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Currently, the locality group prealloc list is freed only when there is a block allocation failure. This can result in large number of entries in the preallocation list making ext4_mb_use_preallocated() expensive. To fix this, we convert the locality group prealloc list to a hash list. The hash index is the order of number of blocks in the prealloc space with a max order of 9. When adding prealloc space to the list we make sure total entries for each order does not exceed 8. If it is more than 8 we discard few entries and make sure the we have only <= 5 entries. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
310 lines
8.2 KiB
C
310 lines
8.2 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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#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 "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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* 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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* 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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#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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* 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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#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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* 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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* 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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* 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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* 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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* 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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* 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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* default group prealloc size 512 blocks
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*/
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#define MB_DEFAULT_GROUP_PREALLOC 512
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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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#ifdef EXT4_BB_MAX_BLOCKS
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#undef EXT4_BB_MAX_BLOCKS
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#endif
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#define EXT4_BB_MAX_BLOCKS 30
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struct ext4_free_metadata {
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ext4_group_t group;
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unsigned short num;
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ext4_grpblk_t blocks[EXT4_BB_MAX_BLOCKS];
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struct list_head list;
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};
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struct ext4_group_info {
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unsigned long bb_state;
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unsigned long bb_tid;
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struct ext4_free_metadata *bb_md_cur;
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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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#define EXT4_GROUP_INFO_NEED_INIT_BIT 0
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#define EXT4_GROUP_INFO_LOCKED_BIT 1
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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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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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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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* 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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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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/* original request */
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struct ext4_free_extent ac_o_ex;
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/* goal request (after normalization) */
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struct ext4_free_extent ac_g_ex;
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/* the best found extent */
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struct ext4_free_extent ac_b_ex;
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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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/* 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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#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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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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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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#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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#define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1)
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static struct proc_dir_entry *proc_root_ext4;
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struct buffer_head *read_block_bitmap(struct super_block *, ext4_group_t);
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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_poll_new_transaction(struct super_block *, handle_t *);
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static void ext4_mb_free_committed_blocks(struct super_block *);
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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 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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bit_spin_lock(EXT4_GROUP_INFO_LOCKED_BIT, &(grinfo->bb_state));
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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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bit_spin_unlock(EXT4_GROUP_INFO_LOCKED_BIT, &(grinfo->bb_state));
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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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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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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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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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