Changeset 869e546 in mainline for uspace/srv/fs/fat/fat_ops.c

Timestamp:

2008-04-20T22:37:13Z (17 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

297f1197

Parents:

34f62f8

Message:

Introduce the foundation for unique and stable FAT VFS node indices.

The first two reserved FAT entries are physically present in each FAT, so fix
the code to be aware of this.

File:

• uspace/srv/fs/fat/fat_ops.c (modified) (15 diffs)

uspace/srv/fs/fat/fat_ops.c

@@ -54 +54 @@
 #define FIN_KEY_INDEX           1
 
-/** Futex protecting both fin_hash and ffn_head. */
-futex_t fin_futex = FUTEX_INITIALIZER;
-
 /** Hash table of FAT in-core nodes. */
 hash_table_t fin_hash;
@@ -116 +113 @@
 }
 
+static fat_idx_t *fat_idx_map(fat_cluster_t pfc, unsigned pdi)
+{
+        return NULL;    /* TODO */
+}
 
 #define FAT_BS(b)               ((fat_bs_t *)((b)->data))
 
+#define FAT_CLST_RES0   0x0000
+#define FAT_CLST_RES1   0x0001  /* internally used to mark root directory */
 #define FAT_CLST_FIRST  0x0002
 #define FAT_CLST_BAD    0xfff7
@@ -124 +127 @@
 #define FAT_CLST_LAST8  0xffff
 
-/** Convert cluster number to an index within a FAT.
- *
- * Format Identifier and cluster numbering is considered.
- */
-#define C2FAT_IDX(c)    (1 + (c) - FAT_CLST_FIRST)
-
-static block_t *fat_block_get(dev_handle_t dev_handle, fs_index_t index,
-    off_t offset)
+static block_t *fat_block_get(fat_node_t *nodep, off_t offset)
 {
         block_t *bb;
@@ -144 +140 @@
         unsigned ssa;           /* size of the system area */
         unsigned clusters;
-        unsigned clst = index;
+        fat_cluster_t clst = nodep->firstc;
         unsigned i;
 
-        bb = block_get(dev_handle, BS_BLOCK);
+        bb = block_get(nodep->idx->dev_handle, BS_BLOCK);
         bps = uint16_t_le2host(FAT_BS(bb)->bps);
         spc = FAT_BS(bb)->spc;
@@ -160 +156 @@
         ssa = rscnt + fatcnt * sf + rds;
 
-        if (!index) {
+        if (nodep->idx->index == FAT_CLST_RES1) {
                 /* root directory special case */
                 assert(offset < rds);
-                b = block_get(dev_handle, rscnt + fatcnt * sf + offset);
+                b = block_get(nodep->idx->dev_handle,
+                    rscnt + fatcnt * sf + offset);
                 return b;
         }
@@ -173 +170 @@
 
                 assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD);
-                fsec = (C2FAT_IDX(clst) * sizeof(uint16_t)) / bps;
-                fidx = C2FAT_IDX(clst) % (bps / sizeof(uint16_t));
+                fsec = (clst * sizeof(fat_cluster_t)) / bps;
+                fidx = clst % (bps / sizeof(fat_cluster_t));
                 /* read FAT1 */
-                b = block_get(dev_handle, rscnt + fsec);
-                clst = uint16_t_le2host(((uint16_t *)b->data)[fidx]);
+                b = block_get(nodep->idx->dev_handle, rscnt + fsec);
+                clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);
                 assert(clst != FAT_CLST_BAD);
                 assert(clst < FAT_CLST_LAST1);
@@ -183 +180 @@
         }
 
-        b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc +
-            offset % spc);
+        b = block_get(nodep->idx->dev_handle, ssa +
+            (clst - FAT_CLST_FIRST) * spc + offset % spc);
 
         return b;
@@ -191 +188 @@
 static void fat_node_initialize(fat_node_t *node)
 {
-        futex_initialize(&node->lock, 1);
+        node->idx = NULL;
         node->type = 0;
-        node->index = 0;
-        node->pindex = 0;
-        node->dev_handle = 0;
         link_initialize(&node->fin_link);
         link_initialize(&node->ffn_link);
@@ -295 +289 @@
         block_t *b;
 
-        bps = fat_bps_get(parentp->dev_handle);
+        bps = fat_bps_get(parentp->idx->dev_handle);
         dps = bps / sizeof(fat_dentry_t);
         blocks = parentp->size / bps + (parentp->size % bps != 0);
@@ -301 +295 @@
                 unsigned dentries;
                 
-                b = fat_block_get(parentp->dev_handle, parentp->index, i);
+                b = fat_block_get(parentp, i);
                 dentries = (i == blocks - 1) ?
                     parentp->size % sizeof(fat_dentry_t) :
@@ -320 +314 @@
                         if (strcmp(name, component) == 0) {
                                 /* hit */
-                                void *node = fat_node_get(parentp->dev_handle,
-                                    (fs_index_t)uint16_t_le2host(d->firstc));
+                                fat_idx_t *idx = fat_idx_map(parentp->firstc,
+                                    i * dps + j);
+                                void *node = fat_node_get(idx->dev_handle,
+                                    idx->index);
                                 block_put(b);
                                 return node;
@@ -337 +333 @@
         if (!fnodep)
                 return 0;
-        return fnodep->index;
+        return fnodep->idx->index;
 }
 
@@ -362 +358 @@
                 return false;
 
-        bps = fat_bps_get(nodep->dev_handle);
+        bps = fat_bps_get(nodep->idx->dev_handle);
         dps = bps / sizeof(fat_dentry_t);
 
@@ -371 +367 @@
                 fat_dentry_t *d;
         
-                b = fat_block_get(nodep->dev_handle, nodep->index, i);
+                b = fat_block_get(nodep, i);
                 dentries = (i == blocks - 1) ?
                     nodep->size % sizeof(fat_dentry_t) :
@@ -399 +395 @@
 static void *fat_root_get(dev_handle_t dev_handle)
 {
-        return fat_node_get(dev_handle, 0);     
+        return fat_node_get(dev_handle, FAT_CLST_RES1);
 }