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Fix inode reading and writing in EXT2 filesystem.

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This commit is contained in:
Enrico Fraccaroli
2021-12-19 11:57:43 +01:00
parent 3013442c9d
commit 8a826f0472
2 changed files with 87 additions and 30 deletions
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mentos/src/fs/ext2.c
+84 -30
View File
@@ -9,7 +9,7 @@
#include "fs/ext2.h"
#define __DEBUG_HEADER__ "[EXT2 ]"
#define __DEBUG_LEVEL__ 100
//#define __DEBUG_LEVEL__ 100
#include "process/scheduler.h"
#include "process/process.h"
@@ -468,11 +468,46 @@ static void ext2_dump_group_descriptor(ext2_group_descriptor_t *gd)
pr_debug("used_dirs_count : %d\n", gd->used_dirs_count);
}
/// @brief Dumps on debugging output the inode.
/// @param inode the object to dump.
static void ext2_dump_inode(ext2_inode_t *inode)
{
pr_debug("mode : %u\n", inode->mode);
pr_debug("uid : %u\n", inode->uid);
pr_debug("size : %u\n", inode->size);
pr_debug("atime : %u\n", inode->atime);
pr_debug("ctime : %u\n", inode->ctime);
pr_debug("mtime : %u\n", inode->mtime);
pr_debug("dtime : %u\n", inode->dtime);
pr_debug("gid : %u\n", inode->gid);
pr_debug("links_count : %u\n", inode->links_count);
pr_debug("blocks_count : %u\n", inode->blocks_count);
pr_debug("flags : %u\n", inode->flags);
pr_debug("osd1 : %u\n", inode->osd1);
pr_debug("data : {\n");
for (int i = 0; i < EXT2_INDIRECT_BLOCKS; ++i)
pr_debug(" data.blocks.D[%2d] : %u\n", i, inode->data.blocks.dir_blocks[i]);
pr_debug(" data.blocks.IND_B : %u\n", inode->data.blocks.indir_block);
pr_debug(" data.blocks.DBL_B : %u\n", inode->data.blocks.doubly_indir_block);
pr_debug(" data.blocks.TRB_B : %u\n", inode->data.blocks.trebly_indir_block);
pr_debug(" data.symblink : %s\n", inode->data.symlink);
pr_debug("data : }\n");
pr_debug("generation : %u\n", inode->generation);
pr_debug("file_acl : %u\n", inode->file_acl);
pr_debug("dir_acl : %u\n", inode->dir_acl);
pr_debug("osd2[0] : %u\n", inode->osd2[0]);
pr_debug("osd2[1] : %u\n", inode->osd2[1]);
pr_debug("osd2[2] : %u\n", inode->osd2[2]);
}
/// @brief Dumps on debugging output the BGDT.
/// @param fs the filesystem of which we print the BGDT.
static void ext2_dump_bgdt(ext2_filesystem_t *fs)
{
// Allocate the cache.
uint8_t *cache = kmem_cache_alloc(fs->ext2_buffer_cache, GFP_KERNEL);
// Clean the cache.
memset(cache, 0, fs->block_size);
for (uint32_t i = 0; i < fs->block_groups_count; ++i) {
// Get the pointer to the current group descriptor.
ext2_group_descriptor_t *gd = &(fs->block_groups[i]);
@@ -648,10 +683,8 @@ static int ext2_read_inode(ext2_filesystem_t *fs, ext2_inode_t *inode, uint32_t
pr_err("You are trying to read an invalid inode index (%d).\n", inode_index);
return -1;
}
// Update the inode index.
inode_index -= 1;
// Retrieve the group index.
uint32_t group_index = inode_index / fs->superblock.inodes_per_group;
uint32_t group_index = (inode_index - 1U) / fs->superblock.inodes_per_group;
if (group_index > fs->block_groups_count) {
pr_err("Invalid group index computed from inode index `%d`.\n", inode_index);
return -1;
@@ -659,21 +692,22 @@ static int ext2_read_inode(ext2_filesystem_t *fs, ext2_inode_t *inode, uint32_t
// Retrieve the group.
ext2_group_descriptor_t *group_desc = &fs->block_groups[group_index];
// Get the index of the inode inside the group.
inode_index -= group_index * fs->superblock.inodes_per_group;
uint32_t index = (inode_index - 1U) % fs->superblock.inodes_per_group;
// Get the block offest.
uint32_t block_offset = (inode_index * fs->superblock.inode_size) / fs->block_size;
// Get the offset inside the block.
uint32_t offset_in_block = inode_index - block_offset * (fs->block_size / fs->superblock.inode_size);
uint32_t block = (index * fs->superblock.inode_size) / fs->block_size;
// Get the real inode index inside the block.
index %= fs->inodes_per_block_count;
// Allocate the cache.
uint8_t *cache = kmem_cache_alloc(fs->ext2_buffer_cache, GFP_KERNEL);
// Clean the cache.
memset(cache, 0, fs->block_size);
// Read the block containing the inode table.
ext2_read_block(fs, group_desc->inode_table + block_offset, cache);
// Get the first entry inside the inode table.
ext2_inode_t *inode_table = (ext2_inode_t *)cache;
ext2_read_block(fs, group_desc->inode_table + block, cache);
// Save the inode content.
memcpy(inode, (ext2_inode_t *)((uintptr_t)cache + (index * fs->superblock.inode_size)), fs->superblock.inode_size);
// Free the cache.
kmem_cache_free(cache);
// Save the inode content.
memcpy(inode, (uint8_t *)((uintptr_t)inode_table + offset_in_block * fs->superblock.inode_size), fs->superblock.inode_size);
return 0;
}
@@ -688,10 +722,8 @@ static int ext2_write_inode(ext2_filesystem_t *fs, ext2_inode_t *inode, uint32_t
pr_err("You are trying to read an invalid inode index (%d).\n", inode_index);
return -1;
}
// Update the inode index.
inode_index -= 1;
// Retrieve the group index.
uint32_t group_index = inode_index / fs->superblock.inodes_per_group;
uint32_t group_index = (inode_index - 1U) / fs->superblock.inodes_per_group;
if (group_index > fs->block_groups_count) {
pr_err("Invalid group index computed from inode index `%d`.\n", inode_index);
return -1;
@@ -699,21 +731,23 @@ static int ext2_write_inode(ext2_filesystem_t *fs, ext2_inode_t *inode, uint32_t
// Retrieve the group.
ext2_group_descriptor_t *group_desc = &fs->block_groups[group_index];
// Get the index of the inode inside the group.
inode_index -= group_index * fs->superblock.inodes_per_group;
uint32_t index = (inode_index - 1U) % fs->superblock.inodes_per_group;
// Get the block offest.
uint32_t block_offset = (inode_index * fs->superblock.inode_size) / fs->block_size;
// Get the offset inside the block.
uint32_t offset_in_block = inode_index - block_offset * (fs->block_size / fs->superblock.inode_size);
uint32_t block = (index * fs->superblock.inode_size) / fs->block_size;
// Get the real inode index inside the block.
index %= fs->inodes_per_block_count;
// Allocate the cache.
uint8_t *cache = kmem_cache_alloc(fs->ext2_buffer_cache, GFP_KERNEL);
// Clean the cache.
memset(cache, 0, fs->block_size);
// Read the block containing the inode table.
ext2_read_block(fs, group_desc->inode_table + block_offset, cache);
// Get the first entry inside the inode table.
ext2_inode_t *inode_table = (ext2_inode_t *)cache;
ext2_read_block(fs, group_desc->inode_table + block, cache);
// Write the inode.
memcpy((uint8_t *)((uintptr_t)inode_table + offset_in_block * fs->superblock.inode_size), inode, fs->superblock.inode_size);
memcpy((ext2_inode_t *)((uintptr_t)cache + (index * fs->superblock.inode_size)), inode, fs->superblock.inode_size);
// Write back the block.
ext2_write_block(fs, group_desc->inode_table + block_offset, (uint8_t *)inode_table);
ext2_write_block(fs, group_desc->inode_table + block, cache);
// Free the cache.
kmem_cache_free(cache);
return 0;
@@ -729,6 +763,8 @@ static uint32_t ext2_allocate_block(ext2_filesystem_t *fs)
spinlock_lock(&fs->spinlock);
// Allocate the cache.
uint8_t *cache = kmem_cache_alloc(fs->ext2_buffer_cache, GFP_KERNEL);
// Clean the cache.
memset(cache, 0, fs->block_size);
// Get the group and bit index of the first free block.
for (group_index = 0; group_index < fs->block_groups_count; ++group_index) {
// Check if there are free blocks in this block group.
@@ -818,6 +854,8 @@ static int ext2_set_real_block_index(ext2_filesystem_t *fs, ext2_inode_t *inode,
// Allocate the cache.
uint8_t *cache = kmem_cache_alloc(fs->ext2_buffer_cache, GFP_KERNEL);
// Clean the cache.
memset(cache, 0, fs->block_size);
// Read the indirect block (which contains pointers to the next set of blocks).
ext2_read_block(fs, inode->data.blocks.indir_block, cache);
// Write the index inside the final block.
@@ -855,6 +893,8 @@ static int ext2_set_real_block_index(ext2_filesystem_t *fs, ext2_inode_t *inode,
// Allocate the cache.
uint8_t *cache = kmem_cache_alloc(fs->ext2_buffer_cache, GFP_KERNEL);
// Clean the cache.
memset(cache, 0, fs->block_size);
// Read the doubly-indirect block (which contains pointers to indirect blocks).
ext2_read_block(fs, inode->data.blocks.doubly_indir_block, cache);
@@ -911,6 +951,8 @@ static int ext2_set_real_block_index(ext2_filesystem_t *fs, ext2_inode_t *inode,
// Allocate the cache.
uint8_t *cache = kmem_cache_alloc(fs->ext2_buffer_cache, GFP_KERNEL);
// Clean the cache.
memset(cache, 0, fs->block_size);
// Read the trebly-indirect block (which contains pointers to doubly-indirect blocks).
ext2_read_block(fs, inode->data.blocks.trebly_indir_block, cache);
@@ -982,6 +1024,7 @@ static uint32_t ext2_get_real_block_index(ext2_filesystem_t *fs, ext2_inode_t *i
uint32_t p2 = fs->pointers_per_block * fs->pointers_per_block;
// Allocate the cache.
uint8_t *cache = kmem_cache_alloc(fs->ext2_buffer_cache, GFP_KERNEL);
// Clean the cache.
memset(cache, 0, fs->block_size);
// Check if the index is among the indirect blocks.
if (block_index < fs->indirect_blocks_index) {
@@ -1129,8 +1172,10 @@ static ssize_t ext2_read_inode_data(ext2_filesystem_t *fs, ext2_inode_t *inode,
uint32_t end_size = end - end_block * fs->block_size;
uint32_t size_to_read = end - offset;
// Allocate the buffer.
// Allocate the cache.
uint8_t *cache = kmem_cache_alloc(fs->ext2_buffer_cache, GFP_KERNEL);
// Clean the cache.
memset(cache, 0, fs->block_size);
if (start_block == end_block) {
// Read the real block.
@@ -1194,8 +1239,10 @@ static ssize_t ext2_write_inode_data(ext2_filesystem_t *fs, ext2_inode_t *inode,
uint32_t end_size = end - end_block * fs->block_size;
uint32_t size_to_write = end - offset;
// Allocate the buffer.
// Allocate the cache.
uint8_t *cache = kmem_cache_alloc(fs->ext2_buffer_cache, GFP_KERNEL);
// Clean the cache.
memset(cache, 0, fs->block_size);
if (start_block == end_block) {
// Read the real block.
@@ -1260,8 +1307,10 @@ free_cache_return_error:
/// @return 0 on success, -1 on failure.
static int ext2_find_entry(ext2_filesystem_t *fs, ino_t ino, const char *name, ext2_dirent_t *direntry)
{
// Allocate the buffer.
// Allocate the cache.
uint8_t *cache = kmem_cache_alloc(fs->ext2_buffer_cache, GFP_KERNEL);
// Clean the cache.
memset(cache, 0, fs->block_size);
// Get the inode associated with the file.
ext2_inode_t inode;
@@ -1348,7 +1397,7 @@ static int ext2_resolve_path(vfs_file_t *directory, char *path, ext2_dirent_t *d
ext2_find_entry(fs, directory->ino, path, direntry);
return 0;
}
ino_t ino = directory->ino;
ino_t ino = directory->ino;
char *token = strtok(path, "/");
while (token) {
if (!ext2_find_entry(fs, ino, token, direntry)) {
@@ -1569,6 +1618,7 @@ static int ext2_close(vfs_file_t *file)
/// @return The number of written bytes in the buffer.
static int ext2_getdents(vfs_file_t *file, dirent_t *dirp, off_t doff, size_t count)
{
pr_debug("ext2_getdents(%s, %p, %d, %d)\n", file->name, dirp, doff, count);
// Get the filesystem.
ext2_filesystem_t *fs = (ext2_filesystem_t *)file->device;
if (fs == NULL) {
@@ -1585,7 +1635,10 @@ static int ext2_getdents(vfs_file_t *file, dirent_t *dirp, off_t doff, size_t co
uint32_t block_index = 0, dir_offset = 0, total_offset = 0, written = 0;
off_t current = 0;
ext2_dirent_t *direntry = NULL;
uint8_t *cache = kmem_cache_alloc(fs->ext2_buffer_cache, GFP_KERNEL);
// Allocate the cache.
uint8_t *cache = kmem_cache_alloc(fs->ext2_buffer_cache, GFP_KERNEL);
// Clean the cache.
memset(cache, 0, fs->block_size);
// Start by reading the first block of the inode.
if (!ext2_read_inode_block(fs, &inode, block_index, cache)) {
@@ -1789,6 +1842,7 @@ static int ext2_fstat(vfs_file_t *file, stat_t *stat)
/// @return 0 if success.
static int ext2_stat(const char *path, stat_t *stat)
{
pr_debug("ext2_stat(%s, %p)\n", path, stat);
// Allocate a variable for the path.
char absolute_path[PATH_MAX];
// If the first character is not the '/' then get the absolute path.
mentos/src/fs/readdir.c
+3
View File
@@ -11,6 +11,7 @@
#include "sys/errno.h"
#include "stdio.h"
#include "fs/vfs.h"
#include "string.h"
int sys_getdents(int fd, dirent_t *dirp, unsigned int count)
{
@@ -42,6 +43,8 @@ int sys_getdents(int fd, dirent_t *dirp, unsigned int count)
if (file == NULL) {
return -ENOSYS;
}
// Clean the buffer.
memset(dirp, 0, count);
// Perform the read.
int actual_read = vfs_getdents(file, dirp, vfd->file_struct->f_pos, count);