Changes in uspace/srv/fs/fat/fat_fat.c [3f93cdbe:991f645] in mainline

File:

• uspace/srv/fs/fat/fat_fat.c (modified) (34 diffs)

uspace/srv/fs/fat/fat_fat.c

@@ -49 +49 @@
 #include <mem.h>
 
+/*
+ * Convenience macros for computing some frequently used values from the
+ * primitive boot sector members.
+ */
+#define RDS(bs)         ((sizeof(fat_dentry_t) * RDE((bs))) / BPS((bs))) + \
+                        (((sizeof(fat_dentry_t) * RDE((bs))) % BPS((bs))) != 0)
+#define SSA(bs)         (RSCNT((bs)) + FATCNT((bs)) * SF((bs)) + RDS(bs))
+
+#define CLBN2PBN(bs, cl, bn) \
+        (SSA((bs)) + ((cl) - FAT_CLST_FIRST) * SPC((bs)) + (bn) % SPC((bs)))
+
 /**
  * The fat_alloc_lock mutex protects all copies of the File Allocation Table
@@ -59 +70 @@
  *
  * @param bs            Buffer holding the boot sector for the file.
- * @param dev_handle    Device handle of the device with the file.
+ * @param devmap_handle Device handle of the device with the file.
  * @param firstc        First cluster to start the walk with.
  * @param lastc         If non-NULL, output argument hodling the last cluster
@@ -70 +81 @@
  */
 int 
-fat_cluster_walk(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc,
+fat_cluster_walk(fat_bs_t *bs, devmap_handle_t devmap_handle, fat_cluster_t firstc,
     fat_cluster_t *lastc, uint16_t *numc, uint16_t max_clusters)
 {
         block_t *b;
-        unsigned bps;
-        unsigned rscnt;         /* block address of the first FAT */
         uint16_t clusters = 0;
         fat_cluster_t clst = firstc;
         int rc;
-
-        bps = uint16_t_le2host(bs->bps);
-        rscnt = uint16_t_le2host(bs->rscnt);
 
         if (firstc == FAT_CLST_RES0) {
@@ -93 +99 @@
 
         while (clst < FAT_CLST_LAST1 && clusters < max_clusters) {
-                bn_t fsec;      /* sector offset relative to FAT1 */
+                aoff64_t fsec;  /* sector offset relative to FAT1 */
                 unsigned fidx;  /* FAT1 entry index */
 
@@ -99 +105 @@
                 if (lastc)
                         *lastc = clst;  /* remember the last cluster number */
-                fsec = (clst * sizeof(fat_cluster_t)) / bps;
-                fidx = clst % (bps / sizeof(fat_cluster_t));
+                fsec = (clst * sizeof(fat_cluster_t)) / BPS(bs);
+                fidx = clst % (BPS(bs) / sizeof(fat_cluster_t));
                 /* read FAT1 */
-                rc = block_get(&b, dev_handle, rscnt + fsec, BLOCK_FLAGS_NONE);
+                rc = block_get(&b, devmap_handle, RSCNT(bs) + fsec,
+                    BLOCK_FLAGS_NONE);
                 if (rc != EOK)
                         return rc;
@@ -125 +132 @@
  * @param block         Pointer to a block pointer for storing result.
  * @param bs            Buffer holding the boot sector of the file system.
- * @param dev_handle    Device handle of the file system.
- * @param firstc        First cluster used by the file. Can be zero if the file
- *                      is empty.
+ * @param nodep         FAT node.
  * @param bn            Block number.
  * @param flags         Flags passed to libblock.
@@ -134 +139 @@
  */
 int
-_fat_block_get(block_t **block, fat_bs_t *bs, dev_handle_t dev_handle,
-    fat_cluster_t firstc, bn_t bn, int flags)
-{
-        unsigned bps;
-        unsigned rscnt;         /* block address of the first FAT */
-        unsigned rde;
-        unsigned rds;           /* root directory size */
-        unsigned sf;
-        unsigned ssa;           /* size of the system area */
+fat_block_get(block_t **block, struct fat_bs *bs, fat_node_t *nodep,
+    aoff64_t bn, int flags)
+{
+        fat_cluster_t firstc = nodep->firstc;
+        fat_cluster_t currc;
+        aoff64_t relbn = bn;
+        int rc;
+
+        if (!nodep->size)
+                return ELIMIT;
+
+        if (nodep->firstc == FAT_CLST_ROOT) 
+                goto fall_through;
+
+        if (((((nodep->size - 1) / BPS(bs)) / SPC(bs)) == bn / SPC(bs)) &&
+            nodep->lastc_cached_valid) {
+                /*
+                 * This is a request to read a block within the last cluster
+                 * when fortunately we have the last cluster number cached.
+                 */
+                return block_get(block, nodep->idx->devmap_handle,
+                    CLBN2PBN(bs, nodep->lastc_cached_value, bn), flags);
+        }
+
+        if (nodep->currc_cached_valid && bn >= nodep->currc_cached_bn) {
+                /*
+                 * We can start with the cluster cached by the previous call to
+                 * fat_block_get().
+                 */
+                firstc = nodep->currc_cached_value;
+                relbn -= (nodep->currc_cached_bn / SPC(bs)) * SPC(bs);
+        }
+
+fall_through:
+        rc = _fat_block_get(block, bs, nodep->idx->devmap_handle, firstc,
+            &currc, relbn, flags);
+        if (rc != EOK)
+                return rc;
+        
+        /*
+         * Update the "current" cluster cache.
+         */
+        nodep->currc_cached_valid = true;
+        nodep->currc_cached_bn = bn;
+        nodep->currc_cached_value = currc;
+
+        return rc;
+}
+
+/** Read block from file located on a FAT file system.
+ *
+ * @param block         Pointer to a block pointer for storing result.
+ * @param bs            Buffer holding the boot sector of the file system.
+ * @param devmap_handle Device handle of the file system.
+ * @param fcl           First cluster used by the file. Can be zero if the file
+ *                      is empty.
+ * @param clp           If not NULL, address where the cluster containing bn
+ *                      will be stored.
+ *                      stored 
+ * @param bn            Block number.
+ * @param flags         Flags passed to libblock.
+ *
+ * @return              EOK on success or a negative error code.
+ */
+int
+_fat_block_get(block_t **block, fat_bs_t *bs, devmap_handle_t devmap_handle,
+    fat_cluster_t fcl, fat_cluster_t *clp, aoff64_t bn, int flags)
+{
         uint16_t clusters;
         unsigned max_clusters;
-        fat_cluster_t lastc;
-        int rc;
-
-        bps = uint16_t_le2host(bs->bps);
-        rscnt = uint16_t_le2host(bs->rscnt);
-        rde = uint16_t_le2host(bs->root_ent_max);
-        sf = uint16_t_le2host(bs->sec_per_fat);
-
-        rds = (sizeof(fat_dentry_t) * rde) / bps;
-        rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);
-        ssa = rscnt + bs->fatcnt * sf + rds;
-
-        if (firstc == FAT_CLST_ROOT) {
+        fat_cluster_t c;
+        int rc;
+
+        /*
+         * This function can only operate on non-zero length files.
+         */
+        if (fcl == FAT_CLST_RES0)
+                return ELIMIT;
+
+        if (fcl == FAT_CLST_ROOT) {
                 /* root directory special case */
-                assert(bn < rds);
-                rc = block_get(block, dev_handle, rscnt + bs->fatcnt * sf + bn,
-                    flags);
+                assert(bn < RDS(bs));
+                rc = block_get(block, devmap_handle,
+                    RSCNT(bs) + FATCNT(bs) * SF(bs) + bn, flags);
                 return rc;
         }
 
-        max_clusters = bn / bs->spc;
-        rc = fat_cluster_walk(bs, dev_handle, firstc, &lastc, &clusters,
-            max_clusters);
+        max_clusters = bn / SPC(bs);
+        rc = fat_cluster_walk(bs, devmap_handle, fcl, &c, &clusters, max_clusters);
         if (rc != EOK)
                 return rc;
         assert(clusters == max_clusters);
 
-        rc = block_get(block, dev_handle,
-            ssa + (lastc - FAT_CLST_FIRST) * bs->spc + bn % bs->spc, flags);
+        rc = block_get(block, devmap_handle, CLBN2PBN(bs, c, bn), flags);
+
+        if (clp)
+                *clp = c;
 
         return rc;
@@ -190 +252 @@
  * @return              EOK on success or a negative error code.
  */
-int fat_fill_gap(fat_bs_t *bs, fat_node_t *nodep, fat_cluster_t mcl, off_t pos)
-{
-        uint16_t bps;
-        unsigned spc;
+int fat_fill_gap(fat_bs_t *bs, fat_node_t *nodep, fat_cluster_t mcl, aoff64_t pos)
+{
         block_t *b;
-        off_t o, boundary;
-        int rc;
-
-        bps = uint16_t_le2host(bs->bps);
-        spc = bs->spc;
-        
-        boundary = ROUND_UP(nodep->size, bps * spc);
+        aoff64_t o, boundary;
+        int rc;
+
+        boundary = ROUND_UP(nodep->size, BPS(bs) * SPC(bs));
 
         /* zero out already allocated space */
         for (o = nodep->size; o < pos && o < boundary;
-            o = ALIGN_DOWN(o + bps, bps)) {
-                int flags = (o % bps == 0) ?
+            o = ALIGN_DOWN(o + BPS(bs), BPS(bs))) {
+                int flags = (o % BPS(bs) == 0) ?
                     BLOCK_FLAGS_NOREAD : BLOCK_FLAGS_NONE;
-                rc = fat_block_get(&b, bs, nodep, o / bps, flags);
-                if (rc != EOK)
-                        return rc;
-                memset(b->data + o % bps, 0, bps - o % bps);
+                rc = fat_block_get(&b, bs, nodep, o / BPS(bs), flags);
+                if (rc != EOK)
+                        return rc;
+                memset(b->data + o % BPS(bs), 0, BPS(bs) - o % BPS(bs));
                 b->dirty = true;                /* need to sync node */
                 rc = block_put(b);
@@ -222 +279 @@
         
         /* zero out the initial part of the new cluster chain */
-        for (o = boundary; o < pos; o += bps) {
-                rc = _fat_block_get(&b, bs, nodep->idx->dev_handle, mcl,
-                    (o - boundary) / bps, BLOCK_FLAGS_NOREAD);
-                if (rc != EOK)
-                        return rc;
-                memset(b->data, 0, min(bps, pos - o));
+        for (o = boundary; o < pos; o += BPS(bs)) {
+                rc = _fat_block_get(&b, bs, nodep->idx->devmap_handle, mcl,
+                    NULL, (o - boundary) / BPS(bs), BLOCK_FLAGS_NOREAD);
+                if (rc != EOK)
+                        return rc;
+                memset(b->data, 0, min(BPS(bs), pos - o));
                 b->dirty = true;                /* need to sync node */
                 rc = block_put(b);
@@ -240 +297 @@
  *
  * @param bs            Buffer holding the boot sector for the file system.
- * @param dev_handle    Device handle for the file system.
+ * @param devmap_handle Device handle for the file system.
  * @param clst          Cluster which to get.
  * @param value         Output argument holding the value of the cluster.
@@ -247 +304 @@
  */
 int
-fat_get_cluster(fat_bs_t *bs, dev_handle_t dev_handle, unsigned fatno,
+fat_get_cluster(fat_bs_t *bs, devmap_handle_t devmap_handle, unsigned fatno,
     fat_cluster_t clst, fat_cluster_t *value)
 {
         block_t *b;
-        uint16_t bps;
-        uint16_t rscnt;
-        uint16_t sf;
         fat_cluster_t *cp;
         int rc;
 
-        bps = uint16_t_le2host(bs->bps);
-        rscnt = uint16_t_le2host(bs->rscnt);
-        sf = uint16_t_le2host(bs->sec_per_fat);
-
-        rc = block_get(&b, dev_handle, rscnt + sf * fatno +
-            (clst * sizeof(fat_cluster_t)) / bps, BLOCK_FLAGS_NONE);
+        rc = block_get(&b, devmap_handle, RSCNT(bs) + SF(bs) * fatno +
+            (clst * sizeof(fat_cluster_t)) / BPS(bs), BLOCK_FLAGS_NONE);
         if (rc != EOK)
                 return rc;
-        cp = (fat_cluster_t *)b->data + clst % (bps / sizeof(fat_cluster_t));
+        cp = (fat_cluster_t *)b->data +
+            clst % (BPS(bs) / sizeof(fat_cluster_t));
         *value = uint16_t_le2host(*cp);
         rc = block_put(b);
@@ -275 +326 @@
  *
  * @param bs            Buffer holding the boot sector for the file system.
- * @param dev_handle    Device handle for the file system.
+ * @param devmap_handle Device handle for the file system.
  * @param fatno         Number of the FAT instance where to make the change.
  * @param clst          Cluster which is to be set.
@@ -283 +334 @@
  */
 int
-fat_set_cluster(fat_bs_t *bs, dev_handle_t dev_handle, unsigned fatno,
+fat_set_cluster(fat_bs_t *bs, devmap_handle_t devmap_handle, unsigned fatno,
     fat_cluster_t clst, fat_cluster_t value)
 {
         block_t *b;
-        uint16_t bps;
-        uint16_t rscnt;
-        uint16_t sf;
         fat_cluster_t *cp;
         int rc;
 
-        bps = uint16_t_le2host(bs->bps);
-        rscnt = uint16_t_le2host(bs->rscnt);
-        sf = uint16_t_le2host(bs->sec_per_fat);
-
-        assert(fatno < bs->fatcnt);
-        rc = block_get(&b, dev_handle, rscnt + sf * fatno +
-            (clst * sizeof(fat_cluster_t)) / bps, BLOCK_FLAGS_NONE);
+        assert(fatno < FATCNT(bs));
+        rc = block_get(&b, devmap_handle, RSCNT(bs) + SF(bs) * fatno +
+            (clst * sizeof(fat_cluster_t)) / BPS(bs), BLOCK_FLAGS_NONE);
         if (rc != EOK)
                 return rc;
-        cp = (fat_cluster_t *)b->data + clst % (bps / sizeof(fat_cluster_t));
+        cp = (fat_cluster_t *)b->data +
+            clst % (BPS(bs) / sizeof(fat_cluster_t));
         *cp = host2uint16_t_le(value);
         b->dirty = true;                /* need to sync block */
@@ -312 +357 @@
  *
  * @param bs            Buffer holding the boot sector of the file system.
- * @param dev_handle    Device handle of the file system.
+ * @param devmap_handle Device handle of the file system.
  * @param lifo          Chain of allocated clusters.
  * @param nclsts        Number of clusters in the lifo chain.
@@ -318 +363 @@
  * @return              EOK on success or a negative error code.
  */
-int fat_alloc_shadow_clusters(fat_bs_t *bs, dev_handle_t dev_handle,
+int fat_alloc_shadow_clusters(fat_bs_t *bs, devmap_handle_t devmap_handle,
     fat_cluster_t *lifo, unsigned nclsts)
 {
@@ -327 +372 @@
         for (fatno = FAT1 + 1; fatno < bs->fatcnt; fatno++) {
                 for (c = 0; c < nclsts; c++) {
-                        rc = fat_set_cluster(bs, dev_handle, fatno, lifo[c],
+                        rc = fat_set_cluster(bs, devmap_handle, fatno, lifo[c],
                             c == 0 ? FAT_CLST_LAST1 : lifo[c - 1]);
                         if (rc != EOK)
@@ -345 +390 @@
  *
  * @param bs            Buffer holding the boot sector of the file system.
- * @param dev_handle    Device handle of the file system.
+ * @param devmap_handle Device handle of the file system.
  * @param nclsts        Number of clusters to allocate.
  * @param mcl           Output parameter where the first cluster in the chain
@@ -355 +400 @@
  */
 int
-fat_alloc_clusters(fat_bs_t *bs, dev_handle_t dev_handle, unsigned nclsts,
+fat_alloc_clusters(fat_bs_t *bs, devmap_handle_t devmap_handle, unsigned nclsts,
     fat_cluster_t *mcl, fat_cluster_t *lcl)
 {
-        uint16_t bps;
-        uint16_t rscnt;
-        uint16_t sf;
-        uint32_t ts;
-        unsigned rde;
-        unsigned rds;
-        unsigned ssa;
         block_t *blk;
         fat_cluster_t *lifo;    /* stack for storing free cluster numbers */ 
@@ -374 +412 @@
         if (!lifo)
                 return ENOMEM;
-        
-        bps = uint16_t_le2host(bs->bps);
-        rscnt = uint16_t_le2host(bs->rscnt);
-        sf = uint16_t_le2host(bs->sec_per_fat);
-        rde = uint16_t_le2host(bs->root_ent_max);
-        ts = (uint32_t) uint16_t_le2host(bs->totsec16);
-        if (ts == 0)
-                ts = uint32_t_le2host(bs->totsec32);
-
-        rds = (sizeof(fat_dentry_t) * rde) / bps;
-        rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);
-        ssa = rscnt + bs->fatcnt * sf + rds;
         
         /*
@@ -391 +417 @@
          */
         fibril_mutex_lock(&fat_alloc_lock);
-        for (b = 0, cl = 0; b < sf; b++) {
-                rc = block_get(&blk, dev_handle, rscnt + b, BLOCK_FLAGS_NONE);
+        for (b = 0, cl = 0; b < SF(bs); b++) {
+                rc = block_get(&blk, devmap_handle, RSCNT(bs) + b,
+                    BLOCK_FLAGS_NONE);
                 if (rc != EOK)
                         goto error;
-                for (c = 0; c < bps / sizeof(fat_cluster_t); c++, cl++) {
+                for (c = 0; c < BPS(bs) / 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.
+                         * Check if the entire 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
+                         * or when the last cluster ends beyond the end of the
+                         * device.
                          */
-                        if ((cl >= 2) && ((cl - 2) * bs->spc + ssa >= ts)) {
+                        if ((cl >= FAT_CLST_FIRST) &&
+                            CLBN2PBN(bs, cl, SPC(bs) - 1) >= TS(bs)) {
                                 rc = block_put(blk);
                                 if (rc != EOK)
@@ -427 +457 @@
                                         /* update the shadow copies of FAT */
                                         rc = fat_alloc_shadow_clusters(bs,
-                                            dev_handle, lifo, nclsts);
+                                            devmap_handle, lifo, nclsts);
                                         if (rc != EOK)
                                                 goto error;
@@ -454 +484 @@
          */
         while (found--) {
-                rc = fat_set_cluster(bs, dev_handle, FAT1, lifo[found],
+                rc = fat_set_cluster(bs, devmap_handle, FAT1, lifo[found],
                     FAT_CLST_RES0);
                 if (rc != EOK) {
@@ -469 +499 @@
  *
  * @param bs            Buffer hodling the boot sector of the file system.
- * @param dev_handle    Device handle of the file system.
+ * @param devmap_handle Device handle of the file system.
  * @param firstc        First cluster in the chain which is to be freed.
  *
@@ -475 +505 @@
  */
 int
-fat_free_clusters(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc)
+fat_free_clusters(fat_bs_t *bs, devmap_handle_t devmap_handle, fat_cluster_t firstc)
 {
         unsigned fatno;
@@ -484 +514 @@
         while (firstc < FAT_CLST_LAST1) {
                 assert(firstc >= FAT_CLST_FIRST && firstc < FAT_CLST_BAD);
-                rc = fat_get_cluster(bs, dev_handle, FAT1, firstc, &nextc);
+                rc = fat_get_cluster(bs, devmap_handle, FAT1, firstc, &nextc);
                 if (rc != EOK)
                         return rc;
                 for (fatno = FAT1; fatno < bs->fatcnt; fatno++) {
-                        rc = fat_set_cluster(bs, dev_handle, fatno, firstc,
+                        rc = fat_set_cluster(bs, devmap_handle, fatno, firstc,
                             FAT_CLST_RES0);
                         if (rc != EOK)
@@ -505 +535 @@
  * @param nodep         Node representing the file.
  * @param mcl           First cluster of the cluster chain to append.
+ * @param lcl           Last cluster of the cluster chain to append.
  *
  * @return              EOK on success or a negative error code.
  */
-int fat_append_clusters(fat_bs_t *bs, fat_node_t *nodep, fat_cluster_t mcl)
-{
-        dev_handle_t dev_handle = nodep->idx->dev_handle;
-        fat_cluster_t lcl;
-        uint16_t numc;
+int
+fat_append_clusters(fat_bs_t *bs, fat_node_t *nodep, fat_cluster_t mcl,
+    fat_cluster_t lcl)
+{
+        devmap_handle_t devmap_handle = nodep->idx->devmap_handle;
+        fat_cluster_t lastc;
         uint8_t fatno;
         int rc;
 
-        rc = fat_cluster_walk(bs, dev_handle, nodep->firstc, &lcl, &numc,
-            (uint16_t) -1);
-        if (rc != EOK)
-                return rc;
-
-        if (numc == 0) {
+        if (nodep->firstc == FAT_CLST_RES0) {
                 /* No clusters allocated to the node yet. */
                 nodep->firstc = mcl;
-                nodep->dirty = true;            /* need to sync node */
-                return EOK;
-        }
-
-        for (fatno = FAT1; fatno < bs->fatcnt; fatno++) {
-                rc = fat_set_cluster(bs, nodep->idx->dev_handle, fatno, lcl,
-                    mcl);
-                if (rc != EOK)
-                        return rc;
-        }
+                nodep->dirty = true;    /* need to sync node */
+        } else {
+                if (nodep->lastc_cached_valid) {
+                        lastc = nodep->lastc_cached_value;
+                        nodep->lastc_cached_valid = false;
+                } else {
+                        rc = fat_cluster_walk(bs, devmap_handle, nodep->firstc,
+                            &lastc, NULL, (uint16_t) -1);
+                        if (rc != EOK)
+                                return rc;
+                }
+
+                for (fatno = FAT1; fatno < bs->fatcnt; fatno++) {
+                        rc = fat_set_cluster(bs, nodep->idx->devmap_handle, fatno,
+                            lastc, mcl);
+                        if (rc != EOK)
+                                return rc;
+                }
+        }
+
+        nodep->lastc_cached_valid = true;
+        nodep->lastc_cached_value = lcl;
 
         return EOK;
@@ -542 +581 @@
  * @param bs            Buffer holding the boot sector of the file system.
  * @param nodep         FAT node where the chopping will take place.
- * @param lastc         Last cluster which will remain in the node. If this
+ * @param lcl           Last cluster which will remain in the node. If this
  *                      argument is FAT_CLST_RES0, then all clusters will
  *                      be chopped off.
@@ -548 +587 @@
  * @return              EOK on success or a negative return code.
  */
-int fat_chop_clusters(fat_bs_t *bs, fat_node_t *nodep, fat_cluster_t lastc)
-{
-        int rc;
-
-        dev_handle_t dev_handle = nodep->idx->dev_handle;
-        if (lastc == FAT_CLST_RES0) {
+int fat_chop_clusters(fat_bs_t *bs, fat_node_t *nodep, fat_cluster_t lcl)
+{
+        int rc;
+        devmap_handle_t devmap_handle = nodep->idx->devmap_handle;
+
+        /*
+         * Invalidate cached cluster numbers.
+         */
+        nodep->lastc_cached_valid = false;
+        if (nodep->currc_cached_value != lcl)
+                nodep->currc_cached_valid = false;
+
+        if (lcl == FAT_CLST_RES0) {
                 /* The node will have zero size and no clusters allocated. */
-                rc = fat_free_clusters(bs, dev_handle, nodep->firstc);
+                rc = fat_free_clusters(bs, devmap_handle, nodep->firstc);
                 if (rc != EOK)
                         return rc;
@@ -564 +610 @@
                 unsigned fatno;
 
-                rc = fat_get_cluster(bs, dev_handle, FAT1, lastc, &nextc);
+                rc = fat_get_cluster(bs, devmap_handle, FAT1, lcl, &nextc);
                 if (rc != EOK)
                         return rc;
@@ -570 +616 @@
                 /* Terminate the cluster chain in all copies of FAT. */
                 for (fatno = FAT1; fatno < bs->fatcnt; fatno++) {
-                        rc = fat_set_cluster(bs, dev_handle, fatno, lastc,
+                        rc = fat_set_cluster(bs, devmap_handle, fatno, lcl,
                             FAT_CLST_LAST1);
                         if (rc != EOK)
@@ -577 +623 @@
 
                 /* Free all following clusters. */
-                rc = fat_free_clusters(bs, dev_handle, nextc);
-                if (rc != EOK)
-                        return rc;
-        }
+                rc = fat_free_clusters(bs, devmap_handle, nextc);
+                if (rc != EOK)
+                        return rc;
+        }
+
+        /*
+         * Update and re-enable the last cluster cache.
+         */
+        nodep->lastc_cached_valid = true;
+        nodep->lastc_cached_value = lcl;
 
         return EOK;
@@ -586 +638 @@
 
 int
-fat_zero_cluster(struct fat_bs *bs, dev_handle_t dev_handle, fat_cluster_t c)
+fat_zero_cluster(struct fat_bs *bs, devmap_handle_t devmap_handle, fat_cluster_t c)
 {
         int i;
         block_t *b;
-        unsigned bps;
-        int rc;
-
-        bps = uint16_t_le2host(bs->bps);
-        
-        for (i = 0; i < bs->spc; i++) {
-                rc = _fat_block_get(&b, bs, dev_handle, c, i,
+        int rc;
+
+        for (i = 0; i < SPC(bs); i++) {
+                rc = _fat_block_get(&b, bs, devmap_handle, c, NULL, i,
                     BLOCK_FLAGS_NOREAD);
                 if (rc != EOK)
                         return rc;
-                memset(b->data, 0, bps);
+                memset(b->data, 0, BPS(bs));
                 b->dirty = true;
                 rc = block_put(b);
@@ -616 +665 @@
  * does not contain a fat file system.
  */
-int fat_sanity_check(fat_bs_t *bs, dev_handle_t dev_handle)
+int fat_sanity_check(fat_bs_t *bs, devmap_handle_t devmap_handle)
 {
         fat_cluster_t e0, e1;
@@ -657 +706 @@
 
         for (fat_no = 0; fat_no < bs->fatcnt; fat_no++) {
-                rc = fat_get_cluster(bs, dev_handle, fat_no, 0, &e0);
+                rc = fat_get_cluster(bs, devmap_handle, fat_no, 0, &e0);
                 if (rc != EOK)
                         return EIO;
 
-                rc = fat_get_cluster(bs, dev_handle, fat_no, 1, &e1);
+                rc = fat_get_cluster(bs, devmap_handle, fat_no, 1, &e1);
                 if (rc != EOK)
                         return EIO;