[linux-lvm] [PATCH] snapshots on unaligned lvs
Chris Mason
mason at suse.com
Thu Oct 11 18:16:36 UTC 2001
Hello everyone,
This patch fixes 1.0.1-rc4 to be able to take snapshots of unaligned
logical volumes (created by some of the betas). It also fixes
a counting error in the loop in lvm_snapshot_COW.
Nothing fancy here, I just changed it to use the hard sector size
as the blocksize sent to brw_kiovec. I've tested with beta7 and
rc4 logical volumes, additional testing is more than welcome.
-chris
--- 0.36/drivers/md/lvm-snap.c Thu, 11 Oct 2001 10:17:22 -0400
+++ 0.36(w)/drivers/md/lvm-snap.c Thu, 11 Oct 2001 14:11:50 -0400
@@ -326,6 +326,7 @@
{
const char * reason;
unsigned long org_start, snap_start, snap_phys_dev, virt_start, pe_off;
+ unsigned long phys_start ;
int idx = lv_snap->lv_remap_ptr, chunk_size = lv_snap->lv_chunk_size;
struct kiobuf * iobuf;
unsigned long blocks[KIO_MAX_SECTORS];
@@ -360,8 +361,14 @@
iobuf = lv_snap->lv_iobuf;
- blksize_org = lvm_get_blksize(org_phys_dev);
- blksize_snap = lvm_get_blksize(snap_phys_dev);
+ blksize_org = get_hardsect_size(org_phys_dev);
+ blksize_snap = get_hardsect_size(snap_phys_dev);
+
+ /* org_start must not change, we use it later on to fill in the
+ ** exception table
+ */
+ phys_start = org_start ;
+
max_blksize = max(blksize_org, blksize_snap);
min_blksize = min(blksize_org, blksize_snap);
max_sectors = KIO_MAX_SECTORS * (min_blksize>>9);
@@ -376,7 +383,7 @@
iobuf->length = nr_sectors << 9;
- if(!lvm_snapshot_prepare_blocks(blocks, org_start,
+ if(!lvm_snapshot_prepare_blocks(blocks, phys_start,
nr_sectors, blksize_org))
goto fail_prepare;
@@ -391,6 +398,9 @@
if (__brw_kiovec(WRITE, 1, &iobuf, snap_phys_dev, blocks,
blksize_snap, lv_snap) != (nr_sectors<<9))
goto fail_raw_write;
+
+ phys_start += nr_sectors ;
+ snap_start += nr_sectors ;
}
#ifdef DEBUG_SNAPSHOT
@@ -605,7 +615,7 @@
snap_phys_dev = lv_snap->lv_block_exception[idx].rdev_new;
snap_pe_start = lv_snap->lv_block_exception[idx - (idx % COW_entries_per_pe)].rsector_new - lv_snap->lv_chunk_size;
- blksize_snap = lvm_get_blksize(snap_phys_dev);
+ blksize_snap = get_hardsect_size(snap_phys_dev);
COW_entries_per_block = blksize_snap / sizeof(lv_COW_table_disk_t);
idx_COW_table = idx % COW_entries_per_pe % COW_entries_per_block;
@@ -654,7 +664,7 @@
idx++;
snap_phys_dev = lv_snap->lv_block_exception[idx].rdev_new;
snap_pe_start = lv_snap->lv_block_exception[idx - (idx % COW_entries_per_pe)].rsector_new - lv_snap->lv_chunk_size;
- blksize_snap = lvm_get_blksize(snap_phys_dev);
+ blksize_snap = get_hardsect_size(snap_phys_dev);
blocks[0] = snap_pe_start >> (blksize_snap >> 10);
} else blocks[0]++;
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