| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com |
| * Written by Alex Tomas <alex@clusterfs.com> |
| */ |
| |
| |
| /* |
| * 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/nospec.h> |
| #include <linux/backing-dev.h> |
| #include <trace/events/ext4.h> |
| |
| /* |
| * 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 |
| * smallest multiple of the stripe value (sbi->s_stripe) which is |
| * greater than the default mb_group_prealloc. |
| * |
| * If "mb_optimize_scan" mount option is set, we maintain in memory group info |
| * structures in two data structures: |
| * |
| * 1) Array of largest free order lists (sbi->s_mb_largest_free_orders) |
| * |
| * Locking: sbi->s_mb_largest_free_orders_locks(array of rw locks) |
| * |
| * This is an array of lists where the index in the array represents the |
| * largest free order in the buddy bitmap of the participating group infos of |
| * that list. So, there are exactly MB_NUM_ORDERS(sb) (which means total |
| * number of buddy bitmap orders possible) number of lists. Group-infos are |
| * placed in appropriate lists. |
| * |
| * 2) Average fragment size rb tree (sbi->s_mb_avg_fragment_size_root) |
| * |
| * Locking: sbi->s_mb_rb_lock (rwlock) |
| * |
| * This is a red black tree consisting of group infos and the tree is sorted |
| * by average fragment sizes (which is calculated as ext4_group_info->bb_free |
| * / ext4_group_info->bb_fragments). |
| * |
| * When "mb_optimize_scan" mount option is set, mballoc consults the above data |
| * structures to decide the order in which groups are to be traversed for |
| * fulfilling an allocation request. |
| * |
| * At CR = 0, we look for groups which have the largest_free_order >= the order |
| * of the request. We directly look at the largest free order list in the data |
| * structure (1) above where largest_free_order = order of the request. If that |
| * list is empty, we look at remaining list in the increasing order of |
| * largest_free_order. This allows us to perform CR = 0 lookup in O(1) time. |
| * |
| * At CR = 1, we only consider groups where average fragment size > request |
| * size. So, we lookup a group which has average fragment size just above or |
| * equal to request size using our rb tree (data structure 2) in O(log N) time. |
| * |
| * If "mb_optimize_scan" mount option is not set, mballoc traverses groups in |
| * linear order which requires O(N) search time for each CR 0 and CR 1 phase. |
| * |
| * 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 |
| * /sys/fs/ext4/<partition>/mb_linear_limit |
| * |
| * 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. |
| * |
| * When "mb_optimize_scan" is turned on, as mentioned above, the groups may not |
| * get traversed linearly. That may result in subsequent allocations being not |
| * close to each other. And so, the underlying device may get filled up in a |
| * non-linear fashion. While that may not matter on non-rotational devices, for |
| * rotational devices that may result in higher seek times. "mb_linear_limit" |
| * tells mballoc how many groups mballoc should search linearly before |
| * performing consulting above data structures for more efficient lookups. For |
| * non rotational devices, this value defaults to 0 and for rotational devices |
| * this is set to MB_DEFAULT_LINEAR_LIMIT. |
| * |
| * 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) |
| * - cr0 lists lock (cr0) |
| * - cr1 tree lock (cr1) |
| * |
| * 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 |
| * |
| * - allocation path (ext4_mb_regular_allocator) |
| * group |
| * cr0/cr1 |
| */ |
| 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 * const 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_mb_new_preallocation(struct ext4_allocation_context *ac); |
| |
| static bool ext4_mb_good_group(struct ext4_allocation_context *ac, |
| ext4_group_t group, int cr); |
| |
| static int ext4_try_to_trim_range(struct super_block *sb, |
| struct ext4_buddy *e4b, ext4_grpblk_t start, |
| ext4_grpblk_t max, ext4_grpblk_t minblocks); |
| |
| /* |
| * The algorithm using this percpu seq counter goes below: |
| * 1. We sample the percpu discard_pa_seq counter before trying for block |
| * allocation in ext4_mb_new_blocks(). |
| * 2. We increment this percpu discard_pa_seq counter when we either allocate |
| * or free these blocks i.e. while marking those blocks as used/free in |
| * mb_mark_used()/mb_free_blocks(). |
| * 3. We also increment this percpu seq counter when we successfully identify |
| * that the bb_prealloc_list is not empty and hence proceed for discarding |
| * of those PAs inside ext4_mb_discard_group_preallocations(). |
| * |
| * Now to make sure that the regular fast path of block allocation is not |
| * affected, as a small optimization we only sample the percpu seq counter |
| * on that cpu. Only when the block allocation fails and when freed blocks |
| * found were 0, that is when we sample percpu seq counter for all cpus using |
| * below function ext4_get_discard_pa_seq_sum(). This happens after making |
| * sure that all the PAs on grp->bb_prealloc_list got freed or if it's empty. |
| */ |
| static DEFINE_PER_CPU(u64, discard_pa_seq); |
| static inline u64 ext4_get_discard_pa_seq_sum(void) |
| { |
| int __cpu; |
| u64 __seq = 0; |
| |
| for_each_possible_cpu(__cpu) |
| __seq += per_cpu(discard_pa_seq, __cpu); |
| return __seq; |
| } |
| |
| 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; |
| } |
| |
| 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); |
| } |
| |
| static inline void mb_set_bit(int bit, void *addr) |
| { |
| addr = mb_correct_addr_and_bit(&bit, addr); |
| ext4_set_bit(bit, addr); |
| } |
| |
| static inline void mb_clear_bit(int bit, void *addr) |
| { |
| addr = mb_correct_addr_and_bit(&bit, addr); |
| ext4_clear_bit(bit, addr); |
| } |
| |
| 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); |
| } |
| |
| 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; |
| } |
| |
| 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; |
| } |
| |
| 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; |
| } |
| |
| #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); |
| ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group, |
| EXT4_GROUP_INFO_BBITMAP_CORRUPT); |
| } |
| mb_clear_bit(first + i, e4b->bd_info->bb_bitmap); |
| } |
| } |
| |
| 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); |
| } |
| } |
| |
| static void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap) |
| { |
| if (unlikely(e4b->bd_info->bb_bitmap == NULL)) |
| return; |
| 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(); |
| } |
| } |
| } |
| } |
| |
| static void mb_group_bb_bitmap_alloc(struct super_block *sb, |
| struct ext4_group_info *grp, ext4_group_t group) |
| { |
| struct buffer_head *bh; |
| |
| grp->bb_bitmap = kmalloc(sb->s_blocksize, GFP_NOFS); |
| if (!grp->bb_bitmap) |
| return; |
| |
| bh = ext4_read_block_bitmap(sb, group); |
| if (IS_ERR_OR_NULL(bh)) { |
| kfree(grp->bb_bitmap); |
| grp->bb_bitmap = NULL; |
| return; |
| } |
| |
| memcpy(grp->bb_bitmap, bh->b_data, sb->s_blocksize); |
| put_bh(bh); |
| } |
| |
| static void mb_group_bb_bitmap_free(struct ext4_group_info *grp) |
| { |
| kfree(grp->bb_bitmap); |
| } |
| |
| #else |
| static inline void mb_free_blocks_double(struct inode *inode, |
| struct ext4_buddy *e4b, int first, int count) |
| { |
| return; |
| } |
| static inline void mb_mark_used_double(struct ext4_buddy *e4b, |
| int first, int count) |
| { |
| return; |
| } |
| static inline void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap) |
| { |
| return; |
| } |
| |
| static inline void mb_group_bb_bitmap_alloc(struct super_block *sb, |
| struct ext4_group_info *grp, ext4_group_t group) |
| { |
| return; |
| } |
| |
| static inline void mb_group_bb_bitmap_free(struct ext4_group_info *grp) |
| { |
| return; |
| } |
| #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; |
| |
| if (e4b->bd_info->bb_check_counter++ % 10) |
| 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 0 */ |
| if (!mb_test_bit(i << 1, buddy2)) { |
| MB_CHECK_ASSERT( |
| mb_test_bit((i<<1)+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; |
| } |
| #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; |
| } |
| } |
| |
| static void ext4_mb_rb_insert(struct rb_root *root, struct rb_node *new, |
| int (*cmp)(struct rb_node *, struct rb_node *)) |
| { |
| struct rb_node **iter = &root->rb_node, *parent = NULL; |
| |
| while (*iter) { |
| parent = *iter; |
| if (cmp(new, *iter) > 0) |
| iter = &((*iter)->rb_left); |
| else |
| iter = &((*iter)->rb_right); |
| } |
| |
| rb_link_node(new, parent, iter); |
| rb_insert_color(new, root); |
| } |
| |
| static int |
| ext4_mb_avg_fragment_size_cmp(struct rb_node *rb1, struct rb_node *rb2) |
| { |
| struct ext4_group_info *grp1 = rb_entry(rb1, |
| struct ext4_group_info, |
| bb_avg_fragment_size_rb); |
| struct ext4_group_info *grp2 = rb_entry(rb2, |
| struct ext4_group_info, |
| bb_avg_fragment_size_rb); |
| int num_frags_1, num_frags_2; |
| |
| num_frags_1 = grp1->bb_fragments ? |
| grp1->bb_free / grp1->bb_fragments : 0; |
| num_frags_2 = grp2->bb_fragments ? |
| grp2->bb_free / grp2->bb_fragments : 0; |
| |
| return (num_frags_2 - num_frags_1); |
| } |
| |
| /* |
| * Reinsert grpinfo into the avg_fragment_size tree with new average |
| * fragment size. |
| */ |
| static void |
| mb_update_avg_fragment_size(struct super_block *sb, struct ext4_group_info *grp) |
| { |
| struct ext4_sb_info *sbi = EXT4_SB(sb); |
| |
| if (!test_opt2(sb, MB_OPTIMIZE_SCAN) || grp->bb_free == 0) |
| return; |
| |
| write_lock(&sbi->s_mb_rb_lock); |
| if (!RB_EMPTY_NODE(&grp->bb_avg_fragment_size_rb)) { |
| rb_erase(&grp->bb_avg_fragment_size_rb, |
| &sbi->s_mb_avg_fragment_size_root); |
| RB_CLEAR_NODE(&grp->bb_avg_fragment_size_rb); |
| } |
| |
| ext4_mb_rb_insert(&sbi->s_mb_avg_fragment_size_root, |
| &grp->bb_avg_fragment_size_rb, |
| ext4_mb_avg_fragment_size_cmp); |
| write_unlock(&sbi->s_mb_rb_lock); |
| } |
| |
| /* |
| * Choose next group by traversing largest_free_order lists. Updates *new_cr if |
| * cr level needs an update. |
| */ |
| static void ext4_mb_choose_next_group_cr0(struct ext4_allocation_context *ac, |
| int *new_cr, ext4_group_t *group, ext4_group_t ngroups) |
| { |
| struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); |
| struct ext4_group_info *iter, *grp; |
| int i; |
| |
| if (ac->ac_status == AC_STATUS_FOUND) |
| return; |
| |
| if (unlikely(sbi->s_mb_stats && ac->ac_flags & EXT4_MB_CR0_OPTIMIZED)) |
| atomic_inc(&sbi->s_bal_cr0_bad_suggestions); |
| |
| grp = NULL; |
| for (i = ac->ac_2order; i < MB_NUM_ORDERS(ac->ac_sb); i++) { |
| if (list_empty(&sbi->s_mb_largest_free_orders[i])) |
| continue; |
| read_lock(&sbi->s_mb_largest_free_orders_locks[i]); |
| if (list_empty(&sbi->s_mb_largest_free_orders[i])) { |
| read_unlock(&sbi->s_mb_largest_free_orders_locks[i]); |
| continue; |
| } |
| grp = NULL; |
| list_for_each_entry(iter, &sbi->s_mb_largest_free_orders[i], |
| bb_largest_free_order_node) { |
| if (sbi->s_mb_stats) |
| atomic64_inc(&sbi->s_bal_cX_groups_considered[0]); |
| if (likely(ext4_mb_good_group(ac, iter->bb_group, 0))) { |
| grp = iter; |
| break; |
| } |
| } |
| read_unlock(&sbi->s_mb_largest_free_orders_locks[i]); |
| if (grp) |
| break; |
| } |
| |
| if (!grp) { |
| /* Increment cr and search again */ |
| *new_cr = 1; |
| } else { |
| *group = grp->bb_group; |
| ac->ac_last_optimal_group = *group; |
| ac->ac_flags |= EXT4_MB_CR0_OPTIMIZED; |
| } |
| } |
| |
| /* |
| * Choose next group by traversing average fragment size tree. Updates *new_cr |
| * if cr lvel needs an update. Sets EXT4_MB_SEARCH_NEXT_LINEAR to indicate that |
| * the linear search should continue for one iteration since there's lock |
| * contention on the rb tree lock. |
| */ |
| static void ext4_mb_choose_next_group_cr1(struct ext4_allocation_context *ac, |
| int *new_cr, ext4_group_t *group, ext4_group_t ngroups) |
| { |
| struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); |
| int avg_fragment_size, best_so_far; |
| struct rb_node *node, *found; |
| struct ext4_group_info *grp; |
| |
| /* |
| * If there is contention on the lock, instead of waiting for the lock |
| * to become available, just continue searching lineraly. We'll resume |
| * our rb tree search later starting at ac->ac_last_optimal_group. |
| */ |
| if (!read_trylock(&sbi->s_mb_rb_lock)) { |
| ac->ac_flags |= EXT4_MB_SEARCH_NEXT_LINEAR; |
| return; |
| } |
| |
| if (unlikely(ac->ac_flags & EXT4_MB_CR1_OPTIMIZED)) { |
| if (sbi->s_mb_stats) |
| atomic_inc(&sbi->s_bal_cr1_bad_suggestions); |
| /* We have found something at CR 1 in the past */ |
| grp = ext4_get_group_info(ac->ac_sb, ac->ac_last_optimal_group); |
| for (found = rb_next(&grp->bb_avg_fragment_size_rb); found != NULL; |
| found = rb_next(found)) { |
| grp = rb_entry(found, struct ext4_group_info, |
| bb_avg_fragment_size_rb); |
| if (sbi->s_mb_stats) |
| atomic64_inc(&sbi->s_bal_cX_groups_considered[1]); |
| if (likely(ext4_mb_good_group(ac, grp->bb_group, 1))) |
| break; |
| } |
| goto done; |
| } |
| |
| node = sbi->s_mb_avg_fragment_size_root.rb_node; |
| best_so_far = 0; |
| found = NULL; |
| |
| while (node) { |
| grp = rb_entry(node, struct ext4_group_info, |
| bb_avg_fragment_size_rb); |
| avg_fragment_size = 0; |
| if (ext4_mb_good_group(ac, grp->bb_group, 1)) { |
| avg_fragment_size = grp->bb_fragments ? |
| grp->bb_free / grp->bb_fragments : 0; |
| if (!best_so_far || avg_fragment_size < best_so_far) { |
| best_so_far = avg_fragment_size; |
| found = node; |
| } |
| } |
| if (avg_fragment_size > ac->ac_g_ex.fe_len) |
| node = node->rb_right; |
| else |
| node = node->rb_left; |
| } |
| |
| done: |
| if (found) { |
| grp = rb_entry(found, struct ext4_group_info, |
| bb_avg_fragment_size_rb); |
| *group = grp->bb_group; |
| ac->ac_flags |= EXT4_MB_CR1_OPTIMIZED; |
| } else { |
| *new_cr = 2; |
| } |
| |
| read_unlock(&sbi->s_mb_rb_lock); |
| ac->ac_last_optimal_group = *group; |
| } |
| |
| static inline int should_optimize_scan(struct ext4_allocation_context *ac) |
| { |
| if (unlikely(!test_opt2(ac->ac_sb, MB_OPTIMIZE_SCAN))) |
| return 0; |
| if (ac->ac_criteria >= 2) |
| return 0; |
| if (!ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)) |
| return 0; |
| return 1; |
| } |
| |
| /* |
| * Return next linear group for allocation. If linear traversal should not be |
| * performed, this function just returns the same group |
| */ |
| static int |
| next_linear_group(struct ext4_allocation_context *ac, int group, int ngroups) |
| { |
| if (!should_optimize_scan(ac)) |
| goto inc_and_return; |
| |
| if (ac->ac_groups_linear_remaining) { |
| ac->ac_groups_linear_remaining--; |
| goto inc_and_return; |
| } |
| |
| if (ac->ac_flags & EXT4_MB_SEARCH_NEXT_LINEAR) { |
| ac->ac_flags &= ~EXT4_MB_SEARCH_NEXT_LINEAR; |
| goto inc_and_return; |
| } |
| |
| return group; |
| inc_and_return: |
| /* |
| * Artificially restricted ngroups for non-extent |
| * files makes group > ngroups possible on first loop. |
| */ |
| return group + 1 >= ngroups ? 0 : group + 1; |
| } |
| |
| /* |
| * ext4_mb_choose_next_group: choose next group for allocation. |
| * |
| * @ac Allocation Context |
| * @new_cr This is an output parameter. If the there is no good group |
| * available at current CR level, this field is updated to indicate |
| * the new cr level that should be used. |
| * @group This is an input / output parameter. As an input it indicates the |
| * next group that the allocator intends to use for allocation. As |
| * output, this field indicates the next group that should be used as |
| * determined by the optimization functions. |
| * @ngroups Total number of groups |
| */ |
| static void ext4_mb_choose_next_group(struct ext4_allocation_context *ac, |
| int *new_cr, ext4_group_t *group, ext4_group_t ngroups) |
| { |
| *new_cr = ac->ac_criteria; |
| |
| if (!should_optimize_scan(ac) || ac->ac_groups_linear_remaining) |
| return; |
| |
| if (*new_cr == 0) { |
| ext4_mb_choose_next_group_cr0(ac, new_cr, group, ngroups); |
| } else if (*new_cr == 1) { |
| ext4_mb_choose_next_group_cr1(ac, new_cr, group, ngroups); |
| } else { |
| /* |
| * TODO: For CR=2, we can arrange groups in an rb tree sorted by |
| * bb_free. But until that happens, we should never come here. |
| */ |
| WARN_ON(1); |
| } |
| } |
| |
| /* |
| * 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) |
| { |
| struct ext4_sb_info *sbi = EXT4_SB(sb); |
| int i; |
| |
| if (test_opt2(sb, MB_OPTIMIZE_SCAN) && grp->bb_largest_free_order >= 0) { |
| write_lock(&sbi->s_mb_largest_free_orders_locks[ |
| grp->bb_largest_free_order]); |
| list_del_init(&grp->bb_largest_free_order_node); |
| write_unlock(&sbi->s_mb_largest_free_orders_locks[ |
| grp->bb_largest_free_order]); |
| } |
| grp->bb_largest_free_order = -1; /* uninit */ |
| |
| for (i = MB_NUM_ORDERS(sb) - 1; i >= 0; i--) { |
| if (grp->bb_counters[i] > 0) { |
| grp->bb_largest_free_order = i; |
| break; |
| } |
| } |
| if (test_opt2(sb, MB_OPTIMIZE_SCAN) && |
| grp->bb_largest_free_order >= 0 && grp->bb_free) { |
| write_lock(&sbi->s_mb_largest_free_orders_locks[ |
| grp->bb_largest_free_order]); |
| list_add_tail(&grp->bb_largest_free_order_node, |
| &sbi->s_mb_largest_free_orders[grp->bb_largest_free_order]); |
| write_unlock(&sbi->s_mb_largest_free_orders_locks[ |
| grp->bb_largest_free_order]); |
| } |
| } |
| |
| 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; |
| ext4_mark_group_bitmap_corrupted(sb, group, |
| EXT4_GROUP_INFO_BBITMAP_CORRUPT); |
| } |
| mb_set_largest_free_order(sb, grp); |
| |
| clear_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state)); |
| |
| period = get_cycles() - period; |
| atomic_inc(&sbi->s_mb_buddies_generated); |
| atomic64_add(period, &sbi->s_mb_generation_time); |
| mb_update_avg_fragment_size(sb, grp); |
| } |
| |
| /* 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; |
| |
| inode = page->mapping->host; |
| sb = inode->i_sb; |
| ngroups = ext4_get_groups_count(sb); |
| blocksize = i_blocksize(inode); |
| blocks_per_page = PAGE_SIZE / blocksize; |
| |
| mb_debug(sb, "init page %lu\n", page->index); |
| |
| 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, false); |
| if (IS_ERR(bh[i])) { |
| err = PTR_ERR(bh[i]); |
| bh[i] = NULL; |
| goto out; |
| } |
| mb_debug(sb, "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(sb, "put buddy for group %u in page %lu/%x\n", |
| group, page->index, i * blocksize); |
| trace_ext4_mb_buddy_bitmap_load(sb, group); |
| grinfo = ext4_get_group_info(sb, group); |
| grinfo->bb_fragments = 0; |
| memset(grinfo->bb_counters, 0, |
| sizeof(*grinfo->bb_counters) * |
| (MB_NUM_ORDERS(sb))); |
| /* |
| * incore got set to the group block bitmap below |
| */ |
| ext4_lock_group(sb, group); |
| /* init the buddy */ |
| memset(data, 0xff, blocksize); |
| ext4_mb_generate_buddy(sb, data, incore, group); |
| ext4_unlock_group(sb, group); |
| incore = NULL; |
| } else { |
| /* this is block of bitmap */ |
| BUG_ON(incore != NULL); |
| mb_debug(sb, "put bitmap for group %u in page %lu/%x\n", |
| group, page->index, i * blocksize); |
| trace_ext4_mb_bitmap_load(sb, group); |
| |
| /* see comments in ext4_mb_put_pa() */ |
| ext4_lock_group(sb, group); |
| memcpy(data, bitmap, blocksize); |
| |
| /* mark all preallocated blks used in in-core bitmap */ |
| ext4_mb_generate_from_pa(sb, data, group); |
| ext4_mb_generate_from_freelist(sb, data, group); |
| ext4_unlock_group(sb, group); |
| |
| /* set incore so that the buddy information can be |
| * generated using this |
| */ |
| incore = data; |
| } |
| } |
| SetPageUptodate(page); |
| |
| out: |
| if (bh) { |
| for (i = 0; i < groups_per_page; i++) |
| brelse(bh[i]); |
| if (bh != &bhs) |
| kfree(bh); |
| } |
| return err; |
| } |
| |
| /* |
| * Lock the buddy and bitmap pages. This make sure other parallel init_group |
| * on the same buddy page doesn't happen whild holding the buddy page lock. |
| * Return locked buddy and bitmap pages on e4b struct. If buddy and bitmap |
| * are on the same page e4b->bd_buddy_page is NULL and return value is 0. |
| */ |
| static int ext4_mb_get_buddy_page_lock(struct super_block *sb, |
| ext4_group_t group, struct ext4_buddy *e4b, gfp_t gfp) |
| { |
| struct inode *inode = EXT4_SB(sb)->s_buddy_cache; |
| int block, pnum, poff; |
| int blocks_per_page; |
| struct page *page; |
| |
| e4b->bd_buddy_page = NULL; |
| e4b->bd_bitmap_page = NULL; |
| |
| blocks_per_page = PAGE_SIZE / sb->s_blocksize; |
| /* |
| * the buddy cache inode stores the block bitmap |
| * and buddy information in consecutive blocks. |
| * So for each group we need two blocks. |
| */ |
| block = group * 2; |
| pnum = block / blocks_per_page; |
| poff = block % blocks_per_page; |
| page = find_or_create_page(inode->i_mapping, pnum, gfp); |
| if (!page) |
| return -ENOMEM; |
| BUG_ON(page->mapping != inode->i_mapping); |
| e4b->bd_bitmap_page = page; |
| e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize); |
| |
| if (blocks_per_page >= 2) { |
| /* buddy and bitmap are on the same page */ |
| return 0; |
| } |
| |
| block++; |
| pnum = block / blocks_per_page; |
| page = find_or_create_page(inode->i_mapping, pnum, gfp); |
| if (!page) |
| return -ENOMEM; |
| BUG_ON(page->mapping != inode->i_mapping); |
| e4b->bd_buddy_page = page; |
| return 0; |
| } |
| |
| static void ext4_mb_put_buddy_page_lock(struct ext4_buddy *e4b) |
| { |
| if (e4b->bd_bitmap_page) { |
| unlock_page(e4b->bd_bitmap_page); |
| put_page(e4b->bd_bitmap_page); |
| } |
| if (e4b->bd_buddy_page) { |
| unlock_page(e4b->bd_buddy_page); |
| put_page(e4b->bd_buddy_page); |
| } |
| } |
| |
| /* |
| * Locking note: This routine calls ext4_mb_init_cache(), which takes the |
| * block group lock of all groups for this page; do not hold the BG lock when |
| * calling this routine! |
| */ |
| static noinline_for_stack |
| int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp) |
| { |
| |
| struct ext4_group_info *this_grp; |
| struct ext4_buddy e4b; |
| struct page *page; |
| int ret = 0; |
| |
| might_sleep(); |
| mb_debug(sb, "init group %u\n", group); |
| this_grp = ext4_get_group_info(sb, group); |
| /* |
| * This ensures that we don't reinit the buddy cache |
| * page which map to the group from which we are already |
| * allocating. If we are looking at the buddy cache we would |
| * have taken a reference using ext4_mb_load_buddy and that |
| * would have pinned buddy page to page cache. |
| * The call to ext4_mb_get_buddy_page_lock will mark the |
| * page accessed. |
| */ |
| ret = ext4_mb_get_buddy_page_lock(sb, group, &e4b, gfp); |
| if (ret || !EXT4_MB_GRP_NEED_INIT(this_grp)) { |
| /* |
| * somebody initialized the group |
| * return without doing anything |
| */ |
| goto err; |
| } |
| |
| page = e4b.bd_bitmap_page; |
| ret = ext4_mb_init_cache(page, NULL, gfp); |
| if (ret) |
| goto err; |
| if (!PageUptodate(page)) { |
| ret = -EIO; |
| goto err; |
| } |
| |
| if (e4b.bd_buddy_page == NULL) { |
| /* |
| * If both the bitmap and buddy are in |
| * the same page we don't need to force |
| * init the buddy |
| */ |
| ret = 0; |
| goto err; |
| } |
| /* init buddy cache */ |
| page = e4b.bd_buddy_page; |
| ret = ext4_mb_init_cache(page, e4b.bd_bitmap, gfp); |
| if (ret) |
| goto err; |
| if (!PageUptodate(page)) { |
| ret = -EIO; |
| goto err; |
| } |
| err: |
| ext4_mb_put_buddy_page_lock(&e4b); |
| return ret; |
| } |
| |
| /* |
| * Locking note: This routine calls ext4_mb_init_cache(), which takes the |
| * block group lock of all groups for this page; do not hold the BG lock when |
| * calling this routine! |
| */ |
| static noinline_for_stack int |
| ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group, |
| struct ext4_buddy *e4b, gfp_t gfp) |
| { |
| int blocks_per_page; |
| int block; |
| int pnum; |
| int poff; |
| struct page *page; |
| int ret; |
| struct ext4_group_info *grp; |
| struct ext4_sb_info *sbi = EXT4_SB(sb); |
| struct inode *inode = sbi->s_buddy_cache; |
| |
| might_sleep(); |
| mb_debug(sb, "load group %u\n", group); |
| |
| blocks_per_page = PAGE_SIZE / sb->s_blocksize; |
| grp = ext4_get_group_info(sb, group); |
| |
| e4b->bd_blkbits = sb->s_blocksize_bits; |
| e4b->bd_info = grp; |
| e4b->bd_sb = sb; |
| e4b->bd_group = group; |
| e4b->bd_buddy_page = NULL; |
| e4b->bd_bitmap_page = NULL; |
| |
| if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) { |
| /* |
| * we need full data about the group |
| * to make a good selection |
| */ |
| ret = ext4_mb_init_group(sb, group, gfp); |
| if (ret) |
| return ret; |
| } |
| |
| /* |
| * the buddy cache inode stores the block bitmap |
| * and buddy information in consecutive blocks. |
| * So for each group we need two blocks. |
| */ |
| block = group * 2; |
| pnum = block / blocks_per_page; |
| poff = block % blocks_per_page; |
| |
| /* we could use find_or_create_page(), but it locks page |
| * what we'd like to avoid in fast path ... */ |
| page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED); |
| if (page == NULL || !PageUptodate(page)) { |
| if (page) |
| /* |
| * drop the page reference and try |
| * to get the page with lock. If we |
| * are not uptodate that implies |
| * somebody just created the page but |
| * is yet to initialize the same. So |
| * wait for it to initialize. |
| */ |
| put_page(page); |
| page = find_or_create_page(inode->i_mapping, pnum, gfp); |
| if (page) { |
| BUG_ON(page->mapping != inode->i_mapping); |
| if (!PageUptodate(page)) { |
| ret = ext4_mb_init_cache(page, NULL, gfp); |
| if (ret) { |
| unlock_page(page); |
| goto err; |
| } |
| mb_cmp_bitmaps(e4b, page_address(page) + |
| (poff * sb->s_blocksize)); |
| } |
| unlock_page(page); |
| } |
| } |
| if (page == NULL) { |
| ret = -ENOMEM; |
| goto err; |
| } |
| if (!PageUptodate(page)) { |
| ret = -EIO; |
| goto err; |
| } |
| |
| /* Pages marked accessed already */ |
| e4b->bd_bitmap_page = page; |
| e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize); |
| |
| block++; |
| pnum = block / blocks_per_page; |
| poff = block % blocks_per_page; |
| |
| page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED); |
| if (page == NULL || !PageUptodate(page)) { |
| if (page) |
| put_page(page); |
| page = find_or_create_page(inode->i_mapping, pnum, gfp); |
| if (page) { |
| BUG_ON(page->mapping != inode->i_mapping); |
| if (!PageUptodate(page)) { |
| ret = ext4_mb_init_cache(page, e4b->bd_bitmap, |
| gfp); |
| if (ret) { |
| unlock_page(page); |
| goto err; |
| } |
| } |
| unlock_page(page); |
| } |
| } |
| if (page == NULL) { |
| ret = -ENOMEM; |
| goto err; |
| } |
| if (!PageUptodate(page)) { |
| ret = -EIO; |
| goto err; |
| } |
| |
| /* Pages marked accessed already */ |
| e4b->bd_buddy_page = page; |
| e4b->bd_buddy = page_address(page) + (poff * sb->s_blocksize); |
| |
| return 0; |
| |
| err: |
| if (page) |
| put_page(page); |
| if (e4b->bd_bitmap_page) |
| put_page(e4b->bd_bitmap_page); |
| if (e4b->bd_buddy_page) |
| put_page(e4b->bd_buddy_page); |
| e4b->bd_buddy = NULL; |
| e4b->bd_bitmap = NULL; |
| return ret; |
| } |
| |
| static int ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group, |
| struct ext4_buddy *e4b) |
| { |
| return ext4_mb_load_buddy_gfp(sb, group, e4b, GFP_NOFS); |
| } |
| |
| static void ext4_mb_unload_buddy(struct ext4_buddy *e4b) |
| { |
| if (e4b->bd_bitmap_page) |
| put_page(e4b->bd_bitmap_page); |
| if (e4b->bd_buddy_page) |
| put_page(e4b->bd_buddy_page); |
| } |
| |
| |
| static int mb_find_order_for_block(struct ext4_buddy *e4b, int block) |
| { |
| int order = 1, max; |
| void *bb; |
| |
| BUG_ON(e4b->bd_bitmap == e4b->bd_buddy); |
| BUG_ON(block >= (1 << (e4b->bd_blkbits + 3))); |
| |
| while (order <= e4b->bd_blkbits + 1) { |
| bb = mb_find_buddy(e4b, order, &max); |
| if (!mb_test_bit(block >> order, bb)) { |
| /* this block is part of buddy of order 'order' */ |
| return order; |
| } |
| order++; |
| } |
| return 0; |
| } |
| |
| static void mb_clear_bits(void *bm, int cur, int len) |
| { |
| __u32 *addr; |
| |
| len = cur + len; |
| while (cur < len) { |
| if ((cur & 31) == 0 && (len - cur) >= 32) { |
| /* fast path: clear whole word at once */ |
| addr = bm + (cur >> 3); |
| *addr = 0; |
| cur += 32; |
| continue; |
| } |
| mb_clear_bit(cur, bm); |
| cur++; |
| } |
| } |
| |
| /* clear bits in given range |
| * will return first found zero bit if any, -1 otherwise |
| */ |
| static int mb_test_and_clear_bits(void *bm, int cur, int len) |
| { |
| __u32 *addr; |
| int zero_bit = -1; |
| |
| len = cur + len; |
| while (cur < len) { |
| if ((cur & 31) == 0 && (len - cur) >= 32) { |
| /* fast path: clear whole word at once */ |
| addr = bm + (cur >> 3); |
| if (*addr != (__u32)(-1) && zero_bit == -1) |
| zero_bit = cur + mb_find_next_zero_bit(addr, 32, 0); |
| *addr = 0; |
| cur += 32; |
| continue; |
| } |
| if (!mb_test_and_clear_bit(cur, bm) && zero_bit == -1) |
| zero_bit = cur; |
| cur++; |
| } |
| |
| return zero_bit; |
| } |
| |
| void mb_set_bits(void *bm, int cur, int len) |
| { |
| __u32 *addr; |
| |
| len = cur + len; |
| while (cur < len) { |
| if ((cur & 31) == 0 && (len - cur) >= 32) { |
| /* fast path: set whole word at once */ |
| addr = bm + (cur >> 3); |
| *addr = 0xffffffff; |
| cur += 32; |
| continue; |
| } |
| mb_set_bit(cur, bm); |
| cur++; |
| } |
| } |
| |
| static inline int mb_buddy_adjust_border(int* bit, void* bitmap, int side) |
| { |
| if (mb_test_bit(*bit + side, bitmap)) { |
| mb_clear_bit(*bit, bitmap); |
| (*bit) -= side; |
| return 1; |
| } |
| else { |
| (*bit) += side; |
| mb_set_bit(*bit, bitmap); |
| return -1; |
| } |
| } |
| |
| static void mb_buddy_mark_free(struct ext4_buddy *e4b, int first, int last) |
| { |
| int max; |
| int order = 1; |
| void *buddy = mb_find_buddy(e4b, order, &max); |
| |
| while (buddy) { |
| void *buddy2; |
| |
| /* Bits in range [first; last] are known to be set since |
| * corresponding blocks were allocated. Bits in range |
| * (first; last) will stay set because they form buddies on |
| * upper layer. We just deal with borders if they don't |
| * align with upper layer and then go up. |
| * Releasing entire group is all about clearing |
| * single bit of highest order buddy. |
| */ |
| |
| /* Example: |
| * --------------------------------- |
| * | 1 | 1 | 1 | 1 | |
| * --------------------------------- |
| * | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| * --------------------------------- |
| * 0 1 2 3 4 5 6 7 |
| * \_____________________/ |
| * |
| * Neither [1] nor [6] is aligned to above layer. |
| * Left neighbour [0] is free, so mark it busy, |
| * decrease bb_counters and extend range to |
| * [0; 6] |
| * Right neighbour [7] is busy. It can't be coaleasced with [6], so |
| * mark [6] free, increase bb_counters and shrink range to |
| * [0; 5]. |
| * Then shift range to [0; 2], go up and do the same. |
| */ |
| |
| |
| if (first & 1) |
| e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&first, buddy, -1); |
| if (!(last & 1)) |
| e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&last, buddy, 1); |
| if (first > last) |
| break; |
| order++; |
| |
| if (first == last || !(buddy2 = mb_find_buddy(e4b, order, &max))) { |
| mb_clear_bits(buddy, first, last - first + 1); |
| e4b->bd_info->bb_counters[order - 1] += last - first + 1; |
| break; |
| } |
| first >>= 1; |
| last >>= 1; |
| buddy = buddy2; |
| } |
| } |
| |
| static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b, |
| int first, int count) |
| { |
| int left_is_free = 0; |
| int right_is_free = 0; |
| int block; |
| int last = first + count - 1; |
| struct super_block *sb = e4b->bd_sb; |
| |
| if (WARN_ON(count == 0)) |
| return; |
| BUG_ON(last >= (sb->s_blocksize << 3)); |
| assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group)); |
| /* Don't bother if the block group is corrupt. */ |
| if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))) |
| return; |
| |
| mb_check_buddy(e4b); |
| mb_free_blocks_double(inode, e4b, first, count); |
| |
| this_cpu_inc(discard_pa_seq); |
| e4b->bd_info->bb_free += count; |
| if (first < e4b->bd_info->bb_first_free) |
| e4b->bd_info->bb_first_free = first; |
| |
| /* access memory sequentially: check left neighbour, |
| * clear range and then check right neighbour |
| */ |
| if (first != 0) |
| left_is_free = !mb_test_bit(first - 1, e4b->bd_bitmap); |
| block = mb_test_and_clear_bits(e4b->bd_bitmap, first, count); |
| if (last + 1 < EXT4_SB(sb)->s_mb_maxs[0]) |
| right_is_free = !mb_test_bit(last + 1, e4b->bd_bitmap); |
| |
| if (unlikely(block != -1)) { |
| struct ext4_sb_info *sbi = EXT4_SB(sb); |
| ext4_fsblk_t blocknr; |
| |
| blocknr = ext4_group_first_block_no(sb, e4b->bd_group); |
| blocknr += EXT4_C2B(sbi, block); |
| if (!(sbi->s_mount_state & EXT4_FC_REPLAY)) { |
| ext4_grp_locked_error(sb, e4b->bd_group, |
| inode ? inode->i_ino : 0, |
| blocknr, |
| "freeing already freed block (bit %u); block bitmap corrupt.", |
| block); |
| ext4_mark_group_bitmap_corrupted( |
| sb, e4b->bd_group, |
| EXT4_GROUP_INFO_BBITMAP_CORRUPT); |
| } |
| goto done; |
| } |
| |
| /* let's maintain fragments counter */ |
| if (left_is_free && right_is_free) |
| e4b->bd_info->bb_fragments--; |
| else if (!left_is_free && !right_is_free) |
| e4b->bd_info->bb_fragments++; |
| |
| /* buddy[0] == bd_bitmap is a special case, so handle |
| * it right away and let mb_buddy_mark_free stay free of |
| * zero order checks. |
| * Check if neighbours are to be coaleasced, |
| * adjust bitmap bb_counters and borders appropriately. |
| */ |
| if (first & 1) { |
| first += !left_is_free; |
| e4b->bd_info->bb_counters[0] += left_is_free ? -1 : 1; |
| } |
| if (!(last & 1)) { |
| last -= !right_is_free; |
| e4b->bd_info->bb_counters[0] += right_is_free ? -1 : 1; |
| } |
| |
| if (first <= last) |
| mb_buddy_mark_free(e4b, first >> 1, last >> 1); |
| |
| done: |
| mb_set_largest_free_order(sb, e4b->bd_info); |
| mb_update_avg_fragment_size(sb, e4b->bd_info); |
| mb_check_buddy(e4b); |
| } |
| |
| static int mb_find_extent(struct ext4_buddy *e4b, int block, |
| int needed, struct ext4_free_extent *ex) |
| { |
| int next = block; |
| int max, order; |
| void *buddy; |
| |
| assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group)); |
| BUG_ON(ex == NULL); |
| |
| buddy = mb_find_buddy(e4b, 0, &max); |
| BUG_ON(buddy == NULL); |
| BUG_ON(block >= max); |
| if (mb_test_bit(block, buddy)) { |
| ex->fe_len = 0; |
| ex->fe_start = 0; |
| ex->fe_group = 0; |
| return 0; |
| } |
| |
| /* find actual order */ |
| order = mb_find_order_for_block(e4b, block); |
| block = block >> order; |
| |
| ex->fe_len = 1 << order; |
| ex->fe_start = block << order; |
| ex->fe_group = e4b->bd_group; |
| |
| /* calc difference from given start */ |
| next = next - ex->fe_start; |
| ex->fe_len -= next; |
| ex->fe_start += next; |
| |
| while (needed > ex->fe_len && |
| mb_find_buddy(e4b, order, &max)) { |
| |
| if (block + 1 >= max) |
| break; |
| |
| next = (block + 1) * (1 << order); |
| if (mb_test_bit(next, e4b->bd_bitmap)) |
| break; |
| |
| order = mb_find_order_for_block(e4b, next); |
| |
| block = next >> order; |
| ex->fe_len += 1 << order; |
| } |
| |
| if (ex->fe_start + ex->fe_len > EXT4_CLUSTERS_PER_GROUP(e4b->bd_sb)) { |
| /* Should never happen! (but apparently sometimes does?!?) */ |
| WARN_ON(1); |
| ext4_grp_locked_error(e4b->bd_sb, e4b->bd_group, 0, 0, |
| "corruption or bug in mb_find_extent " |
| "block=%d, order=%d needed=%d ex=%u/%d/%d@%u", |
| block, order, needed, ex->fe_group, ex->fe_start, |
| ex->fe_len, ex->fe_logical); |
| ex->fe_len = 0; |
| ex->fe_start = 0; |
| ex->fe_group = 0; |
| } |
| return ex->fe_len; |
| } |
| |
| static int mb_mark_used(struct ext4_buddy *e4b, struct ext4_free_extent *ex) |
| { |
| int ord; |
| int mlen = 0; |
| int max = 0; |
| int cur; |
| int start = ex->fe_start; |
| int len = ex->fe_len; |
| unsigned ret = 0; |
| int len0 = len; |
| void *buddy; |
| |
| BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3)); |
| BUG_ON(e4b->bd_group != ex->fe_group); |
| assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group)); |
| mb_check_buddy(e4b); |
| mb_mark_used_double(e4b, start, len); |
| |
| this_cpu_inc(discard_pa_seq); |
| e4b->bd_info->bb_free -= len; |
| if (e4b->bd_info->bb_first_free == start) |
| e4b->bd_info->bb_first_free += len; |
| |
| /* let's maintain fragments counter */ |
| if (start != 0) |
| mlen = !mb_test_bit(start - 1, e4b->bd_bitmap); |
| if (start + len < EXT4_SB(e4b->bd_sb)->s_mb_maxs[0]) |
| max = !mb_test_bit(start + len, e4b->bd_bitmap); |
| if (mlen && max) |
| e4b->bd_info->bb_fragments++; |
| else if (!mlen && !max) |
| e4b->bd_info->bb_fragments--; |
| |
| /* let's maintain buddy itself */ |
| while (len) { |
| ord = mb_find_order_for_block(e4b, start); |
| |
| if (((start >> ord) << ord) == start && len >= (1 << ord)) { |
| /* the whole chunk may be allocated at once! */ |
| mlen = 1 << ord; |
| buddy = mb_find_buddy(e4b, ord, &max); |
| BUG_ON((start >> ord) >= max); |
| mb_set_bit(start >> ord, buddy); |
| e4b->bd_info->bb_counters[ord]--; |
| start += mlen; |
| len -= mlen; |
| BUG_ON(len < 0); |
| continue; |
| } |
| |
| /* store for history */ |
| if (ret == 0) |
| ret = len | (ord << 16); |
| |
| /* we have to split large buddy */ |
| BUG_ON(ord <= 0); |
| buddy = mb_find_buddy(e4b, ord, &max); |
| mb_set_bit(start >> ord, buddy); |
| e4b->bd_info->bb_counters[ord]--; |
| |
| ord--; |
| cur = (start >> ord) & ~1U; |
| buddy = mb_find_buddy(e4b, ord, &max); |
| mb_clear_bit(cur, buddy); |
| mb_clear_bit(cur + 1, buddy); |
| e4b->bd_info->bb_counters[ord]++; |
| e4b->bd_info->bb_counters[ord]++; |
| } |
| mb_set_largest_free_order(e4b->bd_sb, e4b->bd_info); |
| |
| mb_update_avg_fragment_size(e4b->bd_sb, e4b->bd_info); |
| mb_set_bits(e4b->bd_bitmap, ex->fe_start, len0); |
| mb_check_buddy(e4b); |
| |
| return ret; |
| } |
| |
| /* |
| * Must be called under group lock! |
| */ |
| static void ext4_mb_use_best_found(struct ext4_allocation_context *ac, |
| struct ext4_buddy *e4b) |
| { |
| struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); |
| int ret; |
| |
| BUG_ON(ac->ac_b_ex.fe_group != e4b->bd_group); |
| BUG_ON(ac->ac_status == AC_STATUS_FOUND); |
| |
| ac->ac_b_ex.fe_len = min(ac->ac_b_ex.fe_len, ac->ac_g_ex.fe_len); |
| ac->ac_b_ex.fe_logical = ac->ac_g_ex.fe_logical; |
| ret = mb_mark_used(e4b, &ac->ac_b_ex); |
| |
| /* preallocation can change ac_b_ex, thus we store actually |
| * allocated blocks for history */ |
| ac->ac_f_ex = ac->ac_b_ex; |
| |
| ac->ac_status = AC_STATUS_FOUND; |
| ac->ac_tail = ret & 0xffff; |
| ac->ac_buddy = ret >> 16; |
| |
| /* |
| * take the page reference. We want the page to be pinned |
| * so that we don't get a ext4_mb_init_cache_call for this |
| * group until we update the bitmap. That would mean we |
| * double allocate blocks. The reference is dropped |
| * in ext4_mb_release_context |
| */ |
| ac->ac_bitmap_page = e4b->bd_bitmap_page; |
| get_page(ac->ac_bitmap_page); |
| ac->ac_buddy_page = e4b->bd_buddy_page; |
| get_page(ac->ac_buddy_page); |
| /* store last allocated for subsequent stream allocation */ |
| if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) { |
| spin_lock(&sbi->s_md_lock); |
| sbi->s_mb_last_group = ac->ac_f_ex.fe_group; |
| sbi->s_mb_last_start = ac->ac_f_ex.fe_start; |
| spin_unlock(&sbi->s_md_lock); |
| } |
| /* |
| * As we've just preallocated more space than |
| * user requested originally, we store allocated |
| * space in a special descriptor. |
| */ |
| if (ac->ac_o_ex.fe_len < ac->ac_b_ex.fe_len) |
| ext4_mb_new_preallocation(ac); |
| |
| } |
| |
| static void ext4_mb_check_limits(struct ext4_allocation_context *ac, |
| struct ext4_buddy *e4b, |
| int finish_group) |
| { |
| struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); |
| struct ext4_free_extent *bex = &ac->ac_b_ex; |
| struct ext4_free_extent *gex = &ac->ac_g_ex; |
| struct ext4_free_extent ex; |
| int max; |
| |
| if (ac->ac_status == AC_STATUS_FOUND) |
| return; |
| /* |
| * We don't want to scan for a whole year |
| */ |
| if (ac->ac_found > sbi->s_mb_max_to_scan && |
| !(ac->ac_flags & EXT4_MB_HINT_FIRST)) { |
| ac->ac_status = AC_STATUS_BREAK; |
| return; |
| } |
| |
| /* |
| * Haven't found good chunk so far, let's continue |
| */ |
| if (bex->fe_len < gex->fe_len) |
| return; |
| |
| if ((finish_group || ac->ac_found > sbi->s_mb_min_to_scan) |
| && bex->fe_group == e4b->bd_group) { |
| /* recheck chunk's availability - we don't know |
| * when it was found (within this lock-unlock |
| * period or not) */ |
| max = mb_find_extent(e4b, bex->fe_start, gex->fe_len, &ex); |
| if (max >= gex->fe_len) { |
| ext4_mb_use_best_found(ac, e4b); |
| return; |
| } |
| } |
| } |
| |
| /* |
| * The routine checks whether found extent is good enough. If it is, |
| * then the extent gets marked used and flag is set to the context |
| * to stop scanning. Otherwise, the extent is compared with the |
| * previous found extent and if new one is better, then it's stored |
| * in the context. Later, the best found extent will be used, if |
| * mballoc can't find good enough extent. |
| * |
| * FIXME: real allocation policy is to be designed yet! |
| */ |
| static void ext4_mb_measure_extent(struct ext4_allocation_context *ac, |
| struct ext4_free_extent *ex, |
| struct ext4_buddy *e4b) |
| { |
| struct ext4_free_extent *bex = &ac->ac_b_ex; |
| struct ext4_free_extent *gex = &ac->ac_g_ex; |
| |
| BUG_ON(ex->fe_len <= 0); |
| BUG_ON(ex->fe_len > EXT4_CLUSTERS_PER_GROUP(ac->ac_sb)); |
| BUG_ON(ex->fe_start >= EXT4_CLUSTERS_PER_GROUP(ac->ac_sb)); |
| BUG_ON(ac->ac_status != AC_STATUS_CONTINUE); |
| |
| ac->ac_found++; |
| |
| /* |
| * The special case - take what you catch first |
| */ |
| if (unlikely(ac->ac_flags & EXT4_MB_HINT_FIRST)) { |
| *bex = *ex; |
| ext4_mb_use_best_found(ac, e4b); |
| return; |
| } |
| |
| /* |
| * Let's check whether the chuck is good enough |
| */ |
| if (ex->fe_len == gex->fe_len) { |
| *bex = *ex; |
| ext4_mb_use_best_found(ac, e4b); |
| return; |
| } |
| |
| /* |
| * If this is first found extent, just store it in the context |
| */ |
| if (bex->fe_len == 0) { |
| *bex = *ex; |
| return; |
| } |
| |
| /* |
| * If new found extent is better, store it in the context |
| */ |
| if (bex->fe_len < gex->fe_len) { |
| /* if the request isn't satisfied, any found extent |
| * larger than previous best one is better */ |
| if (ex->fe_len > bex->fe_len) |
| *bex = *ex; |
| } else if (ex->fe_len > gex->fe_len) { |
| /* if the request is satisfied, then we try to find |
| * an extent that still satisfy the request, but is |
| * smaller than previous one */ |
| if (ex->fe_len < bex->fe_len) |
| *bex = *ex; |
| } |
| |
| ext4_mb_check_limits(ac, e4b, 0); |
| } |
| |
| static noinline_for_stack |
| int ext4_mb_try_best_found(struct ext4_allocation_context *ac, |
| struct ext4_buddy *e4b) |
| { |
| struct ext4_free_extent ex = ac->ac_b_ex; |
| ext4_group_t group = ex.fe_group; |
| int max; |
| int err; |
| |
| BUG_ON(ex.fe_len <= 0); |
| err = ext4_mb_load_buddy(ac->ac_sb, group, e4b); |
| if (err) |
| return err; |
| |
| ext4_lock_group(ac->ac_sb, group); |
| max = mb_find_extent(e4b, ex.fe_start, ex.fe_len, &ex); |
| |
| if (max > 0) { |
| ac->ac_b_ex = ex; |
| ext4_mb_use_best_found(ac, e4b); |
| } |
| |
| ext4_unlock_group(ac->ac_sb, group); |
| ext4_mb_unload_buddy(e4b); |
| |
| return 0; |
| } |
| |
| static noinline_for_stack |
| int ext4_mb_find_by_goal(struct ext4_allocation_context *ac, |
| struct ext4_buddy *e4b) |
| { |
| ext4_group_t group = ac->ac_g_ex.fe_group; |
| int max; |
| int err; |
| struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); |
| struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group); |
| struct ext4_free_extent ex; |
| |
| if (!(ac->ac_flags & EXT4_MB_HINT_TRY_GOAL)) |
| return 0; |
| if (grp->bb_free == 0) |
| return 0; |
| |
| err = ext4_mb_load_buddy(ac->ac_sb, group, e4b); |
| if (err) |
| return err; |
| |
| if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))) { |
| ext4_mb_unload_buddy(e4b); |
| return 0; |
| } |
| |
| ext4_lock_group(ac->ac_sb, group); |
| max = mb_find_extent(e4b, ac->ac_g_ex.fe_start, |
| ac->ac_g_ex.fe_len, &ex); |
| ex.fe_logical = 0xDEADFA11; /* debug value */ |
| |
| if (max >= ac->ac_g_ex.fe_len && ac->ac_g_ex.fe_len == sbi->s_stripe) { |
| ext4_fsblk_t start; |
| |
| start = ext4_group_first_block_no(ac->ac_sb, e4b->bd_group) + |
| ex.fe_start; |
| /* use do_div to get remainder (would be 64-bit modulo) */ |
| if (do_div(start, sbi->s_stripe) == 0) { |
| ac->ac_found++; |
| ac->ac_b_ex = ex; |
| ext4_mb_use_best_found(ac, e4b); |
| } |
| } else if (max >= ac->ac_g_ex.fe_len) { |
| BUG_ON(ex.fe_len <= 0); |
| BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group); |
| BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start); |
| ac->ac_found++; |
| ac->ac_b_ex = ex; |
| ext4_mb_use_best_found(ac, e4b); |
| } else if (max > 0 && (ac->ac_flags & EXT4_MB_HINT_MERGE)) { |
| /* Sometimes, caller may want to merge even small |
| * number of blocks to an existing extent */ |
| BUG_ON(ex.fe_len <= 0); |
| BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group); |
| BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start); |
| ac->ac_found++; |
| ac->ac_b_ex = ex; |
| ext4_mb_use_best_found(ac, e4b); |
| } |
| ext4_unlock_group(ac->ac_sb, group); |
| ext4_mb_unload_buddy(e4b); |
| |
| return 0; |
| } |
| |
| /* |
| * The routine scans buddy structures (not bitmap!) from given order |
| * to max order and tries to find big enough chunk to satisfy the req |
| */ |
| static noinline_for_stack |
| void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac, |
| struct ext4_buddy *e4b) |
| { |
| struct super_block *sb = ac->ac_sb; |
| struct ext4_group_info *grp = e4b->bd_info; |
| void *buddy; |
| int i; |
| int k; |
| int max; |
| |
| BUG_ON(ac->ac_2order <= 0); |
| for (i = ac->ac_2order; i < MB_NUM_ORDERS(sb); i++) { |
| if (grp->bb_counters[i] == 0) |
| continue; |
| |
| buddy = mb_find_buddy(e4b, i, &max); |
| BUG_ON(buddy == NULL); |
| |
| k = mb_find_next_zero_bit(buddy, max, 0); |
| if (k >= max) { |
| ext4_grp_locked_error(ac->ac_sb, e4b->bd_group, 0, 0, |
| "%d free clusters of order %d. But found 0", |
| grp->bb_counters[i], i); |
| ext4_mark_group_bitmap_corrupted(ac->ac_sb, |
| e4b->bd_group, |
| EXT4_GROUP_INFO_BBITMAP_CORRUPT); |
| break; |
| } |
| ac->ac_found++; |
| |
| ac->ac_b_ex.fe_len = 1 << i; |
| ac->ac_b_ex.fe_start = k << i; |
| ac->ac_b_ex.fe_group = e4b->bd_group; |
| |
| ext4_mb_use_best_found(ac, e4b); |
| |
| BUG_ON(ac->ac_f_ex.fe_len != ac->ac_g_ex.fe_len); |
| |
| if (EXT4_SB(sb)->s_mb_stats) |
| atomic_inc(&EXT4_SB(sb)->s_bal_2orders); |
| |
| break; |
| } |
| } |
| |
| /* |
| * The routine scans the group and measures all found extents. |
| * In order to optimize scanning, caller must pass number of |
| * free blocks in the group, so the routine can know upper limit. |
| */ |
| static noinline_for_stack |
| void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac, |
| struct ext4_buddy *e4b) |
| { |
| struct super_block *sb = ac->ac_sb; |
| void *bitmap = e4b->bd_bitmap; |
| struct ext4_free_extent ex; |
| int i; |
| int free; |
| |
| free = e4b->bd_info->bb_free; |
| if (WARN_ON(free <= 0)) |
| return; |
| |
| i = e4b->bd_info->bb_first_free; |
| |
| while (free && ac->ac_status == AC_STATUS_CONTINUE) { |
| i = mb_find_next_zero_bit(bitmap, |
| EXT4_CLUSTERS_PER_GROUP(sb), i); |
| if (i >= EXT4_CLUSTERS_PER_GROUP(sb)) { |
| /* |
| * IF we have corrupt bitmap, we won't find any |
| * free blocks even though group info says we |
| * have free blocks |
| */ |
| ext4_grp_locked_error(sb, e4b->bd_group, 0, 0, |
| "%d free clusters as per " |
| "group info. But bitmap says 0", |
| free); |
| ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group, |
| EXT4_GROUP_INFO_BBITMAP_CORRUPT); |
| break; |
| } |
| |
| mb_find_extent(e4b, i, ac->ac_g_ex.fe_len, &ex); |
| if (WARN_ON(ex.fe_len <= 0)) |
| break; |
| if (free < ex.fe_len) { |
| ext4_grp_locked_error(sb, e4b->bd_group, 0, 0, |
| "%d free clusters as per " |
| "group info. But got %d blocks", |
| free, ex.fe_len); |
| ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group, |
| EXT4_GROUP_INFO_BBITMAP_CORRUPT); |
| /* |
| * The number of free blocks differs. This mostly |
| * indicate that the bitmap is corrupt. So exit |
| * without claiming the space. |
| */ |
| break; |
| } |
| ex.fe_logical = 0xDEADC0DE; /* debug value */ |
| ext4_mb_measure_extent(ac, &ex, e4b); |
| |
| i += ex.fe_len; |
| free -= ex.fe_len; |
| } |
| |
| ext4_mb_check_limits(ac, e4b, 1); |
| } |
| |
| /* |
| * This is a special case for storages like raid5 |
| * we try to find stripe-aligned chunks for stripe-size-multiple requests |
| */ |
| static noinline_for_stack |
| void ext4_mb_scan_aligned(struct ext4_allocation_context *ac, |
| struct ext4_buddy *e4b) |
| { |
| struct super_block *sb = ac->ac_sb; |
| struct ext4_sb_info *sbi = EXT4_SB(sb); |
| void *bitmap = e4b->bd_bitmap; |
| struct ext4_free_extent ex; |
| ext4_fsblk_t first_group_block; |
| ext4_fsblk_t a; |
| ext4_grpblk_t i; |
| int max; |
| |
| BUG_ON(sbi->s_stripe == 0); |
| |
| /* find first stripe-aligned block in group */ |
| first_group_block = ext4_group_first_block_no(sb, e4b->bd_group); |
| |
| a = first_group_block + sbi->s_stripe - 1; |
| do_div(a, sbi->s_stripe); |
| i = (a * sbi->s_stripe) - first_group_block; |
| |
| while (i < EXT4_CLUSTERS_PER_GROUP(sb)) { |
| if (!mb_test_bit(i, bitmap)) { |
| max = mb_find_extent(e4b, i, sbi->s_stripe, &ex); |
| if (max >= sbi->s_stripe) { |
| ac->ac_found++; |
| ex.fe_logical = 0xDEADF00D; /* debug value */ |
| ac->ac_b_ex = ex; |
| ext4_mb_use_best_found(ac, e4b); |
| break; |
| } |
| } |
| i += sbi->s_stripe; |
| } |
| } |
| |
| /* |
| * This is also called BEFORE we load the buddy bitmap. |
| * Returns either 1 or 0 indicating that the group is either suitable |
| * for the allocation or not. |
| */ |
| static bool ext4_mb_good_group(struct ext4_allocation_context *ac, |
| ext4_group_t group, int cr) |
| { |
| ext4_grpblk_t free, fragments; |
| int flex_size = ext4_flex_bg_size(EXT4_SB(ac->ac_sb)); |
| struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group); |
| |
| BUG_ON(cr < 0 || cr >= 4); |
| |
| if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(grp))) |
| return false; |
| |
| free = grp->bb_free; |
| if (free == 0) |
| return false; |
| |
| fragments = grp->bb_fragments; |
| if (fragments == 0) |
| return false; |
| |
| switch (cr) { |
| case 0: |
| BUG_ON(ac->ac_2order == 0); |
| |
| /* Avoid using the first bg of a flexgroup for data files */ |
| if ((ac->ac_flags & EXT4_MB_HINT_DATA) && |
| (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) && |
| ((group % flex_size) == 0)) |
| return false; |
| |
| if (free < ac->ac_g_ex.fe_len) |
| return false; |
| |
| if (ac->ac_2order >= MB_NUM_ORDERS(ac->ac_sb)) |
| return true; |
| |
| if (grp->bb_largest_free_order < ac->ac_2order) |
| return false; |
| |
| return true; |
| case 1: |
| if ((free / fragments) >= ac->ac_g_ex.fe_len) |
| return true; |
| break; |
| case 2: |
| if (free >= ac->ac_g_ex.fe_len) |
| return true; |
| break; |
| case 3: |
| return true; |
| default: |
| BUG(); |
| } |
| |
| return false; |
| } |
| |
| /* |
| * This could return negative error code if something goes wrong |
| * during ext4_mb_init_group(). This should not be called with |
| * ext4_lock_group() held. |
| * |
| * Note: because we are conditionally operating with the group lock in |
| * the EXT4_MB_STRICT_CHECK case, we need to fake out sparse in this |
| * function using __acquire and __release. This means we need to be |
| * super careful before messing with the error path handling via "goto |
| * out"! |
| */ |
| static int ext4_mb_good_group_nolock(struct ext4_allocation_context *ac, |
| ext4_group_t group, int cr) |
| { |
| struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group); |
| struct super_block *sb = ac->ac_sb; |
| struct ext4_sb_info *sbi = EXT4_SB(sb); |
| bool should_lock = ac->ac_flags & EXT4_MB_STRICT_CHECK; |
| ext4_grpblk_t free; |
| int ret = 0; |
| |
| if (sbi->s_mb_stats) |
| atomic64_inc(&sbi->s_bal_cX_groups_considered[ac->ac_criteria]); |
| if (should_lock) { |
| ext4_lock_group(sb, group); |
| __release(ext4_group_lock_ptr(sb, group)); |
| } |
| free = grp->bb_free; |
| if (free == 0) |
| goto out; |
| if (cr <= 2 && free < ac->ac_g_ex.fe_len) |
| goto out; |
| if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(grp))) |
| goto out; |
| if (should_lock) { |
| __acquire(ext4_group_lock_ptr(sb, group)); |
| ext4_unlock_group(sb, group); |
| } |
| |
| /* We only do this if the grp has never been initialized */ |
| if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) { |
| struct ext4_group_desc *gdp = |
| ext4_get_group_desc(sb, group, NULL); |
| int ret; |
| |
| /* cr=0/1 is a very optimistic search to find large |
| * good chunks almost for free. If buddy data is not |
| * ready, then this optimization makes no sense. But |
| * we never skip the first block group in a flex_bg, |
| * since this gets used for metadata block allocation, |
| * and we want to make sure we locate metadata blocks |
| * in the first block group in the flex_bg if possible. |
| */ |
| if (cr < 2 && |
| (!sbi->s_log_groups_per_flex || |
| ((group & ((1 << sbi->s_log_groups_per_flex) - 1)) != 0)) && |
| !(ext4_has_group_desc_csum(sb) && |
| (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)))) |
| return 0; |
| ret = ext4_mb_init_group(sb, group, GFP_NOFS); |
| if (ret) |
| return ret; |
| } |
| |
| if (should_lock) { |
| ext4_lock_group(sb, group); |
| __release(ext4_group_lock_ptr(sb, group)); |
| } |
| ret = ext4_mb_good_group(ac, group, cr); |
| out: |
| if (should_lock) { |
| __acquire(ext4_group_lock_ptr(sb, group)); |
| ext4_unlock_group(sb, group); |
| } |
| return ret; |
| } |
| |
| /* |
| * Start prefetching @nr block bitmaps starting at @group. |
| * Return the next group which needs to be prefetched. |
| */ |
| ext4_group_t ext4_mb_prefetch(struct super_block *sb, ext4_group_t group, |
| unsigned int nr, int *cnt) |
| { |
| ext4_group_t ngroups = ext4_get_groups_count(sb); |
| struct buffer_head *bh; |
| struct blk_plug plug; |
| |
| blk_start_plug(&plug); |
| while (nr-- > 0) { |
| struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group, |
| NULL); |
| struct ext4_group_info *grp = ext4_get_group_info(sb, group); |
| |
| /* |
| * Prefetch block groups with free blocks; but don't |
| * bother if it is marked uninitialized on disk, since |
| * it won't require I/O to read. Also only try to |
| * prefetch once, so we avoid getblk() call, which can |
| * be expensive. |
| */ |
| if (!EXT4_MB_GRP_TEST_AND_SET_READ(grp) && |
| EXT4_MB_GRP_NEED_INIT(grp) && |
| ext4_free_group_clusters(sb, gdp) > 0 && |
| !(ext4_has_group_desc_csum(sb) && |
| (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)))) { |
| bh = ext4_read_block_bitmap_nowait(sb, group, true); |
| if (bh && !IS_ERR(bh)) { |
| if (!buffer_uptodate(bh) && cnt) |
| (*cnt)++; |
| brelse(bh); |
| } |
| } |
| if (++group >= ngroups) |
| group = 0; |
| } |
| blk_finish_plug(&plug); |
| return group; |
| } |
| |
| /* |
| * Prefetching reads the block bitmap into the buffer cache; but we |
| * need to make sure that the buddy bitmap in the page cache has been |
| * initialized. Note that ext4_mb_init_group() will block if the I/O |
| * is not yet completed, or indeed if it was not initiated by |
| * ext4_mb_prefetch did not start the I/O. |
| * |
| * TODO: We should actually kick off the buddy bitmap setup in a work |
| * queue when the buffer I/O is completed, so that we don't block |
| * waiting for the block allocation bitmap read to finish when |
| * ext4_mb_prefetch_fini is called from ext4_mb_regular_allocator(). |
| */ |
| void ext4_mb_prefetch_fini(struct super_block *sb, ext4_group_t group, |
| unsigned int nr) |
| { |
| while (nr-- > 0) { |
| struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group, |
| NULL); |
| struct ext4_group_info *grp = ext4_get_group_info(sb, group); |
| |
| if (!group) |
| group = ext4_get_groups_count(sb); |
| group--; |
| grp = ext4_get_group_info(sb, group); |
| |
| if (EXT4_MB_GRP_NEED_INIT(grp) && |
| ext4_free_group_clusters(sb, gdp) > 0 && |
| !(ext4_has_group_desc_csum(sb) && |
| (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)))) { |
| if (ext4_mb_init_group(sb, group, GFP_NOFS)) |
| break; |
| } |
| } |
| } |
| |
| static noinline_for_stack int |
| ext4_mb_regular_allocator(struct ext4_allocation_context *ac) |
| { |
| ext4_group_t prefetch_grp = 0, ngroups, group, i; |
| int cr = -1; |
| int err = 0, first_err = 0; |
| unsigned int nr = 0, prefetch_ios = 0; |
| struct ext4_sb_info *sbi; |
| struct super_block *sb; |
| struct ext4_buddy e4b; |
| int lost; |
| |
| sb = ac->ac_sb; |
| sbi = EXT4_SB(sb); |
| ngroups = ext4_get_groups_count(sb); |
| /* non-extent files are limited to low blocks/groups */ |
| if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS))) |
| ngroups = sbi->s_blockfile_groups; |
| |
| BUG_ON(ac->ac_status == AC_STATUS_FOUND); |
| |
| /* first, try the goal */ |
| err = ext4_mb_find_by_goal(ac, &e4b); |
| if (err || ac->ac_status == AC_STATUS_FOUND) |
| goto out; |
| |
| if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY)) |
| goto out; |
| |
| /* |
| * ac->ac_2order is set only if the fe_len is a power of 2 |
| * if ac->ac_2order is set we also set criteria to 0 so that we |
| * try exact allocation using buddy. |
| */ |
| i = fls(ac->ac_g_ex.fe_len); |
| ac->ac_2order = 0; |
| /* |
| * We search using buddy data only if the order of the request |
| * is greater than equal to the sbi_s_mb_order2_reqs |
| * You can tune it via /sys/fs/ext4/<partition>/mb_order2_req |
| * We also support searching for power-of-two requests only for |
| * requests upto maximum buddy size we have constructed. |
| */ |
| if (i >= sbi->s_mb_order2_reqs && i <= MB_NUM_ORDERS(sb)) { |
| /* |
| * This should tell if fe_len is exactly power of 2 |
| */ |
| if ((ac->ac_g_ex.fe_len & (~(1 << (i - 1)))) == 0) |
| ac->ac_2order = array_index_nospec(i - 1, |
| MB_NUM_ORDERS(sb)); |
| } |
| |
| /* if stream allocation is enabled, use global goal */ |
| if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) { |
| /* TBD: may be hot point */ |
| spin_lock(&sbi->s_md_lock); |
| ac->ac_g_ex.fe_group = sbi->s_mb_last_group; |
| ac->ac_g_ex.fe_start = sbi->s_mb_last_start; |
| spin_unlock(&sbi->s_md_lock); |
| } |
| |
| /* Let's just scan groups to find more-less suitable blocks */ |
| cr = ac->ac_2order ? 0 : 1; |
| /* |
| * cr == 0 try to get exact allocation, |
| * cr == 3 try to get anything |
| */ |
| repeat: |
| for (; cr < 4 && ac->ac_status == AC_STATUS_CONTINUE; cr++) { |
| ac->ac_criteria = cr; |
| /* |
| * searching for the right group start |
| * from the goal value specified |
| */ |
| group = ac->ac_g_ex.fe_group; |
| ac->ac_last_optimal_group = group; |
| ac->ac_groups_linear_remaining = sbi->s_mb_max_linear_groups; |
| prefetch_grp = group; |
| |
| for (i = 0; i < ngroups; group = next_linear_group(ac, group, ngroups), |
| i++) { |
| int ret = 0, new_cr; |
| |
| cond_resched(); |
| |
| ext4_mb_choose_next_group(ac, &new_cr, &group, ngroups); |
| if (new_cr != cr) { |
| cr = new_cr; |
| goto repeat; |
| } |
| |
| /* |
| * Batch reads of the block allocation bitmaps |
| * to get multiple READs in flight; limit |
| * prefetching at cr=0/1, otherwise mballoc can |
| * spend a lot of time loading imperfect groups |
| */ |
| if ((prefetch_grp == group) && |
| (cr > 1 || |
| prefetch_ios < sbi->s_mb_prefetch_limit)) { |
| unsigned int curr_ios = prefetch_ios; |
| |
| nr = sbi->s_mb_prefetch; |
| if (ext4_has_feature_flex_bg(sb)) { |
| nr = 1 << sbi->s_log_groups_per_flex; |
| nr -= group & (nr - 1); |
| nr = min(nr, sbi->s_mb_prefetch); |
| } |
| prefetch_grp = ext4_mb_prefetch(sb, group, |
| nr, &prefetch_ios); |
| if (prefetch_ios == curr_ios) |
| nr = 0; |
| } |
| |
| /* This now checks without needing the buddy page */ |
| ret = ext4_mb_good_group_nolock(ac, group, cr); |
| if (ret <= 0) { |
| if (!first_err) |
| first_err = ret; |
| continue; |
| } |
| |
| err = ext4_mb_load_buddy(sb, group, &e4b); |
| if (err) |
| goto out; |
| |
| ext4_lock_group(sb, group); |
| |
| /* |
| * We need to check again after locking the |
| * block group |
| */ |
| ret = ext4_mb_good_group(ac, group, cr); |
| if (ret == 0) { |
| ext4_unlock_group(sb, group); |
| ext4_mb_unload_buddy(&e4b); |
| continue; |
| } |
| |
| ac->ac_groups_scanned++; |
| if (cr == 0) |
| ext4_mb_simple_scan_group(ac, &e4b); |
| else if (cr == 1 && sbi->s_stripe && |
| !(ac->ac_g_ex.fe_len % sbi->s_stripe)) |
| ext4_mb_scan_aligned(ac, &e4b); |
| else |
| ext4_mb_complex_scan_group(ac, &e4b); |
| |
| ext4_unlock_group(sb, group); |
| ext4_mb_unload_buddy(&e4b); |
| |
| if (ac->ac_status != AC_STATUS_CONTINUE) |
| break; |
| } |
| /* Processed all groups and haven't found blocks */ |
| if (sbi->s_mb_stats && i == ngroups) |
| atomic64_inc(&sbi->s_bal_cX_failed[cr]); |
| } |
| |
| if (ac->ac_b_ex.fe_len > 0 && ac->ac_status != AC_STATUS_FOUND && |
| !(ac->ac_flags & EXT4_MB_HINT_FIRST)) { |
| /* |
| * We've been searching too long. Let's try to allocate |
| * the best chunk we've found so far |
| */ |
| ext4_mb_try_best_found(ac, &e4b); |
| if (ac->ac_status != AC_STATUS_FOUND) { |
| /* |
| * Someone more lucky has already allocated it. |
| * The only thing we can do is just take first |
| * found block(s) |
| */ |
| lost = atomic_inc_return(&sbi->s_mb_lost_chunks); |
| mb_debug(sb, "lost chunk, group: %u, start: %d, len: %d, lost: %d\n", |
| ac->ac_b_ex.fe_group, ac->ac_b_ex.fe_start, |
| ac->ac_b_ex.fe_len, lost); |
| |
| ac->ac_b_ex.fe_group = 0; |
| ac->ac_b_ex.fe_start = 0; |
| ac->ac_b_ex.fe_len = 0; |
| ac->ac_status = AC_STATUS_CONTINUE; |
| ac->ac_flags |= EXT4_MB_HINT_FIRST; |
| cr = 3; |
| goto repeat; |
| } |
| } |
| |
| if (sbi->s_mb_stats && ac->ac_status == AC_STATUS_FOUND) |
| atomic64_inc(&sbi->s_bal_cX_hits[ac->ac_criteria]); |
| out: |
| if (!err && ac->ac_status != AC_STATUS_FOUND && first_err) |
| err = first_err; |
| |
| mb_debug(sb, "Best len %d, origin len %d, ac_status %u, ac_flags 0x%x, cr %d ret %d\n", |
| ac->ac_b_ex.fe_len, ac->ac_o_ex.fe_len, ac->ac_status, |
| ac->ac_flags, cr, err); |
| |
| if (nr) |
| ext4_mb_prefetch_fini(sb, prefetch_grp, nr); |
| |
| return err; |
| } |
| |
| static void *ext4_mb_seq_groups_start(struct seq_file *seq, loff_t *pos) |
| { |
| struct super_block *sb = pde_data(file_inode(seq->file)); |
| ext4_group_t group; |
| |
| if (*pos < 0 || *pos >= ext4_get_groups_count(sb)) |
| return NULL; |
| group = *pos + 1; |
| return (void *) ((unsigned long) group); |
| } |
| |
| static void *ext4_mb_seq_groups_next(struct seq_file *seq, void *v, loff_t *pos) |
| { |
| struct super_block *sb = pde_data(file_inode(seq->file)); |
| ext4_group_t group; |
| |
| ++*pos; |
| if (*pos < 0 || *pos >= ext4_get_groups_count(sb)) |
| return NULL; |
| group = *pos + 1; |
| return (void *) ((unsigned long) group); |
| } |
| |
| static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v) |
| { |
| struct super_block *sb = pde_data(file_inode(seq->file)); |
| ext4_group_t group = (ext4_group_t) ((unsigned long) v); |
| int i; |
| int err, buddy_loaded = 0; |
| struct ext4_buddy e4b; |
| struct ext4_group_info *grinfo; |
| unsigned char blocksize_bits = min_t(unsigned char, |
| sb->s_blocksize_bits, |
| EXT4_MAX_BLOCK_LOG_SIZE); |
| struct sg { |
| struct ext4_group_info info; |
| ext4_grpblk_t counters[EXT4_MAX_BLOCK_LOG_SIZE + 2]; |
| } sg; |
| |
| group--; |
| if (group == 0) |
| seq_puts(seq, "#group: free frags first [" |
| " 2^0 2^1 2^2 2^3 2^4 2^5 2^6 " |
| " 2^7 2^8 2^9 2^10 2^11 2^12 2^13 ]\n"); |
| |
| i = (blocksize_bits + 2) * sizeof(sg.info.bb_counters[0]) + |
| sizeof(struct ext4_group_info); |
| |
| grinfo = ext4_get_group_info(sb, group); |
| /* Load the group info in memory only if not already loaded. */ |
| if (unlikely(EXT4_MB_GRP_NEED_INIT(grinfo))) { |
| err = ext4_mb_load_buddy(sb, group, &e4b); |
| if (err) { |
| seq_printf(seq, "#%-5u: I/O error\n", group); |
| return 0; |
| } |
| buddy_loaded = 1; |
| } |
| |
| memcpy(&sg, ext4_get_group_info(sb, group), i); |
| |
| if (buddy_loaded) |
| ext4_mb_unload_buddy(&e4b); |
| |
| seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg.info.bb_free, |
| sg.info.bb_fragments, sg.info.bb_first_free); |
| for (i = 0; i <= 13; i++) |
| seq_printf(seq, " %-5u", i <= blocksize_bits + 1 ? |
| sg.info.bb_counters[i] : 0); |
| seq_puts(seq, " ]\n"); |
| |
| return 0; |
| } |
| |
| static void ext4_mb_seq_groups_stop(struct seq_file *seq, void *v) |
| { |
| } |
| |
| const struct seq_operations ext4_mb_seq_groups_ops = { |
| .start = ext4_mb_seq_groups_start, |
| .next = ext4_mb_seq_groups_next, |
| .stop = ext4_mb_seq_groups_stop, |
| .show = ext4_mb_seq_groups_show, |
| }; |
| |
| int ext4_seq_mb_stats_show(struct seq_file *seq, void *offset) |
| { |
| struct super_block *sb = seq->private; |
| struct ext4_sb_info *sbi = EXT4_SB(sb); |
| |
| seq_puts(seq, "mballoc:\n"); |
| if (!sbi->s_mb_stats) { |
| seq_puts(seq, "\tmb stats collection turned off.\n"); |
| seq_puts(seq, "\tTo enable, please write \"1\" to sysfs file mb_stats.\n"); |
| return 0; |
| } |
| seq_printf(seq, "\treqs: %u\n", atomic_read(&sbi->s_bal_reqs)); |
| seq_printf(seq, "\tsuccess: %u\n", atomic_read(&sbi->s_bal_success)); |
| |
| seq_printf(seq, "\tgroups_scanned: %u\n", atomic_read(&sbi->s_bal_groups_scanned)); |
| |
| seq_puts(seq, "\tcr0_stats:\n"); |
| seq_printf(seq, "\t\thits: %llu\n", atomic64_read(&sbi->s_bal_cX_hits[0])); |
| seq_printf(seq, "\t\tgroups_considered: %llu\n", |
| atomic64_read(&sbi->s_bal_cX_groups_considered[0])); |
| seq_printf(seq, "\t\tuseless_loops: %llu\n", |
| atomic64_read(&sbi->s_bal_cX_failed[0])); |
| seq_printf(seq, "\t\tbad_suggestions: %u\n", |
| atomic_read(&sbi->s_bal_cr0_bad_suggestions)); |
| |
| seq_puts(seq, "\tcr1_stats:\n"); |
| seq_printf(seq, "\t\thits: %llu\n", atomic64_read(&sbi->s_bal_cX_hits[1])); |
| seq_printf(seq, "\t\tgroups_considered: %llu\n", |
| atomic64_read(&sbi->s_bal_cX_groups_considered[1])); |
| seq_printf(seq, "\t\tuseless_loops: %llu\n", |
| atomic64_read(&sbi->s_bal_cX_failed[1])); |
| seq_printf(seq, "\t\tbad_suggestions: %u\n", |
| atomic_read(&sbi->s_bal_cr1_bad_suggestions)); |
| |
| seq_puts(seq, "\tcr2_stats:\n"); |
| seq_printf(seq, "\t\thits: %llu\n", atomic64_read(&sbi->s_bal_cX_hits[2])); |
| seq_printf(seq, "\t\tgroups_considered: %llu\n", |
| atomic64_read(&sbi->s_bal_cX_groups_considered[2])); |
| seq_printf(seq, "\t\tuseless_loops: %llu\n", |
| atomic64_read(&sbi->s_bal_cX_failed[2])); |
| |
| seq_puts(seq, "\tcr3_stats:\n"); |
| seq_printf(seq, "\t\thits: %llu\n", atomic64_read(&sbi->s_bal_cX_hits[3])); |
| seq_printf(seq, "\t\tgroups_considered: %llu\n", |
| atomic64_read(&sbi->s_bal_cX_groups_considered[3])); |
| seq_printf(seq, "\t\tuseless_loops: %llu\n", |
| atomic64_read(&sbi->s_bal_cX_failed[3])); |
| seq_printf(seq, "\textents_scanned: %u\n", atomic_read(&sbi->s_bal_ex_scanned)); |
| seq_printf(seq, "\t\tgoal_hits: %u\n", atomic_read(&sbi->s_bal_goals)); |
| seq_printf(seq, "\t\t2^n_hits: %u\n", atomic_read(&sbi->s_bal_2orders)); |
| seq_printf(seq, "\t\tbreaks: %u\n", atomic_read(&sbi->s_bal_breaks)); |
| seq_printf(seq, "\t\tlost: %u\n", atomic_read(&sbi->s_mb_lost_chunks)); |
| |
| seq_printf(seq, "\tbuddies_generated: %u/%u\n", |
| atomic_read(&sbi->s_mb_buddies_generated), |
| ext4_get_groups_count(sb)); |
| seq_printf(seq, "\tbuddies_time_used: %llu\n", |
| atomic64_read(&sbi->s_mb_generation_time)); |
| seq_printf(seq, "\tpreallocated: %u\n", |
| atomic_read(&sbi->s_mb_preallocated)); |
| seq_printf(seq, "\tdiscarded: %u\n", |
| atomic_read(&sbi->s_mb_discarded)); |
| return 0; |
| } |
| |
| static void *ext4_mb_seq_structs_summary_start(struct seq_file *seq, loff_t *pos) |
| __acquires(&EXT4_SB(sb)->s_mb_rb_lock) |
| { |
| struct super_block *sb = pde_data(file_inode(seq->file)); |
| unsigned long position; |
| |
| read_lock(&EXT4_SB(sb)->s_mb_rb_lock); |
| |
| if (*pos < 0 || *pos >= MB_NUM_ORDERS(sb) + 1) |
| return NULL; |
| position = *pos + 1; |
| return (void *) ((unsigned long) position); |
| } |
| |
| static void *ext4_mb_seq_structs_summary_next(struct seq_file *seq, void *v, loff_t *pos) |
| { |
| struct super_block *sb = pde_data(file_inode(seq->file)); |
| unsigned long position; |
| |
| ++*pos; |
| if (*pos < 0 || *pos >= MB_NUM_ORDERS(sb) + 1) |
| return NULL; |
| position = *pos + 1; |
| return (void *) ((unsigned long) position); |
| } |
| |
| static int ext4_mb_seq_structs_summary_show(struct seq_file *seq, void *v) |
| { |
| struct super_block *sb = pde_data(file_inode(seq->file)); |
| struct ext4_sb_info *sbi = EXT4_SB(sb); |
| unsigned long position = ((unsigned long) v); |
| struct ext4_group_info *grp; |
| struct rb_node *n; |
| unsigned int count, min, max; |
| |
| position--; |
| if (position >= MB_NUM_ORDERS(sb)) { |
| seq_puts(seq, "fragment_size_tree:\n"); |
| n = rb_first(&sbi->s_mb_avg_fragment_size_root); |
| if (!n) { |
| seq_puts(seq, "\ttree_min: 0\n\ttree_max: 0\n\ttree_nodes: 0\n"); |
| return 0; |
| } |
| grp = rb_entry(n, struct ext4_group_info, bb_avg_fragment_size_rb); |
| min = grp->bb_fragments ? grp->bb_free / grp->bb_fragments : 0; |
| count = 1; |
| while (rb_next(n)) { |
| count++; |
| n = rb_next(n); |
| } |
| grp = rb_entry(n, struct ext4_group_info, bb_avg_fragment_size_rb); |
| max = grp->bb_fragments ? grp->bb_free / grp->bb_fragments : 0; |
| |
| seq_printf(seq, "\ttree_min: %u\n\ttree_max: %u\n\ttree_nodes: %u\n", |
| min, max, count); |
| return 0; |
| } |
| |
| if (position == 0) { |
| seq_printf(seq, "optimize_scan: %d\n", |
| test_opt2(sb, MB_OPTIMIZE_SCAN) ? 1 : 0); |
| seq_puts(seq, "max_free_order_lists:\n"); |
| } |
| count = 0; |
| list_for_each_entry(grp, &sbi->s_mb_largest_free_orders[position], |
| bb_largest_free_order_node) |
| count++; |
| seq_printf(seq, "\tlist_order_%u_groups: %u\n", |
| (unsigned int)position, count); |
| |
| return 0; |
| } |
| |
| static void ext4_mb_seq_structs_summary_stop(struct seq_file *seq, void *v) |
| __releases(&EXT4_SB(sb)->s_mb_rb_lock) |
| { |
| struct super_block *sb = pde_data(file_inode(seq->file)); |
| |
| read_unlock(&EXT4_SB(sb)->s_mb_rb_lock); |
| } |
| |
| const struct seq_operations ext4_mb_seq_structs_summary_ops = { |
| .start = ext4_mb_seq_structs_summary_start, |
| .next = ext4_mb_seq_structs_summary_next, |
| .stop = ext4_mb_seq_structs_summary_stop, |
| .show = ext4_mb_seq_structs_summary_show, |
| }; |
| |
| static struct kmem_cache *get_groupinfo_cache(int blocksize_bits) |
| { |
| int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE; |
| struct kmem_cache *cachep = ext4_groupinfo_caches[cache_index]; |
| |
| BUG_ON(!cachep); |
| return cachep; |
| } |
| |
| /* |
| |