| Message ID | 1378695482-29805-7-git-send-email-xiawenc@linux.vnet.ibm.com |
|---|---|
| State | New |
| Headers | show |
On 09/08/2013 08:58 PM, Wenchao Xia wrote: > The message will be print out with a macro enabled, which can s/print/printed/ > be used to check which error path is taken. > > Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> > --- > block/qcow2-snapshot.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ > 1 files changed, 46 insertions(+), 0 deletions(-) > > @@ -381,12 +413,20 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info) > ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, > sn->l1_table_offset, s->l1_size * sizeof(uint64_t)); > if (ret < 0) { > +#ifdef QCOW2_SNAPSHOT_PRINT_ERROR_PATH > + printf("qcow2: Failed in overlap check before update L1 table for " > + "snapshot\n"); > +#endif > goto dealloc_cluster; > } > > + BLKDBG_EVENT(bs->file, BLKDBG_SNAPSHOT_L1_UPDATE); Should this BLKDBG be part of patch 5? In general, the move to avoid fprintf except under recompilation seems okay; but it seems odd to be removing the diagnosis altogether. If you had gone one step further and refactored the code to wire in Error* support, then you could change fprintf to passing the Error back up the stack to the caller rather than losing it except during a debug build.
On Mon, Sep 30, 2013 at 04:08:53PM -0600, Eric Blake wrote: > On 09/08/2013 08:58 PM, Wenchao Xia wrote: > > The message will be print out with a macro enabled, which can > > s/print/printed/ > > > be used to check which error path is taken. > > > > Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> > > --- > > block/qcow2-snapshot.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ > > 1 files changed, 46 insertions(+), 0 deletions(-) > > > > > @@ -381,12 +413,20 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info) > > ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, > > sn->l1_table_offset, s->l1_size * sizeof(uint64_t)); > > if (ret < 0) { > > +#ifdef QCOW2_SNAPSHOT_PRINT_ERROR_PATH > > + printf("qcow2: Failed in overlap check before update L1 table for " > > + "snapshot\n"); > > +#endif > > goto dealloc_cluster; > > } > > > > + BLKDBG_EVENT(bs->file, BLKDBG_SNAPSHOT_L1_UPDATE); > > Should this BLKDBG be part of patch 5? > > In general, the move to avoid fprintf except under recompilation seems > okay; but it seems odd to be removing the diagnosis altogether. If you > had gone one step further and refactored the code to wire in Error* > support, then you could change fprintf to passing the Error back up the > stack to the caller rather than losing it except during a debug build. I agree with Eric. Use Error* and make snapshot commands print a detailed error to the monitor. When diagnostics are compiled out we can't help troubleshoot user problems. Stefan
δΊ 2013/10/2 20:23, Stefan Hajnoczi ει: > On Mon, Sep 30, 2013 at 04:08:53PM -0600, Eric Blake wrote: >> On 09/08/2013 08:58 PM, Wenchao Xia wrote: >>> The message will be print out with a macro enabled, which can >> s/print/printed/ >> >>> be used to check which error path is taken. >>> >>> Signed-off-by: Wenchao Xia<xiawenc@linux.vnet.ibm.com> >>> --- >>> block/qcow2-snapshot.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ >>> 1 files changed, 46 insertions(+), 0 deletions(-) >>> >>> @@ -381,12 +413,20 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info) >>> ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, >>> sn->l1_table_offset, s->l1_size * sizeof(uint64_t)); >>> if (ret< 0) { >>> +#ifdef QCOW2_SNAPSHOT_PRINT_ERROR_PATH >>> + printf("qcow2: Failed in overlap check before update L1 table for " >>> + "snapshot\n"); >>> +#endif >>> goto dealloc_cluster; >>> } >>> >>> + BLKDBG_EVENT(bs->file, BLKDBG_SNAPSHOT_L1_UPDATE); >> Should this BLKDBG be part of patch 5? >> >> In general, the move to avoid fprintf except under recompilation seems >> okay; but it seems odd to be removing the diagnosis altogether. If you >> had gone one step further and refactored the code to wire in Error* >> support, then you could change fprintf to passing the Error back up the >> stack to the caller rather than losing it except during a debug build. > I agree with Eric. Use Error* and make snapshot commands print a > detailed error to the monitor. > > When diagnostics are compiled out we can't help troubleshoot user > problems. > > Stefan > Make sense, will add *errp to report the errors.
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c index 92b87f8..7f24486 100644 --- a/block/qcow2-snapshot.c +++ b/block/qcow2-snapshot.c @@ -26,6 +26,8 @@ #include "block/block_int.h" #include "block/qcow2.h" +/* #define QCOW2_SNAPSHOT_PRINT_ERROR_PATH */ + typedef struct QEMU_PACKED QCowSnapshotHeader { /* header is 8 byte aligned */ uint64_t l1_table_offset; @@ -182,10 +184,16 @@ static int qcow2_write_snapshots(BlockDriverState *bs) snapshots_offset = qcow2_alloc_clusters(bs, snapshots_size); offset = snapshots_offset; if (offset < 0) { +#ifdef QCOW2_SNAPSHOT_PRINT_ERROR_PATH + printf("qcow2: Failed in allocation of snapshot list\n"); +#endif return offset; } ret = bdrv_flush(bs); if (ret < 0) { +#ifdef QCOW2_SNAPSHOT_PRINT_ERROR_PATH + printf("qcow2: Failed in flush after snapshot list allocation\n"); +#endif goto fail; } @@ -194,6 +202,9 @@ static int qcow2_write_snapshots(BlockDriverState *bs) ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, offset, s->snapshots_size); if (ret < 0) { +#ifdef QCOW2_SNAPSHOT_PRINT_ERROR_PATH + printf("qcow2: Failed in overlap check before update snapshot list\n"); +#endif goto fail; } @@ -227,24 +238,36 @@ static int qcow2_write_snapshots(BlockDriverState *bs) ret = bdrv_pwrite(bs->file, offset, &h, sizeof(h)); if (ret < 0) { +#ifdef QCOW2_SNAPSHOT_PRINT_ERROR_PATH + printf("qcow2: Failed in update of snapshot header\n"); +#endif goto fail; } offset += sizeof(h); ret = bdrv_pwrite(bs->file, offset, &extra, sizeof(extra)); if (ret < 0) { +#ifdef QCOW2_SNAPSHOT_PRINT_ERROR_PATH + printf("qcow2: Failed in update of extra snapshot info\n"); +#endif goto fail; } offset += sizeof(extra); ret = bdrv_pwrite(bs->file, offset, sn->id_str, id_str_size); if (ret < 0) { +#ifdef QCOW2_SNAPSHOT_PRINT_ERROR_PATH + printf("qcow2: Failed in update of snapshot id\n"); +#endif goto fail; } offset += id_str_size; ret = bdrv_pwrite(bs->file, offset, sn->name, name_size); if (ret < 0) { +#ifdef QCOW2_SNAPSHOT_PRINT_ERROR_PATH + printf("qcow2: Failed in update of snapshot name\n"); +#endif goto fail; } offset += name_size; @@ -256,6 +279,9 @@ static int qcow2_write_snapshots(BlockDriverState *bs) */ ret = bdrv_flush(bs); if (ret < 0) { +#ifdef QCOW2_SNAPSHOT_PRINT_ERROR_PATH + printf("qcow2: Failed in flush after update snapshot list\n"); +#endif goto fail; } @@ -269,6 +295,9 @@ static int qcow2_write_snapshots(BlockDriverState *bs) ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, nb_snapshots), &header_data, sizeof(header_data)); if (ret < 0) { +#ifdef QCOW2_SNAPSHOT_PRINT_ERROR_PATH + printf("qcow2: Failed in update qcow2 header in snapshot creation\n"); +#endif goto fail; } @@ -366,6 +395,9 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info) l1_table_offset = qcow2_alloc_clusters(bs, s->l1_size * sizeof(uint64_t)); if (l1_table_offset < 0) { ret = l1_table_offset; +#ifdef QCOW2_SNAPSHOT_PRINT_ERROR_PATH + printf("qcow2: Failed in allocation of L1 table for snapshot\n"); +#endif goto fail; } @@ -381,12 +413,20 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info) ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, sn->l1_table_offset, s->l1_size * sizeof(uint64_t)); if (ret < 0) { +#ifdef QCOW2_SNAPSHOT_PRINT_ERROR_PATH + printf("qcow2: Failed in overlap check before update L1 table for " + "snapshot\n"); +#endif goto dealloc_cluster; } + BLKDBG_EVENT(bs->file, BLKDBG_SNAPSHOT_L1_UPDATE); ret = bdrv_pwrite(bs->file, sn->l1_table_offset, l1_table, s->l1_size * sizeof(uint64_t)); if (ret < 0) { +#ifdef QCOW2_SNAPSHOT_PRINT_ERROR_PATH + printf("qcow2: Failed in update of L1 table for snapshot\n"); +#endif goto dealloc_cluster; } @@ -400,6 +440,9 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info) */ ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1); if (ret < 0) { +#ifdef QCOW2_SNAPSHOT_PRINT_ERROR_PATH + printf("qcow2: Failed in update refcount for snapshot\n"); +#endif goto dealloc_cluster; } @@ -419,6 +462,9 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info) g_free(s->snapshots); s->snapshots = old_snapshot_list; s->nb_snapshots = old_snapshot_num; +#ifdef QCOW2_SNAPSHOT_PRINT_ERROR_PATH + printf("qcow2: Failed in update of snapshot list and header\n"); +#endif goto restore_refcount; }
The message will be print out with a macro enabled, which can be used to check which error path is taken. Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> --- block/qcow2-snapshot.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 46 insertions(+), 0 deletions(-)