fs: ext4: cache extent data
When a file contains extents, U-Boot currently reads extent-related data
for each block in the file, even if that data is located in the same
block each time. This significantly slows down loading of files that use
extents. Implement a very dumb cache to prevent repeatedly reading the
same block. Files with extents now load as fast as files without.
Note: There are many cases where read_allocated_block() is called. This
patch only addresses one of those places; all others still read redundant
data in any case they did before. This is a minimal patch to fix the
load command; other cases aren't fixed.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
diff --git a/fs/ext4/ext4_common.c b/fs/ext4/ext4_common.c
index 67e2471..29308e3 100644
--- a/fs/ext4/ext4_common.c
+++ b/fs/ext4/ext4_common.c
@@ -510,7 +510,8 @@
restart_read:
/* read the block no allocated to a file */
- first_block_no_of_root = read_allocated_block(g_parent_inode, blk_idx);
+ first_block_no_of_root = read_allocated_block(g_parent_inode, blk_idx,
+ NULL);
if (first_block_no_of_root <= 0)
goto fail;
@@ -646,7 +647,7 @@
/* get the block no allocated to a file */
for (blk_idx = 0; blk_idx < directory_blocks; blk_idx++) {
- blknr = read_allocated_block(parent_inode, blk_idx);
+ blknr = read_allocated_block(parent_inode, blk_idx, NULL);
if (blknr <= 0)
goto fail;
@@ -943,7 +944,7 @@
/* read the block no allocated to a file */
for (blk_idx = 0; blk_idx < directory_blocks; blk_idx++) {
- blknr = read_allocated_block(g_parent_inode, blk_idx);
+ blknr = read_allocated_block(g_parent_inode, blk_idx, NULL);
if (blknr <= 0)
break;
inodeno = unlink_filename(filename, blknr);
@@ -1522,7 +1523,7 @@
#endif
static struct ext4_extent_header *ext4fs_get_extent_block
- (struct ext2_data *data, char *buf,
+ (struct ext2_data *data, struct ext_block_cache *cache,
struct ext4_extent_header *ext_block,
uint32_t fileblock, int log2_blksz)
{
@@ -1551,12 +1552,10 @@
block = le16_to_cpu(index[i].ei_leaf_hi);
block = (block << 32) + le32_to_cpu(index[i].ei_leaf_lo);
-
- if (ext4fs_devread((lbaint_t)block << log2_blksz, 0, blksz,
- buf))
- ext_block = (struct ext4_extent_header *)buf;
- else
+ block <<= log2_blksz;
+ if (!ext_cache_read(cache, (lbaint_t)block, blksz))
return NULL;
+ ext_block = (struct ext4_extent_header *)cache->buf;
}
}
@@ -1613,7 +1612,8 @@
return 1;
}
-long int read_allocated_block(struct ext2_inode *inode, int fileblock)
+long int read_allocated_block(struct ext2_inode *inode, int fileblock,
+ struct ext_block_cache *cache)
{
long int blknr;
int blksz;
@@ -1630,20 +1630,26 @@
if (le32_to_cpu(inode->flags) & EXT4_EXTENTS_FL) {
long int startblock, endblock;
- char *buf = zalloc(blksz);
- if (!buf)
- return -ENOMEM;
+ struct ext_block_cache *c, cd;
struct ext4_extent_header *ext_block;
struct ext4_extent *extent;
int i;
+
+ if (cache) {
+ c = cache;
+ } else {
+ c = &cd;
+ ext_cache_init(c);
+ }
ext_block =
- ext4fs_get_extent_block(ext4fs_root, buf,
+ ext4fs_get_extent_block(ext4fs_root, c,
(struct ext4_extent_header *)
inode->b.blocks.dir_blocks,
fileblock, log2_blksz);
if (!ext_block) {
printf("invalid extent block\n");
- free(buf);
+ if (!cache)
+ ext_cache_fini(c);
return -EINVAL;
}
@@ -1655,19 +1661,22 @@
if (startblock > fileblock) {
/* Sparse file */
- free(buf);
+ if (!cache)
+ ext_cache_fini(c);
return 0;
} else if (fileblock < endblock) {
start = le16_to_cpu(extent[i].ee_start_hi);
start = (start << 32) +
le32_to_cpu(extent[i].ee_start_lo);
- free(buf);
+ if (!cache)
+ ext_cache_fini(c);
return (fileblock - startblock) + start;
}
}
- free(buf);
+ if (!cache)
+ ext_cache_fini(c);
return 0;
}