1 files changed, 266 insertions, 0 deletions

diff --git a/fs/ext3/balloc.c b/fs/ext3/balloc.c
index b3db2264942..045995c8ce5 100644
--- a/fs/ext3/balloc.c
+++ b/fs/ext3/balloc.c
@@ -20,6 +20,7 @@
 #include <linux/ext3_jbd.h>
 #include <linux/quotaops.h>
 #include <linux/buffer_head.h>
+#include <linux/blkdev.h>
 
 /*
  * balloc.c contains the blocks allocation and deallocation routines
@@ -39,6 +40,21 @@
 
 #define in_range(b, first, len)	((b) >= (first) && (b) <= (first) + (len) - 1)
 
+/*
+ * Calculate the block group number and offset, given a block number
+ */
+static void ext3_get_group_no_and_offset(struct super_block *sb,
+	ext3_fsblk_t blocknr, unsigned long *blockgrpp, ext3_grpblk_t *offsetp)
+{
+	struct ext3_super_block *es = EXT3_SB(sb)->s_es;
+
+	blocknr = blocknr - le32_to_cpu(es->s_first_data_block);
+	if (offsetp)
+		*offsetp = blocknr % EXT3_BLOCKS_PER_GROUP(sb);
+	if (blockgrpp)
+		*blockgrpp = blocknr / EXT3_BLOCKS_PER_GROUP(sb);
+}
+
 /**
  * ext3_get_group_desc() -- load group descriptor from disk
  * @sb:			super block
@@ -1885,3 +1901,253 @@ unsigned long ext3_bg_num_gdb(struct super_block *sb, int group)
 	return ext3_bg_num_gdb_meta(sb,group);
 
 }
+
+/**
+ * ext3_trim_all_free -- function to trim all free space in alloc. group
+ * @sb:			super block for file system
+ * @group:		allocation group to trim
+ * @start:		first group block to examine
+ * @max:		last group block to examine
+ * @gdp:		allocation group description structure
+ * @minblocks:		minimum extent block count
+ *
+ * ext3_trim_all_free walks through group's block bitmap searching for free
+ * blocks. When the free block is found, it tries to allocate this block and
+ * consequent free block to get the biggest free extent possible, until it
+ * reaches any used block. Then issue a TRIM command on this extent and free
+ * the extent in the block bitmap. This is done until whole group is scanned.
+ */
+ext3_grpblk_t ext3_trim_all_free(struct super_block *sb, unsigned int group,
+				ext3_grpblk_t start, ext3_grpblk_t max,
+				ext3_grpblk_t minblocks)
+{
+	handle_t *handle;
+	ext3_grpblk_t next, free_blocks, bit, freed, count = 0;
+	ext3_fsblk_t discard_block;
+	struct ext3_sb_info *sbi;
+	struct buffer_head *gdp_bh, *bitmap_bh = NULL;
+	struct ext3_group_desc *gdp;
+	int err = 0, ret = 0;
+
+	/*
+	 * We will update one block bitmap, and one group descriptor
+	 */
+	handle = ext3_journal_start_sb(sb, 2);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	bitmap_bh = read_block_bitmap(sb, group);
+	if (!bitmap_bh) {
+		err = -EIO;
+		goto err_out;
+	}
+
+	BUFFER_TRACE(bitmap_bh, "getting undo access");
+	err = ext3_journal_get_undo_access(handle, bitmap_bh);
+	if (err)
+		goto err_out;
+
+	gdp = ext3_get_group_desc(sb, group, &gdp_bh);
+	if (!gdp) {
+		err = -EIO;
+		goto err_out;
+	}
+
+	BUFFER_TRACE(gdp_bh, "get_write_access");
+	err = ext3_journal_get_write_access(handle, gdp_bh);
+	if (err)
+		goto err_out;
+
+	free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
+	sbi = EXT3_SB(sb);
+
+	 /* Walk through the whole group */
+	while (start < max) {
+		start = bitmap_search_next_usable_block(start, bitmap_bh, max);
+		if (start < 0)
+			break;
+		next = start;
+
+		/*
+		 * Allocate contiguous free extents by setting bits in the
+		 * block bitmap
+		 */
+		while (next < max
+			&& claim_block(sb_bgl_lock(sbi, group),
+					next, bitmap_bh)) {
+			next++;
+		}
+
+		 /* We did not claim any blocks */
+		if (next == start)
+			continue;
+
+		discard_block = (ext3_fsblk_t)start +
+				ext3_group_first_block_no(sb, group);
+
+		/* Update counters */
+		spin_lock(sb_bgl_lock(sbi, group));
+		le16_add_cpu(&gdp->bg_free_blocks_count, start - next);
+		spin_unlock(sb_bgl_lock(sbi, group));
+		percpu_counter_sub(&sbi->s_freeblocks_counter, next - start);
+
+		/* Do not issue a TRIM on extents smaller than minblocks */
+		if ((next - start) < minblocks)
+			goto free_extent;
+
+		 /* Send the TRIM command down to the device */
+		err = sb_issue_discard(sb, discard_block, next - start,
+				       GFP_NOFS, 0);
+		count += (next - start);
+free_extent:
+		freed = 0;
+
+		/*
+		 * Clear bits in the bitmap
+		 */
+		for (bit = start; bit < next; bit++) {
+			BUFFER_TRACE(bitmap_bh, "clear bit");
+			if (!ext3_clear_bit_atomic(sb_bgl_lock(sbi, group),
+						bit, bitmap_bh->b_data)) {
+				ext3_error(sb, __func__,
+					"bit already cleared for block "E3FSBLK,
+					 (unsigned long)bit);
+				BUFFER_TRACE(bitmap_bh, "bit already cleared");
+			} else {
+				freed++;
+			}
+		}
+
+		/* Update couters */
+		spin_lock(sb_bgl_lock(sbi, group));
+		le16_add_cpu(&gdp->bg_free_blocks_count, freed);
+		spin_unlock(sb_bgl_lock(sbi, group));
+		percpu_counter_add(&sbi->s_freeblocks_counter, freed);
+
+		start = next;
+		if (err < 0) {
+			if (err != -EOPNOTSUPP)
+				ext3_warning(sb, __func__, "Discard command "
+					     "returned error %d\n", err);
+			break;
+		}
+
+		if (fatal_signal_pending(current)) {
+			err = -ERESTARTSYS;
+			break;
+		}
+
+		cond_resched();
+
+		/* No more suitable extents */
+		if ((free_blocks - count) < minblocks)
+			break;
+	}
+
+	/* We dirtied the bitmap block */
+	BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
+	ret = ext3_journal_dirty_metadata(handle, bitmap_bh);
+	if (!err)
+		err = ret;
+
+	/* And the group descriptor block */
+	BUFFER_TRACE(gdp_bh, "dirtied group descriptor block");
+	ret = ext3_journal_dirty_metadata(handle, gdp_bh);
+	if (!err)
+		err = ret;
+
+	ext3_debug("trimmed %d blocks in the group %d\n",
+		count, group);
+
+err_out:
+	if (err)
+		count = err;
+	ext3_journal_stop(handle);
+	brelse(bitmap_bh);
+
+	return count;
+}
+
+/**
+ * ext3_trim_fs() -- trim ioctl handle function
+ * @sb:			superblock for filesystem
+ * @start:		First Byte to trim
+ * @len:		number of Bytes to trim from start
+ * @minlen:		minimum extent length in Bytes
+ *
+ * ext3_trim_fs goes through all allocation groups containing Bytes from
+ * start to start+len. For each such a group ext3_trim_all_free function
+ * is invoked to trim all free space.
+ */
+int ext3_trim_fs(struct super_block *sb, struct fstrim_range *range)
+{
+	ext3_grpblk_t last_block, first_block, free_blocks;
+	unsigned long first_group, last_group;
+	unsigned long group, ngroups;
+	struct ext3_group_desc *gdp;
+	struct ext3_super_block *es = EXT3_SB(sb)->s_es;
+	uint64_t start, len, minlen, trimmed;
+	ext3_fsblk_t max_blks = le32_to_cpu(es->s_blocks_count);
+	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 > EXT3_BLOCKS_PER_GROUP(sb)))
+		return -EINVAL;
+	if (start >= max_blks)
+		goto out;
+	if (start < le32_to_cpu(es->s_first_data_block)) {
+		len -= le32_to_cpu(es->s_first_data_block) - start;
+		start = le32_to_cpu(es->s_first_data_block);
+	}
+	if (start + len > max_blks)
+		len = max_blks - start;
+
+	ngroups = EXT3_SB(sb)->s_groups_count;
+	smp_rmb();
+
+	/* Determine first and last group to examine based on start and len */
+	ext3_get_group_no_and_offset(sb, (ext3_fsblk_t) start,
+				     &first_group, &first_block);
+	ext3_get_group_no_and_offset(sb, (ext3_fsblk_t) (start + len),
+				     &last_group, &last_block);
+	last_group = (last_group > ngroups - 1) ? ngroups - 1 : last_group;
+	last_block = EXT3_BLOCKS_PER_GROUP(sb);
+
+	if (first_group > last_group)
+		return -EINVAL;
+
+	for (group = first_group; group <= last_group; group++) {
+		gdp = ext3_get_group_desc(sb, group, NULL);
+		if (!gdp)
+			break;
+
+		free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
+		if (free_blocks < minlen)
+			continue;
+
+		if (len >= EXT3_BLOCKS_PER_GROUP(sb))
+			len -= (EXT3_BLOCKS_PER_GROUP(sb) - first_block);
+		else
+			last_block = first_block + len;
+
+		ret = ext3_trim_all_free(sb, group, first_block,
+					last_block, minlen);
+		if (ret < 0)
+			break;
+
+		trimmed += ret;
+		first_block = 0;
+	}
+
+	if (ret >= 0)
+		ret = 0;
+
+out:
+	range->len = trimmed * sb->s_blocksize;
+
+	return ret;
+}