qcow2: Return error for snapshot operation with data file

[qemu.git] / block / qcow2-snapshot.c

diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index 92f4dfc083e467d753c86073a1b47a989214d9f9..a6ffae89a6c6f7eb27a76c801d5e415a18dae83f 100644 (file)
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -22,10 +22,13 @@
  * THE SOFTWARE.
  */
 
-#include "qemu-common.h"
+#include "qemu/osdep.h"
+#include "qapi/error.h"
 #include "block/block_int.h"
-#include "block/qcow2.h"
+#include "qcow2.h"
+#include "qemu/bswap.h"
 #include "qemu/error-report.h"
+#include "qemu/cutils.h"
 
 void qcow2_free_snapshots(BlockDriverState *bs)
 {
@@ -63,7 +66,7 @@ int qcow2_read_snapshots(BlockDriverState *bs)
 
     for(i = 0; i < s->nb_snapshots; i++) {
         /* Read statically sized part of the snapshot header */
-        offset = align_offset(offset, 8);
+        offset = ROUND_UP(offset, 8);
         ret = bdrv_pread(bs->file, offset, &h, sizeof(h));
         if (ret < 0) {
             goto fail;
@@ -152,7 +155,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs)
     offset = 0;
     for(i = 0; i < s->nb_snapshots; i++) {
         sn = s->snapshots + i;
-        offset = align_offset(offset, 8);
+        offset = ROUND_UP(offset, 8);
         offset += sizeof(h);
         offset += sizeof(extra);
         offset += strlen(sn->id_str);
@@ -181,7 +184,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs)
 
     /* The snapshot list position has not yet been updated, so these clusters
      * must indeed be completely free */
-    ret = qcow2_pre_write_overlap_check(bs, 0, offset, snapshots_size);
+    ret = qcow2_pre_write_overlap_check(bs, 0, offset, snapshots_size, false);
     if (ret < 0) {
         goto fail;
     }
@@ -212,7 +215,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs)
         assert(id_str_size <= UINT16_MAX && name_size <= UINT16_MAX);
         h.id_str_size = cpu_to_be16(id_str_size);
         h.name_size = cpu_to_be16(name_size);
-        offset = align_offset(offset, 8);
+        offset = ROUND_UP(offset, 8);
 
         ret = bdrv_pwrite(bs->file, offset, &h, sizeof(h));
         if (ret < 0) {
@@ -350,16 +353,15 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
         return -EFBIG;
     }
 
+    if (has_data_file(bs)) {
+        return -ENOTSUP;
+    }
+
     memset(sn, 0, sizeof(*sn));
 
     /* Generate an ID */
     find_new_snapshot_id(bs, sn_info->id_str, sizeof(sn_info->id_str));
 
-    /* Check that the ID is unique */
-    if (find_snapshot_by_id_and_name(bs, sn_info->id_str, NULL) >= 0) {
-        return -EEXIST;
-    }
-
     /* Populate sn with passed data */
     sn->id_str = g_strdup(sn_info->id_str);
     sn->name = g_strdup(sn_info->name);
@@ -391,7 +393,7 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
     }
 
     ret = qcow2_pre_write_overlap_check(bs, 0, sn->l1_table_offset,
-                                        s->l1_size * sizeof(uint64_t));
+                                        s->l1_size * sizeof(uint64_t), false);
     if (ret < 0) {
         goto fail;
     }
@@ -437,10 +439,9 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
 
     /* The VM state isn't needed any more in the active L1 table; in fact, it
      * hurts by causing expensive COW for the next snapshot. */
-    qcow2_discard_clusters(bs, qcow2_vm_state_offset(s),
-                           align_offset(sn->vm_state_size, s->cluster_size)
-                                >> BDRV_SECTOR_BITS,
-                           QCOW2_DISCARD_NEVER, false);
+    qcow2_cluster_discard(bs, qcow2_vm_state_offset(s),
+                          ROUND_UP(sn->vm_state_size, s->cluster_size),
+                          QCOW2_DISCARD_NEVER, false);
 
 #ifdef DEBUG_ALLOC
     {
@@ -463,11 +464,16 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
 {
     BDRVQcow2State *s = bs->opaque;
     QCowSnapshot *sn;
+    Error *local_err = NULL;
     int i, snapshot_index;
     int cur_l1_bytes, sn_l1_bytes;
     int ret;
     uint64_t *sn_l1_table = NULL;
 
+    if (has_data_file(bs)) {
+        return -ENOTSUP;
+    }
+
     /* Search the snapshot */
     snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
     if (snapshot_index < 0) {
@@ -475,6 +481,14 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
     }
     sn = &s->snapshots[snapshot_index];
 
+    ret = qcow2_validate_table(bs, sn->l1_table_offset, sn->l1_size,
+                               sizeof(uint64_t), QCOW_MAX_L1_SIZE,
+                               "Snapshot L1 table", &local_err);
+    if (ret < 0) {
+        error_report_err(local_err);
+        goto fail;
+    }
+
     if (sn->disk_size != bs->total_sectors * BDRV_SECTOR_SIZE) {
         error_report("qcow2: Loading snapshots with different disk "
             "size is not implemented");
@@ -509,7 +523,8 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
         goto fail;
     }
 
-    ret = bdrv_pread(bs->file, sn->l1_table_offset, sn_l1_table, sn_l1_bytes);
+    ret = bdrv_pread(bs->file, sn->l1_table_offset,
+                     sn_l1_table, sn_l1_bytes);
     if (ret < 0) {
         goto fail;
     }
@@ -521,7 +536,8 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
     }
 
     ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L1,
-                                        s->l1_table_offset, cur_l1_bytes);
+                                        s->l1_table_offset, cur_l1_bytes,
+                                        false);
     if (ret < 0) {
         goto fail;
     }
@@ -591,6 +607,10 @@ int qcow2_snapshot_delete(BlockDriverState *bs,
     QCowSnapshot sn;
     int snapshot_index, ret;
 
+    if (has_data_file(bs)) {
+        return -ENOTSUP;
+    }
+
     /* Search the snapshot */
     snapshot_index = find_snapshot_by_id_and_name(bs, snapshot_id, name);
     if (snapshot_index < 0) {
@@ -599,6 +619,13 @@ int qcow2_snapshot_delete(BlockDriverState *bs,
     }
     sn = s->snapshots[snapshot_index];
 
+    ret = qcow2_validate_table(bs, sn.l1_table_offset, sn.l1_size,
+                               sizeof(uint64_t), QCOW_MAX_L1_SIZE,
+                               "Snapshot L1 table", errp);
+    if (ret < 0) {
+        return ret;
+    }
+
     /* Remove it from the snapshot list */
     memmove(s->snapshots + snapshot_index,
             s->snapshots + snapshot_index + 1,
@@ -655,6 +682,9 @@ int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
     QCowSnapshot *sn;
     int i;
 
+    if (has_data_file(bs)) {
+        return -ENOTSUP;
+    }
     if (!s->nb_snapshots) {
         *psn_tab = NULL;
         return s->nb_snapshots;
@@ -701,18 +731,21 @@ int qcow2_snapshot_load_tmp(BlockDriverState *bs,
     sn = &s->snapshots[snapshot_index];
 
     /* Allocate and read in the snapshot's L1 table */
-    if (sn->l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) {
-        error_setg(errp, "Snapshot L1 table too large");
-        return -EFBIG;
+    ret = qcow2_validate_table(bs, sn->l1_table_offset, sn->l1_size,
+                               sizeof(uint64_t), QCOW_MAX_L1_SIZE,
+                               "Snapshot L1 table", errp);
+    if (ret < 0) {
+        return ret;
     }
     new_l1_bytes = sn->l1_size * sizeof(uint64_t);
-    new_l1_table = qemu_try_blockalign(bs->file,
-                                       align_offset(new_l1_bytes, 512));
+    new_l1_table = qemu_try_blockalign(bs->file->bs,
+                                       ROUND_UP(new_l1_bytes, 512));
     if (new_l1_table == NULL) {
         return -ENOMEM;
     }
 
-    ret = bdrv_pread(bs->file, sn->l1_table_offset, new_l1_table, new_l1_bytes);
+    ret = bdrv_pread(bs->file, sn->l1_table_offset,
+                     new_l1_table, new_l1_bytes);
     if (ret < 0) {
         error_setg(errp, "Failed to read l1 table for snapshot");
         qemu_vfree(new_l1_table);