Release 4.10 fs/ext4/mballoc.c
/*
* Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
* Written by Alex Tomas <alex@clusterfs.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will 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 to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
*/
/*
* mballoc.c contains the multiblocks allocation routines
*/
#include "ext4_jbd2.h"
#include "mballoc.h"
#include <linux/log2.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/backing-dev.h>
#include <trace/events/ext4.h>
#ifdef CONFIG_EXT4_DEBUG
ushort ext4_mballoc_debug __read_mostly;
module_param_named(mballoc_debug, ext4_mballoc_debug, ushort, 0644);
MODULE_PARM_DESC(mballoc_debug, "Debugging level for ext4's mballoc");
#endif
/*
* MUSTDO:
* - test ext4_ext_search_left() and ext4_ext_search_right()
* - search for metadata in few groups
*
* TODO v4:
* - normalization should take into account whether file is still open
* - discard preallocations if no free space left (policy?)
* - don't normalize tails
* - quota
* - reservation for superuser
*
* TODO v3:
* - bitmap read-ahead (proposed by Oleg Drokin aka green)
* - track min/max extents in each group for better group selection
* - mb_mark_used() may allocate chunk right after splitting buddy
* - tree of groups sorted by number of free blocks
* - error handling
*/
/*
* The allocation request involve request for multiple number of blocks
* near to the goal(block) value specified.
*
* During initialization phase of the allocator we decide to use the
* group preallocation or inode preallocation depending on the size of
* the file. The size of the file could be the resulting file size we
* would have after allocation, or the current file size, which ever
* is larger. If the size is less than sbi->s_mb_stream_request we
* select to use the group preallocation. The default value of
* s_mb_stream_request is 16 blocks. This can also be tuned via
* /sys/fs/ext4/<partition>/mb_stream_req. The value is represented in
* terms of number of blocks.
*
* The main motivation for having small file use group preallocation is to
* ensure that we have small files closer together on the disk.
*
* First stage the allocator looks at the inode prealloc list,
* ext4_inode_info->i_prealloc_list, which contains list of prealloc
* spaces for this particular inode. The inode prealloc space is
* represented as:
*
* pa_lstart -> the logical start block for this prealloc space
* pa_pstart -> the physical start block for this prealloc space
* pa_len -> length for this prealloc space (in clusters)
* pa_free -> free space available in this prealloc space (in clusters)
*
* The inode preallocation space is used looking at the _logical_ start
* block. If only the logical file block falls within the range of prealloc
* space we will consume the particular prealloc space. This makes sure that
* we have contiguous physical blocks representing the file blocks
*
* The important thing to be noted in case of inode prealloc space is that
* we don't modify the values associated to inode prealloc space except
* pa_free.
*
* If we are not able to find blocks in the inode prealloc space and if we
* have the group allocation flag set then we look at the locality group
* prealloc space. These are per CPU prealloc list represented as
*
* ext4_sb_info.s_locality_groups[smp_processor_id()]
*
* The reason for having a per cpu locality group is to reduce the contention
* between CPUs. It is possible to get scheduled at this point.
*
* The locality group prealloc space is used looking at whether we have
* enough free space (pa_free) within the prealloc space.
*
* If we can't allocate blocks via inode prealloc or/and locality group
* prealloc then we look at the buddy cache. The buddy cache is represented
* by ext4_sb_info.s_buddy_cache (struct inode) whose file offset gets
* mapped to the buddy and bitmap information regarding different
* groups. The buddy information is attached to buddy cache inode so that
* we can access them through the page cache. The information regarding
* each group is loaded via ext4_mb_load_buddy. The information involve
* block bitmap and buddy information. The information are stored in the
* inode as:
*
* { page }
* [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
*
*
* one block each for bitmap and buddy information. So for each group we
* take up 2 blocks. A page can contain blocks_per_page (PAGE_SIZE /
* blocksize) blocks. So it can have information regarding groups_per_page
* which is blocks_per_page/2
*
* The buddy cache inode is not stored on disk. The inode is thrown
* away when the filesystem is unmounted.
*
* We look for count number of blocks in the buddy cache. If we were able
* to locate that many free blocks we return with additional information
* regarding rest of the contiguous physical block available
*
* Before allocating blocks via buddy cache we normalize the request
* blocks. This ensure we ask for more blocks that we needed. The extra
* blocks that we get after allocation is added to the respective prealloc
* list. In case of inode preallocation we follow a list of heuristics
* based on file size. This can be found in ext4_mb_normalize_request. If
* we are doing a group prealloc we try to normalize the request to
* sbi->s_mb_group_prealloc. The default value of s_mb_group_prealloc is
* dependent on the cluster size; for non-bigalloc file systems, it is
* 512 blocks. This can be tuned via
* /sys/fs/ext4/<partition>/mb_group_prealloc. The value is represented in
* terms of number of blocks. If we have mounted the file system with -O
* stripe=<value> option the group prealloc request is normalized to the
* the smallest multiple of the stripe value (sbi->s_stripe) which is
* greater than the default mb_group_prealloc.
*
* The regular allocator (using the buddy cache) supports a few tunables.
*
* /sys/fs/ext4/<partition>/mb_min_to_scan
* /sys/fs/ext4/<partition>/mb_max_to_scan
* /sys/fs/ext4/<partition>/mb_order2_req
*
* The regular allocator uses buddy scan only if the request len is power of
* 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The
* value of s_mb_order2_reqs can be tuned via
* /sys/fs/ext4/<partition>/mb_order2_req. If the request len is equal to
* stripe size (sbi->s_stripe), we try to search for contiguous block in
* stripe size. This should result in better allocation on RAID setups. If
* not, we search in the specific group using bitmap for best extents. The
* tunable min_to_scan and max_to_scan control the behaviour here.
* min_to_scan indicate how long the mballoc __must__ look for a best
* extent and max_to_scan indicates how long the mballoc __can__ look for a
* best extent in the found extents. Searching for the blocks starts with
* the group specified as the goal value in allocation context via
* ac_g_ex. Each group is first checked based on the criteria whether it
* can be used for allocation. ext4_mb_good_group explains how the groups are
* checked.
*
* Both the prealloc space are getting populated as above. So for the first
* request we will hit the buddy cache which will result in this prealloc
* space getting filled. The prealloc space is then later used for the
* subsequent request.
*/
/*
* mballoc operates on the following data:
* - on-disk bitmap
* - in-core buddy (actually includes buddy and bitmap)
* - preallocation descriptors (PAs)
*
* there are two types of preallocations:
* - inode
* assiged to specific inode and can be used for this inode only.
* it describes part of inode's space preallocated to specific
* physical blocks. any block from that preallocated can be used
* independent. the descriptor just tracks number of blocks left
* unused. so, before taking some block from descriptor, one must
* make sure corresponded logical block isn't allocated yet. this
* also means that freeing any block within descriptor's range
* must discard all preallocated blocks.
* - locality group
* assigned to specific locality group which does not translate to
* permanent set of inodes: inode can join and leave group. space
* from this type of preallocation can be used for any inode. thus
* it's consumed from the beginning to the end.
*
* relation between them can be expressed as:
* in-core buddy = on-disk bitmap + preallocation descriptors
*
* this mean blocks mballoc considers used are:
* - allocated blocks (persistent)
* - preallocated blocks (non-persistent)
*
* consistency in mballoc world means that at any time a block is either
* free or used in ALL structures. notice: "any time" should not be read
* literally -- time is discrete and delimited by locks.
*
* to keep it simple, we don't use block numbers, instead we count number of
* blocks: how many blocks marked used/free in on-disk bitmap, buddy and PA.
*
* all operations can be expressed as:
* - init buddy: buddy = on-disk + PAs
* - new PA: buddy += N; PA = N
* - use inode PA: on-disk += N; PA -= N
* - discard inode PA buddy -= on-disk - PA; PA = 0
* - use locality group PA on-disk += N; PA -= N
* - discard locality group PA buddy -= PA; PA = 0
* note: 'buddy -= on-disk - PA' is used to show that on-disk bitmap
* is used in real operation because we can't know actual used
* bits from PA, only from on-disk bitmap
*
* if we follow this strict logic, then all operations above should be atomic.
* given some of them can block, we'd have to use something like semaphores
* killing performance on high-end SMP hardware. let's try to relax it using
* the following knowledge:
* 1) if buddy is referenced, it's already initialized
* 2) while block is used in buddy and the buddy is referenced,
* nobody can re-allocate that block
* 3) we work on bitmaps and '+' actually means 'set bits'. if on-disk has
* bit set and PA claims same block, it's OK. IOW, one can set bit in
* on-disk bitmap if buddy has same bit set or/and PA covers corresponded
* block
*
* so, now we're building a concurrency table:
* - init buddy vs.
* - new PA
* blocks for PA are allocated in the buddy, buddy must be referenced
* until PA is linked to allocation group to avoid concurrent buddy init
* - use inode PA
* we need to make sure that either on-disk bitmap or PA has uptodate data
* given (3) we care that PA-=N operation doesn't interfere with init
* - discard inode PA
* the simplest way would be to have buddy initialized by the discard
* - use locality group PA
* again PA-=N must be serialized with init
* - discard locality group PA
* the simplest way would be to have buddy initialized by the discard
* - new PA vs.
* - use inode PA
* i_data_sem serializes them
* - discard inode PA
* discard process must wait until PA isn't used by another process
* - use locality group PA
* some mutex should serialize them
* - discard locality group PA
* discard process must wait until PA isn't used by another process
* - use inode PA
* - use inode PA
* i_data_sem or another mutex should serializes them
* - discard inode PA
* discard process must wait until PA isn't used by another process
* - use locality group PA
* nothing wrong here -- they're different PAs covering different blocks
* - discard locality group PA
* discard process must wait until PA isn't used by another process
*
* now we're ready to make few consequences:
* - PA is referenced and while it is no discard is possible
* - PA is referenced until block isn't marked in on-disk bitmap
* - PA changes only after on-disk bitmap
* - discard must not compete with init. either init is done before
* any discard or they're serialized somehow
* - buddy init as sum of on-disk bitmap and PAs is done atomically
*
* a special case when we've used PA to emptiness. no need to modify buddy
* in this case, but we should care about concurrent init
*
*/
/*
* Logic in few words:
*
* - allocation:
* load group
* find blocks
* mark bits in on-disk bitmap
* release group
*
* - use preallocation:
* find proper PA (per-inode or group)
* load group
* mark bits in on-disk bitmap
* release group
* release PA
*
* - free:
* load group
* mark bits in on-disk bitmap
* release group
*
* - discard preallocations in group:
* mark PAs deleted
* move them onto local list
* load on-disk bitmap
* load group
* remove PA from object (inode or locality group)
* mark free blocks in-core
*
* - discard inode's preallocations:
*/
/*
* Locking rules
*
* Locks:
* - bitlock on a group (group)
* - object (inode/locality) (object)
* - per-pa lock (pa)
*
* Paths:
* - new pa
* object
* group
*
* - find and use pa:
* pa
*
* - release consumed pa:
* pa
* group
* object
*
* - generate in-core bitmap:
* group
* pa
*
* - discard all for given object (inode, locality group):
* object
* pa
* group
*
* - discard all for given group:
* group
* pa
* group
* object
*
*/
static struct kmem_cache *ext4_pspace_cachep;
static struct kmem_cache *ext4_ac_cachep;
static struct kmem_cache *ext4_free_data_cachep;
/* We create slab caches for groupinfo data structures based on the
* superblock block size. There will be one per mounted filesystem for
* each unique s_blocksize_bits */
#define NR_GRPINFO_CACHES 8
static struct kmem_cache *ext4_groupinfo_caches[NR_GRPINFO_CACHES];
static const char *ext4_groupinfo_slab_names[NR_GRPINFO_CACHES] = {
"ext4_groupinfo_1k", "ext4_groupinfo_2k", "ext4_groupinfo_4k",
"ext4_groupinfo_8k", "ext4_groupinfo_16k", "ext4_groupinfo_32k",
"ext4_groupinfo_64k", "ext4_groupinfo_128k"
};
static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
ext4_group_t group);
static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
ext4_group_t group);
static void ext4_free_data_callback(struct super_block *sb,
struct ext4_journal_cb_entry *jce, int rc);
static inline void *mb_correct_addr_and_bit(int *bit, void *addr)
{
#if BITS_PER_LONG == 64
*bit += ((unsigned long) addr & 7UL) << 3;
addr = (void *) ((unsigned long) addr & ~7UL);
#elif BITS_PER_LONG == 32
*bit += ((unsigned long) addr & 3UL) << 3;
addr = (void *) ((unsigned long) addr & ~3UL);
#else
#error "how many bits you are?!"
#endif
return addr;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| aneesh kumar | aneesh kumar | 79 | 79.00% | 1 | 50.00% |
| alex tomas | alex tomas | 21 | 21.00% | 1 | 50.00% |
| Total | 100 | 100.00% | 2 | 100.00% |
static inline int mb_test_bit(int bit, void *addr)
{
/*
* ext4_test_bit on architecture like powerpc
* needs unsigned long aligned address
*/
addr = mb_correct_addr_and_bit(&bit, addr);
return ext4_test_bit(bit, addr);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| alex tomas | alex tomas | 30 | 90.91% | 1 | 50.00% |
| aneesh kumar | aneesh kumar | 3 | 9.09% | 1 | 50.00% |
| Total | 33 | 100.00% | 2 | 100.00% |
static inline void mb_set_bit(int bit, void *addr)
{
addr = mb_correct_addr_and_bit(&bit, addr);
ext4_set_bit(bit, addr);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| alex tomas | alex tomas | 28 | 90.32% | 1 | 50.00% |
| aneesh kumar | aneesh kumar | 3 | 9.68% | 1 | 50.00% |
| Total | 31 | 100.00% | 2 | 100.00% |
static inline void mb_clear_bit(int bit, void *addr)
{
addr = mb_correct_addr_and_bit(&bit, addr);
ext4_clear_bit(bit, addr);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| alex tomas | alex tomas | 28 | 90.32% | 1 | 50.00% |
| aneesh kumar | aneesh kumar | 3 | 9.68% | 1 | 50.00% |
| Total | 31 | 100.00% | 2 | 100.00% |
static inline int mb_test_and_clear_bit(int bit, void *addr)
{
addr = mb_correct_addr_and_bit(&bit, addr);
return ext4_test_and_clear_bit(bit, addr);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| andrey sidorov | andrey sidorov | 32 | 100.00% | 1 | 100.00% |
| Total | 32 | 100.00% | 1 | 100.00% |
static inline int mb_find_next_zero_bit(void *addr, int max, int start)
{
int fix = 0, ret, tmpmax;
addr = mb_correct_addr_and_bit(&fix, addr);
tmpmax = max + fix;
start += fix;
ret = ext4_find_next_zero_bit(addr, tmpmax, start) - fix;
if (ret > max)
return max;
return ret;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| aneesh kumar | aneesh kumar | 71 | 100.00% | 2 | 100.00% |
| Total | 71 | 100.00% | 2 | 100.00% |
static inline int mb_find_next_bit(void *addr, int max, int start)
{
int fix = 0, ret, tmpmax;
addr = mb_correct_addr_and_bit(&fix, addr);
tmpmax = max + fix;
start += fix;
ret = ext4_find_next_bit(addr, tmpmax, start) - fix;
if (ret > max)
return max;
return ret;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| aneesh kumar | aneesh kumar | 71 | 100.00% | 2 | 100.00% |
| Total | 71 | 100.00% | 2 | 100.00% |
static void *mb_find_buddy(struct ext4_buddy *e4b, int order, int *max)
{
char *bb;
BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
BUG_ON(max == NULL);
if (order > e4b->bd_blkbits + 1) {
*max = 0;
return NULL;
}
/* at order 0 we see each particular block */
if (order == 0) {
*max = 1 << (e4b->bd_blkbits + 3);
return e4b->bd_bitmap;
}
bb = e4b->bd_buddy + EXT4_SB(e4b->bd_sb)->s_mb_offsets[order];
*max = EXT4_SB(e4b->bd_sb)->s_mb_maxs[order];
return bb;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| alex tomas | alex tomas | 108 | 87.10% | 1 | 33.33% |
| theodore tso | theodore tso | 8 | 6.45% | 1 | 33.33% |
| coly li | coly li | 8 | 6.45% | 1 | 33.33% |
| Total | 124 | 100.00% | 3 | 100.00% |
#ifdef DOUBLE_CHECK
static void mb_free_blocks_double(struct inode *inode, struct ext4_buddy *e4b,
int first, int count)
{
int i;
struct super_block *sb = e4b->bd_sb;
if (unlikely(e4b->bd_info->bb_bitmap == NULL))
return;
assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
for (i = 0; i < count; i++) {
if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) {
ext4_fsblk_t blocknr;
blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
blocknr += EXT4_C2B(EXT4_SB(sb), first + i);
ext4_grp_locked_error(sb, e4b->bd_group,
inode ? inode->i_ino : 0,
blocknr,
"freeing block already freed "
"(bit %u)",
first + i);
}
mb_clear_bit(first + i, e4b->bd_info->bb_bitmap);
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| alex tomas | alex tomas | 138 | 86.25% | 1 | 16.67% |
| theodore tso | theodore tso | 11 | 6.88% | 2 | 33.33% |
| aneesh kumar | aneesh kumar | 5 | 3.12% | 1 | 16.67% |
| akinobu mita | akinobu mita | 4 | 2.50% | 1 | 16.67% |
| vincent minet | vincent minet | 2 | 1.25% | 1 | 16.67% |
| Total | 160 | 100.00% | 6 | 100.00% |
static void mb_mark_used_double(struct ext4_buddy *e4b, int first, int count)
{
int i;
if (unlikely(e4b->bd_info->bb_bitmap == NULL))
return;
assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
for (i = 0; i < count; i++) {
BUG_ON(mb_test_bit(first + i, e4b->bd_info->bb_bitmap));
mb_set_bit(first + i, e4b->bd_info->bb_bitmap);
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| alex tomas | alex tomas | 90 | 97.83% | 1 | 50.00% |
| vincent minet | vincent minet | 2 | 2.17% | 1 | 50.00% |
| Total | 92 | 100.00% | 2 | 100.00% |
static void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
{
if (memcmp(e4b->bd_info->bb_bitmap, bitmap, e4b->bd_sb->s_blocksize)) {
unsigned char *b1, *b2;
int i;
b1 = (unsigned char *) e4b->bd_info->bb_bitmap;
b2 = (unsigned char *) bitmap;
for (i = 0; i < e4b->bd_sb->s_blocksize; i++) {
if (b1[i] != b2[i]) {
ext4_msg(e4b->bd_sb, KERN_ERR,
"corruption in group %u "
"at byte %u(%u): %x in copy != %x "
"on disk/prealloc",
e4b->bd_group, i, i * 8, b1[i], b2[i]);
BUG();
}
}
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| alex tomas | alex tomas | 128 | 92.75% | 1 | 25.00% |
| theodore tso | theodore tso | 10 | 7.25% | 3 | 75.00% |
| Total | 138 | 100.00% | 4 | 100.00% |
#else
static inline void mb_free_blocks_double(struct inode *inode,
struct ext4_buddy *e4b, int first, int count)
{
return;
}
Contributors
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| alex tomas | alex tomas | 24 | 100.00% | 1 | 100.00% |
| Total | 24 | 100.00% | 1 | 100.00% |
static inline void mb_mark_used_double(struct ext4_buddy *e4b,
int first, int count)
{
return;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| alex tomas | alex tomas | 19 | 100.00% | 1 | 100.00% |
| Total | 19 | 100.00% | 1 | 100.00% |
static inline void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
{
return;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| alex tomas | alex tomas | 17 | 100.00% | 1 | 100.00% |
| Total | 17 | 100.00% | 1 | 100.00% |
#endif
#ifdef AGGRESSIVE_CHECK
#define MB_CHECK_ASSERT(assert) \
do { \
if (!(assert)) { \
printk(KERN_EMERG \
"Assertion failure in %s() at %s:%d: \"%s\"\n", \
function, file, line, # assert); \
BUG(); \
} \
} while (0)
static int __mb_check_buddy(struct ext4_buddy *e4b, char *file,
const char *function, int line)
{
struct super_block *sb = e4b->bd_sb;
int order = e4b->bd_blkbits + 1;
int max;
int max2;
int i;
int j;
int k;
int count;
struct ext4_group_info *grp;
int fragments = 0;
int fstart;
struct list_head *cur;
void *buddy;
void *buddy2;
{
static int mb_check_counter;
if (mb_check_counter++ % 100 != 0)
return 0;
}
while (order > 1) {
buddy = mb_find_buddy(e4b, order, &max);
MB_CHECK_ASSERT(buddy);
buddy2 = mb_find_buddy(e4b, order - 1, &max2);
MB_CHECK_ASSERT(buddy2);
MB_CHECK_ASSERT(buddy != buddy2);
MB_CHECK_ASSERT(max * 2 == max2);
count = 0;
for (i = 0; i < max; i++) {
if (mb_test_bit(i, buddy)) {
/* only single bit in buddy2 may be 1 */
if (!mb_test_bit(i << 1, buddy2)) {
MB_CHECK_ASSERT(
mb_test_bit((i<<1)+1, buddy2));
} else if (!mb_test_bit((i << 1) + 1, buddy2)) {
MB_CHECK_ASSERT(
mb_test_bit(i << 1, buddy2));
}
continue;
}
/* both bits in buddy2 must be 1 */
MB_CHECK_ASSERT(mb_test_bit(i << 1, buddy2));
MB_CHECK_ASSERT(mb_test_bit((i << 1) + 1, buddy2));
for (j = 0; j < (1 << order); j++) {
k = (i * (1 << order)) + j;
MB_CHECK_ASSERT(
!mb_test_bit(k, e4b->bd_bitmap));
}
count++;
}
MB_CHECK_ASSERT(e4b->bd_info->bb_counters[order] == count);
order--;
}
fstart = -1;
buddy = mb_find_buddy(e4b, 0, &max);
for (i = 0; i < max; i++) {
if (!mb_test_bit(i, buddy)) {
MB_CHECK_ASSERT(i >= e4b->bd_info->bb_first_free);
if (fstart == -1) {
fragments++;
fstart = i;
}
continue;
}
fstart = -1;
/* check used bits only */
for (j = 0; j < e4b->bd_blkbits + 1; j++) {
buddy2 = mb_find_buddy(e4b, j, &max2);
k = i >> j;
MB_CHECK_ASSERT(k < max2);
MB_CHECK_ASSERT(mb_test_bit(k, buddy2));
}
}
MB_CHECK_ASSERT(!EXT4_MB_GRP_NEED_INIT(e4b->bd_info));
MB_CHECK_ASSERT(e4b->bd_info->bb_fragments == fragments);
grp = ext4_get_group_info(sb, e4b->bd_group);
list_for_each(cur, &grp->bb_prealloc_list) {
ext4_group_t groupnr;
struct ext4_prealloc_space *pa;
pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &groupnr, &k);
MB_CHECK_ASSERT(groupnr == e4b->bd_group);
for (i = 0; i < pa->pa_len; i++)
MB_CHECK_ASSERT(mb_test_bit(k + i, buddy));
}
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| alex tomas | alex tomas | 592 | 99.00% | 1 | 25.00% |
| solofo ramangalahy | solofo ramangalahy | 3 | 0.50% | 1 | 25.00% |
| theodore tso | theodore tso | 2 | 0.33% | 1 | 25.00% |
| robin dong | robin dong | 1 | 0.17% | 1 | 25.00% |
| Total | 598 | 100.00% | 4 | 100.00% |
#undef MB_CHECK_ASSERT
#define mb_check_buddy(e4b) __mb_check_buddy(e4b, \
__FILE__, __func__, __LINE__)
#else
#define mb_check_buddy(e4b)
#endif
/*
* Divide blocks started from @first with length @len into
* smaller chunks with power of 2 blocks.
* Clear the bits in bitmap which the blocks of the chunk(s) covered,
* then increase bb_counters[] for corresponded chunk size.
*/
static void ext4_mb_mark_free_simple(struct super_block *sb,
void *buddy, ext4_grpblk_t first, ext4_grpblk_t len,
struct ext4_group_info *grp)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_grpblk_t min;
ext4_grpblk_t max;
ext4_grpblk_t chunk;
unsigned int border;
BUG_ON(len > EXT4_CLUSTERS_PER_GROUP(sb));
border = 2 << sb->s_blocksize_bits;
while (len > 0) {
/* find how many blocks can be covered since this position */
max = ffs(first | border) - 1;
/* find how many blocks of power 2 we need to mark */
min = fls(len) - 1;
if (max < min)
min = max;
chunk = 1 << min;
/* mark multiblock chunks only */
grp->bb_counters[min]++;
if (min > 0)
mb_clear_bit(first >> min,
buddy + sbi->s_mb_offsets[min]);
len -= chunk;
first += chunk;
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| alex tomas | alex tomas | 144 | 94.74% | 1 | 20.00% |
| eric sandeen | eric sandeen | 5 | 3.29% | 1 | 20.00% |
| chandan rajendra | chandan rajendra | 1 | 0.66% | 1 | 20.00% |
| valerie clement | valerie clement | 1 | 0.66% | 1 | 20.00% |
| theodore tso | theodore tso | 1 | 0.66% | 1 | 20.00% |
| Total | 152 | 100.00% | 5 | 100.00% |
/*
* Cache the order of the largest free extent we have available in this block
* group.
*/
static void
mb_set_largest_free_order(struct super_block *sb, struct ext4_group_info *grp)
{
int i;
int bits;
grp->bb_largest_free_order = -1; /* uninit */
bits = sb->s_blocksize_bits + 1;
for (i = bits; i >= 0; i--) {
if (grp->bb_counters[i] > 0) {
grp->bb_largest_free_order = i;
break;
}
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| curt wohlgemuth | curt wohlgemuth | 73 | 100.00% | 1 | 100.00% |
| Total | 73 | 100.00% | 1 | 100.00% |
static noinline_for_stack
void ext4_mb_generate_buddy(struct super_block *sb,
void *buddy, void *bitmap, ext4_group_t group)
{
struct ext4_group_info *grp = ext4_get_group_info(sb, group);
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
ext4_grpblk_t i = 0;
ext4_grpblk_t first;
ext4_grpblk_t len;
unsigned free = 0;
unsigned fragments = 0;
unsigned long long period = get_cycles();
/* initialize buddy from bitmap which is aggregation
* of on-disk bitmap and preallocations */
i = mb_find_next_zero_bit(bitmap, max, 0);
grp->bb_first_free = i;
while (i < max) {
fragments++;
first = i;
i = mb_find_next_bit(bitmap, max, i);
len = i - first;
free += len;
if (len > 1)
ext4_mb_mark_free_simple(sb, buddy, first, len, grp);
else
grp->bb_counters[0]++;
if (i < max)
i = mb_find_next_zero_bit(bitmap, max, i);
}
grp->bb_fragments = fragments;
if (free != grp->bb_free) {
ext4_grp_locked_error(sb, group, 0, 0,
"block bitmap and bg descriptor "
"inconsistent: %u vs %u free clusters",
free, grp->bb_free);
/*
* If we intend to continue, we consider group descriptor
* corrupt and update bb_free using bitmap value
*/
grp->bb_free = free;
if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
percpu_counter_sub(&sbi->s_freeclusters_counter,
grp->bb_free);
set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
}
mb_set_largest_free_order(sb, grp);
clear_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state));
period = get_cycles() - period;
spin_lock(&EXT4_SB(sb)->s_bal_lock);
EXT4_SB(sb)->s_mb_buddies_generated++;
EXT4_SB(sb)->s_mb_generation_time += period;
spin_unlock(&EXT4_SB(sb)->s_bal_lock);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| alex tomas | alex tomas | 252 | 79.00% | 1 | 8.33% |
| namjae jeon | namjae jeon | 30 | 9.40% | 1 | 8.33% |
| darrick j. wong | darrick j. wong | 11 | 3.45% | 1 | 8.33% |
| aneesh kumar | aneesh kumar | 9 | 2.82% | 3 | 25.00% |
| curt wohlgemuth | curt wohlgemuth | 7 | 2.19% | 1 | 8.33% |
| theodore tso | theodore tso | 5 | 1.57% | 3 | 25.00% |
| eric sandeen | eric sandeen | 5 | 1.57% | 2 | 16.67% |
| Total | 319 | 100.00% | 12 | 100.00% |
static void mb_regenerate_buddy(struct ext4_buddy *e4b)
{
int count;
int order = 1;
void *buddy;
while ((buddy = mb_find_buddy(e4b, order++, &count))) {
ext4_set_bits(buddy, 0, count);
}
e4b->bd_info->bb_fragments = 0;
memset(e4b->bd_info->bb_counters, 0,
sizeof(*e4b->bd_info->bb_counters) *
(e4b->bd_sb->s_blocksize_bits + 2));
ext4_mb_generate_buddy(e4b->bd_sb, e4b->bd_buddy,
e4b->bd_bitmap, e4b->bd_group);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| andrey sidorov | andrey sidorov | 109 | 100.00% | 1 | 100.00% |
| Total | 109 | 100.00% | 1 | 100.00% |
/* The buddy information is attached the buddy cache inode
* for convenience. The information regarding each group
* is loaded via ext4_mb_load_buddy. The information involve
* block bitmap and buddy information. The information are
* stored in the inode as
*
* { page }
* [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
*
*
* one block each for bitmap and buddy information.
* So for each group we take up 2 blocks. A page can
* contain blocks_per_page (PAGE_SIZE / blocksize) blocks.
* So it can have information regarding groups_per_page which
* is blocks_per_page/2
*
* Locking note: This routine takes the block group lock of all groups
* for this page; do not hold this lock when calling this routine!
*/
static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp)
{
ext4_group_t ngroups;
int blocksize;
int blocks_per_page;
int groups_per_page;
int err = 0;
int i;
ext4_group_t first_group, group;
int first_block;
struct super_block *sb;
struct buffer_head *bhs;
struct buffer_head **bh = NULL;
struct inode *inode;
char *data;
char *bitmap;
struct ext4_group_info *grinfo;
mb_debug(1, "init page %lu\n", page->index);
inode = page->mapping->host;
sb = inode->i_sb;
ngroups = ext4_get_groups_count(sb);
blocksize = 1 << inode->i_blkbits;
blocks_per_page = PAGE_SIZE / blocksize;
groups_per_page = blocks_per_page >> 1;
if (groups_per_page == 0)
groups_per_page = 1;
/* allocate buffer_heads to read bitmaps */
if (groups_per_page > 1) {
i = sizeof(struct buffer_head *) * groups_per_page;
bh = kzalloc(i, gfp);
if (bh == NULL) {
err = -ENOMEM;
goto out;
}
} else
bh = &bhs;
first_group = page->index * blocks_per_page / 2;
/* read all groups the page covers into the cache */
for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
if (group >= ngroups)
break;
grinfo = ext4_get_group_info(sb, group);
/*
* If page is uptodate then we came here after online resize
* which added some new uninitialized group info structs, so
* we must skip all initialized uptodate buddies on the page,
* which may be currently in use by an allocating task.
*/
if (PageUptodate(page) && !EXT4_MB_GRP_NEED_INIT(grinfo)) {
bh[i] = NULL;
continue;
}
bh[i] = ext4_read_block_bitmap_nowait(sb, group);
if (IS_ERR(bh[i])) {
err = PTR_ERR(bh[i]);
bh[i] = NULL;
goto out;
}
mb_debug(1, "read bitmap for group %u\n", group);
}
/* wait for I/O completion */
for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
int err2;
if (!bh[i])
continue;
err2 = ext4_wait_block_bitmap(sb, group, bh[i]);
if (!err)
err = err2;
}
first_block = page->index * blocks_per_page;
for (i = 0; i < blocks_per_page; i++) {
group = (first_block + i) >> 1;
if (group >= ngroups)
break;
if (!bh[group - first_group])
/* skip initialized uptodate buddy */
continue;
if (!buffer_verified(bh[group - first_group]))
/* Skip faulty bitmaps */
continue;
err = 0;
/*
* data carry information regarding this
* particular group in the format specified
* above
*
*/
data = page_address(page) + (i * blocksize);
bitmap = bh[group - first_group]->b_data;
/*
* We place the buddy block and bitmap block
* close together
*/
if ((first_block + i) & 1) {
/* this is block of buddy */
BUG_ON(incore == NULL);
mb_debug(1, "put buddy for group %u in page %lu/%x\n",
group, page->index, i * blocksize);