Little cleanup and new code that collects and defers contiguous sector reads
into one potentially more efficient larger sequential read action.
This matters for example on SD Card protocol.
Signed-off-by: Andy Green <[EMAIL PROTECTED]>
---
src/fs/ext2.c | 73 +++++++++++++++++++++++++++++++++++++++++++++------------
1 files changed, 58 insertions(+), 15 deletions(-)
diff --git a/src/fs/ext2.c b/src/fs/ext2.c
index acb979f..21165a3 100644
--- a/src/fs/ext2.c
+++ b/src/fs/ext2.c
@@ -189,9 +189,6 @@ int indir2_blkno = -1;
static int ext2fs_blockgroup
(struct ext2_data *data, int group, struct ext2_block_group *blkgrp) {
-#ifdef DEBUG
- puts("ext2fs read blockgroup\n");
-#endif
return ext2fs_devread
((__le32_to_cpu(data->sblock.first_data_block) +
1), LOG2_EXT2_BLOCK_SIZE(data),
@@ -212,9 +209,6 @@ static int ext2fs_read_inode
/* It is easier to calculate if the first inode is 0. */
ino--;
-#ifdef DEBUG
- puts("ext2fs read inode %d\n", ino);
-#endif
status = ext2fs_blockgroup(data,
ino /
__le32_to_cpu(sblock->inodes_per_group),
@@ -375,9 +369,9 @@ static int ext2fs_read_block(ext2fs_node_t node, int
fileblock) {
}
blknr = __le32_to_cpu(indir2_block[rblock % perblock]);
}
- /* Tripple indirect. */
+ /* Triple indirect. */
else {
- puts("** ext2fs doesn't support tripple indirect blocks. **\n");
+ puts("** ext2fs doesn't support triple indirect blocks. **\n");
return -1;
}
#ifdef DEBUG
@@ -387,13 +381,19 @@ static int ext2fs_read_block(ext2fs_node_t node, int
fileblock) {
}
-int ext2fs_read_file
- (ext2fs_node_t node, int pos, unsigned int len, char *buf) {
+int ext2fs_read_file(ext2fs_node_t node, int pos, unsigned int len, char *buf)
{
int i;
int blockcnt;
int log2blocksize = LOG2_EXT2_BLOCK_SIZE(node->data);
int blocksize = 1 <<(log2blocksize + DISK_SECTOR_BITS);
unsigned int filesize = __le32_to_cpu(node->inode.size);
+ int previous_block_number = -1;
+ int delayed_start = 0;
+ int delayed_extent = 0;
+ int delayed_skipfirst = 0;
+ int delayed_next = 0;
+ char * delayed_buf = NULL;
+ int status;
/* Adjust len so it we can't read past the end of the file. */
if (len > filesize) {
@@ -435,14 +435,57 @@ int ext2fs_read_file
if (blknr) {
int status;
- status = ext2fs_devread(blknr, 0 /* already accounted
*/, skipfirst, blockend, buf);
- if (status == 0)
- return -1;
- } else
- memset(buf, 0, blocksize - skipfirst);
+ if (previous_block_number != -1) {
+ if (delayed_next == blknr) {
+ delayed_extent += blockend;
+ delayed_next += blockend >> SECTOR_BITS;
+ } else { /* spill */
+ status = ext2fs_devread(delayed_start,
+ 0, delayed_skipfirst,
+ delayed_extent, delayed_buf);
+ if (status == 0)
+ return -1;
+ previous_block_number = blknr;
+ delayed_start = blknr;
+ delayed_extent = blockend;
+ delayed_skipfirst = skipfirst;
+ delayed_buf = buf;
+ delayed_next = blknr + (blockend >>
SECTOR_BITS);
+ }
+ } else {
+ previous_block_number = blknr;
+ delayed_start = blknr;
+ delayed_extent = blockend;
+ delayed_skipfirst = skipfirst;
+ delayed_buf = buf;
+ delayed_next = blknr + (blockend >>
SECTOR_BITS);
+ }
+ } else {
+ if (previous_block_number != -1) {
+ /* spill */
+ status = ext2fs_devread(delayed_start,
+ 0, delayed_skipfirst,
+ delayed_extent, delayed_buf);
+ if (status == 0)
+ return -1;
+ previous_block_number = -1;
+ }
+ memset(buf, 0, blocksize - skipfirst);
+ }
buf += blocksize - skipfirst;
}
+
+ if (previous_block_number != -1) {
+ /* spill */
+ status = ext2fs_devread(delayed_start,
+ 0, delayed_skipfirst,
+ delayed_extent, delayed_buf);
+ if (status == 0)
+ return -1;
+ previous_block_number = -1;
+ }
+
return(len);
}
