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mufs: optimise memory footprint of read_dirent()

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S.J.R. van Schaik 2017-06-16 15:52:12 +02:00
parent 555e28e229
commit 0484f082ee
1 changed files with 17 additions and 16 deletions
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33
source/fs/mufs/dir.c
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@ -225,31 +225,32 @@ size_t read_dirent(struct mufs *fs, struct mufs_tree *tree,
struct mufs_dirent *dirent, uint32_t va) struct mufs_dirent *dirent, uint32_t va)
{ {
struct flash_dev *dev = fs->dev; struct flash_dev *dev = fs->dev;
char data[1 << dev->log2_block_size]; struct mufs_dentry entry;
struct mufs_dentry *entry; size_t len, block_size = 1 << dev->log2_block_size;
uint32_t offset; uint32_t offset;
offset = va & ((UINT32_C(1) << dev->log2_block_size) - 1); offset = va & ((UINT32_C(1) << dev->log2_block_size) - 1);
va = align(va, dev->log2_block_size); va = align(va, dev->log2_block_size);
if (mufs_tree_read(tree, data, va, 1 << dev->log2_block_size) == 0) if (block_size - offset < sizeof entry)
return 0; return 0;
if (offset + sizeof *entry > (UINT32_C(1) << dev->log2_block_size)) if (mufs_tree_read(tree, &entry, va + offset, sizeof entry) == 0)
return 0; return 0;
entry = (struct mufs_dentry *)(data + offset); if (!entry.type)
if (!entry->type)
return 0; return 0;
if (offset + sizeof *entry + entry->path_len > if (block_size - offset < sizeof entry + entry.path_len)
(UINT32_C(1) << dev->log2_block_size))
return 0; return 0;
memcpy(dirent->path, data + offset + sizeof *entry, entry->path_len); len = min(entry.path_len, sizeof dirent->path - 1);
dirent->path[entry->path_len] = '\0';
dirent->type = entry->type; if (mufs_tree_read(tree, dirent->path, va + offset + sizeof entry,
len) == 0)
return 0;
dirent->path[len] = '\0';
dirent->type = entry.type;
if (mufs_lookup_page(tree, &dirent->tree.va, va) < 0) if (mufs_lookup_page(tree, &dirent->tree.va, va) < 0)
return 0; return 0;
@ -257,11 +258,11 @@ size_t read_dirent(struct mufs *fs, struct mufs_tree *tree,
dirent->tree.fs = fs; dirent->tree.fs = fs;
dirent->tree.va = (dirent->tree.va << dev->log2_block_size) + offset + dirent->tree.va = (dirent->tree.va << dev->log2_block_size) + offset +
offsetof(struct mufs_dentry, tree); offsetof(struct mufs_dentry, tree);
dirent->tree.file_size = entry->tree.file_size; dirent->tree.file_size = entry.tree.file_size;
dirent->tree.root = entry->tree.root; dirent->tree.root = entry.tree.root;
dirent->tree.depth = entry->tree.depth; dirent->tree.depth = entry.tree.depth;
return sizeof *entry + entry->path_len; return sizeof entry + entry.path_len;
} }
size_t write_dirent(struct mufs_tree *tree, size_t write_dirent(struct mufs_tree *tree,