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>

10 files changed, 385 insertions, 24 deletions

diff --git a/Documentation/filesystems/jfs.txt b/Documentation/filesystems/jfs.txt
index 26ebde77e821..2f94f9ca1794 100644
--- a/Documentation/filesystems/jfs.txt
+++ b/Documentation/filesystems/jfs.txt
@@ -3,6 +3,7 @@ IBM's Journaled File System (JFS) for Linux
 JFS Homepage:  http://jfs.sourceforge.net/
 
 The following mount options are supported:
+(*) == default
 
 iocharset=name  Character set to use for converting from Unicode to
                 ASCII.  The default is to do no conversion.  Use
@@ -21,12 +22,12 @@ nointegrity	Do not write to the journal.  The primary use of this option
                 from backup media.  The integrity of the volume is not
                 guaranteed if the system abnormally abends.
 
-integrity       Default.  Commit metadata changes to the journal.  Use this
-                option to remount a volume where the nointegrity option was
+integrity(*)    Commit metadata changes to the journal.  Use this option to
+                remount a volume where the nointegrity option was
                 previously specified in order to restore normal behavior.
 
 errors=continue         Keep going on a filesystem error.
-errors=remount-ro       Default. Remount the filesystem read-only on an error.
+errors=remount-ro(*)    Remount the filesystem read-only on an error.
 errors=panic            Panic and halt the machine if an error occurs.
 
 uid=value       Override on-disk uid with specified value
@@ -35,6 +36,18 @@ umask=value	Override on-disk umask with specified octal value.  For
                 directories, the execute bit will be set if the corresponding
                 read bit is set.
 
+discard=minlen  This enables/disables the use of discard/TRIM commands.
+discard         The discard/TRIM commands are sent to the underlying
+nodiscard(*)    block device when blocks are freed. This is useful for SSD
+                devices and sparse/thinly-provisioned LUNs.  The FITRIM ioctl
+                command is also available together with the nodiscard option.
+                The value of minlen specifies the minimum blockcount, when
+                a TRIM command to the block device is considered usefull.
+                When no value is given to the discard option, it defaults to
+                64 blocks, which means 256KiB in JFS.
+                The minlen value of discard overrides the minlen value given
+                on an FITRIM ioctl().
+
 Please send bugs, comments, cards and letters to shaggy@linux.vnet.ibm.com.
 
 The JFS mailing list can be subscribed to by using the link labeled
diff --git a/fs/jfs/Makefile b/fs/jfs/Makefile
index a58fa72d7e59..d20d4737b3ef 100644
--- a/fs/jfs/Makefile
+++ b/fs/jfs/Makefile
@@ -6,7 +6,7 @@ obj-$(CONFIG_JFS_FS) += jfs.o
 
 jfs-y    := super.o file.o inode.o namei.o jfs_mount.o jfs_umount.o \
             jfs_xtree.o jfs_imap.o jfs_debug.o jfs_dmap.o \
-            jfs_unicode.o jfs_dtree.o jfs_inode.o \
+            jfs_unicode.o jfs_dtree.o jfs_inode.o jfs_discard.o \
             jfs_extent.o symlink.o jfs_metapage.o \
             jfs_logmgr.o jfs_txnmgr.o jfs_uniupr.o \
             resize.o xattr.o ioctl.o
diff --git a/fs/jfs/ioctl.c b/fs/jfs/ioctl.c
index f19d1e04a374..bc555ff417e9 100644
--- a/fs/jfs/ioctl.c
+++ b/fs/jfs/ioctl.c
@@ -11,13 +11,17 @@
 #include <linux/mount.h>
 #include <linux/time.h>
 #include <linux/sched.h>
+#include <linux/blkdev.h>
 #include <asm/current.h>
 #include <asm/uaccess.h>
 
+#include "jfs_filsys.h"
+#include "jfs_debug.h"
 #include "jfs_incore.h"
 #include "jfs_dinode.h"
 #include "jfs_inode.h"
-
+#include "jfs_dmap.h"
+#include "jfs_discard.h"
 
 static struct {
         long jfs_flag;
@@ -123,6 +127,40 @@ setflags_out:
                 mnt_drop_write_file(filp);
                 return err;
         }
+
+        case FITRIM:
+        {
+                struct super_block *sb = inode->i_sb;
+                struct request_queue *q = bdev_get_queue(sb->s_bdev);
+                struct fstrim_range range;
+                s64 ret = 0;
+
+                if (!capable(CAP_SYS_ADMIN))
+                        return -EPERM;
+
+                if (!blk_queue_discard(q)) {
+                        jfs_warn("FITRIM not supported on device");
+                        return -EOPNOTSUPP;
+                }
+
+                if (copy_from_user(&range, (struct fstrim_range __user *)arg,
+                    sizeof(range)))
+                        return -EFAULT;
+
+                range.minlen = max_t(unsigned int, range.minlen,
+                        q->limits.discard_granularity);
+
+                ret = jfs_ioc_trim(inode, &range);
+                if (ret < 0)
+                        return ret;
+
+                if (copy_to_user((struct fstrim_range __user *)arg, &range,
+                    sizeof(range)))
+                        return -EFAULT;
+
+                return 0;
+        }
+
         default:
                 return -ENOTTY;
         }
@@ -142,6 +180,9 @@ long jfs_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
         case JFS_IOC_SETFLAGS32:
                 cmd = JFS_IOC_SETFLAGS;
                 break;
+        case FITRIM:
+                cmd = FITRIM;
+                break;
         }
         return jfs_ioctl(filp, cmd, arg);
 }
diff --git a/fs/jfs/jfs_discard.c b/fs/jfs/jfs_discard.c
new file mode 100644
index 000000000000..9947563e4175
--- /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
+ *