jim owens
2010-Jan-04 21:13 UTC
[RFC 05/12 RESEND PATCH] Btrfs: remove dead code for unplugging pages.
The code in btrfs_unplug_io_fn() to selectively unplug just the
stripes affected by a page had been previously disabled. The
unneeded code for unplug_page in __btrfs_map_block made changes
for btrfs directio more difficult so I''m removing all of it.
Signed-off-by: jim owens <jowens@hp.com>
---
fs/btrfs/disk-io.c | 62 ++---------------------------------------------
fs/btrfs/volumes.c | 67 +++++++++++++--------------------------------------
fs/btrfs/volumes.h | 2 -
3 files changed, 20 insertions(+), 111 deletions(-)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 009e3bd..72c08fa 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1289,10 +1289,10 @@ static int btrfs_congested_fn(void *congested_data, int
bdi_bits)
}
/*
- * this unplugs every device on the box, and it is only used when page
- * is null
+ * this unplugs every device on the box, and yes that is ugly
+ * but there are currently no low cost alternatives
*/
-static void __unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
+static void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
{
struct btrfs_device *device;
struct btrfs_fs_info *info;
@@ -1308,62 +1308,6 @@ static void __unplug_io_fn(struct backing_dev_info *bdi,
struct page *page)
}
}
-static void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
-{
- struct inode *inode;
- struct extent_map_tree *em_tree;
- struct extent_map *em;
- struct address_space *mapping;
- u64 offset;
-
- /* the generic O_DIRECT read code does this */
- if (1 || !page) {
- __unplug_io_fn(bdi, page);
- return;
- }
-
- /*
- * page->mapping may change at any time. Get a consistent copy
- * and use that for everything below
- */
- smp_mb();
- mapping = page->mapping;
- if (!mapping)
- return;
-
- inode = mapping->host;
-
- /*
- * don''t do the expensive searching for a small number of
- * devices
- */
- if (BTRFS_I(inode)->root->fs_info->fs_devices->open_devices <=
2) {
- __unplug_io_fn(bdi, page);
- return;
- }
-
- offset = page_offset(page);
-
- em_tree = &BTRFS_I(inode)->extent_tree;
- read_lock(&em_tree->lock);
- em = lookup_extent_mapping(em_tree, offset, PAGE_CACHE_SIZE);
- read_unlock(&em_tree->lock);
- if (!em) {
- __unplug_io_fn(bdi, page);
- return;
- }
-
- if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
- free_extent_map(em);
- __unplug_io_fn(bdi, page);
- return;
- }
- offset = offset - em->start;
- btrfs_unplug_page(&BTRFS_I(inode)->root->fs_info->mapping_tree,
- em->block_start + offset, page);
- free_extent_map(em);
-}
-
/*
* If this fails, caller must call bdi_destroy() to get rid of the
* bdi again.
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index e6599ef..0e3146a 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2614,10 +2614,10 @@ static int find_live_mirror(struct map_lookup *map, int
first, int num,
return optimal;
}
-static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
+int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
u64 logical, u64 *length,
struct btrfs_multi_bio **multi_ret,
- int mirror_num, struct page *unplug_page)
+ int mirror_num)
{
struct extent_map *em;
struct map_lookup *map;
@@ -2629,15 +2629,12 @@ static int __btrfs_map_block(struct btrfs_mapping_tree
*map_tree, int rw,
int i;
int num_stripes;
int max_errors;
- struct btrfs_multi_bio *multi = NULL;
+ struct btrfs_multi_bio *multi;
read_lock(&em_tree->lock);
em = lookup_extent_mapping(em_tree, logical, *length);
read_unlock(&em_tree->lock);
- if (!em && unplug_page)
- return 0;
-
if (!em) {
printk(KERN_CRIT "unable to find logical %llu len %llu\n",
(unsigned long long)logical,
@@ -2673,7 +2670,7 @@ static int __btrfs_map_block(struct btrfs_mapping_tree
*map_tree, int rw,
*length = min(*length, em->len - offset);
}
- if (!multi_ret && !unplug_page)
+ if (!multi_ret)
goto out;
if (mirror_num > map->num_stripes)
@@ -2691,7 +2688,7 @@ static int __btrfs_map_block(struct btrfs_mapping_tree
*map_tree, int rw,
num_stripes = 1;
stripe_index = 0;
if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
- if (unplug_page || (rw & (1 << BIO_RW)))
+ if (rw & (1 << BIO_RW))
num_stripes = map->num_stripes;
else if (mirror_num)
stripe_index = mirror_num - 1;
@@ -2713,7 +2710,7 @@ static int __btrfs_map_block(struct btrfs_mapping_tree
*map_tree, int rw,
stripe_index = do_div(stripe_nr, factor);
stripe_index *= map->sub_stripes;
- if (unplug_page || (rw & (1 << BIO_RW)))
+ if (rw & (1 << BIO_RW))
num_stripes = map->sub_stripes;
else if (mirror_num)
stripe_index += mirror_num - 1;
@@ -2732,34 +2729,20 @@ static int __btrfs_map_block(struct btrfs_mapping_tree
*map_tree, int rw,
}
BUG_ON(stripe_index >= map->num_stripes);
- if (multi_ret) {
- multi = kzalloc(btrfs_multi_bio_size(num_stripes), GFP_NOFS);
- if (!multi)
- return -ENOMEM;
- *multi_ret = multi;
+ multi = kzalloc(btrfs_multi_bio_size(num_stripes), GFP_NOFS);
+ if (!multi)
+ return -ENOMEM;
+ *multi_ret = multi;
- atomic_set(&multi->error, 0);
- multi->num_stripes = num_stripes;
- multi->max_errors = max_errors;
- }
+ atomic_set(&multi->error, 0);
+ multi->num_stripes = num_stripes;
+ multi->max_errors = max_errors;
for (i = 0; i < num_stripes; i++) {
- if (unplug_page) {
- struct btrfs_device *device;
- struct backing_dev_info *bdi;
-
- device = map->stripes[stripe_index].dev;
- if (device->bdev) {
- bdi = blk_get_backing_dev_info(device->bdev);
- if (bdi->unplug_io_fn)
- bdi->unplug_io_fn(bdi, unplug_page);
- }
- } else {
- multi->stripes[i].physical - map->stripes[stripe_index].physical +
- stripe_offset + stripe_nr * map->stripe_len;
- multi->stripes[i].dev = map->stripes[stripe_index].dev;
- }
+ multi->stripes[i].physical + map->stripes[stripe_index].physical +
+ stripe_offset + stripe_nr * map->stripe_len;
+ multi->stripes[i].dev = map->stripes[stripe_index].dev;
stripe_index++;
}
out:
@@ -2767,14 +2750,6 @@ out:
return 0;
}
-int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
- u64 logical, u64 *length,
- struct btrfs_multi_bio **multi_ret, int mirror_num)
-{
- return __btrfs_map_block(map_tree, rw, logical, length, multi_ret,
- mirror_num, NULL);
-}
-
int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
u64 chunk_start, u64 physical, u64 devid,
u64 **logical, int *naddrs, int *stripe_len)
@@ -2840,14 +2815,6 @@ int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
return 0;
}
-int btrfs_unplug_page(struct btrfs_mapping_tree *map_tree,
- u64 logical, struct page *page)
-{
- u64 length = PAGE_CACHE_SIZE;
- return __btrfs_map_block(map_tree, READ, logical, &length,
- NULL, 0, page);
-}
-
static void end_bio_multi_stripe(struct bio *bio, int err)
{
struct btrfs_multi_bio *multi = bio->bi_private;
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 31b0fab..d5aab74 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -169,8 +169,6 @@ int btrfs_add_device(struct btrfs_trans_handle *trans,
int btrfs_rm_device(struct btrfs_root *root, char *device_path);
int btrfs_cleanup_fs_uuids(void);
int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64
len);
-int btrfs_unplug_page(struct btrfs_mapping_tree *map_tree,
- u64 logical, struct page *page);
int btrfs_grow_device(struct btrfs_trans_handle *trans,
struct btrfs_device *device, u64 new_size);
struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
--
1.5.6.3
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