ext4_std_error(sb, err);
return;
}
+
+/**
+ * ext4_trim_extent -- function to TRIM one single free extent in the group
+ * @sb: super block for the file system
+ * @start: starting block of the free extent in the alloc. group
+ * @count: number of blocks to TRIM
+ * @group: alloc. group we are working with
+ * @e4b: ext4 buddy for the group
+ *
+ * Trim "count" blocks starting at "start" in the "group". To assure that no
+ * one will allocate those blocks, mark it as used in buddy bitmap. This must
+ * be called with under the group lock.
+ */
+static int ext4_trim_extent(struct super_block *sb, int start, int count,
+ ext4_group_t group, struct ext4_buddy *e4b)
+{
+ struct ext4_free_extent ex;
+ int ret = 0;
+
+ assert_spin_locked(ext4_group_lock_ptr(sb, group));
+
+ ex.fe_start = start;
+ ex.fe_group = group;
+ ex.fe_len = count;
+
+ /*
+ * Mark blocks used, so no one can reuse them while
+ * being trimmed.
+ */
+ mb_mark_used(e4b, &ex);
+ ext4_unlock_group(sb, group);
+
+ ret = ext4_issue_discard(sb, group, start, count);
+ if (ret)
+ ext4_std_error(sb, ret);
+
+ ext4_lock_group(sb, group);
+ mb_free_blocks(NULL, e4b, start, ex.fe_len);
+ return ret;
+}
+
+/**
+ * ext4_trim_all_free -- function to trim all free space in alloc. group
+ * @sb: super block for file system
+ * @e4b: ext4 buddy
+ * @start: first group block to examine
+ * @max: last group block to examine
+ * @minblocks: minimum extent block count
+ *
+ * ext4_trim_all_free walks through group's buddy bitmap searching for free
+ * extents. When the free block is found, ext4_trim_extent is called to TRIM
+ * the extent.
+ *
+ *
+ * ext4_trim_all_free walks through group's block bitmap searching for free
+ * extents. When the free extent is found, mark it as used in group buddy
+ * bitmap. Then issue a TRIM command on this extent and free the extent in
+ * the group buddy bitmap. This is done until whole group is scanned.
+ */
+ext4_grpblk_t ext4_trim_all_free(struct super_block *sb, struct ext4_buddy *e4b,
+ ext4_grpblk_t start, ext4_grpblk_t max, ext4_grpblk_t minblocks)
+{
+ void *bitmap;
+ ext4_grpblk_t next, count = 0;
+ ext4_group_t group;
+ int ret = 0;
+
+ BUG_ON(e4b == NULL);
+
+ bitmap = e4b->bd_bitmap;
+ group = e4b->bd_group;
+ start = (e4b->bd_info->bb_first_free > start) ?
+ e4b->bd_info->bb_first_free : start;
+ ext4_lock_group(sb, group);
+
+ while (start < max) {
+ start = mb_find_next_zero_bit(bitmap, max, start);
+ if (start >= max)
+ break;
+ next = mb_find_next_bit(bitmap, max, start);
+
+ if ((next - start) >= minblocks) {
+ ret = ext4_trim_extent(sb, start,
+ next - start, group, e4b);
+ if (ret < 0)
+ break;
+ count += next - start;
+ }
+ start = next + 1;
+
+ if (fatal_signal_pending(current)) {
+ count = -ERESTARTSYS;
+ break;
+ }
+
+ if (need_resched()) {
+ ext4_unlock_group(sb, group);
+ cond_resched();
+ ext4_lock_group(sb, group);
+ }
+
+ if ((e4b->bd_info->bb_free - count) < minblocks)
+ break;
+ }
+ ext4_unlock_group(sb, group);
+
+ ext4_debug("trimmed %d blocks in the group %d\n",
+ count, group);
+
+ if (ret < 0)
+ count = ret;
+
+ return count;
+}
+
+/**
+ * ext4_trim_fs() -- trim ioctl handle function
+ * @sb: superblock for filesystem
+ * @range: fstrim_range structure
+ *
+ * start: First Byte to trim
+ * len: number of Bytes to trim from start
+ * minlen: minimum extent length in Bytes
+ * ext4_trim_fs goes through all allocation groups containing Bytes from
+ * start to start+len. For each such a group ext4_trim_all_free function
+ * is invoked to trim all free space.
+ */
+int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
+{
+ struct ext4_buddy e4b;
+ ext4_group_t first_group, last_group;
+ ext4_group_t group, ngroups = ext4_get_groups_count(sb);
+ ext4_grpblk_t cnt = 0, first_block, last_block;
+ uint64_t start, len, minlen, trimmed;
+ int ret = 0;
+
+ start = range->start >> sb->s_blocksize_bits;
+ len = range->len >> sb->s_blocksize_bits;
+ minlen = range->minlen >> sb->s_blocksize_bits;
+ trimmed = 0;
+
+ if (unlikely(minlen > EXT4_BLOCKS_PER_GROUP(sb)))
+ return -EINVAL;
+
+ /* Determine first and last group to examine based on start and len */
+ ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) start,
+ &first_group, &first_block);
+ ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) (start + len),
+ &last_group, &last_block);
+ last_group = (last_group > ngroups - 1) ? ngroups - 1 : last_group;
+ last_block = EXT4_BLOCKS_PER_GROUP(sb);
+
+ if (first_group > last_group)
+ return -EINVAL;
+
+ for (group = first_group; group <= last_group; group++) {
+ ret = ext4_mb_load_buddy(sb, group, &e4b);
+ if (ret) {
+ ext4_error(sb, "Error in loading buddy "
+ "information for %u", group);
+ break;
+ }
+
+ if (len >= EXT4_BLOCKS_PER_GROUP(sb))
+ len -= (EXT4_BLOCKS_PER_GROUP(sb) - first_block);
+ else
+ last_block = len;
+
+ if (e4b.bd_info->bb_free >= minlen) {
+ cnt = ext4_trim_all_free(sb, &e4b, first_block,
+ last_block, minlen);
+ if (cnt < 0) {
+ ret = cnt;
+ ext4_mb_unload_buddy(&e4b);
+ break;
+ }
+ }
+ ext4_mb_unload_buddy(&e4b);
+ trimmed += cnt;
+ first_block = 0;
+ }
+ range->len = trimmed * sb->s_blocksize;
+
+ return ret;
+}
projects / mv-sheeva.git / commitdiff