jim owens
2010-Jan-04 21:14 UTC
[RFC 10/12 PATCH] Btrfs: add direct I/O checksum option to btrfs_lookup_csums_range.
Direct I/O needs to efficiently fetch an extent range of checksums
so an option is added to copy raw checksums into a buffer instead
of locally allocating and returning btrfs_ordered_sum structs.
Signed-off-by: jim owens <jowens@hp.com>
---
fs/btrfs/ctree.h | 2 +-
fs/btrfs/file-item.c | 28 +++++++++++++++++++++++++---
fs/btrfs/inode.c | 2 +-
fs/btrfs/relocation.c | 2 +-
fs/btrfs/tree-log.c | 4 ++--
5 files changed, 30 insertions(+), 8 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 9f806dd..bf04876 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2280,7 +2280,7 @@ int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct btrfs_path *path,
u64 isize);
int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start,
- u64 end, struct list_head *list);
+ u64 end, struct list_head *list, u32 *csums);
/* inode.c */
/* RHEL and EL kernels have a patch that renames PG_checked to FsMisc */
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 9b99886..72c76bd 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -245,7 +245,7 @@ found:
}
int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
- struct list_head *list)
+ struct list_head *list, u32 *csums)
{
struct btrfs_key key;
struct btrfs_path *path;
@@ -302,8 +302,15 @@ int btrfs_lookup_csums_range(struct btrfs_root *root, u64
start, u64 end,
if (key.offset > end)
break;
- if (key.offset > start)
+ if (key.offset > start) {
+ if (csums) {
+ size_t num;
+ num = (key.offset - start) / root->sectorsize;
+ memset(csums, 0, num * csum_size);
+ csums += num;
+ }
start = key.offset;
+ }
size = btrfs_item_size_nr(leaf, path->slots[0]);
csum_end = key.offset + (size / csum_size) * root->sectorsize;
@@ -315,7 +322,16 @@ int btrfs_lookup_csums_range(struct btrfs_root *root, u64
start, u64 end,
csum_end = min(csum_end, end + 1);
item = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_csum_item);
- while (start < csum_end) {
+ if (csums) {
+ size_t num = (csum_end - start) / root->sectorsize;
+ offset = (start - key.offset) /
+ root->sectorsize * csum_size;
+ read_extent_buffer(path->nodes[0], csums,
+ ((unsigned long)item) +
+ offset, num * csum_size);
+ csums += num;
+ start = csum_end;
+ } else while (start < csum_end) {
size = min_t(size_t, csum_end - start,
MAX_ORDERED_SUM_BYTES(root));
sums = kzalloc(btrfs_ordered_sum_size(root, size),
@@ -346,6 +362,12 @@ int btrfs_lookup_csums_range(struct btrfs_root *root, u64
start, u64 end,
}
path->slots[0]++;
}
+
+ if (csums && start < end) {
+ size_t num = (end - start + 1) / root->sectorsize;
+ memset(csums, 0, num * csum_size);
+ }
+
ret = 0;
fail:
btrfs_free_path(path);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 152015c..fbc5bd1 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -978,7 +978,7 @@ static noinline int csum_exist_in_range(struct btrfs_root
*root,
LIST_HEAD(list);
ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
- bytenr + num_bytes - 1, &list);
+ bytenr + num_bytes - 1, &list, NULL);
if (ret == 0 && list_empty(&list))
return 0;
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index a972868..0056769 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -3789,7 +3789,7 @@ int btrfs_reloc_clone_csums(struct inode *inode, u64
file_pos, u64 len)
disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
- disk_bytenr + len - 1, &list);
+ disk_bytenr + len - 1, &list, NULL);
while (!list_empty(&list)) {
sums = list_entry(list.next, struct btrfs_ordered_sum, list);
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 4a9434b..51ed422 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -604,7 +604,7 @@ static noinline int replay_one_extent(struct
btrfs_trans_handle *trans,
ret = btrfs_lookup_csums_range(root->log_root,
csum_start, csum_end - 1,
- &ordered_sums);
+ &ordered_sums, NULL);
BUG_ON(ret);
while (!list_empty(&ordered_sums)) {
struct btrfs_ordered_sum *sums;
@@ -2645,7 +2645,7 @@ static noinline int copy_items(struct btrfs_trans_handle
*trans,
ret = btrfs_lookup_csums_range(
log->fs_info->csum_root,
ds + cs, ds + cs + cl - 1,
- &ordered_sums);
+ &ordered_sums, NULL);
BUG_ON(ret);
}
}
--
1.5.6.3
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