Changeset a8c14aa in mainline for uspace/srv/fs/fat/fat_fat.c

Timestamp:

2011-05-02T10:17:33Z (13 years ago)

Author:

Oleg Romanenko <romanenko.oleg@…>

Branches:

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

Children:

88a27f1

Parents:

979c313a

Message:

Initial support for writing on FAT32. fat_get_cluster correctly store info
in FAT. But I leave FSInfo sector unmodified because it is not necessary
to store free sectors count in it.

File:

• uspace/srv/fs/fat/fat_fat.c (modified) (2 diffs)

uspace/srv/fs/fat/fat_fat.c

@@ -380 +380 @@
     fat_cluster_t clst, fat_cluster_t value)
 {
-        block_t *b, *b1;
+        block_t *b, *b1=NULL;
         aoff64_t offset;
-        fat_cluster_t *cp, temp;
-        int rc;
-        int spans = 0;
+        int rc;
 
         assert(fatno < FATCNT(bs));
@@ -398 +396 @@
                 return rc;
 
-        /* This cluster access spans a sector boundary. Check only for FAT12 */
-        if (FAT_IS_FAT12(bs) && (offset % BPS(bs)+1 == BPS(bs))) {
-                /* Is it last sector of FAT? */
-                if (offset / BPS(bs) < SF(bs)) {
-                        /* No. Reading next sector */
-                        rc = block_get(&b1, devmap_handle, 1 + RSCNT(bs) +
-                            SF(bs)*fatno + offset / BPS(bs), BLOCK_FLAGS_NONE);
-                        if (rc != EOK) {
+        value = host2uint32_t_le(value);
+
+        if (FAT_IS_FAT12(bs)) {
+                uint16_t temp;
+                bool border = false;
+                /* This cluster access spans a sector boundary. Check only for FAT12 */
+                if (offset % BPS(bs)+1 == BPS(bs)) {
+                        /* Is it last sector of FAT? */
+                        if (offset / BPS(bs) < SF(bs)) {
+                                /* No. Reading next sector */
+                                rc = block_get(&b1, devmap_handle, 1 + RSCNT(bs) +
+                                        SF(bs)*fatno + offset / BPS(bs), BLOCK_FLAGS_NONE);
+                                if (rc != EOK) {
+                                        block_put(b);
+                                        return rc;
+                                }
+                                /*
+                                * Combining value with last byte of current sector and
+                                * first byte of next sector
+                                */
+                                temp  = *(uint8_t *)(b->data + BPS(bs) - 1);
+                                temp |= *(uint8_t *)(b1->data) << 8;
+                                border = true;
+                        }
+                        else {
+                                /* Yes. It is last sector of fat */
                                 block_put(b);
-                                return rc;
+                                return ERANGE;
                         }
-                        /*
-                         * Combining value with last byte of current sector and
-                         * first byte of next sector
-                         */
-                        spans=1;
-                        cp = &temp;
-                        *cp  = *(uint8_t *)(b->data + BPS(bs) - 1);
-                        *cp |= *(uint8_t *)(b1->data);
+                }
+                else
+                        temp = *(uint16_t *)(b->data + offset % BPS(bs));
+
+                if (IS_ODD(clst)) {
+                        temp &= 0x000f;
+                        temp |= value << 4;
                 }
                 else {
-                        /* Yes. It is last sector of fat */
+                        temp &= 0xf000;
+                        temp |= value & FAT12_MASK;
+                }
+
+                if (border) {
+                        *(uint8_t *)(b->data + BPS(bs) - 1) = temp & 0xff;
+                        *(uint8_t *)(b1->data) = temp >> 8;
+                        b1->dirty = true;
+                } else
+                        *(uint16_t *)(b->data + offset % BPS(bs)) = temp;
+        }
+        else {
+                if (FAT_IS_FAT32(bs)) {
+                        *(uint32_t *)(b->data + offset % BPS(bs)) &= 0xf0000000;
+                        *(uint32_t *)(b->data + offset % BPS(bs)) |= (value & FAT32_MASK);
+                } else
+                        *(uint16_t *)(b->data + offset % BPS(bs)) = value;
+        }
+
+        if (b1 && b1->dirty) {
+                rc = block_put(b1);
+                if (rc != EOK) {
                         block_put(b);
-                        return ERANGE;
-                }
-        }
-        else
-                cp = (fat_cluster_t *)(b->data + offset % BPS(bs));
-
-        value = host2uint16_t_le(value);
-        if (FAT_IS_FAT12(bs)) {
-                if (clst & 0x0001) {
-                        *cp &= 0x000f;
-                        *cp |= value << 4;
-                }
-                else {
-                        *cp &= 0xf000;
-                        *cp |= value & 0x0fff;
-                }
-
-                if (spans)
-                {
-                        *(uint8_t *)(b->data + BPS(bs) - 1) = cp[0];
-                        *(uint8_t *)(b1->data) = cp[1];
-
-                        b1->dirty = true;
-                        rc = block_put(b1);
-                        if (rc != EOK) {
-                                block_put(b);
-                                return rc;
-                        }
-                }
-        }
-        else
-                *cp = value;
+                        return rc;
+                }
+        }
 
         b->dirty = true;        /* need to sync block */