On 16.08.23 12:32, Andrey Zhadchenko wrote:
Implement find_hole() for dm-ploop target.
Iterate over clusters until we find hole or data by using
ploop_bat_entries() which will do all our work
Feature: dm: implement SEEK_HOLE for dm-qcow2 and dm-ploop
https://jira.vzint.dev/browse/PSBM-145746
Signed-off-by: Andrey Zhadchenko <andrey.zhadche...@virtuozzo.com>
---
drivers/md/dm-ploop-map.c | 50 ++++++++++++++++++++++++++++++++++++
drivers/md/dm-ploop-target.c | 1 +
drivers/md/dm-ploop.h | 1 +
3 files changed, 52 insertions(+)
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index 3f0803cb8e47..6fa146f8fe9a 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -1989,3 +1989,53 @@ int ploop_prepare_reloc_index_wb(struct ploop *ploop,
return err;
}
ALLOW_ERROR_INJECTION(ploop_prepare_reloc_index_wb, ERRNO);
+
+loff_t ploop_llseek_hole(struct dm_target *ti, loff_t offset, int whence)
+{
+ struct ploop *ploop = ti->private;
+ u32 clu, dst_clu;
+ loff_t result;
+
+ clu = SEC_TO_CLU(ploop, to_sector(offset) + ploop->skip_off);
+
+ while (clu < ploop->nr_bat_entries) {
+
+ /*
+ * Assume a locked cluster to have a data.
+ * In worst case someone will read zeroes
+ */
+ if (ploop_postpone_if_cluster_locked(ploop, NULL, clu)) {
+ if (whence & SEEK_DATA)
+ break;
+ if (whence & SEEK_HOLE) {
+ clu++;
+ continue;
+ }
+ }
+
+ /*
+ * It *may* be possible to speed this up by iterating over
clusters
+ * in mapped metadata page, but this is a bit problematic
+ * since we want to check if cluster is locked
+ */
+ dst_clu = ploop_bat_entries(ploop, clu, NULL, NULL);
+
+ if (whence & SEEK_DATA && dst_clu != BAT_ENTRY_NONE)
+ break;
+ if (whence & SEEK_HOLE && dst_clu == BAT_ENTRY_NONE)
+ break;
+
+ clu++;
+ }
+
+ result = to_bytes(CLU_TO_SEC(ploop, clu) - ploop->skip_off);
+ if (result < offset)
+ result = offset;
+
+ if (clu >= ploop->nr_bat_entries) {
+ if (whence & SEEK_DATA)
+ result = -ENXIO;
What about SEEK_HOLE error here ?
--
Regards,
Alexander Atanasov
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