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Message-Id: <1304688009-10014-1-git-send-email-xiaoqiangnk@gmail.com>
Date: Fri, 6 May 2011 21:20:09 +0800
From: Yongqiang Yang <xiaoqiangnk@...il.com>
To: linux-ext4@...r.kernel.org
Cc: tytso@....edu, Yongqiang Yang <xiaoqiangnk@...il.com>
Subject: [PATCH] ext4:Teach ext4_ext_split to caculate extents efficiently.
ext4_ext_split can caculate extents to be moved in an efficient
way showed by this patch.
Signed-off-by: Yongqiang Yang <xiaoqiangnk@...il.com>
---
fs/ext4/extents.c | 84 +++++++++++++++++++++++++++++------------------------
1 files changed, 46 insertions(+), 38 deletions(-)
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index e363f21..baf846f 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -474,9 +474,43 @@ static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
}
ext_debug("\n");
}
+
+static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
+ ext4_fsblk_t newblock, int level)
+{
+ int depth = ext_depth(inode);
+ struct ext4_extent *ex;
+
+ if (depth != level) {
+ struct ext4_extent_idx *idx;
+ idx = path[level].p_idx;
+ while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
+ ext_debug("%d: move %d:%llu in new index %llu\n", level,
+ le32_to_cpu(idx->ei_block),
+ ext4_idx_pblock(idx),
+ newblock);
+ idx++;
+ }
+
+ return;
+ }
+
+ ex = path[depth].p_ext;
+ while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
+ ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
+ le32_to_cpu(ex->ee_block),
+ ext4_ext_pblock(ex),
+ ext4_ext_is_uninitialized(ex),
+ ext4_ext_get_actual_len(ex),
+ newblock);
+ ex++;
+ }
+}
+
#else
#define ext4_ext_show_path(inode, path)
#define ext4_ext_show_leaf(inode, path)
+#define ext4_ext_show_move(inode, path, newblock, level)
#endif
void ext4_ext_drop_refs(struct ext4_ext_path *path)
@@ -799,7 +833,6 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode,
int depth = ext_depth(inode);
struct ext4_extent_header *neh;
struct ext4_extent_idx *fidx;
- struct ext4_extent *ex;
int i = at, k, m, a;
ext4_fsblk_t newblock, oldblock;
__le32 border;
@@ -876,7 +909,6 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode,
neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
neh->eh_magic = EXT4_EXT_MAGIC;
neh->eh_depth = 0;
- ex = EXT_FIRST_EXTENT(neh);
/* move remainder of path[depth] to the new leaf */
if (unlikely(path[depth].p_hdr->eh_entries !=
@@ -888,25 +920,12 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode,
goto cleanup;
}
/* start copy from next extent */
- /* TODO: we could do it by single memmove */
- m = 0;
- path[depth].p_ext++;
- while (path[depth].p_ext <=
- EXT_MAX_EXTENT(path[depth].p_hdr)) {
- ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
- le32_to_cpu(path[depth].p_ext->ee_block),
- ext4_ext_pblock(path[depth].p_ext),
- ext4_ext_is_uninitialized(path[depth].p_ext),
- ext4_ext_get_actual_len(path[depth].p_ext),
- newblock);
- /*memmove(ex++, path[depth].p_ext++,
- sizeof(struct ext4_extent));
- neh->eh_entries++;*/
- path[depth].p_ext++;
- m++;
- }
+ m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
+ ext4_ext_show_move(inode, path, newblock, depth);
if (m) {
- memmove(ex, path[depth].p_ext-m, sizeof(struct ext4_extent)*m);
+ struct ext4_extent *ex;
+ ex = EXT_FIRST_EXTENT(neh);
+ memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
le16_add_cpu(&neh->eh_entries, m);
}
@@ -968,12 +987,8 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode,
ext_debug("int.index at %d (block %llu): %u -> %llu\n",
i, newblock, le32_to_cpu(border), oldblock);
- /* copy indexes */
- m = 0;
- path[i].p_idx++;
- ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
- EXT_MAX_INDEX(path[i].p_hdr));
+ /* move remainder of path[i] to the new index block */
if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
EXT_LAST_INDEX(path[i].p_hdr))) {
EXT4_ERROR_INODE(inode,
@@ -982,20 +997,13 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode,
err = -EIO;
goto cleanup;
}
- while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) {
- ext_debug("%d: move %d:%llu in new index %llu\n", i,
- le32_to_cpu(path[i].p_idx->ei_block),
- ext4_idx_pblock(path[i].p_idx),
- newblock);
- /*memmove(++fidx, path[i].p_idx++,
- sizeof(struct ext4_extent_idx));
- neh->eh_entries++;
- BUG_ON(neh->eh_entries > neh->eh_max);*/
- path[i].p_idx++;
- m++;
- }
+ /* start copy indexes */
+ m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
+ ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
+ EXT_MAX_INDEX(path[i].p_hdr));
+ ext4_ext_show_move(inode, path, newblock, i);
if (m) {
- memmove(++fidx, path[i].p_idx - m,
+ memmove(++fidx, path[i].p_idx,
sizeof(struct ext4_extent_idx) * m);
le16_add_cpu(&neh->eh_entries, m);
}
--
1.7.5.1
--
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