Changes in uspace/srv/fs/fat/fat_fat.c [2f636b6:3a8faba] in mainline

File:

• uspace/srv/fs/fat/fat_fat.c (modified) (4 diffs)

uspace/srv/fs/fat/fat_fat.c

@@ -359 +359 @@
         uint16_t rscnt;
         uint16_t sf;
+        uint16_t ts;
+        unsigned rde;
+        unsigned rds;
+        unsigned ssa;
         block_t *blk;
         fat_cluster_t *lifo;    /* stack for storing free cluster numbers */ 
@@ -372 +376 @@
         rscnt = uint16_t_le2host(bs->rscnt);
         sf = uint16_t_le2host(bs->sec_per_fat);
+        rde = uint16_t_le2host(bs->root_ent_max);
+        ts = uint16_t_le2host(bs->totsec16);
+
+        rds = (sizeof(fat_dentry_t) * rde) / bps;
+        rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);
+        ssa = rscnt + bs->fatcnt * sf + rds;
         
         /*
@@ -382 +392 @@
                         goto error;
                 for (c = 0; c < bps / sizeof(fat_cluster_t); c++, cl++) {
+                        /*
+                         * Check if the cluster is physically there. This check
+                         * becomes necessary when the file system is created
+                         * with fewer total sectors than how many is inferred
+                         * from the size of the file allocation table.
+                         */
+                        if ((cl - 2) * bs->spc + ssa >= ts) {
+                                rc = block_put(blk);
+                                if (rc != EOK)
+                                        goto error;
+                                goto out;
+                        }
+
                         fat_cluster_t *clst = (fat_cluster_t *)blk->data + c;
                         if (uint16_t_le2host(*clst) == FAT_CLST_RES0) {
@@ -419 +442 @@
                 }
         }
+out:
         fibril_mutex_unlock(&fat_alloc_lock);