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authorLi Zefan <lizf@cn.fujitsu.com>2011-12-01 12:55:47 +0800
committerLi Zefan <lizf@cn.fujitsu.com>2012-01-11 10:26:44 +0800
commitde11cc12df17337979e0929d2831887432f236ca (patch)
treea9232dd3531707f49c5e56523019a1e0ce081876 /fs
parent125ccb0ae6806dbec31abf4a85448971df3b4e39 (diff)
downloadop-kernel-dev-de11cc12df17337979e0929d2831887432f236ca.zip
op-kernel-dev-de11cc12df17337979e0929d2831887432f236ca.tar.gz
Btrfs: don't pre-allocate btrfs bio
We pre-allocate a btrfs bio with fixed size, and then may re-allocate memory if we find stripes are bigger than the fixed size. But this pre-allocation is not necessary. Also we don't have to calcuate the stripe number twice. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/volumes.c67
1 files changed, 21 insertions, 46 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 73f673c..540fdd2 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2897,26 +2897,13 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
u64 stripe_nr;
u64 stripe_nr_orig;
u64 stripe_nr_end;
- int stripes_allocated = 8;
- int stripes_required = 1;
int stripe_index;
int i;
+ int ret = 0;
int num_stripes;
int max_errors = 0;
struct btrfs_bio *bbio = NULL;
- if (bbio_ret && !(rw & (REQ_WRITE | REQ_DISCARD)))
- stripes_allocated = 1;
-again:
- if (bbio_ret) {
- bbio = kzalloc(btrfs_bio_size(stripes_allocated),
- GFP_NOFS);
- if (!bbio)
- return -ENOMEM;
-
- atomic_set(&bbio->error, 0);
- }
-
read_lock(&em_tree->lock);
em = lookup_extent_mapping(em_tree, logical, *length);
read_unlock(&em_tree->lock);
@@ -2935,32 +2922,6 @@ again:
if (mirror_num > map->num_stripes)
mirror_num = 0;
- /* if our btrfs_bio struct is too small, back off and try again */
- if (rw & REQ_WRITE) {
- if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
- BTRFS_BLOCK_GROUP_DUP)) {
- stripes_required = map->num_stripes;
- max_errors = 1;
- } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
- stripes_required = map->sub_stripes;
- max_errors = 1;
- }
- }
- if (rw & REQ_DISCARD) {
- if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
- BTRFS_BLOCK_GROUP_RAID1 |
- BTRFS_BLOCK_GROUP_DUP |
- BTRFS_BLOCK_GROUP_RAID10)) {
- stripes_required = map->num_stripes;
- }
- }
- if (bbio_ret && (rw & (REQ_WRITE | REQ_DISCARD)) &&
- stripes_allocated < stripes_required) {
- stripes_allocated = map->num_stripes;
- free_extent_map(em);
- kfree(bbio);
- goto again;
- }
stripe_nr = offset;
/*
* stripe_nr counts the total number of stripes we have to stride
@@ -3055,6 +3016,13 @@ again:
}
BUG_ON(stripe_index >= map->num_stripes);
+ bbio = kzalloc(btrfs_bio_size(num_stripes), GFP_NOFS);
+ if (!bbio) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ atomic_set(&bbio->error, 0);
+
if (rw & REQ_DISCARD) {
for (i = 0; i < num_stripes; i++) {
bbio->stripes[i].physical =
@@ -3151,15 +3119,22 @@ again:
stripe_index++;
}
}
- if (bbio_ret) {
- *bbio_ret = bbio;
- bbio->num_stripes = num_stripes;
- bbio->max_errors = max_errors;
- bbio->mirror_num = mirror_num;
+
+ if (rw & REQ_WRITE) {
+ if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
+ BTRFS_BLOCK_GROUP_RAID10 |
+ BTRFS_BLOCK_GROUP_DUP)) {
+ max_errors = 1;
+ }
}
+
+ *bbio_ret = bbio;
+ bbio->num_stripes = num_stripes;
+ bbio->max_errors = max_errors;
+ bbio->mirror_num = mirror_num;
out:
free_extent_map(em);
- return 0;
+ return ret;
}
int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
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