From: Jing Zhang <[email protected]>
Date: Sat Apr 3 15:11:47 2010
The story about the life of PA starts with kmem_cache_alloc(),
followed by atomic_set() at [line:3369/3429],
...
[many algorithms of EXT4]
...
ac->ac_pa = pa;
...
and is about to finish in the function, ext4_mb_release_context().
Check-Point-01, [line:4101-4125]
First, the rcu_read_lock() method used conflicts with
that at [line:4019].
Second, whether RCU, by its defination, is capable of
protecting competive writers should be concerned.
Third, the locality group, please see [line:2418], is
designed to be PERCPU.
Also note, after added, pa could be at any position on
the lg_prealloc_list.
If the length of list is greater than 8, let's goto next check point.
Check-Point-02, [line:4019-4057]
First, the atomic_read() at [line:4023] is not able to assure that
this pa is the one we just used for block allocation. It is inited
to be 1 at [line:3369/3429]. The pa_count at [line:4023] is just the
number of CAs holding this pa, and I guess its value is 1 in case of
newly created pa.
Second, PAs are selected without good considerations of the sort
effort mentioned above.
Third, the selected PAs may include the just added pa at [line:4111],
(let's lable it pa-4111)
and if selected, let's goto next check point.
Check-Point-03, [line:4074]
The victim, pa-4111, is destroied.
Check-Point-04, [line:4167-4168]
After ext4_mb_add_n_trim() returns,
ext4_mb_put_pa() may be crashed by pa-4111.
Check-Point-05, [line:3261-3269]
First, [line:3261-3262] are copied here,
if (!atomic_dec_and_test(&pa->pa_count) || pa->pa_free != 0)
return;
and are changed to,
__3261 if (!atomic_dec_and_test(&pa->pa_count))
__3262 return;
__3263 if (pa->pa_free != 0)
__3264 return;
If the changed equals the original,
the return at __3264 will kill the pa which is parameter,
no matter pa == pa-4111. It is a black hole.
Second, pa may also be killed by the return at [line:3268].
Fixing black hole was tried, but failed, by which I was fried a few days.
The relationship between PA cache and kmem_cache should be
improved in this patch by simplifying the mechanism of
lg/inode PA cache management.
Based upon the original, lg PA cache is changed as less as possible to
be,
that lg PA cache is managed in simple and/or naive way,
briefly with consideration of pa_count.
[1] when pa is created, atomic_set(&pa->pa_count,1);
[2] before assigned to ac_pa, pa_count++;
[3] before added to lg cache, pa_count++;
and
[4] after usage by ac, put_pa(pa);
[5] after deleted from lg cache, put_pa(pa);
[6] after deleted from group list, put_pa(pa);
And it is also applied to inode PA cache.
-zj
Cc: Theodore Ts'o <[email protected]>
Cc: Andreas Dilger <[email protected]>
Cc: Dave Kleikamp <[email protected]>
Cc: "Aneesh Kumar K. V" <[email protected]>
Signed-off-by: Jing Zhang <[email protected]>
---
--- linux-2.6.32/fs/ext4/mballoc.h 2009-12-03 11:51:22.000000000 +0800
+++ fs/ext4-black-hole/mballoc.h 2010-04-01 20:45:30.000000000 +0800
@@ -233,4 +233,17 @@ static inline ext4_fsblk_t ext4_grp_offs
+ le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
return block;
}
+
+static inline void ext4_mb_get_pa(struct ext4_prealloc_space *pa)
+{
+ atomic_inc(&pa->pa_count);
+}
+
+static void ext4_mb_pa_callback(struct rcu_head *);
+
+static inline void ext4_mb_put_pa(struct ext4_prealloc_space *pa)
+{
+ if (atomic_dec_and_test(&pa->pa_count))
+ call_rcu(&pa->u.pa_rcu, ext4_mb_pa_callback);
+}
#endif
--- linux-2.6.32/fs/ext4/mballoc.c 2009-12-03 11:51:22.000000000 +0800
+++ fs/ext4-black-hole/mballoc-02.c 2010-04-03 13:35:34.000000000 +0800
@@ -2449,8 +2449,8 @@ static void ext4_mb_cleanup_pa(struct ex
list_for_each_safe(cur, tmp, &grp->bb_prealloc_list) {
pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
list_del(&pa->pa_group_list);
+ ext4_mb_put_pa(pa);
count++;
- kmem_cache_free(ext4_pspace_cachep, pa);
}
if (count)
mb_debug(1, "mballoc: %u PAs left\n", count);
@@ -2898,13 +2898,7 @@ ext4_mb_normalize_request(struct ext4_al
list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
ext4_lblk_t pa_end;
- if (pa->pa_deleted)
- continue;
spin_lock(&pa->pa_lock);
- if (pa->pa_deleted) {
- spin_unlock(&pa->pa_lock);
- continue;
- }
pa_end = pa->pa_lstart + pa->pa_len;
@@ -2932,18 +2926,6 @@ ext4_mb_normalize_request(struct ext4_al
rcu_read_unlock();
size = end - start;
- /* XXX: extra loop to check we really don't overlap preallocations */
- rcu_read_lock();
- list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
- ext4_lblk_t pa_end;
- spin_lock(&pa->pa_lock);
- if (pa->pa_deleted == 0) {
- pa_end = pa->pa_lstart + pa->pa_len;
- BUG_ON(!(start >= pa_end || end <= pa->pa_lstart));
- }
- spin_unlock(&pa->pa_lock);
- }
- rcu_read_unlock();
if (start + size <= ac->ac_o_ex.fe_logical &&
start > ac->ac_o_ex.fe_logical) {
@@ -3071,7 +3053,7 @@ ext4_mb_check_group_pa(ext4_fsblk_t goal
ext4_fsblk_t cur_distance, new_distance;
if (cpa == NULL) {
- atomic_inc(&pa->pa_count);
+ ext4_mb_get_pa(pa);
return pa;
}
cur_distance = abs(goal_block - cpa->pa_pstart);
@@ -3081,8 +3063,8 @@ ext4_mb_check_group_pa(ext4_fsblk_t goal
return cpa;
/* drop the previous reference */
- atomic_dec(&cpa->pa_count);
- atomic_inc(&pa->pa_count);
+ ext4_mb_put_pa(cpa);
+ ext4_mb_get_pa(pa);
return pa;
}
@@ -3119,8 +3101,8 @@ ext4_mb_use_preallocated(struct ext4_all
/* found preallocated blocks, use them */
spin_lock(&pa->pa_lock);
- if (pa->pa_deleted == 0 && pa->pa_free) {
- atomic_inc(&pa->pa_count);
+ if (pa->pa_free) {
+ ext4_mb_get_pa(pa);
ext4_mb_use_inode_pa(ac, pa);
spin_unlock(&pa->pa_lock);
ac->ac_criteria = 10;
@@ -3156,8 +3138,7 @@ ext4_mb_use_preallocated(struct ext4_all
list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[i],
pa_inode_list) {
spin_lock(&pa->pa_lock);
- if (pa->pa_deleted == 0 &&
- pa->pa_free >= ac->ac_o_ex.fe_len) {
+ if (pa->pa_free >= ac->ac_o_ex.fe_len) {
cpa = ext4_mb_check_group_pa(goal_block,
pa, cpa);
@@ -3249,64 +3230,6 @@ static void ext4_mb_pa_callback(struct r
}
/*
- * drops a reference to preallocated space descriptor
- * if this was the last reference and the space is consumed
- */
-static void ext4_mb_put_pa(struct ext4_allocation_context *ac,
- struct super_block *sb, struct ext4_prealloc_space *pa)
-{
- ext4_group_t grp;
- ext4_fsblk_t grp_blk;
-
- if (!atomic_dec_and_test(&pa->pa_count) || pa->pa_free != 0)
- return;
-
- /* in this short window concurrent discard can set pa_deleted */
- spin_lock(&pa->pa_lock);
- if (pa->pa_deleted == 1) {
- spin_unlock(&pa->pa_lock);
- return;
- }
-
- pa->pa_deleted = 1;
- spin_unlock(&pa->pa_lock);
-
- grp_blk = pa->pa_pstart;
- /*
- * If doing group-based preallocation, pa_pstart may be in the
- * next group when pa is used up
- */
- if (pa->pa_type == MB_GROUP_PA)
- grp_blk--;
-
- ext4_get_group_no_and_offset(sb, grp_blk, &grp, NULL);
-
- /*
- * possible race:
- *
- * P1 (buddy init) P2 (regular allocation)
- * find block B in PA
- * copy on-disk bitmap to buddy
- * mark B in on-disk bitmap
- * drop PA from group
- * mark all PAs in buddy
- *
- * thus, P1 initializes buddy with B available. to prevent this
- * we make "copy" and "mark all PAs" atomic and serialize "drop PA"
- * against that pair
- */
- ext4_lock_group(sb, grp);
- list_del(&pa->pa_group_list);
- ext4_unlock_group(sb, grp);
-
- spin_lock(pa->pa_obj_lock);
- list_del_rcu(&pa->pa_inode_list);
- spin_unlock(pa->pa_obj_lock);
-
- call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
-}
-
-/*
* creates new preallocated space for given inode
*/
static noinline_for_stack int
@@ -3377,6 +3300,7 @@ ext4_mb_new_inode_pa(struct ext4_allocat
pa->pa_pstart, pa->pa_len, pa->pa_lstart);
trace_ext4_mb_new_inode_pa(ac, pa);
+ ext4_mb_get_pa(pa);
ext4_mb_use_inode_pa(ac, pa);
atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated);
@@ -3390,6 +3314,7 @@ ext4_mb_new_inode_pa(struct ext4_allocat
list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
+ ext4_mb_get_pa(pa);
spin_lock(pa->pa_obj_lock);
list_add_rcu(&pa->pa_inode_list, &ei->i_prealloc_list);
spin_unlock(pa->pa_obj_lock);
@@ -3437,6 +3362,7 @@ ext4_mb_new_group_pa(struct ext4_allocat
pa->pa_pstart, pa->pa_len, pa->pa_lstart);
trace_ext4_mb_new_group_pa(ac, pa);
+ ext4_mb_get_pa(pa);
ext4_mb_use_group_pa(ac, pa);
atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated);
@@ -3493,7 +3419,6 @@ ext4_mb_release_inode_pa(struct ext4_bud
int err = 0;
int free = 0;
- BUG_ON(pa->pa_deleted == 0);
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
grp_blk_start = pa->pa_pstart - bit;
BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
@@ -3557,7 +3482,6 @@ ext4_mb_release_group_pa(struct ext4_bud
ext4_grpblk_t bit;
trace_ext4_mb_release_group_pa(ac, pa);
- BUG_ON(pa->pa_deleted == 0);
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
mb_free_blocks(pa->pa_inode, e4b, bit, pa->pa_len);
@@ -3593,14 +3517,14 @@ ext4_mb_discard_group_preallocations(str
struct buffer_head *bitmap_bh = NULL;
struct ext4_prealloc_space *pa, *tmp;
struct ext4_allocation_context *ac;
- struct list_head list;
struct ext4_buddy e4b;
int err;
- int busy = 0;
int free = 0;
mb_debug(1, "discard preallocation for group %u\n", group);
+ if (needed <= 0)
+ return free;
if (list_empty(&grp->bb_prealloc_list))
return 0;
@@ -3622,74 +3546,33 @@ ext4_mb_discard_group_preallocations(str
if (needed == 0)
needed = EXT4_BLOCKS_PER_GROUP(sb) + 1;
- INIT_LIST_HEAD(&list);
ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
if (ac)
ac->ac_sb = sb;
-repeat:
+
ext4_lock_group(sb, group);
- list_for_each_entry_safe(pa, tmp,
+ /* it is LRU */
+ list_for_each_entry_safe_reverse(pa, tmp,
&grp->bb_prealloc_list, pa_group_list) {
spin_lock(&pa->pa_lock);
- if (atomic_read(&pa->pa_count)) {
- spin_unlock(&pa->pa_lock);
- busy = 1;
- continue;
- }
- if (pa->pa_deleted) {
- spin_unlock(&pa->pa_lock);
- continue;
- }
-
- /* seems this one can be freed ... */
- pa->pa_deleted = 1;
-
/* we can trust pa_free ... */
free += pa->pa_free;
-
spin_unlock(&pa->pa_lock);
- list_del(&pa->pa_group_list);
- list_add(&pa->u.pa_tmp_list, &list);
- }
-
- /* if we still need more blocks and some PAs were used, try again */
- if (free < needed && busy) {
- busy = 0;
- ext4_unlock_group(sb, group);
- /*
- * Yield the CPU here so that we don't get soft lockup
- * in non preempt case.
- */
- yield();
- goto repeat;
- }
-
- /* found anything to free? */
- if (list_empty(&list)) {
- BUG_ON(free != 0);
- goto out;
- }
-
- /* now free all selected PAs */
- list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
-
- /* remove from object (inode or locality group) */
- spin_lock(pa->pa_obj_lock);
- list_del_rcu(&pa->pa_inode_list);
- spin_unlock(pa->pa_obj_lock);
-
+ list_del_init(&pa->pa_group_list);
if (pa->pa_type == MB_GROUP_PA)
ext4_mb_release_group_pa(&e4b, pa, ac);
else
- ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa, ac);
-
- list_del(&pa->u.pa_tmp_list);
- call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
+ ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa, ac);
+ ext4_mb_put_pa(pa);
+ /*
+ * no suck, please, just do the needed.
+ */
+ if (free >= needed)
+ break;
}
-
-out:
ext4_unlock_group(sb, group);
+
if (ac)
kmem_cache_free(ext4_ac_cachep, ac);
ext4_mb_release_desc(&e4b);
@@ -3709,110 +3592,23 @@ out:
void ext4_discard_preallocations(struct inode *inode)
{
struct ext4_inode_info *ei = EXT4_I(inode);
- struct super_block *sb = inode->i_sb;
- struct buffer_head *bitmap_bh = NULL;
struct ext4_prealloc_space *pa, *tmp;
- struct ext4_allocation_context *ac;
- ext4_group_t group = 0;
- struct list_head list;
- struct ext4_buddy e4b;
- int err;
if (!S_ISREG(inode->i_mode)) {
- /*BUG_ON(!list_empty(&ei->i_prealloc_list));*/
return;
}
mb_debug(1, "discard preallocation for inode %lu\n", inode->i_ino);
trace_ext4_discard_preallocations(inode);
- INIT_LIST_HEAD(&list);
-
- ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
- if (ac) {
- ac->ac_sb = sb;
- ac->ac_inode = inode;
- }
-repeat:
- /* first, collect all pa's in the inode */
spin_lock(&ei->i_prealloc_lock);
while (!list_empty(&ei->i_prealloc_list)) {
pa = list_entry(ei->i_prealloc_list.next,
struct ext4_prealloc_space, pa_inode_list);
- BUG_ON(pa->pa_obj_lock != &ei->i_prealloc_lock);
- spin_lock(&pa->pa_lock);
- if (atomic_read(&pa->pa_count)) {
- /* this shouldn't happen often - nobody should
- * use preallocation while we're discarding it */
- spin_unlock(&pa->pa_lock);
- spin_unlock(&ei->i_prealloc_lock);
- printk(KERN_ERR "uh-oh! used pa while discarding\n");
- WARN_ON(1);
- schedule_timeout_uninterruptible(HZ);
- goto repeat;
-
- }
- if (pa->pa_deleted == 0) {
- pa->pa_deleted = 1;
- spin_unlock(&pa->pa_lock);
- list_del_rcu(&pa->pa_inode_list);
- list_add(&pa->u.pa_tmp_list, &list);
- continue;
- }
-
- /* someone is deleting pa right now */
- spin_unlock(&pa->pa_lock);
- spin_unlock(&ei->i_prealloc_lock);
-
- /* we have to wait here because pa_deleted
- * doesn't mean pa is already unlinked from
- * the list. as we might be called from
- * ->clear_inode() the inode will get freed
- * and concurrent thread which is unlinking
- * pa from inode's list may access already
- * freed memory, bad-bad-bad */
-
- /* XXX: if this happens too often, we can
- * add a flag to force wait only in case
- * of ->clear_inode(), but not in case of
- * regular truncate */
- schedule_timeout_uninterruptible(HZ);
- goto repeat;
+ list_del_rcu(&pa->pa_inode_list);
+ ext4_mb_put_pa(pa);
}
spin_unlock(&ei->i_prealloc_lock);
-
- list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
- BUG_ON(pa->pa_type != MB_INODE_PA);
- ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, NULL);
-
- err = ext4_mb_load_buddy(sb, group, &e4b);
- if (err) {
- ext4_error(sb, __func__, "Error in loading buddy "
- "information for %u", group);
- continue;
- }
-
- bitmap_bh = ext4_read_block_bitmap(sb, group);
- if (bitmap_bh == NULL) {
- ext4_error(sb, __func__, "Error in reading block "
- "bitmap for %u", group);
- ext4_mb_release_desc(&e4b);
- continue;
- }
-
- ext4_lock_group(sb, group);
- list_del(&pa->pa_group_list);
- ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa, ac);
- ext4_unlock_group(sb, group);
-
- ext4_mb_release_desc(&e4b);
- put_bh(bitmap_bh);
-
- list_del(&pa->u.pa_tmp_list);
- call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
- }
- if (ac)
- kmem_cache_free(ext4_ac_cachep, ac);
}
/*
@@ -3998,85 +3794,6 @@ ext4_mb_initialize_context(struct ext4_a
}
-static noinline_for_stack void
-ext4_mb_discard_lg_preallocations(struct super_block *sb,
- struct ext4_locality_group *lg,
- int order, int total_entries)
-{
- ext4_group_t group = 0;
- struct ext4_buddy e4b;
- struct list_head discard_list;
- struct ext4_prealloc_space *pa, *tmp;
- struct ext4_allocation_context *ac;
-
- mb_debug(1, "discard locality group preallocation\n");
-
- INIT_LIST_HEAD(&discard_list);
- ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
- if (ac)
- ac->ac_sb = sb;
-
- spin_lock(&lg->lg_prealloc_lock);
- list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[order],
- pa_inode_list) {
- spin_lock(&pa->pa_lock);
- if (atomic_read(&pa->pa_count)) {
- /*
- * This is the pa that we just used
- * for block allocation. So don't
- * free that
- */
- spin_unlock(&pa->pa_lock);
- continue;
- }
- if (pa->pa_deleted) {
- spin_unlock(&pa->pa_lock);
- continue;
- }
- /* only lg prealloc space */
- BUG_ON(pa->pa_type != MB_GROUP_PA);
-
- /* seems this one can be freed ... */
- pa->pa_deleted = 1;
- spin_unlock(&pa->pa_lock);
-
- list_del_rcu(&pa->pa_inode_list);
- list_add(&pa->u.pa_tmp_list, &discard_list);
-
- total_entries--;
- if (total_entries <= 5) {
- /*
- * we want to keep only 5 entries
- * allowing it to grow to 8. This
- * mak sure we don't call discard
- * soon for this list.
- */
- break;
- }
- }
- spin_unlock(&lg->lg_prealloc_lock);
-
- list_for_each_entry_safe(pa, tmp, &discard_list, u.pa_tmp_list) {
-
- ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, NULL);
- if (ext4_mb_load_buddy(sb, group, &e4b)) {
- ext4_error(sb, __func__, "Error in loading buddy "
- "information for %u", group);
- continue;
- }
- ext4_lock_group(sb, group);
- list_del(&pa->pa_group_list);
- ext4_mb_release_group_pa(&e4b, pa, ac);
- ext4_unlock_group(sb, group);
-
- ext4_mb_release_desc(&e4b);
- list_del(&pa->u.pa_tmp_list);
- call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
- }
- if (ac)
- kmem_cache_free(ext4_ac_cachep, ac);
-}
-
/*
* We have incremented pa_count. So it cannot be freed at this
* point. Also we hold lg_mutex. So no parallel allocation is
@@ -4089,48 +3806,48 @@ ext4_mb_discard_lg_preallocations(struct
static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac)
{
int order, added = 0, lg_prealloc_count = 1;
- struct super_block *sb = ac->ac_sb;
struct ext4_locality_group *lg = ac->ac_lg;
struct ext4_prealloc_space *tmp_pa, *pa = ac->ac_pa;
+ /* is in cache already? */
+ int needed = list_empty(&pa->pa_inode_list);
order = fls(pa->pa_free) - 1;
if (order > PREALLOC_TB_SIZE - 1)
/* The max size of hash table is PREALLOC_TB_SIZE */
order = PREALLOC_TB_SIZE - 1;
- /* Add the prealloc space to lg */
- rcu_read_lock();
+
+ /* why not &lg->lg_prealloc_list[order].lock? */
+ spin_lock(&lg->lg_prealloc_lock);
+
+#define __lg_cache_wm 5 /* water mark */
+
list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[order],
- pa_inode_list) {
- spin_lock(&tmp_pa->pa_lock);
- if (tmp_pa->pa_deleted) {
- spin_unlock(&tmp_pa->pa_lock);
- continue;
- }
- if (!added && pa->pa_free < tmp_pa->pa_free) {
- /* Add to the tail of the previous entry */
- list_add_tail_rcu(&pa->pa_inode_list,
- &tmp_pa->pa_inode_list);
- added = 1;
- /*
- * we want to count the total
- * number of entries in the list
- */
+ pa_inode_list) {
+ if (lg_prealloc_count++ <= __lg_cache_wm) {
+ if (needed && ! added && pa->pa_free) {
+ spin_lock(&tmp_pa->pa_lock);
+ if (pa->pa_free < tmp_pa->pa_free) {
+ ext4_mb_get_pa(pa);
+ list_add_tail_rcu(&pa->pa_inode_list,
+ &tmp_pa->pa_inode_list);
+ added = 1;
+ }
+ spin_unlock(&tmp_pa->pa_lock);
+ }
+ } else {
+ list_del_rcu(&tmp_pa->pa_inode_list);
+ ext4_mb_put_pa(tmp_pa);
}
- spin_unlock(&tmp_pa->pa_lock);
- lg_prealloc_count++;
}
- if (!added)
- list_add_tail_rcu(&pa->pa_inode_list,
- &lg->lg_prealloc_list[order]);
- rcu_read_unlock();
-
- /* Now trim the list to be not more than 8 elements */
- if (lg_prealloc_count > 8) {
- ext4_mb_discard_lg_preallocations(sb, lg,
- order, lg_prealloc_count);
- return;
+ if (needed && !added && pa->pa_free) {
+ ext4_mb_get_pa(pa);
+ list_add_rcu(&pa->pa_inode_list,
+ &lg->lg_prealloc_list[order]);
}
- return ;
+
+#undef __lg_cache_wm
+
+ spin_unlock(&lg->lg_prealloc_lock);
}
/*
@@ -4153,20 +3870,11 @@ static int ext4_mb_release_context(struc
if (ac->alloc_semp)
up_read(ac->alloc_semp);
if (pa) {
- /*
- * We want to add the pa to the right bucket.
- * Remove it from the list and while adding
- * make sure the list to which we are adding
- * doesn't grow big. We need to release
- * alloc_semp before calling ext4_mb_add_n_trim()
- */
- if ((pa->pa_type == MB_GROUP_PA) && likely(pa->pa_free)) {
- spin_lock(pa->pa_obj_lock);
- list_del_rcu(&pa->pa_inode_list);
- spin_unlock(pa->pa_obj_lock);
+ if (pa->pa_type == MB_GROUP_PA) {
+ /* we have to update lg PA cache */
ext4_mb_add_n_trim(ac);
}
- ext4_mb_put_pa(ac, ac->ac_sb, pa);
+ ext4_mb_put_pa(pa);
}
if (ac->ac_bitmap_page)
page_cache_release(ac->ac_bitmap_page);