Btrfs: verify csums on read
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 7914b31..0442813 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -249,15 +249,16 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 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,