fs/jfs: TRIM support for JFS Filesystem
This patch adds support for the two linux interfaces of the discard/TRIM
command for SSD devices and sparse/thinly-provisioned LUNs.
JFS will support batched discard via FITRIM ioctl and online discard
with the discard mount option.
Signed-off-by: Tino Reichardt <list-jfs@mcmilk.de>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
diff --git a/fs/jfs/jfs_discard.c b/fs/jfs/jfs_discard.c
new file mode 100644
index 0000000..9947563
--- /dev/null
+++ b/fs/jfs/jfs_discard.c
@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) Tino Reichardt, 2012
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+ * the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/blkdev.h>
+
+#include "jfs_incore.h"
+#include "jfs_superblock.h"
+#include "jfs_discard.h"
+#include "jfs_dmap.h"
+#include "jfs_debug.h"
+
+
+/*
+ * NAME: jfs_issue_discard()
+ *
+ * FUNCTION: TRIM the specified block range on device, if supported
+ *
+ * PARAMETERS:
+ * ip - pointer to in-core inode
+ * blkno - starting block number to be trimmed (0..N)
+ * nblocks - number of blocks to be trimmed
+ *
+ * RETURN VALUES:
+ * none
+ *
+ * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
+ */
+void jfs_issue_discard(struct inode *ip, u64 blkno, u64 nblocks)
+{
+ struct super_block *sb = ip->i_sb;
+ int r = 0;
+
+ r = sb_issue_discard(sb, blkno, nblocks, GFP_NOFS, 0);
+ if (unlikely(r != 0)) {
+ jfs_err("JFS: sb_issue_discard" \
+ "(%p, %llu, %llu, GFP_NOFS, 0) = %d => failed!\n",
+ sb, (unsigned long long)blkno,
+ (unsigned long long)nblocks, r);
+ }
+
+ jfs_info("JFS: sb_issue_discard" \
+ "(%p, %llu, %llu, GFP_NOFS, 0) = %d\n",
+ sb, (unsigned long long)blkno,
+ (unsigned long long)nblocks, r);
+
+ return;
+}
+
+/*
+ * NAME: jfs_ioc_trim()
+ *
+ * FUNCTION: attempt to discard (TRIM) all free blocks from the
+ * filesystem.
+ *
+ * PARAMETERS:
+ * ip - pointer to in-core inode;
+ * range - the range, given by user space
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * -EIO - i/o error
+ */
+int jfs_ioc_trim(struct inode *ip, struct fstrim_range *range)
+{
+ struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
+ struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
+ struct super_block *sb = ipbmap->i_sb;
+ int agno, agno_end;
+ s64 start, end, minlen;
+ u64 trimmed = 0;
+
+ /**
+ * convert byte values to block size of filesystem:
+ * start: First Byte to trim
+ * len: number of Bytes to trim from start
+ * minlen: minimum extent length in Bytes
+ */
+ start = range->start >> sb->s_blocksize_bits;
+ if (start < 0)
+ start = 0;
+ end = start + (range->len >> sb->s_blocksize_bits) - 1;
+ if (end >= bmp->db_mapsize)
+ end = bmp->db_mapsize - 1;
+ minlen = range->minlen >> sb->s_blocksize_bits;
+ if (minlen <= 0)
+ minlen = 1;
+
+ /**
+ * we trim all ag's within the range
+ */
+ agno = BLKTOAG(start, JFS_SBI(ip->i_sb));
+ agno_end = BLKTOAG(end, JFS_SBI(ip->i_sb));
+ while (agno <= agno_end) {
+ trimmed += dbDiscardAG(ip, agno, minlen);
+ agno++;
+ }
+ range->len = trimmed << sb->s_blocksize_bits;
+
+ return 0;
+}
