This patch dramatically drops the amount of time u-boot needs to read a file from an ext2 partition. On a typical 2 to 5 MB file (kernels and initrds) it goes from tens of seconds to a couple seconds.
All we are doing here is grouping contiguous blocks into one read.
Boot tested on Globalscale Technologies Dreamplug (Kirkwood ARM SoC) with three different files. sha1sums were calculated in Linux userspace, and then confirmed after ext2load.
Signed-off-by: Jason Cooper u-boot@lakedaemon.net --- fs/ext2/ext2fs.c | 26 ++++++++++++++++++++++++-- 1 files changed, 24 insertions(+), 2 deletions(-)
diff --git a/fs/ext2/ext2fs.c b/fs/ext2/ext2fs.c index e119e13..8531db5 100644 --- a/fs/ext2/ext2fs.c +++ b/fs/ext2/ext2fs.c @@ -414,7 +414,6 @@ int ext2fs_read_file if (blknr < 0) { return (-1); } - blknr = blknr << log2blocksize;
/* Last block. */ if (i == blockcnt - 1) { @@ -432,6 +431,29 @@ int ext2fs_read_file blockend -= skipfirst; }
+ /* grab middle blocks in one go */ + if (i != pos / blocksize && i != blockcnt - 1 && blockcnt > 3) { + int oldblk = blknr; + int blocknxt; + while (i < blockcnt - 1) { + blocknxt = ext2fs_read_block(node, i + 1); + if (blocknxt == (oldblk + 1)) { + oldblk = blocknxt; + i++; + } else { + blocknxt = ext2fs_read_block(node, i); + break; + } + } + + if (oldblk == blknr) + blockend = blocksize; + else + blockend = (1 + blocknxt - blknr) * blocksize; + } + + blknr = blknr << log2blocksize; + /* If the block number is 0 this block is not stored on disk but is zero filled instead. */ if (blknr) { @@ -444,7 +466,7 @@ int ext2fs_read_file } else { memset (buf, 0, blocksize - skipfirst); } - buf += blocksize - skipfirst; + buf += blockend - skipfirst; } return (len); }