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-rw-r--r--fs/read_write.c204
1 files changed, 204 insertions, 0 deletions
diff --git a/fs/read_write.c b/fs/read_write.c
index 6674a4b83c54..dbf3f7ffdf3f 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1667,6 +1667,114 @@ static int clone_verify_area(struct file *file, loff_t pos, u64 len, bool write)
return security_file_permission(file, write ? MAY_WRITE : MAY_READ);
}
+/*
+ * Check that the two inodes are eligible for cloning, the ranges make
+ * sense, and then flush all dirty data. Caller must ensure that the
+ * inodes have been locked against any other modifications.
+ */
+int vfs_clone_file_prep_inodes(struct inode *inode_in, loff_t pos_in,
+ struct inode *inode_out, loff_t pos_out,
+ u64 *len, bool is_dedupe)
+{
+ loff_t bs = inode_out->i_sb->s_blocksize;
+ loff_t blen;
+ loff_t isize;
+ bool same_inode = (inode_in == inode_out);
+ int ret;
+
+ /* Don't touch certain kinds of inodes */
+ if (IS_IMMUTABLE(inode_out))
+ return -EPERM;
+
+ if (IS_SWAPFILE(inode_in) || IS_SWAPFILE(inode_out))
+ return -ETXTBSY;
+
+ /* Don't reflink dirs, pipes, sockets... */
+ if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode))
+ return -EISDIR;
+ if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))
+ return -EINVAL;
+
+ /* Are we going all the way to the end? */
+ isize = i_size_read(inode_in);
+ if (isize == 0) {
+ *len = 0;
+ return 0;
+ }
+
+ /* Zero length dedupe exits immediately; reflink goes to EOF. */
+ if (*len == 0) {
+ if (is_dedupe) {
+ *len = 0;
+ return 0;
+ }
+ *len = isize - pos_in;
+ }
+
+ /* Ensure offsets don't wrap and the input is inside i_size */
+ if (pos_in + *len < pos_in || pos_out + *len < pos_out ||
+ pos_in + *len > isize)
+ return -EINVAL;
+
+ /* Don't allow dedupe past EOF in the dest file */
+ if (is_dedupe) {
+ loff_t disize;
+
+ disize = i_size_read(inode_out);
+ if (pos_out >= disize || pos_out + *len > disize)
+ return -EINVAL;
+ }
+
+ /* If we're linking to EOF, continue to the block boundary. */
+ if (pos_in + *len == isize)
+ blen = ALIGN(isize, bs) - pos_in;
+ else
+ blen = *len;
+
+ /* Only reflink if we're aligned to block boundaries */
+ if (!IS_ALIGNED(pos_in, bs) || !IS_ALIGNED(pos_in + blen, bs) ||
+ !IS_ALIGNED(pos_out, bs) || !IS_ALIGNED(pos_out + blen, bs))
+ return -EINVAL;
+
+ /* Don't allow overlapped reflink within the same file */
+ if (same_inode) {
+ if (pos_out + blen > pos_in && pos_out < pos_in + blen)
+ return -EINVAL;
+ }
+
+ /* Wait for the completion of any pending IOs on both files */
+ inode_dio_wait(inode_in);
+ if (!same_inode)
+ inode_dio_wait(inode_out);
+
+ ret = filemap_write_and_wait_range(inode_in->i_mapping,
+ pos_in, pos_in + *len - 1);
+ if (ret)
+ return ret;
+
+ ret = filemap_write_and_wait_range(inode_out->i_mapping,
+ pos_out, pos_out + *len - 1);
+ if (ret)
+ return ret;
+
+ /*
+ * Check that the extents are the same.
+ */
+ if (is_dedupe) {
+ bool is_same = false;
+
+ ret = vfs_dedupe_file_range_compare(inode_in, pos_in,
+ inode_out, pos_out, *len, &is_same);
+ if (ret)
+ return ret;
+ if (!is_same)
+ return -EBADE;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(vfs_clone_file_prep_inodes);
+
int vfs_clone_file_range(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out, u64 len)
{
@@ -1718,6 +1826,102 @@ int vfs_clone_file_range(struct file *file_in, loff_t pos_in,
}
EXPORT_SYMBOL(vfs_clone_file_range);
+/*
+ * Read a page's worth of file data into the page cache. Return the page
+ * locked.
+ */
+static struct page *vfs_dedupe_get_page(struct inode *inode, loff_t offset)
+{
+ struct address_space *mapping;
+ struct page *page;
+ pgoff_t n;
+
+ n = offset >> PAGE_SHIFT;
+ mapping = inode->i_mapping;
+ page = read_mapping_page(mapping, n, NULL);
+ if (IS_ERR(page))
+ return page;
+ if (!PageUptodate(page)) {
+ put_page(page);
+ return ERR_PTR(-EIO);
+ }
+ lock_page(page);
+ return page;
+}
+
+/*
+ * Compare extents of two files to see if they are the same.
+ * Caller must have locked both inodes to prevent write races.
+ */
+int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
+ struct inode *dest, loff_t destoff,
+ loff_t len, bool *is_same)
+{
+ loff_t src_poff;
+ loff_t dest_poff;
+ void *src_addr;
+ void *dest_addr;
+ struct page *src_page;
+ struct page *dest_page;
+ loff_t cmp_len;
+ bool same;
+ int error;
+
+ error = -EINVAL;
+ same = true;
+ while (len) {
+ src_poff = srcoff & (PAGE_SIZE - 1);
+ dest_poff = destoff & (PAGE_SIZE - 1);
+ cmp_len = min(PAGE_SIZE - src_poff,
+ PAGE_SIZE - dest_poff);
+ cmp_len = min(cmp_len, len);
+ if (cmp_len <= 0)
+ goto out_error;
+
+ src_page = vfs_dedupe_get_page(src, srcoff);
+ if (IS_ERR(src_page)) {
+ error = PTR_ERR(src_page);
+ goto out_error;
+ }
+ dest_page = vfs_dedupe_get_page(dest, destoff);
+ if (IS_ERR(dest_page)) {
+ error = PTR_ERR(dest_page);
+ unlock_page(src_page);
+ put_page(src_page);
+ goto out_error;
+ }
+ src_addr = kmap_atomic(src_page);
+ dest_addr = kmap_atomic(dest_page);
+
+ flush_dcache_page(src_page);
+ flush_dcache_page(dest_page);
+
+ if (memcmp(src_addr + src_poff, dest_addr + dest_poff, cmp_len))
+ same = false;
+
+ kunmap_atomic(dest_addr);
+ kunmap_atomic(src_addr);
+ unlock_page(dest_page);
+ unlock_page(src_page);
+ put_page(dest_page);
+ put_page(src_page);
+
+ if (!same)
+ break;
+
+ srcoff += cmp_len;
+ destoff += cmp_len;
+ len -= cmp_len;
+ }
+
+ *is_same = same;
+ return 0;
+
+out_error:
+ return error;
+}
+EXPORT_SYMBOL(vfs_dedupe_file_range_compare);
+
int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
{
struct file_dedupe_range_info *info;