mirror of
https://github.com/schoebel/mars
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110 lines
3.2 KiB
C
110 lines
3.2 KiB
C
/*
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* MARS Long Distance Replication Software
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*
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* This file is part of MARS project: http://schoebel.github.io/mars/
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*
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* Copyright (C) 2010-2014 Thomas Schoebel-Theuer
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* Copyright (C) 2011-2014 1&1 Internet AG
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifndef MARS_LIB_MAPFREE_H
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#define MARS_LIB_MAPFREE_H
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/* Mapfree infrastructure.
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*
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* Purposes:
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*
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* 1) Open files only once when possible, do ref-counting on struct mapfree_info
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*
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* 2) Automatically call invalidate_mapping_pages() in the background on
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* "unused" areas to free resources.
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* Used areas can be indicated by calling mapfree_set() frequently.
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* Usage model: tailored to sequential logfiles.
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*
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* 3) Do it all in a completely decoupled manner, in order to prevent resource deadlocks.
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*
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* 4) Also to prevent deadlocks: always set mapping_set_gfp_mask() accordingly.
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*/
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#include <linux/rwsem.h>
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#include "mars.h"
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extern int mapfree_period_sec;
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extern int mapfree_grace_keep_mb;
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enum dirty_stage {
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DIRTY_SUBMITTED,
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DIRTY_COMPLETING,
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DIRTY_FINISHED,
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/* Keep this the last element */
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DIRTY_MAX
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} __packed;
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struct dirty_length {
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rwlock_t dl_lock;
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u64 dl_appends;
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loff_t dl_length;
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};
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struct mapfree_info {
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struct list_head mf_head;
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struct list_head mf_dirty_anchor;
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char *mf_name;
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struct file *mf_filp;
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int mf_flags;
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int mf_mode;
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atomic_t mf_count;
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/* private */
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struct rw_semaphore mf_mutex;
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loff_t mf_min[2];
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loff_t mf_last;
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loff_t mf_max;
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long long mf_jiffies;
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unsigned int mf_hash;
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bool mf_finished;
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struct dirty_length mf_length[DIRTY_MAX];
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};
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struct mapfree_info *mapfree_get(const char *filename, int flags, int *error);
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void mapfree_put(struct mapfree_info *mf);
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void mapfree_set(struct mapfree_info *mf, loff_t min, loff_t max);
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void mapfree_pages(struct mapfree_info *mf, int grace_keep);
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loff_t mapfree_real_size(struct mapfree_info *mf);
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////////////////// dirty IOs in append mode //////////////////
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void mf_dirty_append(struct mapfree_info *mf, enum dirty_stage stage, loff_t newlen);
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void mf_dirty_reduce(struct mapfree_info *mf, enum dirty_stage stage, loff_t newlen);
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loff_t mf_dirty_length(struct mapfree_info *mf, enum dirty_stage stage);
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////////////////// dirty IOs on the fly //////////////////
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loff_t mf_get_any_dirty(const char *filename, int stage);
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////////////////// module init stuff /////////////////////////
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int __init init_mars_mapfree(void);
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void exit_mars_mapfree(void);
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#endif
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