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		3e624fc72f
		
	
	
	
	
		
			
			The multiblock allocator needs to be able to release blocks (and issue a blkdev discard request) when the transaction which freed those blocks is committed. Previously this was done via a polling mechanism when blocks are allocated or freed. A much better way of doing things is to create a jbd2 callback function and attaching the list of blocks to be freed directly to the transaction structure. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
		
			
				
	
	
		
			317 lines
		
	
	
		
			8.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			317 lines
		
	
	
		
			8.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  *  fs/ext4/mballoc.h
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|  *
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|  *  Written by: Alex Tomas <alex@clusterfs.com>
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|  *
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|  */
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| #ifndef _EXT4_MBALLOC_H
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| #define _EXT4_MBALLOC_H
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| 
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| #include <linux/time.h>
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| #include <linux/fs.h>
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| #include <linux/namei.h>
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| #include <linux/quotaops.h>
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| #include <linux/buffer_head.h>
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| #include <linux/module.h>
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| #include <linux/swap.h>
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| #include <linux/proc_fs.h>
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| #include <linux/pagemap.h>
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| #include <linux/seq_file.h>
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| #include <linux/version.h>
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| #include <linux/blkdev.h>
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| #include <linux/marker.h>
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| #include "ext4_jbd2.h"
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| #include "ext4.h"
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| #include "group.h"
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| 
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| /*
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|  * with AGGRESSIVE_CHECK allocator runs consistency checks over
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|  * structures. these checks slow things down a lot
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|  */
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| #define AGGRESSIVE_CHECK__
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| 
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| /*
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|  * with DOUBLE_CHECK defined mballoc creates persistent in-core
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|  * bitmaps, maintains and uses them to check for double allocations
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|  */
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| #define DOUBLE_CHECK__
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| 
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| /*
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|  */
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| #define MB_DEBUG__
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| #ifdef MB_DEBUG
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| #define mb_debug(fmt, a...)	printk(fmt, ##a)
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| #else
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| #define mb_debug(fmt, a...)
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| #endif
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| 
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| /*
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|  * with EXT4_MB_HISTORY mballoc stores last N allocations in memory
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|  * and you can monitor it in /proc/fs/ext4/<dev>/mb_history
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|  */
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| #define EXT4_MB_HISTORY
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| #define EXT4_MB_HISTORY_ALLOC		1	/* allocation */
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| #define EXT4_MB_HISTORY_PREALLOC	2	/* preallocated blocks used */
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| #define EXT4_MB_HISTORY_DISCARD		4	/* preallocation discarded */
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| #define EXT4_MB_HISTORY_FREE		8	/* free */
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| 
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| #define EXT4_MB_HISTORY_DEFAULT		(EXT4_MB_HISTORY_ALLOC | \
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| 					 EXT4_MB_HISTORY_PREALLOC)
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| 
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| /*
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|  * How long mballoc can look for a best extent (in found extents)
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|  */
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| #define MB_DEFAULT_MAX_TO_SCAN		200
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| 
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| /*
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|  * How long mballoc must look for a best extent
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|  */
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| #define MB_DEFAULT_MIN_TO_SCAN		10
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| 
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| /*
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|  * How many groups mballoc will scan looking for the best chunk
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|  */
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| #define MB_DEFAULT_MAX_GROUPS_TO_SCAN	5
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| 
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| /*
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|  * with 'ext4_mb_stats' allocator will collect stats that will be
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|  * shown at umount. The collecting costs though!
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|  */
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| #define MB_DEFAULT_STATS		1
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| 
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| /*
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|  * files smaller than MB_DEFAULT_STREAM_THRESHOLD are served
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|  * by the stream allocator, which purpose is to pack requests
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|  * as close each to other as possible to produce smooth I/O traffic
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|  * We use locality group prealloc space for stream request.
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|  * We can tune the same via /proc/fs/ext4/<parition>/stream_req
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|  */
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| #define MB_DEFAULT_STREAM_THRESHOLD	16	/* 64K */
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| 
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| /*
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|  * for which requests use 2^N search using buddies
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|  */
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| #define MB_DEFAULT_ORDER2_REQS		2
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| 
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| /*
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|  * default group prealloc size 512 blocks
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|  */
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| #define MB_DEFAULT_GROUP_PREALLOC	512
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| 
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| static struct kmem_cache *ext4_pspace_cachep;
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| static struct kmem_cache *ext4_ac_cachep;
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| static struct kmem_cache *ext4_free_ext_cachep;
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| 
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| struct ext4_free_data {
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| 	/* this links the free block information from group_info */
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| 	struct rb_node node;
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| 
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| 	/* this links the free block information from ext4_sb_info */
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| 	struct list_head list;
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| 
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| 	/* group which free block extent belongs */
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| 	ext4_group_t group;
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| 
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| 	/* free block extent */
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| 	ext4_grpblk_t start_blk;
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| 	ext4_grpblk_t count;
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| 
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| 	/* transaction which freed this extent */
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| 	tid_t	t_tid;
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| };
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| 
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| struct ext4_group_info {
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| 	unsigned long	bb_state;
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| 	struct rb_root  bb_free_root;
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| 	unsigned short	bb_first_free;
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| 	unsigned short	bb_free;
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| 	unsigned short	bb_fragments;
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| 	struct		list_head bb_prealloc_list;
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| #ifdef DOUBLE_CHECK
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| 	void		*bb_bitmap;
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| #endif
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| 	unsigned short	bb_counters[];
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| };
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| 
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| #define EXT4_GROUP_INFO_NEED_INIT_BIT	0
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| #define EXT4_GROUP_INFO_LOCKED_BIT	1
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| 
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| #define EXT4_MB_GRP_NEED_INIT(grp)	\
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| 	(test_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &((grp)->bb_state)))
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| 
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| 
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| struct ext4_prealloc_space {
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| 	struct list_head	pa_inode_list;
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| 	struct list_head	pa_group_list;
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| 	union {
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| 		struct list_head pa_tmp_list;
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| 		struct rcu_head	pa_rcu;
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| 	} u;
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| 	spinlock_t		pa_lock;
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| 	atomic_t		pa_count;
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| 	unsigned		pa_deleted;
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| 	ext4_fsblk_t		pa_pstart;	/* phys. block */
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| 	ext4_lblk_t		pa_lstart;	/* log. block */
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| 	unsigned short		pa_len;		/* len of preallocated chunk */
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| 	unsigned short		pa_free;	/* how many blocks are free */
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| 	unsigned short		pa_linear;	/* consumed in one direction
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| 						 * strictly, for grp prealloc */
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| 	spinlock_t		*pa_obj_lock;
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| 	struct inode		*pa_inode;	/* hack, for history only */
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| };
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| 
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| 
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| struct ext4_free_extent {
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| 	ext4_lblk_t fe_logical;
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| 	ext4_grpblk_t fe_start;
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| 	ext4_group_t fe_group;
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| 	int fe_len;
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| };
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| 
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| /*
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|  * Locality group:
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|  *   we try to group all related changes together
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|  *   so that writeback can flush/allocate them together as well
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|  *   Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC
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|  *   (512). We store prealloc space into the hash based on the pa_free blocks
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|  *   order value.ie, fls(pa_free)-1;
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|  */
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| #define PREALLOC_TB_SIZE 10
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| struct ext4_locality_group {
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| 	/* for allocator */
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| 	/* to serialize allocates */
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| 	struct mutex		lg_mutex;
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| 	/* list of preallocations */
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| 	struct list_head	lg_prealloc_list[PREALLOC_TB_SIZE];
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| 	spinlock_t		lg_prealloc_lock;
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| };
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| 
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| struct ext4_allocation_context {
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| 	struct inode *ac_inode;
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| 	struct super_block *ac_sb;
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| 
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| 	/* original request */
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| 	struct ext4_free_extent ac_o_ex;
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| 
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| 	/* goal request (after normalization) */
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| 	struct ext4_free_extent ac_g_ex;
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| 
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| 	/* the best found extent */
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| 	struct ext4_free_extent ac_b_ex;
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| 
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| 	/* copy of the bext found extent taken before preallocation efforts */
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| 	struct ext4_free_extent ac_f_ex;
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| 
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| 	/* number of iterations done. we have to track to limit searching */
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| 	unsigned long ac_ex_scanned;
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| 	__u16 ac_groups_scanned;
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| 	__u16 ac_found;
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| 	__u16 ac_tail;
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| 	__u16 ac_buddy;
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| 	__u16 ac_flags;		/* allocation hints */
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| 	__u8 ac_status;
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| 	__u8 ac_criteria;
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| 	__u8 ac_repeats;
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| 	__u8 ac_2order;		/* if request is to allocate 2^N blocks and
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| 				 * N > 0, the field stores N, otherwise 0 */
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| 	__u8 ac_op;		/* operation, for history only */
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| 	struct page *ac_bitmap_page;
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| 	struct page *ac_buddy_page;
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| 	struct ext4_prealloc_space *ac_pa;
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| 	struct ext4_locality_group *ac_lg;
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| };
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| 
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| #define AC_STATUS_CONTINUE	1
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| #define AC_STATUS_FOUND		2
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| #define AC_STATUS_BREAK		3
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| 
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| struct ext4_mb_history {
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| 	struct ext4_free_extent orig;	/* orig allocation */
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| 	struct ext4_free_extent goal;	/* goal allocation */
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| 	struct ext4_free_extent result;	/* result allocation */
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| 	unsigned pid;
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| 	unsigned ino;
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| 	__u16 found;	/* how many extents have been found */
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| 	__u16 groups;	/* how many groups have been scanned */
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| 	__u16 tail;	/* what tail broke some buddy */
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| 	__u16 buddy;	/* buddy the tail ^^^ broke */
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| 	__u16 flags;
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| 	__u8 cr:3;	/* which phase the result extent was found at */
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| 	__u8 op:4;
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| 	__u8 merged:1;
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| };
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| 
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| struct ext4_buddy {
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| 	struct page *bd_buddy_page;
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| 	void *bd_buddy;
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| 	struct page *bd_bitmap_page;
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| 	void *bd_bitmap;
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| 	struct ext4_group_info *bd_info;
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| 	struct super_block *bd_sb;
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| 	__u16 bd_blkbits;
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| 	ext4_group_t bd_group;
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| };
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| #define EXT4_MB_BITMAP(e4b)	((e4b)->bd_bitmap)
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| #define EXT4_MB_BUDDY(e4b)	((e4b)->bd_buddy)
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| 
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| #ifndef EXT4_MB_HISTORY
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| static inline void ext4_mb_store_history(struct ext4_allocation_context *ac)
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| {
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| 	return;
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| }
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| #else
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| static void ext4_mb_store_history(struct ext4_allocation_context *ac);
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| #endif
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| 
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| #define in_range(b, first, len)	((b) >= (first) && (b) <= (first) + (len) - 1)
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| 
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| struct buffer_head *read_block_bitmap(struct super_block *, ext4_group_t);
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| 
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| static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
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| 					ext4_group_t group);
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| static void ext4_mb_return_to_preallocation(struct inode *inode,
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| 					struct ext4_buddy *e4b, sector_t block,
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| 					int count);
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| static void ext4_mb_put_pa(struct ext4_allocation_context *,
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| 			struct super_block *, struct ext4_prealloc_space *pa);
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| static int ext4_mb_init_per_dev_proc(struct super_block *sb);
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| static int ext4_mb_destroy_per_dev_proc(struct super_block *sb);
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| static void release_blocks_on_commit(journal_t *journal, transaction_t *txn);
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| 
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| 
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| static inline void ext4_lock_group(struct super_block *sb, ext4_group_t group)
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| {
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| 	struct ext4_group_info *grinfo = ext4_get_group_info(sb, group);
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| 
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| 	bit_spin_lock(EXT4_GROUP_INFO_LOCKED_BIT, &(grinfo->bb_state));
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| }
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| 
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| static inline void ext4_unlock_group(struct super_block *sb,
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| 					ext4_group_t group)
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| {
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| 	struct ext4_group_info *grinfo = ext4_get_group_info(sb, group);
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| 
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| 	bit_spin_unlock(EXT4_GROUP_INFO_LOCKED_BIT, &(grinfo->bb_state));
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| }
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| 
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| static inline int ext4_is_group_locked(struct super_block *sb,
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| 					ext4_group_t group)
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| {
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| 	struct ext4_group_info *grinfo = ext4_get_group_info(sb, group);
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| 
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| 	return bit_spin_is_locked(EXT4_GROUP_INFO_LOCKED_BIT,
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| 						&(grinfo->bb_state));
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| }
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| 
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| static ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
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| 					struct ext4_free_extent *fex)
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| {
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| 	ext4_fsblk_t block;
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| 
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| 	block = (ext4_fsblk_t) fex->fe_group * EXT4_BLOCKS_PER_GROUP(sb)
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| 			+ fex->fe_start
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| 			+ le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
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| 	return block;
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| }
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| #endif
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