V2: 1: all fail case will goto fail section. 2: add the goto code. v3: Address Stefan's comments: 2: don't goto fail after allocation failure. 3: use sn->l1size correctly in qcow2_free_cluster(). 4-7: add test case to verify the error paths. Other: 1: new patch fix a existing bug, which will be exposed in error path test.
v4: General change: rebased on upstream since error path for qcow2_write_snapshots() already exist in upstream. removed old patch 1 since it is fixed by Max in upstream. 5: moved the snapshot_l1_update event just before write operation, instead of before overlap check, since it is more straight. 6: remove a duplicated error path test about flush after snapshot list update, add a filter which replace number to X, since now in error in report detailed message including error cluster number. Address Stefan's comments: 1, 2, 4: add *errp to store detailed error message, instead of error_report() and compile time determined debug printf message. 3: do not free cluster when fail in header update for safety reason. Address Eric's comments: 1, 2, 4: add *errp to store detailed error message, instead of error_report() and compile time determined debug printf message. 5: squashed patches that add and use debug events. 6: added comments about test only on Linux. v5: General change: 6: rebased on upstream, use case number 070, adjust 070.out due to error message change in this version. Address Max's comments: 1 use error_setg_errno() when possible, remove "ret =" in functions when possible since the function does not need to return int value, fix 32bit/ 64bit issue in printf for "sizeof" and "offse", typo fix. 2 use error_setg_errno() when possible, fix 32bit/64bit issue in printf for "sizeof" and "offse", typo fix. 3 typo fix in comments. 5 typo fix in commit message. Address Eric's comments: 2 fix 32bit/64bit issue in printf for "sizeof" and "offse". v6: Address Jeff's comments: 6: add quote for image name in test case. v7: Rebased on Stefan's block tree, since I need to test after Fam's cache mode series. 6: change case number to 075 to avoid conflict, add a comments in case that it covers only default cache mode, qemu-img snapshot would not be affected by case's cache setting. v8: Address Stefan's comments: 1/8: typo fix. 2/8: remove the type case for sizeof and offsetof. 3/8, 4/8: new patches help appending error message and detect error. 5/8: old patch that skip cluster free when header update fail, is removed. Instead, this patch improved qcow2_write_snapshots()'s rollback procedure by restore header. 6/8: new variable *err_rollback is introduced to detect sub function's rollback error. With new function introduced by patch 3/8, message pending is simplified so old variable Error *err is removed. Renamed code section "dealloc_cluster" to "dealloc_l1_table" to tip better. Note: patch 5/8 and 6/8 does a full mirrored rollback operation, and follows the rule that skip following steps when one step fail in rollback procedure. 8/8: changed the qcow2 header update fail case correspondly. v9: Address Peter's comments: 3/8: rename *err to *errp in API param, it works like error_setg() when *errp is not set. v10: Address Max's comments: 5/8, 6/8: Better commit message and error message. Wenchao Xia (8): 1 snapshot: add parameter *errp in snapshot create 2 qcow2: add error message in qcow2_write_snapshots() 3 util: add error_append() 4 qcow2: return int for qcow2_free_clusters() 5 qcow2: full rollback on fail in qcow2_write_snapshots() 6 qcow2: rollback on fail in qcow2_snapshot_create() 7 blkdebug: add debug events for snapshot 8 qemu-iotests: add test for qcow2 snapshot block/blkdebug.c | 4 + block/qcow2-refcount.c | 8 +- block/qcow2-snapshot.c | 164 ++++++++++++++++++++++++----- block/qcow2.h | 10 +- block/rbd.c | 19 ++-- block/sheepdog.c | 28 +++-- block/snapshot.c | 19 +++- blockdev.c | 10 +- include/block/block.h | 4 + include/block/block_int.h | 5 +- include/block/snapshot.h | 5 +- include/qapi/error.h | 6 + qemu-img.c | 10 +- savevm.c | 12 ++- tests/qemu-iotests/075 | 216 ++++++++++++++++++++++++++++++++++++++ tests/qemu-iotests/075.out | 32 ++++++ tests/qemu-iotests/common.filter | 7 ++ tests/qemu-iotests/group | 1 + util/error.c | 44 +++++++- 19 files changed, 523 insertions(+), 81 deletions(-) create mode 100755 tests/qemu-iotests/075 create mode 100644 tests/qemu-iotests/075.out
