From 56cd63f1998821dae67ab0e13d57600ad3b5ba59 Mon Sep 17 00:00:00 2001
From: Marvin Borner
Date: Fri, 5 Feb 2021 19:38:01 +0100
Subject: No buffer mallocing in ext2 read
---
kernel/features/fs.c | 57 ++++++++++++++++++++++++++++------------------------
1 file changed, 31 insertions(+), 26 deletions(-)
(limited to 'kernel/features/fs.c')
diff --git a/kernel/features/fs.c b/kernel/features/fs.c
index 48e736a..3adb4ed 100644
--- a/kernel/features/fs.c
+++ b/kernel/features/fs.c
@@ -263,32 +263,39 @@ void device_install(void)
* EXT2
*/
-void *buffer_read(u32 block, struct device *dev)
+void *buffer_read2(u32 block, struct device *dev)
{
void *buf = malloc(BLOCK_SIZE);
dev->read(buf, block * SECTOR_COUNT, SECTOR_COUNT, dev);
return buf;
}
-struct ext2_superblock *get_superblock(struct device *dev)
+void *buffer_read(u32 block, void *buf, u32 sector_count, struct device *dev)
{
- struct ext2_superblock *sb = buffer_read(EXT2_SUPER, dev);
+ dev->read(buf, block * SECTOR_COUNT, sector_count, dev);
+ return buf;
+}
+
+struct ext2_superblock *get_superblock(void *buf, struct device *dev)
+{
+ struct ext2_superblock *sb = buffer_read(EXT2_SUPER, buf, SECTOR_COUNT, dev);
if (sb->magic != EXT2_MAGIC)
return NULL;
return sb;
}
-struct ext2_bgd *get_bgd(struct device *dev)
+struct ext2_bgd *get_bgd(void *buf, struct device *dev)
{
- return buffer_read(EXT2_SUPER + 1, dev);
+ return buffer_read(EXT2_SUPER + 1, buf, SECTOR_COUNT, dev);
}
-struct ext2_inode *get_inode(u32 i, struct device *dev)
+struct ext2_inode *get_inode(u32 i, void *buf, struct device *dev)
{
- struct ext2_superblock *s = get_superblock(dev);
+ u8 super[BLOCK_SIZE] = { 0 }, bgd[BLOCK_SIZE] = { 0 };
+ struct ext2_superblock *s = get_superblock(super, dev);
assert(s);
- struct ext2_bgd *b = get_bgd(dev);
+ struct ext2_bgd *b = get_bgd(bgd, dev);
assert(b);
u32 block_group = (i - 1) / s->inodes_per_group;
@@ -296,16 +303,18 @@ struct ext2_inode *get_inode(u32 i, struct device *dev)
u32 block = (index * EXT2_INODE_SIZE) / BLOCK_SIZE;
b += block_group;
- u32 *data = buffer_read(b->inode_table + block, dev);
+ buffer_read(b->inode_table + block, buf, SECTOR_COUNT, dev);
struct ext2_inode *in =
- (struct ext2_inode *)((u32)data +
+ (struct ext2_inode *)((u32)buf +
(index % (BLOCK_SIZE / EXT2_INODE_SIZE)) * EXT2_INODE_SIZE);
+ //printf("%d: %d, %d\n", i, in->last_access_time, in->size);
return in;
}
u32 read_indirect(u32 indirect, u32 block_num, struct device *dev)
{
- char *data = buffer_read(indirect, dev);
+ u8 buf[BLOCK_SIZE] = { 0 };
+ char *data = buffer_read(indirect, buf, SECTOR_COUNT, dev);
return *(u32 *)((u32)data + block_num * sizeof(u32));
}
@@ -328,29 +337,22 @@ u32 read_inode(struct ext2_inode *in, void *buf, u32 offset, u32 count, struct d
u32 indirect = 0;
u32 blocknum = 0;
- char *data = 0;
// TODO: Support triply indirect pointers
// TODO: This can be heavily optimized by saving the indirect block lists
for (u32 i = 0; i < num_blocks; i++) {
if (i < 12) {
blocknum = in->block[i];
- data = buffer_read(blocknum, dev);
- memcpy((u32 *)((u32)buf + i * BLOCK_SIZE), data, BLOCK_SIZE);
} else if (i < BLOCK_COUNT + 12) {
indirect = in->block[12];
blocknum = read_indirect(indirect, i - 12, dev);
- data = buffer_read(blocknum, dev);
- memcpy((u32 *)((u32)buf + i * BLOCK_SIZE), data, BLOCK_SIZE);
} else {
indirect = in->block[13];
blocknum = read_indirect(indirect, (i - (BLOCK_COUNT + 12)) / BLOCK_COUNT,
dev);
blocknum = read_indirect(blocknum, (i - (BLOCK_COUNT + 12)) % BLOCK_COUNT,
dev);
- data = buffer_read(blocknum, dev);
- memcpy((u32 *)((u32)buf + i * BLOCK_SIZE), data, BLOCK_SIZE);
}
- /* printf("Loaded %d of %d\n", i + 1, num_blocks); */
+ buffer_read(blocknum, (u32 *)((u32)buf + i * BLOCK_SIZE), SECTOR_COUNT, dev);
}
return count;
@@ -361,14 +363,15 @@ u32 find_inode(const char *name, u32 dir_inode, struct device *dev)
if (!dir_inode)
return (unsigned)-1;
- struct ext2_inode *i = get_inode(dir_inode, dev);
+ u8 ibuf[BLOCK_SIZE] = { 0 };
+ struct ext2_inode *i = get_inode(dir_inode, ibuf, dev);
char *buf = malloc(BLOCK_SIZE * i->blocks / 2);
memset(buf, 0, BLOCK_SIZE * i->blocks / 2);
for (u32 q = 0; q < i->blocks / 2; q++) {
- char *data = buffer_read(i->block[q], dev);
- memcpy((u32 *)((u32)buf + q * BLOCK_SIZE), data, BLOCK_SIZE);
+ buffer_read(i->block[q], (u32 *)buf + q * BLOCK_SIZE, SECTOR_COUNT, dev);
+ //memcpy((u32 *)((u32)buf + q * BLOCK_SIZE), data, BLOCK_SIZE);
}
struct ext2_dirent *d = (struct ext2_dirent *)buf;
@@ -389,7 +392,7 @@ u32 find_inode(const char *name, u32 dir_inode, struct device *dev)
return (unsigned)-1;
}
-struct ext2_inode *find_inode_by_path(const char *path, struct device *dev)
+struct ext2_inode *find_inode_by_path(const char *path, void *buf, struct device *dev)
{
if (path[0] != '/')
return 0;
@@ -425,12 +428,13 @@ struct ext2_inode *find_inode_by_path(const char *path, struct device *dev)
if ((signed)inode <= 0)
return 0;
- return get_inode(inode, dev);
+ return get_inode(inode, buf, dev);
}
u32 ext2_read(const char *path, void *buf, u32 offset, u32 count, struct device *dev)
{
- struct ext2_inode *in = find_inode_by_path(path, dev);
+ u8 ibuf[BLOCK_SIZE] = { 0 };
+ struct ext2_inode *in = find_inode_by_path(path, ibuf, dev);
if (in)
return read_inode(in, buf, offset, count, dev);
else
@@ -442,7 +446,8 @@ u32 ext2_stat(const char *path, struct stat *buf, struct device *dev)
if (!buf)
return 1;
- struct ext2_inode *in = find_inode_by_path(path, dev);
+ u8 ibuf[BLOCK_SIZE] = { 0 };
+ struct ext2_inode *in = find_inode_by_path(path, ibuf, dev);
if (!in)
return 1;
--
cgit v1.2.3