From 1b2c54d63cde7e8cf15aa6319aba168d81c7e364 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Wed, 14 Oct 2020 16:38:47 -0700 Subject: vfs: move the remap range helpers to remap_range.c Complete the migration by moving the file remapping helper functions out of read_write.c and into remap_range.c. This reduces the clutter in the first file and (eventually) will make it so that we can compile out the second file if it isn't needed. Signed-off-by: Darrick J. Wong --- fs/read_write.c | 473 -------------------------------------------------------- 1 file changed, 473 deletions(-) (limited to 'fs/read_write.c') diff --git a/fs/read_write.c b/fs/read_write.c index d3428189f36b..f0877f1c0c49 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1832,476 +1832,3 @@ out1: out2: return ret; } - -static int remap_verify_area(struct file *file, loff_t pos, loff_t len, - bool write) -{ - struct inode *inode = file_inode(file); - - if (unlikely(pos < 0 || len < 0)) - return -EINVAL; - - if (unlikely((loff_t) (pos + len) < 0)) - return -EINVAL; - - if (unlikely(inode->i_flctx && mandatory_lock(inode))) { - loff_t end = len ? pos + len - 1 : OFFSET_MAX; - int retval; - - retval = locks_mandatory_area(inode, file, pos, end, - write ? F_WRLCK : F_RDLCK); - if (retval < 0) - return retval; - } - - return security_file_permission(file, write ? MAY_WRITE : MAY_READ); -} -/* - * Ensure that we don't remap a partial EOF block in the middle of something - * else. Assume that the offsets have already been checked for block - * alignment. - * - * For clone we only link a partial EOF block above or at the destination file's - * EOF. For deduplication we accept a partial EOF block only if it ends at the - * destination file's EOF (can not link it into the middle of a file). - * - * Shorten the request if possible. - */ -static int generic_remap_check_len(struct inode *inode_in, - struct inode *inode_out, - loff_t pos_out, - loff_t *len, - unsigned int remap_flags) -{ - u64 blkmask = i_blocksize(inode_in) - 1; - loff_t new_len = *len; - - if ((*len & blkmask) == 0) - return 0; - - if (pos_out + *len < i_size_read(inode_out)) - new_len &= ~blkmask; - - if (new_len == *len) - return 0; - - if (remap_flags & REMAP_FILE_CAN_SHORTEN) { - *len = new_len; - return 0; - } - - return (remap_flags & REMAP_FILE_DEDUP) ? -EBADE : -EINVAL; -} - -/* Read a page's worth of file data into the page cache. */ -static struct page *vfs_dedupe_get_page(struct inode *inode, loff_t offset) -{ - struct page *page; - - page = read_mapping_page(inode->i_mapping, offset >> PAGE_SHIFT, NULL); - if (IS_ERR(page)) - return page; - if (!PageUptodate(page)) { - put_page(page); - return ERR_PTR(-EIO); - } - return page; -} - -/* - * Lock two pages, ensuring that we lock in offset order if the pages are from - * the same file. - */ -static void vfs_lock_two_pages(struct page *page1, struct page *page2) -{ - /* Always lock in order of increasing index. */ - if (page1->index > page2->index) - swap(page1, page2); - - lock_page(page1); - if (page1 != page2) - lock_page(page2); -} - -/* Unlock two pages, being careful not to unlock the same page twice. */ -static void vfs_unlock_two_pages(struct page *page1, struct page *page2) -{ - unlock_page(page1); - if (page1 != page2) - unlock_page(page2); -} - -/* - * Compare extents of two files to see if they are the same. - * Caller must have locked both inodes to prevent write races. - */ -static 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); - put_page(src_page); - goto out_error; - } - - vfs_lock_two_pages(src_page, dest_page); - - /* - * Now that we've locked both pages, make sure they're still - * mapped to the file data we're interested in. If not, - * someone is invalidating pages on us and we lose. - */ - if (!PageUptodate(src_page) || !PageUptodate(dest_page) || - src_page->mapping != src->i_mapping || - dest_page->mapping != dest->i_mapping) { - same = false; - goto unlock; - } - - 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: - vfs_unlock_two_pages(src_page, dest_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; -} - -/* - * 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. - * - * If there's an error, then the usual negative error code is returned. - * Otherwise returns 0 with *len set to the request length. - */ -int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, - struct file *file_out, loff_t pos_out, - loff_t *len, unsigned int remap_flags) -{ - struct inode *inode_in = file_inode(file_in); - struct inode *inode_out = file_inode(file_out); - 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; - - /* Zero length dedupe exits immediately; reflink goes to EOF. */ - if (*len == 0) { - loff_t isize = i_size_read(inode_in); - - if ((remap_flags & REMAP_FILE_DEDUP) || pos_in == isize) - return 0; - if (pos_in > isize) - return -EINVAL; - *len = isize - pos_in; - if (*len == 0) - return 0; - } - - /* Check that we don't violate system file offset limits. */ - ret = generic_remap_checks(file_in, pos_in, file_out, pos_out, len, - remap_flags); - if (ret) - return ret; - - /* 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 (remap_flags & REMAP_FILE_DEDUP) { - 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; - } - - ret = generic_remap_check_len(inode_in, inode_out, pos_out, len, - remap_flags); - if (ret) - return ret; - - /* If can't alter the file contents, we're done. */ - if (!(remap_flags & REMAP_FILE_DEDUP)) - ret = file_modified(file_out); - - return ret; -} -EXPORT_SYMBOL(generic_remap_file_range_prep); - -loff_t do_clone_file_range(struct file *file_in, loff_t pos_in, - struct file *file_out, loff_t pos_out, - loff_t len, unsigned int remap_flags) -{ - loff_t ret; - - WARN_ON_ONCE(remap_flags & REMAP_FILE_DEDUP); - - /* - * FICLONE/FICLONERANGE ioctls enforce that src and dest files are on - * the same mount. Practically, they only need to be on the same file - * system. - */ - if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb) - return -EXDEV; - - ret = generic_file_rw_checks(file_in, file_out); - if (ret < 0) - return ret; - - if (!file_in->f_op->remap_file_range) - return -EOPNOTSUPP; - - ret = remap_verify_area(file_in, pos_in, len, false); - if (ret) - return ret; - - ret = remap_verify_area(file_out, pos_out, len, true); - if (ret) - return ret; - - ret = file_in->f_op->remap_file_range(file_in, pos_in, - file_out, pos_out, len, remap_flags); - if (ret < 0) - return ret; - - fsnotify_access(file_in); - fsnotify_modify(file_out); - return ret; -} -EXPORT_SYMBOL(do_clone_file_range); - -loff_t vfs_clone_file_range(struct file *file_in, loff_t pos_in, - struct file *file_out, loff_t pos_out, - loff_t len, unsigned int remap_flags) -{ - loff_t ret; - - file_start_write(file_out); - ret = do_clone_file_range(file_in, pos_in, file_out, pos_out, len, - remap_flags); - file_end_write(file_out); - - return ret; -} -EXPORT_SYMBOL(vfs_clone_file_range); - -/* Check whether we are allowed to dedupe the destination file */ -static bool allow_file_dedupe(struct file *file) -{ - if (capable(CAP_SYS_ADMIN)) - return true; - if (file->f_mode & FMODE_WRITE) - return true; - if (uid_eq(current_fsuid(), file_inode(file)->i_uid)) - return true; - if (!inode_permission(file_inode(file), MAY_WRITE)) - return true; - return false; -} - -loff_t vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos, - struct file *dst_file, loff_t dst_pos, - loff_t len, unsigned int remap_flags) -{ - loff_t ret; - - WARN_ON_ONCE(remap_flags & ~(REMAP_FILE_DEDUP | - REMAP_FILE_CAN_SHORTEN)); - - ret = mnt_want_write_file(dst_file); - if (ret) - return ret; - - ret = remap_verify_area(dst_file, dst_pos, len, true); - if (ret < 0) - goto out_drop_write; - - ret = -EPERM; - if (!allow_file_dedupe(dst_file)) - goto out_drop_write; - - ret = -EXDEV; - if (src_file->f_path.mnt != dst_file->f_path.mnt) - goto out_drop_write; - - ret = -EISDIR; - if (S_ISDIR(file_inode(dst_file)->i_mode)) - goto out_drop_write; - - ret = -EINVAL; - if (!dst_file->f_op->remap_file_range) - goto out_drop_write; - - if (len == 0) { - ret = 0; - goto out_drop_write; - } - - ret = dst_file->f_op->remap_file_range(src_file, src_pos, dst_file, - dst_pos, len, remap_flags | REMAP_FILE_DEDUP); -out_drop_write: - mnt_drop_write_file(dst_file); - - return ret; -} -EXPORT_SYMBOL(vfs_dedupe_file_range_one); - -int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same) -{ - struct file_dedupe_range_info *info; - struct inode *src = file_inode(file); - u64 off; - u64 len; - int i; - int ret; - u16 count = same->dest_count; - loff_t deduped; - - if (!(file->f_mode & FMODE_READ)) - return -EINVAL; - - if (same->reserved1 || same->reserved2) - return -EINVAL; - - off = same->src_offset; - len = same->src_length; - - if (S_ISDIR(src->i_mode)) - return -EISDIR; - - if (!S_ISREG(src->i_mode)) - return -EINVAL; - - if (!file->f_op->remap_file_range) - return -EOPNOTSUPP; - - ret = remap_verify_area(file, off, len, false); - if (ret < 0) - return ret; - ret = 0; - - if (off + len > i_size_read(src)) - return -EINVAL; - - /* Arbitrary 1G limit on a single dedupe request, can be raised. */ - len = min_t(u64, len, 1 << 30); - - /* pre-format output fields to sane values */ - for (i = 0; i < count; i++) { - same->info[i].bytes_deduped = 0ULL; - same->info[i].status = FILE_DEDUPE_RANGE_SAME; - } - - for (i = 0, info = same->info; i < count; i++, info++) { - struct fd dst_fd = fdget(info->dest_fd); - struct file *dst_file = dst_fd.file; - - if (!dst_file) { - info->status = -EBADF; - goto next_loop; - } - - if (info->reserved) { - info->status = -EINVAL; - goto next_fdput; - } - - deduped = vfs_dedupe_file_range_one(file, off, dst_file, - info->dest_offset, len, - REMAP_FILE_CAN_SHORTEN); - if (deduped == -EBADE) - info->status = FILE_DEDUPE_RANGE_DIFFERS; - else if (deduped < 0) - info->status = deduped; - else - info->bytes_deduped = len; - -next_fdput: - fdput(dst_fd); -next_loop: - if (fatal_signal_pending(current)) - break; - } - return ret; -} -EXPORT_SYMBOL(vfs_dedupe_file_range); -- cgit v1.2.3-59-g8ed1b