Re: [PATCH] fs/jfs: TRIM support for JFS Filesystem

From: Tino Reichardt
Date: Sat Jul 28 2012 - 07:08:15 EST

* Tino Reichardt <list-linux-fsdevel@xxxxxxxxx> wrote:
> This patch adds support for the two linux interfaces of the discard/TRIM
> command for SSD devices and sparse/thinly-provisioned LUNs.

Fixed a problem when setting minlen in jfs_ioc_trim().

Signed-off-by: Tino Reichardt <list-jfs@xxxxxxxxx>


--
regards, TR
diff -X exclude -urpN linux-git/Documentation/filesystems/jfs.txt linux_jfs-trim/Documentation/filesystems/jfs.txt
--- linux-git/Documentation/filesystems/jfs.txt 2011-03-01 10:22:59.000000000 +0100
+++ linux_jfs-trim/Documentation/filesystems/jfs.txt 2012-07-26 22:52:33.244721671 +0200
@@ -3,6 +3,7 @@ IBM's Journaled File System (JFS) for Li
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.
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
+integrity(*) Default. 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(*) Default. 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
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@xxxxxxxxxxxxxxxxxxx

The JFS mailing list can be subscribed to by using the link labeled
diff -X exclude -urpN linux-git/fs/jfs/Makefile linux_jfs-trim/fs/jfs/Makefile
--- linux-git/fs/jfs/Makefile 2011-08-17 07:31:10.000000000 +0200
+++ linux_jfs-trim/fs/jfs/Makefile 2012-07-26 22:53:48.640979880 +0200
@@ -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 -X exclude -urpN linux-git/fs/jfs/ioctl.c linux_jfs-trim/fs/jfs/ioctl.c
--- linux-git/fs/jfs/ioctl.c 2012-01-10 19:31:59.000000000 +0100
+++ linux_jfs-trim/fs/jfs/ioctl.c 2012-07-26 22:53:48.640979880 +0200
@@ -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((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,
case JFS_IOC_SETFLAGS32:
cmd = JFS_IOC_SETFLAGS;
break;
+ case FITRIM:
+ cmd = FITRIM;
+ break;
}
return jfs_ioctl(filp, cmd, arg);
}
diff -X exclude -urpN linux-git/fs/jfs/jfs_discard.c linux_jfs-trim/fs/jfs/jfs_discard.c
--- linux-git/fs/jfs/jfs_discard.c 1970-01-01 01:00:00.000000000 +0100
+++ linux_jfs-trim/fs/jfs/jfs_discard.c 2012-07-26 22:53:48.640979880 +0200
@@ -0,0 +1,119 @@
+/*
+ * 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_dmap.h"
+#include "jfs_lock.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)) {
+ printk(KERN_ERR "JFS: sb_issue_discard"
+ "(%p, %llu, %llu, GFP_NOFS, 0) = %d => failure!\n", sb,
+ (unsigned long long)blkno,
+ (unsigned long long)nblocks, r);
+ }
+
+#ifdef JFS_DEBUG_TRIM
+ printk(KERN_INFO "JFS: sb_issue_discard"
+ "(%p, %llu, %llu, GFP_NOFS, 0) = %d\n", sb,
+ (unsigned long long)blkno,
+ (unsigned long long)nblocks, r);
+#endif
+
+ 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 -X exclude -urpN linux-git/fs/jfs/jfs_discard.h linux_jfs-trim/fs/jfs/jfs_discard.h
--- linux-git/fs/jfs/jfs_discard.h 1970-01-01 01:00:00.000000000 +0100
+++ linux_jfs-trim/fs/jfs/jfs_discard.h 2012-07-26 22:53:48.640979880 +0200
@@ -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 -X exclude -urpN linux-git/fs/jfs/jfs_dmap.c linux_jfs-trim/fs/jfs/jfs_dmap.c
--- linux-git/fs/jfs/jfs_dmap.c 2011-08-17 07:31:10.000000000 +0200
+++ linux_jfs-trim/fs/jfs/jfs_dmap.c 2012-07-26 22:53:48.644313195 +0200
@@ -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,
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 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 +351,15 @@ int dbFree(struct inode *ip, s64 blkno,
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 +1104,6 @@ static int dbExtend(struct inode *ip, s6
/* we were not successful */
release_metapage(mp);

-
return (rc);
}

@@ -1590,6 +1598,117 @@ static int dbAllocAny(struct bmap * bmp,


/*
+ * NAME: dbDiscardAG()
+ *
+ * FUNCTION: attempt to discard (TRIM) all free blocks of specific AG
+ *
+ * algorithm:
+ * 1) allocate blocks, as large as possible and save them
+ * 2) trim all these saved block/length values
+ * 3) mark the blocks free again
+ *
+ * benefit:
+ * - we work only on one ag at some time, which is fully blocked
+ * - 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 = 32 * 1024;
+
+ /* prevent others from writing new stuff here, while trimming */
+ IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
+
+ /* worst value: each free block gets an entry */
+ nblocks = bmp->db_agfree[agno];
+ totrim = kmalloc(sizeof(struct range2trim) * range_cnt, GFP_NOFS);
+ if (totrim == NULL) {
+ jfs_error(bmp->db_ipbmap->i_sb,
+ "dbDiscardAG: no space for trim array");
+ IWRITE_UNLOCK(ipbmap);
+ return 0;
+ }
+
+ tt = totrim;
+ while (nblocks >= minlen) {
+ l2nb = BLKSTOL2(nblocks);
+
+ /* 0 = okay, -EIO = fatal, -ENOSPC -> block kleiner */
+ rc = dbAllocAG(bmp, agno, nblocks, l2nb, &blkno);
+ if (rc == 0) {
+ tt->blkno = blkno;
+ tt->nblocks = nblocks;
+ tt++; count++;
+
+#ifdef JFS_DEBUG_TRIM
+ printk(KERN_INFO "JFS: agno=%d/%d, blkno:%ld, nblocks=%ld\n",
+ agno+1, bmp->db_numag, (long int)blkno,
+ (long int)nblocks);
+#endif
+
+ /* 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 */
+ printk(KERN_ERR "JFS: dbDiscardAG: -EIO\n");
+ 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++) {
+ if (!(JFS_SBI(sb)->flag & JFS_DISCARD)) {
+ /* not needed, when online discard is used */
+ 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 -X exclude -urpN linux-git/fs/jfs/jfs_dmap.h linux_jfs-trim/fs/jfs/jfs_dmap.h
--- linux-git/fs/jfs/jfs_dmap.h 2011-08-17 07:31:10.000000000 +0200
+++ linux_jfs-trim/fs/jfs/jfs_dmap.h 2012-07-26 22:53:48.644313195 +0200
@@ -311,4 +311,6 @@ extern int dbAllocBottomUp(struct inode
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 -X exclude -urpN linux-git/fs/jfs/jfs_filsys.h linux_jfs-trim/fs/jfs/jfs_filsys.h
--- linux-git/fs/jfs/jfs_filsys.h 2011-08-17 07:31:10.000000000 +0200
+++ linux_jfs-trim/fs/jfs/jfs_filsys.h 2012-07-26 22:53:48.644313195 +0200
@@ -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 -X exclude -urpN linux-git/fs/jfs/jfs_incore.h linux_jfs-trim/fs/jfs/jfs_incore.h
--- linux-git/fs/jfs/jfs_incore.h 2011-08-17 07:31:10.000000000 +0200
+++ linux_jfs-trim/fs/jfs/jfs_incore.h 2012-07-26 22:53:48.647646510 +0200
@@ -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 -X exclude -urpN linux-git/fs/jfs/super.c linux_jfs-trim/fs/jfs/super.c
--- linux-git/fs/jfs/super.c 2012-07-24 21:31:28.000000000 +0200
+++ linux_jfs-trim/fs/jfs/super.c 2012-07-26 23:00:28.018816264 +0200
@@ -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"
@@ -197,7 +198,8 @@ static void jfs_put_super(struct super_b
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}
};

@@ -324,12 +329,14 @@ static int parse_options(char *options,
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;
@@ -341,6 +348,43 @@ static int parse_options(char *options,
}
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 {
+ printk(KERN_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 {
+ printk(KERN_ERR "JFS: discard option "
+ "not supported on device\n");
+ }
+ break;
+ }
+
default:
printk("jfs: Unrecognized mount option \"%s\" "
" or missing value\n", p);
@@ -625,6 +669,8 @@ static int jfs_show_options(struct seq_f
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)