xfs: Add xfs_log_rlimit.[c|h]

From: Jie Liu <[email protected]>

Add source files for xfs_log_rlimit.[c|h].
The new source would be used for the log space validation.

Signed-off-by Jie Liu <[email protected]>

---
  fs/xfs/Makefile         |    3 +-
  fs/xfs/xfs_log_rlimit.c |  148 +++++++++++++++++++++++++++++++++++++++++++++++
  fs/xfs/xfs_log_rlimit.h |   25 ++++++++
  fs/xfs/xfs_mount.h      |    3 +
  4 files changed, 178 insertions(+), 1 deletion(-)

create mode 100644 fs/xfs/xfs_log_rlimit.c
create mode 100644 fs/xfs/xfs_log_rlimit.h

fs/xfs/Makefile +2 -1

index 6313b69..7e7a49d 100644
@@ -75,7 +75,8 @@ xfs-y				+= xfs_alloc.o \
  				   xfs_log_recover.o \
  				   xfs_mount.o \
  				   xfs_symlink.o \
-				   xfs_trans.o
+				   xfs_trans.o \
+				   xfs_log_rlimit.o
 
  # low-level transaction/log code
  xfs-y				+= xfs_log.o \

fs/xfs/xfs_log_rlimit.c new file +148 -0

new file mode 100644
index 0000000..3e84d46
@@ -0,0 +1,148 @@
+/*
+ * Copyright (c) 2013 Jie Liu.
+ * All Rights Reserved.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it would 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 the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_sb.h"
+#include "xfs_mount.h"
+#include "xfs_trans_space.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_inode.h"
+#include "xfs_log.h"
+#include "xfs_log_priv.h"
+#include "xfs_da_btree.h"
+#include "xfs_attr_leaf.h"
+
+void
+xfs_log_adjust_max_attrsetm_res(
+	struct xfs_mount	*mp)
+{
+	int			size;
+	int			nblks;
+	int			res;
+
+	/*
+	 * Calculate the maximum length in bytes that would be required
+	 * for a local attribute value as large attributes out of line
+	 * are not logged.
+	 */
+	size = xfs_attr_leaf_entsize_local_max(mp->m_sb.sb_blocksize) -
+	       MAXNAMELEN - 1;
+	nblks = XFS_DAENTER_SPACE_RES(mp, XFS_ATTR_FORK);
+	nblks += XFS_B_TO_FSB(mp, size);
+	nblks += XFS_NEXTENTADD_SPACE_RES(mp, size, XFS_ATTR_FORK);
+
+	res = m_tresp(mp)->tr_attrsetm.tr_logres +
+	      m_tresp(mp)->tr_attrsetrt.tr_logres * nblks;
+	mp->m_reservations.tr_attrsetm.tr_logres = res;
+}
+
+/*
+ * Iterate over the log space reservation table to figure out and return
+ * the maximum one in terms of the pre-calculated values which were done
+ * at mount time.
+ */
+void
+xfs_log_get_max_trans_res(
+	struct xfs_mount		*mp,
+	struct xfs_trans_res		*max_tresp)
+{
+	struct xfs_trans_reservations	*mtresp = m_tresp(mp);
+	struct xfs_trans_res		tres_items[XFS_TRANS_RES_NUM];
+	struct xfs_trans_res		*tresp;
+	int				i, logspace  = 0;
+
+	xfs_log_adjust_max_attrsetm_res(mp);
+
+	memcpy(tres_items, mtresp, sizeof(*mtresp));
+	for (i = 0; i < ARRAY_SIZE(tres_items); i++) {
+		struct xfs_trans_res	*p = &tres_items[i];
+		int			tmp = p->tr_logcount > 1 ?
+					      p->tr_logres * p->tr_logcount :
+					      p->tr_logres;
+		if (logspace < tmp) {
+			logspace = tmp;
+			tresp = p;
+		}
+	}
+
+	*max_tresp = *tresp;
+}
+
+/*
+ * Verify if the configured log space is sufficient or not for the specified
+ * log stripe unit.
+ */
+void
+xfs_log_validate_logspace(
+	struct xfs_mount	*mp)
+{
+	struct xlog		*log = mp->m_log;
+	struct xfs_trans_res	tres;
+	int			maxlres;
+	int			minlblks = 0, lsunit = 0;
+
+	xfs_log_get_max_trans_res(mp, &tres);
+
+	maxlres = xfs_log_calc_unit_res(mp, tres.tr_logres);
+	maxlres = tres.tr_logcount > 1 ? maxlres * tres.tr_logcount : maxlres;
+
+	if (xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
+	    log->l_mp->m_sb.sb_logsunit > 1)
+		lsunit = BTOBB(log->l_mp->m_sb.sb_logsunit);
+
+	/*
+	 * Two factors should be taken into account for calculating the minimum
+	 * log space.
+	 * 1) The fundamental limitation is that no single transaction can be
+	 *    larger than half size of the log.
+	 * 2) If the lsunit option is specified, a transaction requires 2 LSU
+	 *    for the reservation because there are two log writes that can
+	 *    require padding - the transaction data and the commit record which
+	 *    are written separately and both can require padding to the LSU.
+	 *    Consider that we can have an active CIL reservation holding 2*LSU,
+	 *    but the CIL is not over a push threshold, in this case, if we
+	 *    don't have enough log space for at one new transaction, which
+	 *    includes another 2*LSU in the reservation, we will run into dead
+	 *    loop situation in log space grant procedure. i.e.
+	 *    xlog_grant_head_wait().
+	 *
+	 *    Hence the log size needs to be able to contain two maximally sized
+	 *    and padded transactions, which is (2 * (2 * LSU + maxlres)).
+	 *
+	 * Also, the log size should be a multiple of the log stripe unit, round
+	 * it up to lsunit boundary if lsunit is specified.
+	 */
+	minlblks = lsunit ? (roundup(BTOBB(maxlres), lsunit) + 2 * lsunit) * 2 :
+			    BTOBB(maxlres) * 2;
+
+	if (log->l_logBBsize < minlblks) {
+		xfs_crit(mp,
+		"Log size %d blocks too small, minimu size is %d blocks",
+			 log->l_logBBsize, minlblks);
+	}
+	if (log->l_logBBsize > XFS_MAX_LOG_BLOCKS) {
+		xfs_crit(mp,
+		"Log size %d blocks too large, maximum size is %lld blocks",
+			 log->l_logBBsize, XFS_MAX_LOG_BLOCKS);
+	}
+	if (log->l_logsize > XFS_MAX_LOG_BYTES) {
+		xfs_crit(mp,
+		"log size %lld bytes too large, maximum size is %lld bytes",
+			 (long long)(log->l_logsize), XFS_MAX_LOG_BYTES);
+	}
+}

fs/xfs/xfs_log_rlimit.h new file +25 -0

new file mode 100644
index 0000000..93d8a0e
@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2013 Jie Liu.
+ * All Rights Reserved.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it would 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 the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#ifndef	__XFS_LOG_RLIMIT_H__
+#define __XFS_LOG_RLIMIT_H__
+
+void xfs_log_adjust_max_attrsetm_res(struct xfs_mount *);
+void xfs_log_get_max_trans_res(struct xfs_mount *, struct xfs_trans_res *);
+void xfs_log_validate_logspace(struct xfs_mount *);
+
+#endif	/* __XFS_LOG_PRIV_H__ */

fs/xfs/xfs_mount.h +0 -0

index 27ae8a9..2b469a5 100644

From: Jie Liu <[email protected]>

Add source files for xfs_log_rlimit.[c|h].
The new source would be used for the log space validation.

Quoted 4 lines · Jeff Liu

From: Jie Liu <[email protected]>

Add source files for xfs_log_rlimit.[c|h].
The new source would be used for the log space validation.

Update: To build the kernel, I'm getting by on a sysadmin hack that looks like this:

fs/xfs/xfs_log_rlimit.c renamed from fs/xfs/xfs_log_rlimit.c.orig +4 -2

@@ -127,8 +127,10 @@
  	 * Also, the log size should be a multiple of the log stripe unit, round
  	 * it up to lsunit boundary if lsunit is specified.
  	 */
-	minlblks = lsunit ? (roundup(BTOBB(maxlres), lsunit) + 2 * lsunit) * 2 :
-			    BTOBB(maxlres) * 2;
+	minlblks = lsunit ?
+		(roundup((const int)(BTOBB(maxlres)), lsunit) +
+		2 * lsunit) * 2 :
+			BTOBB(maxlres) * 2;
 
  	if (log->l_logBBsize < minlblks) {
  		xfs_crit(mp,

However, that makes no sense. There is a roundup in <linux/kernel.h> that goes like this:

/* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
#define roundup(x, y) ( \

{                                                       \
         const typeof(y) __y = y;                        \
         (((x) + (__y - 1)) / __y) * __y;                \
}                                                       \

)

Okay, so that gave me the inspiration to cast the type so gcc-4.8.0 wouldn't call __divdi3. But why did this make a difference?

Disclaimer: I'm not a C macro guru, so I don't know which random sequence of punctuation keys would make roundup() happy.

Michael

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Hi Michael,

Are you compiling kernel on 32-bit system?

Looks this issue is regarding 64-bit division at roundup() on 32-bit if so.

Quoted 5 lines · Jeff Liu

Hi Michael,

Are you compiling kernel on 32-bit system?

Looks this issue is regarding 64-bit division at roundup() on 32-bit if so.

roundup_64() is what you want, then.

Hi Michael,

Are you compiling kernel on 32-bit system?

Looks this issue is regarding 64-bit division at roundup() on 32-bit if so.

Could you please try below fix?

fs/xfs/xfs_log_rlimit.c +1 -1

index 3e84d46..49a88cc 100644
@@ -127,7 +127,7 @@ xfs_log_validate_logspace(
          * Also, the log size should be a multiple of the log stripe unit, round
          * it up to lsunit boundary if lsunit is specified.
          */
-       minlblks = lsunit ? (roundup(BTOBB(maxlres), lsunit) + 2 * lsunit) * 2 :
+       minlblks = lsunit ? (roundup((int)BTOBB(maxlres), lsunit) + 2 * lsunit) * 2 :
                             BTOBB(maxlres) * 2;
 
         if (log->l_logBBsize < minlblks) {

Thanks,
-Jeff