block: BlockDriver: add .filtered_child_is_backing field

[qemu.git] / block / vvfat.c

diff --git a/block/vvfat.c b/block/vvfat.c
index 36e73d4c64518f908ed2baa3a9269aebfe7f5102..c5b14421452c38aab8bccccb6fd363baeb4b767e 100644 (file)
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -499,7 +499,7 @@ static bool valid_filename(const unsigned char *name)
               (c >= 'A' && c <= 'Z') ||
               (c >= 'a' && c <= 'z') ||
               c > 127 ||
-              strchr("$%'-_@~`!(){}^#&.+,;=[]", c) != NULL))
+              strchr(" $%'-_@~`!(){}^#&.+,;=[]", c) != NULL))
         {
             return false;
         }
@@ -882,7 +882,7 @@ static int read_directory(BDRVVVFATState* s, int mapping_index)
     return 0;
 }
 
-static inline uint32_t sector2cluster(BDRVVVFATState* s,off_t sector_num)
+static inline int32_t sector2cluster(BDRVVVFATState* s,off_t sector_num)
 {
     return (sector_num - s->offset_to_root_dir) / s->sectors_per_cluster;
 }
@@ -1488,8 +1488,8 @@ static int vvfat_read(BlockDriverState *bs, int64_t sector_num,
                 DLOG(fprintf(stderr, "sectors %" PRId64 "+%" PRId64
                              " allocated\n", sector_num,
                              n >> BDRV_SECTOR_BITS));
-                if (bdrv_pread(s->qcow, sector_num * BDRV_SECTOR_SIZE,
-                               buf + i * 0x200, n) < 0) {
+                if (bdrv_pread(s->qcow, sector_num * BDRV_SECTOR_SIZE, n,
+                               buf + i * 0x200, 0) < 0) {
                     return -1;
                 }
                 i += (n >> BDRV_SECTOR_BITS) - 1;
@@ -1978,7 +1978,8 @@ static uint32_t get_cluster_count_for_direntry(BDRVVVFATState* s,
                             return -1;
                         }
                         res = bdrv_pwrite(s->qcow, offset * BDRV_SECTOR_SIZE,
-                                          s->cluster_buffer, BDRV_SECTOR_SIZE);
+                                          BDRV_SECTOR_SIZE, s->cluster_buffer,
+                                          0);
                         if (res < 0) {
                             return -2;
                         }
@@ -2981,6 +2982,7 @@ static int vvfat_write(BlockDriverState *bs, int64_t sector_num,
 {
     BDRVVVFATState *s = bs->opaque;
     int i, ret;
+    int first_cluster, last_cluster;
 
 DLOG(checkpoint());
 
@@ -2991,17 +2993,52 @@ DLOG(checkpoint());
 
     vvfat_close_current_file(s);
 
+    if (sector_num == s->offset_to_bootsector && nb_sectors == 1) {
+        /*
+         * Write on bootsector. Allow only changing the reserved1 field,
+         * used to mark volume dirtiness
+         */
+        unsigned char *bootsector = s->first_sectors
+                                    + s->offset_to_bootsector * 0x200;
+        /*
+         * LATER TODO: if FAT32, this is wrong (see init_directories(),
+         * which always creates a FAT16 bootsector)
+         */
+        const int reserved1_offset = offsetof(bootsector_t, u.fat16.reserved1);
+
+        for (i = 0; i < 0x200; i++) {
+            if (i != reserved1_offset && bootsector[i] != buf[i]) {
+                fprintf(stderr, "Tried to write to protected bootsector\n");
+                return -1;
+            }
+        }
+
+        /* Update bootsector with the only updatable byte, and return success */
+        bootsector[reserved1_offset] = buf[reserved1_offset];
+        return 0;
+    }
+
     /*
      * Some sanity checks:
      * - do not allow writing to the boot sector
      */
-
     if (sector_num < s->offset_to_fat)
         return -1;
 
-    for (i = sector2cluster(s, sector_num);
-            i <= sector2cluster(s, sector_num + nb_sectors - 1);) {
-        mapping_t* mapping = find_mapping_for_cluster(s, i);
+    /*
+     * Values will be negative for writes to the FAT, which is located before
+     * the root directory.
+     */
+    first_cluster = sector2cluster(s, sector_num);
+    last_cluster = sector2cluster(s, sector_num + nb_sectors - 1);
+
+    for (i = first_cluster; i <= last_cluster;) {
+        mapping_t *mapping = NULL;
+
+        if (i >= 0) {
+            mapping = find_mapping_for_cluster(s, i);
+        }
+
         if (mapping) {
             if (mapping->read_only) {
                 fprintf(stderr, "Tried to write to write-protected file %s\n",
@@ -3041,25 +3078,27 @@ DLOG(checkpoint());
                 }
             }
             i = mapping->end;
-        } else
+        } else {
             i++;
+        }
     }
 
     /*
      * Use qcow backend. Commit later.
      */
 DLOG(fprintf(stderr, "Write to qcow backend: %d + %d\n", (int)sector_num, nb_sectors));
-    ret = bdrv_pwrite(s->qcow, sector_num * BDRV_SECTOR_SIZE, buf,
-                      nb_sectors * BDRV_SECTOR_SIZE);
+    ret = bdrv_pwrite(s->qcow, sector_num * BDRV_SECTOR_SIZE,
+                      nb_sectors * BDRV_SECTOR_SIZE, buf, 0);
     if (ret < 0) {
         fprintf(stderr, "Error writing to qcow backend\n");
         return ret;
     }
 
-    for (i = sector2cluster(s, sector_num);
-            i <= sector2cluster(s, sector_num + nb_sectors - 1); i++)
-        if (i >= 0)
+    for (i = first_cluster; i <= last_cluster; i++) {
+        if (i >= 0) {
             s->used_clusters[i] |= USED_ALLOCATED;
+        }
+    }
 
 DLOG(checkpoint());
     /* TODO: add timeout */
@@ -3131,10 +3170,9 @@ static int enable_write_target(BlockDriverState *bs, Error **errp)
 
     array_init(&(s->commits), sizeof(commit_t));
 
-    s->qcow_filename = g_malloc(PATH_MAX);
-    ret = get_tmp_filename(s->qcow_filename, PATH_MAX);
-    if (ret < 0) {
-        error_setg_errno(errp, -ret, "can't create temporary file");
+    s->qcow_filename = create_tmp_file(errp);
+    if (!s->qcow_filename) {
+        ret = -ENOENT;
         goto err;
     }