]> git.proxmox.com Git - mirror_qemu.git/blobdiff - block/qcow2-snapshot.c
block: Convert bdrv_pread(v) to BdrvChild
[mirror_qemu.git] / block / qcow2-snapshot.c
index fe7e14cc895106255a6e94f4b0940eb4c9d76d43..2693ebf8120762471e47a4271a94905c7458faba 100644 (file)
  * THE SOFTWARE.
  */
 
-#include "qemu-common.h"
+#include "qemu/osdep.h"
+#include "qapi/error.h"
 #include "block/block_int.h"
 #include "block/qcow2.h"
-
-typedef struct QEMU_PACKED QCowSnapshotHeader {
-    /* header is 8 byte aligned */
-    uint64_t l1_table_offset;
-
-    uint32_t l1_size;
-    uint16_t id_str_size;
-    uint16_t name_size;
-
-    uint32_t date_sec;
-    uint32_t date_nsec;
-
-    uint64_t vm_clock_nsec;
-
-    uint32_t vm_state_size;
-    uint32_t extra_data_size; /* for extension */
-    /* extra data follows */
-    /* id_str follows */
-    /* name follows  */
-} QCowSnapshotHeader;
-
-typedef struct QEMU_PACKED QCowSnapshotExtraData {
-    uint64_t vm_state_size_large;
-    uint64_t disk_size;
-} QCowSnapshotExtraData;
+#include "qemu/bswap.h"
+#include "qemu/error-report.h"
+#include "qemu/cutils.h"
 
 void qcow2_free_snapshots(BlockDriverState *bs)
 {
-    BDRVQcowState *s = bs->opaque;
+    BDRVQcow2State *s = bs->opaque;
     int i;
 
     for(i = 0; i < s->nb_snapshots; i++) {
@@ -67,7 +46,7 @@ void qcow2_free_snapshots(BlockDriverState *bs)
 
 int qcow2_read_snapshots(BlockDriverState *bs)
 {
-    BDRVQcowState *s = bs->opaque;
+    BDRVQcow2State *s = bs->opaque;
     QCowSnapshotHeader h;
     QCowSnapshotExtraData extra;
     QCowSnapshot *sn;
@@ -83,7 +62,7 @@ int qcow2_read_snapshots(BlockDriverState *bs)
     }
 
     offset = s->snapshots_offset;
-    s->snapshots = g_malloc0(s->nb_snapshots * sizeof(QCowSnapshot));
+    s->snapshots = g_new0(QCowSnapshot, s->nb_snapshots);
 
     for(i = 0; i < s->nb_snapshots; i++) {
         /* Read statically sized part of the snapshot header */
@@ -141,8 +120,14 @@ int qcow2_read_snapshots(BlockDriverState *bs)
         }
         offset += name_size;
         sn->name[name_size] = '\0';
+
+        if (offset - s->snapshots_offset > QCOW_MAX_SNAPSHOTS_SIZE) {
+            ret = -EFBIG;
+            goto fail;
+        }
     }
 
+    assert(offset - s->snapshots_offset <= INT_MAX);
     s->snapshots_size = offset - s->snapshots_offset;
     return 0;
 
@@ -154,7 +139,7 @@ fail:
 /* add at the end of the file a new list of snapshots */
 static int qcow2_write_snapshots(BlockDriverState *bs)
 {
-    BDRVQcowState *s = bs->opaque;
+    BDRVQcow2State *s = bs->opaque;
     QCowSnapshot *sn;
     QCowSnapshotHeader h;
     QCowSnapshotExtraData extra;
@@ -163,7 +148,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs)
         uint32_t nb_snapshots;
         uint64_t snapshots_offset;
     } QEMU_PACKED header_data;
-    int64_t offset, snapshots_offset;
+    int64_t offset, snapshots_offset = 0;
     int ret;
 
     /* compute the size of the snapshots */
@@ -175,7 +160,14 @@ static int qcow2_write_snapshots(BlockDriverState *bs)
         offset += sizeof(extra);
         offset += strlen(sn->id_str);
         offset += strlen(sn->name);
+
+        if (offset > QCOW_MAX_SNAPSHOTS_SIZE) {
+            ret = -EFBIG;
+            goto fail;
+        }
     }
+
+    assert(offset <= INT_MAX);
     snapshots_size = offset;
 
     /* Allocate space for the new snapshot list */
@@ -192,8 +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, QCOW2_OL_DEFAULT, offset,
-                                        snapshots_size);
+    ret = qcow2_pre_write_overlap_check(bs, 0, offset, snapshots_size);
     if (ret < 0) {
         goto fail;
     }
@@ -226,25 +217,25 @@ static int qcow2_write_snapshots(BlockDriverState *bs)
         h.name_size = cpu_to_be16(name_size);
         offset = align_offset(offset, 8);
 
-        ret = bdrv_pwrite(bs->file, offset, &h, sizeof(h));
+        ret = bdrv_pwrite(bs->file->bs, offset, &h, sizeof(h));
         if (ret < 0) {
             goto fail;
         }
         offset += sizeof(h);
 
-        ret = bdrv_pwrite(bs->file, offset, &extra, sizeof(extra));
+        ret = bdrv_pwrite(bs->file->bs, offset, &extra, sizeof(extra));
         if (ret < 0) {
             goto fail;
         }
         offset += sizeof(extra);
 
-        ret = bdrv_pwrite(bs->file, offset, sn->id_str, id_str_size);
+        ret = bdrv_pwrite(bs->file->bs, offset, sn->id_str, id_str_size);
         if (ret < 0) {
             goto fail;
         }
         offset += id_str_size;
 
-        ret = bdrv_pwrite(bs->file, offset, sn->name, name_size);
+        ret = bdrv_pwrite(bs->file->bs, offset, sn->name, name_size);
         if (ret < 0) {
             goto fail;
         }
@@ -266,7 +257,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs)
     header_data.nb_snapshots        = cpu_to_be32(s->nb_snapshots);
     header_data.snapshots_offset    = cpu_to_be64(snapshots_offset);
 
-    ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, nb_snapshots),
+    ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, nb_snapshots),
                            &header_data, sizeof(header_data));
     if (ret < 0) {
         goto fail;
@@ -290,9 +281,10 @@ fail:
 static void find_new_snapshot_id(BlockDriverState *bs,
                                  char *id_str, int id_str_size)
 {
-    BDRVQcowState *s = bs->opaque;
+    BDRVQcow2State *s = bs->opaque;
     QCowSnapshot *sn;
-    int i, id, id_max = 0;
+    int i;
+    unsigned long id, id_max = 0;
 
     for(i = 0; i < s->nb_snapshots; i++) {
         sn = s->snapshots + i;
@@ -300,14 +292,14 @@ static void find_new_snapshot_id(BlockDriverState *bs,
         if (id > id_max)
             id_max = id;
     }
-    snprintf(id_str, id_str_size, "%d", id_max + 1);
+    snprintf(id_str, id_str_size, "%lu", id_max + 1);
 }
 
 static int find_snapshot_by_id_and_name(BlockDriverState *bs,
                                         const char *id,
                                         const char *name)
 {
-    BDRVQcowState *s = bs->opaque;
+    BDRVQcow2State *s = bs->opaque;
     int i;
 
     if (id && name) {
@@ -349,7 +341,7 @@ static int find_snapshot_by_id_or_name(BlockDriverState *bs,
 /* if no id is provided, a new one is constructed */
 int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
 {
-    BDRVQcowState *s = bs->opaque;
+    BDRVQcow2State *s = bs->opaque;
     QCowSnapshot *new_snapshot_list = NULL;
     QCowSnapshot *old_snapshot_list = NULL;
     QCowSnapshot sn1, *sn = &sn1;
@@ -357,12 +349,14 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
     uint64_t *l1_table = NULL;
     int64_t l1_table_offset;
 
+    if (s->nb_snapshots >= QCOW_MAX_SNAPSHOTS) {
+        return -EFBIG;
+    }
+
     memset(sn, 0, sizeof(*sn));
 
-    /* Generate an ID if it wasn't passed */
-    if (sn_info->id_str[0] == '\0') {
-        find_new_snapshot_id(bs, sn_info->id_str, sizeof(sn_info->id_str));
-    }
+    /* 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) {
@@ -389,18 +383,23 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
     sn->l1_table_offset = l1_table_offset;
     sn->l1_size = s->l1_size;
 
-    l1_table = g_malloc(s->l1_size * sizeof(uint64_t));
+    l1_table = g_try_new(uint64_t, s->l1_size);
+    if (s->l1_size && l1_table == NULL) {
+        ret = -ENOMEM;
+        goto fail;
+    }
+
     for(i = 0; i < s->l1_size; i++) {
         l1_table[i] = cpu_to_be64(s->l1_table[i]);
     }
 
-    ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT,
-            sn->l1_table_offset, s->l1_size * sizeof(uint64_t));
+    ret = qcow2_pre_write_overlap_check(bs, 0, sn->l1_table_offset,
+                                        s->l1_size * sizeof(uint64_t));
     if (ret < 0) {
         goto fail;
     }
 
-    ret = bdrv_pwrite(bs->file, sn->l1_table_offset, l1_table,
+    ret = bdrv_pwrite(bs->file->bs, sn->l1_table_offset, l1_table,
                       s->l1_size * sizeof(uint64_t));
     if (ret < 0) {
         goto fail;
@@ -420,7 +419,7 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
     }
 
     /* Append the new snapshot to the snapshot list */
-    new_snapshot_list = g_malloc((s->nb_snapshots + 1) * sizeof(QCowSnapshot));
+    new_snapshot_list = g_new(QCowSnapshot, s->nb_snapshots + 1);
     if (s->snapshots) {
         memcpy(new_snapshot_list, s->snapshots,
                s->nb_snapshots * sizeof(QCowSnapshot));
@@ -444,7 +443,7 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
     qcow2_discard_clusters(bs, qcow2_vm_state_offset(s),
                            align_offset(sn->vm_state_size, s->cluster_size)
                                 >> BDRV_SECTOR_BITS,
-                           QCOW2_DISCARD_NEVER);
+                           QCOW2_DISCARD_NEVER, false);
 
 #ifdef DEBUG_ALLOC
     {
@@ -465,7 +464,7 @@ fail:
 /* copy the snapshot 'snapshot_name' into the current disk image */
 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
 {
-    BDRVQcowState *s = bs->opaque;
+    BDRVQcow2State *s = bs->opaque;
     QCowSnapshot *sn;
     int i, snapshot_index;
     int cur_l1_bytes, sn_l1_bytes;
@@ -507,9 +506,14 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
      * Decrease the refcount referenced by the old one only when the L1
      * table is overwritten.
      */
-    sn_l1_table = g_malloc0(cur_l1_bytes);
+    sn_l1_table = g_try_malloc0(cur_l1_bytes);
+    if (cur_l1_bytes && sn_l1_table == NULL) {
+        ret = -ENOMEM;
+        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;
     }
@@ -520,14 +524,13 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
         goto fail;
     }
 
-    ret = qcow2_pre_write_overlap_check(bs,
-            QCOW2_OL_DEFAULT & ~QCOW2_OL_ACTIVE_L1,
-            s->l1_table_offset, cur_l1_bytes);
+    ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L1,
+                                        s->l1_table_offset, cur_l1_bytes);
     if (ret < 0) {
         goto fail;
     }
 
-    ret = bdrv_pwrite_sync(bs->file, s->l1_table_offset, sn_l1_table,
+    ret = bdrv_pwrite_sync(bs->file->bs, s->l1_table_offset, sn_l1_table,
                            cur_l1_bytes);
     if (ret < 0) {
         goto fail;
@@ -588,7 +591,7 @@ int qcow2_snapshot_delete(BlockDriverState *bs,
                           const char *name,
                           Error **errp)
 {
-    BDRVQcowState *s = bs->opaque;
+    BDRVQcow2State *s = bs->opaque;
     QCowSnapshot sn;
     int snapshot_index, ret;
 
@@ -607,7 +610,8 @@ int qcow2_snapshot_delete(BlockDriverState *bs,
     s->nb_snapshots--;
     ret = qcow2_write_snapshots(bs);
     if (ret < 0) {
-        error_setg(errp, "Failed to remove snapshot from snapshot list");
+        error_setg_errno(errp, -ret,
+                         "Failed to remove snapshot from snapshot list");
         return ret;
     }
 
@@ -625,7 +629,7 @@ int qcow2_snapshot_delete(BlockDriverState *bs,
     ret = qcow2_update_snapshot_refcount(bs, sn.l1_table_offset,
                                          sn.l1_size, -1);
     if (ret < 0) {
-        error_setg(errp, "Failed to free the cluster and L1 table");
+        error_setg_errno(errp, -ret, "Failed to free the cluster and L1 table");
         return ret;
     }
     qcow2_free_clusters(bs, sn.l1_table_offset, sn.l1_size * sizeof(uint64_t),
@@ -634,7 +638,8 @@ int qcow2_snapshot_delete(BlockDriverState *bs,
     /* must update the copied flag on the current cluster offsets */
     ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 0);
     if (ret < 0) {
-        error_setg(errp, "Failed to update snapshot status in disk");
+        error_setg_errno(errp, -ret,
+                         "Failed to update snapshot status in disk");
         return ret;
     }
 
@@ -649,7 +654,7 @@ int qcow2_snapshot_delete(BlockDriverState *bs,
 
 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
 {
-    BDRVQcowState *s = bs->opaque;
+    BDRVQcow2State *s = bs->opaque;
     QEMUSnapshotInfo *sn_tab, *sn_info;
     QCowSnapshot *sn;
     int i;
@@ -659,7 +664,7 @@ int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
         return s->nb_snapshots;
     }
 
-    sn_tab = g_malloc0(s->nb_snapshots * sizeof(QEMUSnapshotInfo));
+    sn_tab = g_new0(QEMUSnapshotInfo, s->nb_snapshots);
     for(i = 0; i < s->nb_snapshots; i++) {
         sn_info = sn_tab + i;
         sn = s->snapshots + i;
@@ -676,10 +681,13 @@ int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
     return s->nb_snapshots;
 }
 
-int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name)
+int qcow2_snapshot_load_tmp(BlockDriverState *bs,
+                            const char *snapshot_id,
+                            const char *name,
+                            Error **errp)
 {
     int i, snapshot_index;
-    BDRVQcowState *s = bs->opaque;
+    BDRVQcow2State *s = bs->opaque;
     QCowSnapshot *sn;
     uint64_t *new_l1_table;
     int new_l1_bytes;
@@ -688,24 +696,36 @@ int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name)
     assert(bs->read_only);
 
     /* Search the snapshot */
-    snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_name);
+    snapshot_index = find_snapshot_by_id_and_name(bs, snapshot_id, name);
     if (snapshot_index < 0) {
+        error_setg(errp,
+                   "Can't find snapshot");
         return -ENOENT;
     }
     sn = &s->snapshots[snapshot_index];
 
     /* Allocate and read in the snapshot's L1 table */
-    new_l1_bytes = s->l1_size * sizeof(uint64_t);
-    new_l1_table = g_malloc0(align_offset(new_l1_bytes, 512));
+    if (sn->l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) {
+        error_setg(errp, "Snapshot L1 table too large");
+        return -EFBIG;
+    }
+    new_l1_bytes = sn->l1_size * sizeof(uint64_t);
+    new_l1_table = qemu_try_blockalign(bs->file->bs,
+                                       align_offset(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) {
-        g_free(new_l1_table);
+        error_setg(errp, "Failed to read l1 table for snapshot");
+        qemu_vfree(new_l1_table);
         return ret;
     }
 
     /* Switch the L1 table */
-    g_free(s->l1_table);
+    qemu_vfree(s->l1_table);
 
     s->l1_size = sn->l1_size;
     s->l1_table_offset = sn->l1_table_offset;