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
+ *
+ * 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;
+}
diff --git a/fs/jfs/jfs_discard.h b/fs/jfs/jfs_discard.h
new file mode 100644
index 000000000000..40d1ee6081a0
--- /dev/null
+++ b/fs/jfs/jfs_discard.h
@@ -0,0 +1,26 @@
+/*
+ *   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
+ */
+#ifndef _H_JFS_DISCARD
+#define _H_JFS_DISCARD
+
+struct fstrim_range;
+
+extern void jfs_issue_discard(struct inode *ip, u64 blkno, u64 nblocks);
+extern int jfs_ioc_trim(struct inode *ip, struct fstrim_range *range);
+
+#endif /* _H_JFS_DISCARD */
diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
index 9cbd11a3f804..174feb6a73c1 100644
--- a/fs/jfs/jfs_dmap.c
+++ b/fs/jfs/jfs_dmap.c
@@ -1,5 +1,6 @@
 /*
  *   Copyright (C) International Business Machines Corp., 2000-2004
+ *   Portions 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
@@ -25,6 +26,7 @@
 #include "jfs_lock.h"
 #include "jfs_metapage.h"
 #include "jfs_debug.h"
+#include "jfs_discard.h"
 
 /*
  *      SERIALIZATION of the Block Allocation Map.
@@ -104,7 +106,6 @@ static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
 static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
                       int nblocks);
 static int dbMaxBud(u8 * cp);
-s64 dbMapFileSizeToMapSize(struct inode *ipbmap);
 static int blkstol2(s64 nb);
 
 static int cntlz(u32 value);
@@ -145,7 +146,6 @@ static const s8 budtab[256] = {
         2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -1
 };
 
-
 /*
  * NAME:        dbMount()
  *
@@ -310,7 +310,6 @@ int dbSync(struct inode *ipbmap)
         return (0);
 }
 
-
 /*
  * NAME:        dbFree()
  *
@@ -337,6 +336,7 @@ int dbFree(struct inode *ip, s64 blkno, s64 nblocks)
         s64 lblkno, rem;
         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;
 
         IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
 
@@ -351,6 +351,13 @@ int dbFree(struct inode *ip, s64 blkno, s64 nblocks)
                 return -EIO;
         }
 
+        /**
+         * TRIM the blocks, when mounted with discard option
+         */
+        if (JFS_SBI(sb)->flag & JFS_DISCARD)
+                if (JFS_SBI(sb)->minblks_trim <= nblocks)
+                        jfs_issue_discard(ipbmap, blkno, nblocks);
+
         /*
          * free the blocks a dmap at a time.
          */
@@ -1095,7 +1102,6 @@ static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks)
                 /* we were not successful */
                 release_metapage(mp);
 
-
         return (rc);
 }
 
@@ -1590,6 +1596,117 @@ static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results)
 
 
 /*
+ * NAME:        dbDiscardAG()
+ *
+ * FUNCTION:    attempt to discard (TRIM) all free blocks of specific AG
+ *
+ *              algorithm:
+ *              1) allocate blocks, as large as possible and save them
+ *                 while holding IWRITE_LOCK on ipbmap
+ *              2) trim all these saved block/length values
+ *              3) mark the blocks free again
+ *
+ *              benefit:
+ *              - we work only on one ag at some time, minimizing how long we
+ *                need to lock ipbmap
+ *              - reading / writing the fs is possible most time, even on
+ *                trimming
+ *
+ *              downside:
+ *              - we write two times to the dmapctl and dmap pages
+ *              - but for me, this seems the best way, better ideas?
+ *              /TR 2012
+ *
+ * PARAMETERS:
+ *      ip      - pointer to in-core inode
+ *      agno    - ag to trim
+ *      minlen  - minimum value of contiguous blocks
+ *
+ * RETURN VALUES:
+ *      s64     - actual number of blocks trimmed
+ */
+s64 dbDiscardAG(struct inode *ip, int agno, s64 minlen)
+{
+        struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
+        struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
+        s64 nblocks, blkno;
+        u64 trimmed = 0;
+        int rc, l2nb;
+        struct super_block *sb = ipbmap->i_sb;
+
+        struct range2trim {
+                u64 blkno;
+                u64 nblocks;
+        } *totrim, *tt;
+
+        /* max blkno / nblocks pairs to trim */
+        int count = 0, range_cnt;
+
+        /* prevent others from writing new stuff here, while trimming */
+        IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
+
+        nblocks = bmp->db_agfree[agno];
+        range_cnt = nblocks;
+        do_div(range_cnt, (int)minlen);
+        range_cnt = min(range_cnt + 1, 32 * 1024);
+        totrim = kmalloc(sizeof(struct range2trim) * range_cnt, GFP_NOFS);
+        if (totrim == NULL) {
+                jfs_error(bmp->db_ipbmap->i_sb,
+                          "dbDiscardAG: no memory for trim array");
+                IWRITE_UNLOCK(ipbmap);
+                return 0;
+        }
+
+        tt = totrim;
+        while (nblocks >= minlen) {
+                l2nb = BLKSTOL2(nblocks);
+
+                /* 0 = okay, -EIO = fatal, -ENOSPC -> try smaller block */
+                rc = dbAllocAG(bmp, agno, nblocks, l2nb, &blkno);
+                if (rc == 0) {
+                        tt->blkno = blkno;
+                        tt->nblocks = nblocks;
+                        tt++; count++;
+
+                        /* the whole ag is free, trim now */
+                        if (bmp->db_agfree[agno] == 0)
+                                break;
+
+                        /* give a hint for the next while */
+                        nblocks = bmp->db_agfree[agno];
+                        continue;
+                } else if (rc == -ENOSPC) {
+                        /* search for next smaller log2 block */
+                        l2nb = BLKSTOL2(nblocks) - 1;
+                        nblocks = 1 << l2nb;
+                } else {
+                        /* Trim any already allocated blocks */
+                        jfs_error(bmp->db_ipbmap->i_sb,
+                                "dbDiscardAG: -EIO");
+                        break;
+                }
+
+                /* check, if our trim array is full */
+                if (unlikely(count >= range_cnt - 1))
+                        break;
+        }
+        IWRITE_UNLOCK(ipbmap);
+
+        tt->nblocks = 0; /* mark the current end */
+        for (tt = totrim; tt->nblocks != 0; tt++) {
+                /* when mounted with online discard, dbFree() will
+                 * call jfs_issue_discard() itself */
+                if (!(JFS_SBI(sb)->flag & JFS_DISCARD))
+                        jfs_issue_discard(ip, tt->blkno, tt->nblocks);
+                dbFree(ip, tt->blkno, tt->nblocks);
+                trimmed += tt->nblocks;
+        }
+        kfree(totrim);
+
+        return trimmed;
+}
+
+/*
  * NAME:        dbFindCtl()
  *
  * FUNCTION:    starting at a specified dmap control page level and block
diff --git a/fs/jfs/jfs_dmap.h b/fs/jfs/jfs_dmap.h
index 6dcb906c55d8..562b9a7e4311 100644
--- a/fs/jfs/jfs_dmap.h
+++ b/fs/jfs/jfs_dmap.h
@@ -311,4 +311,6 @@ extern int dbAllocBottomUp(struct inode *ip, s64 blkno, s64 nblocks);
 extern int dbExtendFS(struct inode *ipbmap, s64 blkno, s64 nblocks);
 extern void dbFinalizeBmap(struct inode *ipbmap);
 extern s64 dbMapFileSizeToMapSize(struct inode *ipbmap);
+extern s64 dbDiscardAG(struct inode *ip, int agno, s64 minlen);
+
 #endif                          /* _H_JFS_DMAP */
diff --git a/fs/jfs/jfs_filsys.h b/fs/jfs/jfs_filsys.h
index b3f5463fbe52..b67d64671bb4 100644
--- a/fs/jfs/jfs_filsys.h
+++ b/fs/jfs/jfs_filsys.h
@@ -45,6 +45,9 @@
 /* mount time flag to disable journaling to disk */
 #define JFS_NOINTEGRITY 0x00000040
 
+/* mount time flag to enable TRIM to ssd disks */
+#define JFS_DISCARD     0x00000080
+
 /* commit option */
 #define JFS_COMMIT      0x00000f00      /* commit option mask */
 #define JFS_GROUPCOMMIT 0x00000100      /* group (of 1) commit */
diff --git a/fs/jfs/jfs_incore.h b/fs/jfs/jfs_incore.h
index 584a4a1a6e81..4fa958ae1986 100644
--- a/fs/jfs/jfs_incore.h
+++ b/fs/jfs/jfs_incore.h
@@ -195,6 +195,7 @@ struct jfs_sb_info {
         uint            uid;            /* uid to override on-disk uid */
         uint            gid;            /* gid to override on-disk gid */
         uint            umask;          /* umask to override on-disk umask */
+        uint            minblks_trim;   /* minimum blocks, for online trim */
 };
 
 /* jfs_sb_info commit_state */
diff --git a/fs/jfs/super.c b/fs/jfs/super.c
index c55c7452d285..6f4ac1c070f0 100644
--- a/fs/jfs/super.c
+++ b/fs/jfs/super.c
@@ -33,6 +33,7 @@
 #include <linux/slab.h>
 #include <asm/uaccess.h>
 #include <linux/seq_file.h>
+#include <linux/blkdev.h>
 
 #include "jfs_incore.h"
 #include "jfs_filsys.h"
@@ -100,7 +101,7 @@ void jfs_error(struct super_block *sb, const char * function, ...)
         vsnprintf(error_buf, sizeof(error_buf), function, args);
         va_end(args);
 
-        printk(KERN_ERR "ERROR: (device %s): %s\n", sb->s_id, error_buf);
+        pr_err("ERROR: (device %s): %s\n", sb->s_id, error_buf);
 
         jfs_handle_error(sb);
 }
@@ -197,7 +198,8 @@ static void jfs_put_super(struct super_block *sb)
 enum {
         Opt_integrity, Opt_nointegrity, Opt_iocharset, Opt_resize,
         Opt_resize_nosize, Opt_errors, Opt_ignore, Opt_err, Opt_quota,
-        Opt_usrquota, Opt_grpquota, Opt_uid, Opt_gid, Opt_umask
+        Opt_usrquota, Opt_grpquota, Opt_uid, Opt_gid, Opt_umask,
+        Opt_discard, Opt_nodiscard, Opt_discard_minblk
 };
 
 static const match_table_t tokens = {
@@ -214,6 +216,9 @@ static const match_table_t tokens = {
         {Opt_uid, "uid=%u"},
         {Opt_gid, "gid=%u"},
         {Opt_umask, "umask=%u"},
+        {Opt_discard, "discard"},
+        {Opt_nodiscard, "nodiscard"},
+        {Opt_discard_minblk, "discard=%u"},
         {Opt_err, NULL}
 };
 
@@ -255,8 +260,7 @@ static int parse_options(char *options, struct super_block *sb, s64 *newLVSize,
                         else {
                                 nls_map = load_nls(args[0].from);
                                 if (!nls_map) {
-                                        printk(KERN_ERR
-                                               "JFS: charset not found\n");
+                                        pr_err("JFS: charset not found\n");
                                         goto cleanup;
                                 }
                         }
@@ -272,8 +276,7 @@ static int parse_options(char *options, struct super_block *sb, s64 *newLVSize,
                         *newLVSize = sb->s_bdev->bd_inode->i_size >>
                                 sb->s_blocksize_bits;
                         if (*newLVSize == 0)
-                                printk(KERN_ERR
-                                       "JFS: Cannot determine volume size\n");
+                                pr_err("JFS: Cannot determine volume size\n");
                         break;
                 }
                 case Opt_errors:
@@ -294,8 +297,7 @@ static int parse_options(char *options, struct super_block *sb, s64 *newLVSize,
                                 *flag &= ~JFS_ERR_REMOUNT_RO;
                                 *flag |= JFS_ERR_PANIC;
                         } else {
-                                printk(KERN_ERR
-                                       "JFS: %s is an invalid error handler\n",
+                                pr_err("JFS: %s is an invalid error handler\n",
                                        errors);
                                 goto cleanup;
                         }
@@ -314,8 +316,7 @@ static int parse_options(char *options, struct super_block *sb, s64 *newLVSize,
                 case Opt_usrquota:
                 case Opt_grpquota:
                 case Opt_quota:
-                        printk(KERN_ERR
-                               "JFS: quota operations not supported\n");
+                        pr_err("JFS: quota operations not supported\n");
                         break;
 #endif
                 case Opt_uid:
@@ -324,23 +325,61 @@ static int parse_options(char *options, struct super_block *sb, s64 *newLVSize,
                         sbi->uid = simple_strtoul(uid, &uid, 0);
                         break;
                 }
+
                 case Opt_gid:
                 {
                         char *gid = args[0].from;
                         sbi->gid = simple_strtoul(gid, &gid, 0);
                         break;
                 }
+
                 case Opt_umask:
                 {
                         char *umask = args[0].from;
                         sbi->umask = simple_strtoul(umask, &umask, 8);
                         if (sbi->umask & ~0777) {
-                                printk(KERN_ERR
-                                       "JFS: Invalid value of umask\n");
+                                pr_err("JFS: Invalid value of umask\n");
                                 goto cleanup;
                         }
                         break;
                 }
+
+                case Opt_discard:
+                {
+                        struct request_queue *q = bdev_get_queue(sb->s_bdev);
+                        /* if set to 1, even copying files will cause
+                         * trimming :O
+                         * -> user has more control over the online trimming
+                         */
+                        sbi->minblks_trim = 64;
+                        if (blk_queue_discard(q)) {
+                                *flag |= JFS_DISCARD;
+                        } else {
+                                pr_err("JFS: discard option " \
+                                        "not supported on device\n");
+                        }
+                        break;
+                }
+
+                case Opt_nodiscard:
+                        *flag &= ~JFS_DISCARD;
+                        break;
+
+                case Opt_discard_minblk:
+                {
+                        struct request_queue *q = bdev_get_queue(sb->s_bdev);
+                        char *minblks_trim = args[0].from;
+                        if (blk_queue_discard(q)) {
+                                *flag |= JFS_DISCARD;
+                                sbi->minblks_trim = simple_strtoull(
+                                        minblks_trim, &minblks_trim, 0);
+                        } else {
+                                pr_err("JFS: discard option " \
+                                        "not supported on device\n");
+                        }
+                        break;
+                }
+
                 default:
                         printk("jfs: Unrecognized mount option \"%s\" "
                                         " or missing value\n", p);
@@ -374,8 +413,8 @@ static int jfs_remount(struct super_block *sb, int *flags, char *data)
 
         if (newLVSize) {
                 if (sb->s_flags & MS_RDONLY) {
-                        printk(KERN_ERR
-                  "JFS: resize requires volume to be mounted read-write\n");
+                        pr_err("JFS: resize requires volume" \
+                                " to be mounted read-write\n");
                         return -EROFS;
                 }
                 rc = jfs_extendfs(sb, newLVSize, 0);
@@ -457,7 +496,7 @@ static int jfs_fill_super(struct super_block *sb, void *data, int silent)
 #endif
 
         if (newLVSize) {
-                printk(KERN_ERR "resize option for remount only\n");
+                pr_err("resize option for remount only\n");
                 goto out_kfree;
         }
 
@@ -625,6 +664,8 @@ static int jfs_show_options(struct seq_file *seq, struct dentry *root)
                 seq_printf(seq, ",umask=%03o", sbi->umask);
         if (sbi->flag & JFS_NOINTEGRITY)
                 seq_puts(seq, ",nointegrity");
+        if (sbi->flag & JFS_DISCARD)
+                seq_printf(seq, ",discard=%u", sbi->minblks_trim);
         if (sbi->nls_tab)
                 seq_printf(seq, ",iocharset=%s", sbi->nls_tab->charset);
         if (sbi->flag & JFS_ERR_CONTINUE)