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generic-poky/meta/recipes-devtools/genext2fs/genext2fs-1.4.1/0006-Improve-the-efficiency...

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From ea6cbe2880e02026667b9007db9a742be7dcd52b Mon Sep 17 00:00:00 2001
From: Corey Minyard <cminyard@mvista.com>
Date: Sun, 5 Jun 2011 10:26:11 -0500
Subject: [PATCH 06/19] Improve the efficiency of extend_blk
When doing multiple extensions operations on the same inode, extend_blk()
would search to the end every time. In the current structure, that means
when creating the reserved blocks, it could parse over the block list
many thousands of time on a large filesystem. For an 800MB filesystem,
that took 2/3rds of the time.
So create a structure for holding the inode position and use it to
know where the end is. This neatens things up a bit, too, more
clearly showing when a truncate or extend is occuring. In future
changes, this will also make it efficient for supporting very large
files that cannot be fully allocated in memory.
---
genext2fs.c | 147 ++++++++++++++++++++++++++++++++++++++++-------------------
1 files changed, 100 insertions(+), 47 deletions(-)
diff --git a/genext2fs.c b/genext2fs.c
index 46c9605..e45e520 100644
--- a/genext2fs.c
+++ b/genext2fs.c
@@ -436,6 +436,17 @@ swab32(uint32 val)
((val<<8)&0xFF0000) | (val<<24));
}
+static inline int
+is_blk_empty(uint8 *b)
+{
+ uint32 i;
+ uint32 *v = (uint32 *) b;
+
+ for(i = 0; i < BLOCKSIZE / 4; i++)
+ if (*v++)
+ return 0;
+ return 1;
+}
// on-disk structures
// this trick makes me declare things only once
@@ -1165,7 +1176,6 @@ init_bw(blockwalker *bw)
// used after being freed, so once you start
// freeing blocks don't stop until the end of
// the file. moreover, i_blocks isn't updated.
-// in fact, don't do that, just use extend_blk
// if hole!=0, create a hole in the file
static uint32
walk_bw(filesystem *fs, uint32 nod, blockwalker *bw, int32 *create, uint32 hole)
@@ -1422,52 +1432,80 @@ walk_bw(filesystem *fs, uint32 nod, blockwalker *bw, int32 *create, uint32 hole)
return bk;
}
-// add blocks to an inode (file/dir/etc...)
-static void
-extend_blk(filesystem *fs, uint32 nod, block b, int amount)
+typedef struct
{
- int create = amount;
- blockwalker bw, lbw;
- uint32 bk;
+ blockwalker bw;
+ uint32 nod;
nod_info *ni;
inode *inod;
+} inode_pos;
+#define INODE_POS_TRUNCATE 0
+#define INODE_POS_EXTEND 1
+
+// Call this to set up an ipos structure for future use with
+// extend_inode_blk to append blocks to the given inode. If
+// op is INODE_POS_TRUNCATE, the inode is truncated to zero size.
+// If op is INODE_POS_EXTEND, the position is moved to the end
+// of the inode's data blocks.
+// Call inode_pos_finish when done with the inode_pos structure.
+static void
+inode_pos_init(filesystem *fs, inode_pos *ipos, uint32 nod, int op,
+ blockwalker *endbw)
+{
+ blockwalker lbw;
- inod = get_nod(fs, nod, &ni);
- init_bw(&bw);
- if(amount < 0)
- {
- uint32 i;
- for(i = 0; i < inod->i_blocks / INOBLK + amount; i++)
- walk_bw(fs, nod, &bw, 0, 0);
- while(walk_bw(fs, nod, &bw, &create, 0) != WALK_END)
+ init_bw(&ipos->bw);
+ ipos->nod = nod;
+ ipos->inod = get_nod(fs, nod, &ipos->ni);
+ if (op == INODE_POS_TRUNCATE) {
+ int32 create = -1;
+ while(walk_bw(fs, nod, &ipos->bw, &create, 0) != WALK_END)
/*nop*/;
- inod->i_blocks += amount * INOBLK;
+ ipos->inod->i_blocks = 0;
}
- else
+
+ if (endbw)
+ ipos->bw = *endbw;
+ else {
+ /* Seek to the end */
+ init_bw(&ipos->bw);
+ lbw = ipos->bw;
+ while(walk_bw(fs, nod, &ipos->bw, 0, 0) != WALK_END)
+ lbw = ipos->bw;
+ ipos->bw = lbw;
+ }
+}
+
+// Clean up the inode_pos structure.
+static void
+inode_pos_finish(filesystem *fs, inode_pos *ipos)
+{
+ put_nod(ipos->ni);
+}
+
+// add blocks to an inode (file/dir/etc...) at the given position.
+// This will only work when appending to the end of an inode.
+static void
+extend_inode_blk(filesystem *fs, inode_pos *ipos, block b, int amount)
+{
+ uint32 bk;
+ uint32 pos;
+
+ if (amount < 0)
+ error_msg_and_die("extend_inode_blk: Got negative amount");
+
+ for (pos = 0; amount; pos += BLOCKSIZE)
{
- lbw = bw;
- while((bk = walk_bw(fs, nod, &bw, 0, 0)) != WALK_END)
- lbw = bw;
- bw = lbw;
- while(create)
- {
- int i, copyb = 0;
- if(!(fs->sb->s_reserved[200] & OP_HOLES))
- copyb = 1;
- else
- for(i = 0; i < BLOCKSIZE / 4; i++)
- if(((int32*)(b + BLOCKSIZE * (amount - create)))[i])
- {
- copyb = 1;
- break;
- }
- if((bk = walk_bw(fs, nod, &bw, &create, !copyb)) == WALK_END)
- break;
- if(copyb) {
- blk_info *bi;
- memcpy(get_blk(fs, bk, &bi), b + BLOCKSIZE * (amount - create - 1), BLOCKSIZE);
- put_blk(bi);
- }
+ int hole = ((fs->sb->s_reserved[200] & OP_HOLES) && is_blk_empty(b + pos));
+
+ bk = walk_bw(fs, ipos->nod, &ipos->bw, &amount, hole);
+ if (bk == WALK_END)
+ error_msg_and_die("extend_inode_blk: extend failed");
+ if (!hole) {
+ blk_info *bi;
+ uint8 *block = get_blk(fs, bk, &bi);
+ memcpy(block, b + pos, BLOCKSIZE);
+ put_blk(bi);
}
}
}
@@ -1484,6 +1522,7 @@ add2dir(filesystem *fs, uint32 dnod, uint32 nod, const char* name)
inode *node;
inode *pnode;
nod_info *dni, *ni;
+ inode_pos ipos;
pnode = get_nod(fs, dnod, &dni);
if((pnode->i_mode & FM_IFMT) != FM_IFDIR)
@@ -1534,7 +1573,11 @@ add2dir(filesystem *fs, uint32 dnod, uint32 nod, const char* name)
node->i_links_count++;
put_nod(ni);
next_dir(&dw); // Force the data into the buffer
- extend_blk(fs, dnod, dir_data(&dw), 1);
+
+ inode_pos_init(fs, &ipos, dnod, INODE_POS_EXTEND, &lbw);
+ extend_inode_blk(fs, &ipos, dir_data(&dw), 1);
+ inode_pos_finish(fs, &ipos);
+
put_dir(&dw);
pnode->i_size += BLOCKSIZE;
out:
@@ -1654,8 +1697,9 @@ mklink_fs(filesystem *fs, uint32 parent_nod, const char *name, size_t size, uint
uint32 nod = mknod_fs(fs, parent_nod, name, FM_IFLNK | FM_IRWXU | FM_IRWXG | FM_IRWXO, uid, gid, 0, 0, ctime, mtime);
nod_info *ni;
inode *node = get_nod(fs, nod, &ni);
+ inode_pos ipos;
- extend_blk(fs, nod, 0, - (int)node->i_blocks / INOBLK);
+ inode_pos_init(fs, &ipos, nod, INODE_POS_TRUNCATE, NULL);
node->i_size = size;
if(size <= 4 * (EXT2_TIND_BLOCK+1))
{
@@ -1663,7 +1707,8 @@ mklink_fs(filesystem *fs, uint32 parent_nod, const char *name, size_t size, uint
put_nod(ni);
return nod;
}
- extend_blk(fs, nod, b, rndup(size, BLOCKSIZE) / BLOCKSIZE);
+ extend_inode_blk(fs, &ipos, b, rndup(size, BLOCKSIZE) / BLOCKSIZE);
+ inode_pos_finish(fs, &ipos);
put_nod(ni);
return nod;
}
@@ -1676,8 +1721,9 @@ mkfile_fs(filesystem *fs, uint32 parent_nod, const char *name, uint32 mode, size
uint32 nod = mknod_fs(fs, parent_nod, name, mode|FM_IFREG, uid, gid, 0, 0, ctime, mtime);
nod_info *ni;
inode *node = get_nod(fs, nod, &ni);
+ inode_pos ipos;
- extend_blk(fs, nod, 0, - (int)node->i_blocks / INOBLK);
+ inode_pos_init(fs, &ipos, nod, INODE_POS_TRUNCATE, NULL);
node->i_size = size;
if (size) {
if(!(b = (uint8*)calloc(rndup(size, BLOCKSIZE), 1)))
@@ -1685,9 +1731,11 @@ mkfile_fs(filesystem *fs, uint32 parent_nod, const char *name, uint32 mode, size
if(f)
if (fread(b, size, 1, f) != 1) // FIXME: ugly. use mmap() ...
error_msg_and_die("fread failed");
- extend_blk(fs, nod, b, rndup(size, BLOCKSIZE) / BLOCKSIZE);
+ extend_inode_blk(fs, &ipos, b,
+ rndup(size, BLOCKSIZE) / BLOCKSIZE);
free(b);
}
+ inode_pos_finish(fs, &ipos);
put_nod(ni);
return nod;
}
@@ -2210,6 +2258,7 @@ init_fs(int nbblocks, int nbinodes, int nbresrvd, int holes, uint32 fs_timestamp
inode *itab0;
blk_info *bi;
nod_info *ni;
+ inode_pos ipos;
if(nbresrvd < 0)
error_msg_and_die("reserved blocks value is invalid. Note: options have changed, see --help or the man page.");
@@ -2337,7 +2386,9 @@ init_fs(int nbblocks, int nbinodes, int nbresrvd, int holes, uint32 fs_timestamp
new_dir(fs, EXT2_ROOT_INO, ".", 1, &dw);
shrink_dir(&dw, EXT2_ROOT_INO, "..", 2);
next_dir(&dw); // Force the data into the buffer
- extend_blk(fs, EXT2_ROOT_INO, dir_data(&dw), 1);
+ inode_pos_init(fs, &ipos, EXT2_ROOT_INO, INODE_POS_EXTEND, NULL);
+ extend_inode_blk(fs, &ipos, dir_data(&dw), 1);
+ inode_pos_finish(fs, &ipos);
put_dir(&dw);
// make lost+found directory and reserve blocks
@@ -2355,8 +2406,10 @@ init_fs(int nbblocks, int nbinodes, int nbresrvd, int holes, uint32 fs_timestamp
*/
if (fs->sb->s_r_blocks_count > fs->sb->s_blocks_count * MAX_RESERVED_BLOCKS )
fs->sb->s_r_blocks_count = fs->sb->s_blocks_count * MAX_RESERVED_BLOCKS;
+ inode_pos_init(fs, &ipos, nod, INODE_POS_EXTEND, NULL);
for(i = 1; i < fs->sb->s_r_blocks_count; i++)
- extend_blk(fs, nod, b, 1);
+ extend_inode_blk(fs, &ipos, b, 1);
+ inode_pos_finish(fs, &ipos);
free_workblk(b);
node = get_nod(fs, nod, &ni);
node->i_size = fs->sb->s_r_blocks_count * BLOCKSIZE;
--
1.7.4.1
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