le_count = extent_count;
if (!(seg = alloc_snapshot_seg(snap, 0, 0)))
return_0;
- seg->chunk_size = chunk_size;
- seg->origin = origin;
- seg->cow = cow;
- seg->lv->status |= SNAPSHOT;
-
- origin->origin_count++;
- cow->snapshot = seg;
-
- cow->status &= ~VISIBLE_LV;
-
- /* FIXME Assumes an invisible origin belongs to a sparse device */
- if (!lv_is_visible(origin))
- origin->status |= VIRTUAL_ORIGIN;
-
- dm_list_add(&origin->snapshot_segs, &seg->origin_list);
+ origin->vg->lv_count++;
+ init_snapshot_seg(seg, origin, cow, chunk_size);
return 1;
}
diff --git a/lib/snapshot/snapshot.c b/lib/snapshot/snapshot.c
index 1fdf0ab..d704ff9 100644
--- a/lib/snapshot/snapshot.c
+++ b/lib/snapshot/snapshot.c
@@ -39,8 +39,6 @@ static int _snap_text_import(struct lv_segment *seg, const struct config_node *s
struct logical_volume *org, *cow;
int old_suppress;
- seg->lv->status |= SNAPSHOT;
-
if (!get_config_uint32(sn, "chunk_size", &chunk_size)) {
log_error("Couldn't read chunk size for snapshot.");
return 0;
@@ -74,9 +72,7 @@ static int _snap_text_import(struct lv_segment *seg, const struct config_node *s
return 0;
}
- if (!vg_add_snapshot(seg->lv->name, org, cow,
- &seg->lv->lvid, seg->len, chunk_size))
- return_0;
+ init_snapshot_seg(seg, org, cow, chunk_size);
return 1;
}
diff --git a/tools/lvconvert.c b/tools/lvconvert.c
index c54a2d1..267ff09 100644
--- a/tools/lvconvert.c
+++ b/tools/lvconvert.c
@@ -760,8 +760,7 @@ static int lvconvert_snapshot(struct cmd_context *cmd,
return 0;
}
- if (!vg_add_snapshot(NULL, org, lv, NULL, org->le_count,
- lp->chunk_size)) {
+ if (!vg_add_snapshot(org, lv, NULL, org->le_count, lp->chunk_size)) {
log_error("Couldn't create snapshot.");
return 0;
}
diff --git a/tools/lvcreate.c b/tools/lvcreate.c
index 42608c3..069cc0e 100644
--- a/tools/lvcreate.c
+++ b/tools/lvcreate.c
@@ -918,7 +918,7 @@ static int _lvcreate(struct cmd_context *cmd, struct volume_group *vg,
/* cow LV remains active and becomes snapshot LV */
- if (!vg_add_snapshot(NULL, org, lv, NULL,
+ if (!vg_add_snapshot(org, lv, NULL,
org->le_count, lp->chunk_size)) {
log_error("Couldn't create snapshot.");
goto deactivate_and_revert_new_lv;
--
1.6.2.4
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