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/*
* 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) + 2 * BBSIZE;
min_logblks *= XFS_MIN_LOG_FACTOR;
return XFS_BB_TO_FSB(mp, min_logblks);
}
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