[PATCH 59/60] xfs: Add xfs_log_rlimit.c

Dave Chinner
2013-06-19T04:53:48Z

From: Jie Liu <jeff.liu@oracle.com>

Add source files for xfs_log_rlimit.c The new file is used for log
size calculations and validation shared with userspace.

[dchinner: xfs_log_calc_max_attrsetm_res() does not modify the
tr_attrsetm reservation, just calculates the maximum. ]

[dchinner: rework loop in xfs_log_get_max_trans_res() ]

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/Makefile | 1 +
fs/xfs/xfs_log_format.h | 8 ++-
fs/xfs/xfs_log_rlimit.c | 145 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 153 insertions(+), 1 deletion(-)
create mode 100644 fs/xfs/xfs_log_rlimit.c

diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index c5c38a9..22691eb 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -81,6 +81,7 @@ xfs-y += xfs_alloc.o \
xfs_inode_fork.o \
xfs_inode_buf.o \
xfs_log_recover.o \
+ xfs_log_rlimit.o \
xfs_sb.o \
xfs_symlink_remote.o \
xfs_trans_resv.o
diff --git a/fs/xfs/xfs_log_format.h b/fs/xfs/xfs_log_format.h
index 37a7ff9..8f46b6a 100644
--- a/fs/xfs/xfs_log_format.h
+++ b/fs/xfs/xfs_log_format.h
@@ -1,5 +1,6 @@
/*
* Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
+ * Copyright (c) 2013 Jie Liu.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
@@ -19,6 +20,7 @@
#define __XFS_LOG_FORMAT_H__

struct xfs_mount;
+struct xfs_trans_res;

typedef __uint32_t xlog_tid_t;

@@ -41,6 +43,9 @@ typedef __uint32_t xlog_tid_t;

#define XLOG_HEADER_SIZE 512

+/* Minimum number of transactions that must fit in the log (defined by mkfs) */
+#define XFS_MIN_LOG_FACTOR 3
+
#define XLOG_REC_SHIFT(log) \
BTOBB(1 << (xfs_sb_version_haslogv2(&log->l_mp->m_sb) ? \
XLOG_MAX_RECORD_BSHIFT : XLOG_BIG_RECORD_BSHIFT))
@@ -125,7 +130,6 @@ typedef struct xlog_op_header {
__u16 oh_res2; /* 32 bit align : 2 b */
} xlog_op_header_t;

-
/* valid values for h_fmt */
#define XLOG_FMT_UNKNOWN 0
#define XLOG_FMT_LINUX_LE 1
@@ -178,5 +182,7 @@ typedef struct xfs_log_iovec {
} xfs_log_iovec_t;

int xfs_log_calc_unit_res(struct xfs_mount *mp, int unit_bytes);
+int xfs_log_calc_minimum_size(struct xfs_mount *);
+

#endif /* __XFS_LOG_FORMAT_H__ */
diff --git a/fs/xfs/xfs_log_rlimit.c b/fs/xfs/xfs_log_rlimit.c
new file mode 100644
index 0000000..e3f4b4e
--- /dev/null
+++ b/fs/xfs/xfs_log_rlimit.c
@@ -0,0 +1,145 @@
+/*
+ * 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_log.h"
+#include "xfs_trans.h"
+#include "xfs_ag.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_da_btree.h"
+#include "xfs_attr_leaf.h"
+
+/*
+ * Calculate the maximum length in bytes that would be required for a local
+ * attribute value as large attributes out of line are not logged.
+ */
+STATIC int
+xfs_log_calc_max_attrsetm_res(
+ struct xfs_mount *mp)
+{
+ int size;
+ int nblks;
+
+ 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);
+
+ return M_RES(mp)->tr_attrsetm.tr_logres +
+ M_RES(mp)->tr_attrsetrt.tr_logres * nblks;
+}
+
+/*
+ * 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.
+ */
+STATIC void
+xfs_log_get_max_trans_res(
+ struct xfs_mount *mp,
+ struct xfs_trans_res *max_resp)
+{
+ struct xfs_trans_res *resp;
+ struct xfs_trans_res *end_resp;
+ int log_space = 0;
+ int attr_space;
+
+ attr_space = xfs_log_calc_max_attrsetm_res(mp);
+
+ resp = (struct xfs_trans_res *)M_RES(mp);
+ end_resp = (struct xfs_trans_res *)(M_RES(mp) + 1);
+ for (; resp < end_resp; resp++) {
+ int tmp = resp->tr_logcount > 1 ?
+ resp->tr_logres * resp->tr_logcount :
+ resp->tr_logres;
+ if (log_space < tmp) {
+ log_space = tmp;
+ *max_resp = *resp; /* struct copy */
+ }
+ }
+
+ if (attr_space > log_space) {
+ *max_resp = M_RES(mp)->tr_attrsetm; /* struct copy */
+ max_resp->tr_logres = attr_space;
+ }
+}
+
+/*
+ * Calculate the minimum valid log size for the given superblock configuration.
+ * Used to calculate the minimum log size at mkfs time, and to determine if
+ * the log is large enough or not at mount time. Returns the minimum size in
+ * filesystem block size units.
+ */
+int
+xfs_log_calc_minimum_size(
+ struct xfs_mount *mp)
+{
+ struct xfs_trans_res tres = {0};
+ int max_logres;
+ int min_logblks = 0;
+ int lsunit = 0;
+
+ xfs_log_get_max_trans_res(mp, &tres);
+
+ max_logres = xfs_log_calc_unit_res(mp, tres.tr_logres);
+ if (tres.tr_logcount > 1)
+ max_logres *= tres.tr_logcount;
+
+ if (xfs_sb_version_haslogv2(&mp->m_sb) && mp->m_sb.sb_logsunit > 1)
+ lsunit = BTOBB(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.
+ *
+ * From mkfs.xfs, this is considered by the XFS_MIN_LOG_FACTOR
+ * define, which is set to 3. That means we can definitely fit
+ * maximally sized 2 transactions in the log. We'll use this same
+ * value here.
+ *
+ * 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.
+ */
+ if (lsunit)
+ min_logblks = roundup(BTOBB(max_logres), lsunit) + 2 * lsunit;
+ else
+ min_logblks = BTOBB(max_logres);
+ min_logblks *= XFS_MIN_LOG_FACTOR;
+ return XFS_BB_TO_FSB(mp, min_logblks);
+}