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Btrfs: verify csums on read 

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason 2007-03-29 15:15:27 -04:00 committed by David Woodhouse
parent 75dfe3960e
commit f254e52c1c
6 changed files with 279 additions and 60 deletions
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9
fs/btrfs/ctree.c
View File

@ -109,14 +109,14 @@ static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
return 1;
if (k1.objectid < k2->objectid)
return -1;
if (k1.flags > k2->flags)
return 1;
if (k1.flags < k2->flags)
return -1;
if (k1.offset > k2->offset)
return 1;
if (k1.offset < k2->offset)
return -1;
if (k1.flags > k2->flags)
return 1;
if (k1.flags < k2->flags)
return -1;
return 0;
}
@ -1165,7 +1165,6 @@ int btrfs_insert_empty_item(struct btrfs_trans_handle *trans, struct btrfs_root
BUG();
ret = btrfs_search_slot(trans, root, cpu_key, path, data_size, 1);
if (ret == 0) {
btrfs_release_path(root, path);
return -EEXIST;
}
if (ret < 0)

47
fs/btrfs/ctree.h
View File

@ -21,6 +21,9 @@ struct btrfs_transaction;
*/
#define BTRFS_NAME_LEN 255
/* 32 bytes in various csum fields */
#define BTRFS_CSUM_SIZE 32
/*
* the key defines the order in the tree, and so it also defines (optimal)
* block layout. objectid corresonds to the inode number. The flags
@ -37,21 +40,21 @@ struct btrfs_transaction;
*/
struct btrfs_disk_key {
__le64 objectid;
__le32 flags;
__le64 offset;
__le32 flags;
} __attribute__ ((__packed__));
struct btrfs_key {
u64 objectid;
u32 flags;
u64 offset;
u32 flags;
} __attribute__ ((__packed__));
/*
* every tree block (leaf or node) starts with this header.
*/
struct btrfs_header {
__le32 csum[8];
u8 csum[BTRFS_CSUM_SIZE];
u8 fsid[16]; /* FS specific uuid */
__le64 blocknr; /* which block this node is supposed to live in */
__le64 generation;
@ -75,7 +78,7 @@ struct buffer_head;
* it currently lacks any block count etc etc
*/
struct btrfs_super_block {
__le32 csum[8];
u8 csum[BTRFS_CSUM_SIZE];
/* the first 3 fields must match struct btrfs_header */
u8 fsid[16]; /* FS specific uuid */
__le64 blocknr; /* this block number */
@ -147,7 +150,7 @@ struct btrfs_extent_item {
} __attribute__ ((__packed__));
struct btrfs_inode_timespec {
__le32 sec;
__le64 sec;
__le32 nsec;
} __attribute__ ((__packed__));
@ -214,6 +217,10 @@ struct btrfs_file_extent_item {
__le64 num_blocks;
} __attribute__ ((__packed__));
struct btrfs_csum_item {
u8 csum[BTRFS_CSUM_SIZE];
} __attribute__ ((__packed__));
struct btrfs_inode_map_item {
struct btrfs_disk_key key;
} __attribute__ ((__packed__));
@ -283,27 +290,32 @@ struct btrfs_root {
* a (hopefully) huge chunk of disk
*/
#define BTRFS_EXTENT_DATA_KEY 4
/*
* csum items have the checksums for data in the extents
*/
#define BTRFS_CSUM_ITEM_KEY 5
/*
* root items point to tree roots. There are typically in the root
* tree used by the super block to find all the other trees
*/
#define BTRFS_ROOT_ITEM_KEY 5
#define BTRFS_ROOT_ITEM_KEY 6
/*
* extent items are in the extent map tree. These record which blocks
* are used, and how many references there are to each block
*/
#define BTRFS_EXTENT_ITEM_KEY 6
#define BTRFS_EXTENT_ITEM_KEY 7
/*
* the inode map records which inode numbers are in use and where
* they actually live on disk
*/
#define BTRFS_INODE_MAP_ITEM_KEY 7
#define BTRFS_INODE_MAP_ITEM_KEY 8
/*
* string items are for debugging. They just store a short string of
* data in the FS
*/
#define BTRFS_STRING_ITEM_KEY 8
#define BTRFS_STRING_ITEM_KEY 9
static inline u64 btrfs_inode_generation(struct btrfs_inode_item *i)
{
@ -407,15 +419,15 @@ static inline void btrfs_set_inode_compat_flags(struct btrfs_inode_item *i,
i->compat_flags = cpu_to_le16(val);
}
static inline u32 btrfs_timespec_sec(struct btrfs_inode_timespec *ts)
static inline u64 btrfs_timespec_sec(struct btrfs_inode_timespec *ts)
{
return le32_to_cpu(ts->sec);
return le64_to_cpu(ts->sec);
}
static inline void btrfs_set_timespec_sec(struct btrfs_inode_timespec *ts,
u32 val)
u64 val)
{
ts->sec = cpu_to_le32(val);
ts->sec = cpu_to_le64(val);
}
static inline u32 btrfs_timespec_nsec(struct btrfs_inode_timespec *ts)
@ -429,8 +441,6 @@ static inline void btrfs_set_timespec_nsec(struct btrfs_inode_timespec *ts,
ts->nsec = cpu_to_le32(val);
}
static inline u64 btrfs_extent_owner(struct btrfs_extent_item *ei)
{
return le64_to_cpu(ei->owner);
@ -905,4 +915,11 @@ int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, u64 objectid,
u64 blocknr, int mod);
int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 objectid, u64 offset,
char *data, size_t len);
int btrfs_csum_verify_file_block(struct btrfs_root *root,
u64 objectid, u64 offset,
char *data, size_t len);
#endif

37
fs/btrfs/disk-io.c
View File

@ -127,31 +127,46 @@ static int btree_get_block(struct inode *inode, sector_t iblock,
return 0;
}
static int csum_tree_block(struct btrfs_root * root, struct buffer_head *bh,
int verify)
int btrfs_csum_data(struct btrfs_root * root, char *data, size_t len,
char *result)
{
struct btrfs_node *node = btrfs_buffer_node(bh);
struct scatterlist sg;
struct crypto_hash *tfm = root->fs_info->hash_tfm;
struct hash_desc desc;
int ret;
char result[32];
desc.tfm = tfm;
desc.flags = 0;
sg_init_one(&sg, bh->b_data + 32, bh->b_size - 32);
sg_init_one(&sg, data, len);
spin_lock(&root->fs_info->hash_lock);
ret = crypto_hash_digest(&desc, &sg, bh->b_size - 32, result);
ret = crypto_hash_digest(&desc, &sg, len, result);
spin_unlock(&root->fs_info->hash_lock);
if (ret) {
printk("sha256 digest failed\n");
}
return ret;
}
static int csum_tree_block(struct btrfs_root *root, struct buffer_head *bh,
int verify)
{
char result[BTRFS_CSUM_SIZE];
int ret;
struct btrfs_node *node;
ret = btrfs_csum_data(root, bh->b_data + BTRFS_CSUM_SIZE,
bh->b_size - BTRFS_CSUM_SIZE, result);
if (ret)
return ret;
if (verify) {
if (memcmp(node->header.csum, result, sizeof(result)))
printk("csum verify failed on %Lu\n", bh->b_blocknr);
return -EINVAL;
} else
memcpy(node->header.csum, result, sizeof(node->header.csum));
if (memcmp(bh->b_data, result, BTRFS_CSUM_SIZE)) {
printk("checksum verify failed on %lu\n",
bh->b_blocknr);
return 1;
}
} else {
node = btrfs_buffer_node(bh);
memcpy(&node->header.csum, result, BTRFS_CSUM_SIZE);
}
return 0;
}

2
fs/btrfs/disk-io.h
View File

@ -39,4 +39,6 @@ void btrfs_block_release(struct btrfs_root *root, struct buffer_head *buf);
int write_ctree_super(struct btrfs_trans_handle *trans,
struct btrfs_root *root);
struct buffer_head *btrfs_find_tree_block(struct btrfs_root *root, u64 blocknr);
int btrfs_csum_data(struct btrfs_root * root, char *data, size_t len,
char *result);
#endif

60
fs/btrfs/file-item.c
View File

@ -57,3 +57,63 @@ int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
return ret;
}
int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 objectid, u64 offset,
char *data, size_t len)
{
int ret;
struct btrfs_key file_key;
struct btrfs_path path;
struct btrfs_csum_item *item;
btrfs_init_path(&path);
file_key.objectid = objectid;
file_key.offset = offset;
file_key.flags = 0;
btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
ret = btrfs_insert_empty_item(trans, root, &path, &file_key,
BTRFS_CSUM_SIZE);
if (ret != 0 && ret != -EEXIST)
goto fail;
item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
struct btrfs_csum_item);
ret = 0;
ret = btrfs_csum_data(root, data, len, item->csum);
mark_buffer_dirty(path.nodes[0]);
fail:
btrfs_release_path(root, &path);
return ret;
}
int btrfs_csum_verify_file_block(struct btrfs_root *root,
u64 objectid, u64 offset,
char *data, size_t len)
{
int ret;
struct btrfs_key file_key;
struct btrfs_path path;
struct btrfs_csum_item *item;
char result[BTRFS_CSUM_SIZE];
btrfs_init_path(&path);
file_key.objectid = objectid;
file_key.offset = offset;
file_key.flags = 0;
btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
ret = btrfs_search_slot(NULL, root, &file_key, &path, 0, 0);
if (ret)
goto fail;
item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
struct btrfs_csum_item);
ret = 0;
ret = btrfs_csum_data(root, data, len, result);
WARN_ON(ret);
if (memcmp(result, item->csum, BTRFS_CSUM_SIZE))
ret = 1;
fail:
btrfs_release_path(root, &path);
return ret;
}

184
fs/btrfs/super.c
View File

@ -249,15 +249,16 @@ static int btrfs_truncate_in_trans(struct btrfs_trans_handle *trans,
struct btrfs_key key;
struct btrfs_disk_key *found_key;
struct btrfs_leaf *leaf;
struct btrfs_file_extent_item *fi;
u64 extent_start;
u64 extent_num_blocks;
struct btrfs_file_extent_item *fi = NULL;
u64 extent_start = 0;
u64 extent_num_blocks = 0;
int found_extent;
/* FIXME, add redo link to tree so we don't leak on crash */
key.objectid = inode->i_ino;
key.offset = (u64)-1;
key.flags = 0;
btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
btrfs_set_key_type(&key, BTRFS_CSUM_ITEM_KEY);
while(1) {
btrfs_init_path(&path);
ret = btrfs_search_slot(trans, root, &key, &path, -1, 1);
@ -273,25 +274,32 @@ static int btrfs_truncate_in_trans(struct btrfs_trans_handle *trans,
found_key = &leaf->items[path.slots[0]].key;
if (btrfs_disk_key_objectid(found_key) != inode->i_ino)
break;
if (btrfs_disk_key_type(found_key) != BTRFS_EXTENT_DATA_KEY)
if (btrfs_disk_key_type(found_key) != BTRFS_CSUM_ITEM_KEY &&
btrfs_disk_key_type(found_key) != BTRFS_EXTENT_DATA_KEY)
break;
if (btrfs_disk_key_offset(found_key) < inode->i_size)
break;
fi = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]),
path.slots[0],
struct btrfs_file_extent_item);
extent_start = btrfs_file_extent_disk_blocknr(fi);
extent_num_blocks = btrfs_file_extent_disk_num_blocks(fi);
key.offset = btrfs_disk_key_offset(found_key) - 1;
if (btrfs_disk_key_type(found_key) == BTRFS_EXTENT_DATA_KEY) {
fi = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]),
path.slots[0],
struct btrfs_file_extent_item);
extent_start = btrfs_file_extent_disk_blocknr(fi);
extent_num_blocks =
btrfs_file_extent_disk_num_blocks(fi);
inode->i_blocks -=
btrfs_file_extent_num_blocks(fi) >> 9;
found_extent = 1;
} else {
found_extent = 0;
}
ret = btrfs_del_item(trans, root, &path);
BUG_ON(ret);
inode->i_blocks -= btrfs_file_extent_num_blocks(fi) >> 9;
btrfs_release_path(root, &path);
ret = btrfs_free_extent(trans, root, extent_start,
extent_num_blocks, 0);
BUG_ON(ret);
if (key.offset + 1 == 0)
break;
if (found_extent) {
ret = btrfs_free_extent(trans, root, extent_start,
extent_num_blocks, 0);
BUG_ON(ret);
}
}
btrfs_release_path(root, &path);
ret = 0;
@ -975,10 +983,24 @@ static int dirty_and_release_pages(struct btrfs_trans_handle *trans,
int err = 0;
int ret;
int this_write;
struct inode *inode = file->f_path.dentry->d_inode;
for (i = 0; i < num_pages; i++) {
offset = pos & (PAGE_CACHE_SIZE -1);
this_write = min(PAGE_CACHE_SIZE - offset, write_bytes);
/* FIXME, one block at a time */
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_csum_file_block(trans, root, inode->i_ino,
pages[i]->index << PAGE_CACHE_SHIFT,
kmap(pages[i]), PAGE_CACHE_SIZE);
kunmap(pages[i]);
SetPageChecked(pages[i]);
ret = btrfs_end_transaction(trans, root);
BUG_ON(ret);
mutex_unlock(&root->fs_info->fs_mutex);
ret = nobh_commit_write(file, pages[i], offset,
offset + this_write);
pos += this_write;
@ -1022,7 +1044,7 @@ static int prepare_pages(struct btrfs_trans_handle *trans,
this_write = min(PAGE_CACHE_SIZE - offset, write_bytes);
ret = nobh_prepare_write(pages[i], offset,
offset + this_write,
btrfs_get_block_lock);
btrfs_get_block);
pos += this_write;
if (ret) {
err = ret;
@ -1051,7 +1073,6 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
size_t num_written = 0;
int err = 0;
int ret = 0;
struct btrfs_trans_handle *trans;
struct inode *inode = file->f_path.dentry->d_inode;
struct btrfs_root *root = btrfs_sb(inode->i_sb);
struct page *pages[1];
@ -1077,25 +1098,18 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
size_t write_bytes = min(count, PAGE_CACHE_SIZE - offset);
size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
PAGE_CACHE_SHIFT;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
ret = prepare_pages(trans, root, file, pages, num_pages,
ret = prepare_pages(NULL, root, file, pages, num_pages,
pos, write_bytes);
BUG_ON(ret);
ret = btrfs_copy_from_user(pos, num_pages,
write_bytes, pages, buf);
BUG_ON(ret);
mutex_unlock(&root->fs_info->fs_mutex);
ret = dirty_and_release_pages(trans, root, file, pages,
ret = dirty_and_release_pages(NULL, root, file, pages,
num_pages, pos, write_bytes);
BUG_ON(ret);
btrfs_drop_pages(pages, num_pages);
ret = btrfs_end_transaction(trans, root);
buf += write_bytes;
count -= write_bytes;
pos += write_bytes;
@ -1111,6 +1125,118 @@ out:
return num_written ? num_written : err;
}
static int btrfs_read_actor(read_descriptor_t *desc, struct page *page,
unsigned long offset, unsigned long size)
{
char *kaddr;
unsigned long left, count = desc->count;
if (size > count)
size = count;
if (!PageChecked(page)) {
/* FIXME, do it per block */
struct btrfs_root *root = btrfs_sb(page->mapping->host->i_sb);
int ret = btrfs_csum_verify_file_block(root,
page->mapping->host->i_ino,
page->index << PAGE_CACHE_SHIFT,
kmap(page), PAGE_CACHE_SIZE);
if (ret) {
printk("failed to verify ino %lu page %lu\n",
page->mapping->host->i_ino,
page->index);
memset(page_address(page), 0, PAGE_CACHE_SIZE);
}
SetPageChecked(page);
kunmap(page);
}
/*
* Faults on the destination of a read are common, so do it before
* taking the kmap.
*/
if (!fault_in_pages_writeable(desc->arg.buf, size)) {
kaddr = kmap_atomic(page, KM_USER0);
left = __copy_to_user_inatomic(desc->arg.buf,
kaddr + offset, size);
kunmap_atomic(kaddr, KM_USER0);
if (left == 0)
goto success;
}
/* Do it the slow way */
kaddr = kmap(page);
left = __copy_to_user(desc->arg.buf, kaddr + offset, size);
kunmap(page);
if (left) {
size -= left;
desc->error = -EFAULT;
}
success:
desc->count = count - size;
desc->written += size;
desc->arg.buf += size;
return size;
}
/**
* btrfs_file_aio_read - filesystem read routine
* @iocb: kernel I/O control block
* @iov: io vector request
* @nr_segs: number of segments in the iovec
* @pos: current file position
*/
static ssize_t btrfs_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
struct file *filp = iocb->ki_filp;
ssize_t retval;
unsigned long seg;
size_t count;
loff_t *ppos = &iocb->ki_pos;
count = 0;
for (seg = 0; seg < nr_segs; seg++) {
const struct iovec *iv = &iov[seg];
/*
* If any segment has a negative length, or the cumulative
* length ever wraps negative then return -EINVAL.
*/
count += iv->iov_len;
if (unlikely((ssize_t)(count|iv->iov_len) < 0))
return -EINVAL;
if (access_ok(VERIFY_WRITE, iv->iov_base, iv->iov_len))
continue;
if (seg == 0)
return -EFAULT;
nr_segs = seg;
count -= iv->iov_len; /* This segment is no good */
break;
}
retval = 0;
if (count) {
for (seg = 0; seg < nr_segs; seg++) {
read_descriptor_t desc;
desc.written = 0;
desc.arg.buf = iov[seg].iov_base;
desc.count = iov[seg].iov_len;
if (desc.count == 0)
continue;
desc.error = 0;
do_generic_file_read(filp, ppos, &desc,
btrfs_read_actor);
retval += desc.written;
if (desc.error) {
retval = retval ?: desc.error;
break;
}
}
}
return retval;
}
static int btrfs_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
@ -1166,7 +1292,7 @@ static struct inode_operations btrfs_file_inode_operations = {
static struct file_operations btrfs_file_operations = {
.llseek = generic_file_llseek,
.read = do_sync_read,
.aio_read = generic_file_aio_read,
.aio_read = btrfs_file_aio_read,
.write = btrfs_file_write,
.mmap = generic_file_mmap,
.open = generic_file_open,