diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/Makefile | 2 | ||||
| -rw-r--r-- | fs/read_write.c | 544 | ||||
| -rw-r--r-- | fs/remap_range.c | 571 |
3 files changed, 679 insertions, 438 deletions
diff --git a/fs/Makefile b/fs/Makefile index 7bb2a05fda1f..999d1a23f036 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -14,7 +14,7 @@ obj-y := open.o read_write.o file_table.o super.o \ pnode.o splice.o sync.o utimes.o d_path.o \ stack.o fs_struct.o statfs.o fs_pin.o nsfs.o \ fs_types.o fs_context.o fs_parser.o fsopen.o init.o \ - kernel_read_file.o + kernel_read_file.o remap_range.o ifeq ($(CONFIG_BLOCK),y) obj-y += buffer.o block_dev.o direct-io.o mpage.o diff --git a/fs/read_write.c b/fs/read_write.c index a669fb049b84..75f764b43418 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1411,6 +1411,59 @@ static ssize_t do_copy_file_range(struct file *file_in, loff_t pos_in, } /* + * Performs necessary checks before doing a file copy + * + * Can adjust amount of bytes to copy via @req_count argument. + * Returns appropriate error code that caller should return or + * zero in case the copy should be allowed. + */ +static int generic_copy_file_checks(struct file *file_in, loff_t pos_in, + struct file *file_out, loff_t pos_out, + size_t *req_count, unsigned int flags) +{ + struct inode *inode_in = file_inode(file_in); + struct inode *inode_out = file_inode(file_out); + uint64_t count = *req_count; + loff_t size_in; + int ret; + + ret = generic_file_rw_checks(file_in, file_out); + if (ret) + return 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; + + /* Ensure offsets don't wrap. */ + if (pos_in + count < pos_in || pos_out + count < pos_out) + return -EOVERFLOW; + + /* Shorten the copy to EOF */ + size_in = i_size_read(inode_in); + if (pos_in >= size_in) + count = 0; + else + count = min(count, size_in - (uint64_t)pos_in); + + ret = generic_write_check_limits(file_out, pos_out, &count); + if (ret) + return ret; + + /* Don't allow overlapped copying within the same file. */ + if (inode_in == inode_out && + pos_out + count > pos_in && + pos_out < pos_in + count) + return -EINVAL; + + *req_count = count; + return 0; +} + +/* * copy_file_range() differs from regular file read and write in that it * specifically allows return partial success. When it does so is up to * the copy_file_range method. @@ -1542,475 +1595,92 @@ 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. + * Don't operate on ranges the page cache doesn't support, and don't exceed the + * LFS limits. If pos is under the limit it becomes a short access. If it + * exceeds the limit we return -EFBIG. */ -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) +int generic_write_check_limits(struct file *file, loff_t pos, loff_t *count) { - 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); + struct inode *inode = file->f_mapping->host; + loff_t max_size = inode->i_sb->s_maxbytes; + loff_t limit = rlimit(RLIMIT_FSIZE); - /* - * 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; + if (limit != RLIM_INFINITY) { + if (pos >= limit) { + send_sig(SIGXFSZ, current, 0); + return -EFBIG; } + *count = min(*count, limit - pos); + } - 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; + if (!(file->f_flags & O_LARGEFILE)) + max_size = MAX_NON_LFS; - 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 (unlikely(pos >= max_size)) + return -EFBIG; - if (!same) - break; + *count = min(*count, max_size - pos); - 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. + * Performs necessary checks before doing a write * - * If there's an error, then the usual negative error code is returned. - * Otherwise returns 0 with *len set to the request length. + * Can adjust writing position or amount of bytes to write. + * Returns appropriate error code that caller should return or + * zero in case that write should be allowed. */ -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) +ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from) { - struct inode *inode_in = file_inode(file_in); - struct inode *inode_out = file_inode(file_out); - bool same_inode = (inode_in == inode_out); + struct file *file = iocb->ki_filp; + struct inode *inode = file->f_mapping->host; + loff_t count; 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)) + if (IS_SWAPFILE(inode)) 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; -} + if (!iov_iter_count(from)) + return 0; -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; + /* FIXME: this is for backwards compatibility with 2.4 */ + if (iocb->ki_flags & IOCB_APPEND) + iocb->ki_pos = i_size_read(inode); - WARN_ON_ONCE(remap_flags & ~(REMAP_FILE_DEDUP | - REMAP_FILE_CAN_SHORTEN)); + if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT)) + return -EINVAL; - ret = mnt_want_write_file(dst_file); + count = iov_iter_count(from); + ret = generic_write_check_limits(file, iocb->ki_pos, &count); 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; + iov_iter_truncate(from, count); + return iov_iter_count(from); } -EXPORT_SYMBOL(vfs_dedupe_file_range_one); +EXPORT_SYMBOL(generic_write_checks); -int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same) +/* + * Performs common checks before doing a file copy/clone + * from @file_in to @file_out. + */ +int generic_file_rw_checks(struct file *file_in, struct file *file_out) { - 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; + struct inode *inode_in = file_inode(file_in); + struct inode *inode_out = file_inode(file_out); - if (S_ISDIR(src->i_mode)) + /* Don't copy dirs, pipes, sockets... */ + if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->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)) + if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode)) 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; + if (!(file_in->f_mode & FMODE_READ) || + !(file_out->f_mode & FMODE_WRITE) || + (file_out->f_flags & O_APPEND)) + return -EBADF; -next_fdput: - fdput(dst_fd); -next_loop: - if (fatal_signal_pending(current)) - break; - } - return ret; + return 0; } -EXPORT_SYMBOL(vfs_dedupe_file_range); diff --git a/fs/remap_range.c b/fs/remap_range.c new file mode 100644 index 000000000000..e6099beefa97 --- /dev/null +++ b/fs/remap_range.c @@ -0,0 +1,571 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <linux/slab.h> +#include <linux/stat.h> +#include <linux/sched/xacct.h> +#include <linux/fcntl.h> +#include <linux/file.h> +#include <linux/uio.h> +#include <linux/fsnotify.h> +#include <linux/security.h> +#include <linux/export.h> +#include <linux/syscalls.h> +#include <linux/pagemap.h> +#include <linux/splice.h> +#include <linux/compat.h> +#include <linux/mount.h> +#include <linux/fs.h> +#include "internal.h" + +#include <linux/uaccess.h> +#include <asm/unistd.h> + +/* + * Performs necessary checks before doing a clone. + * + * Can adjust amount of bytes to clone via @req_count argument. + * Returns appropriate error code that caller should return or + * zero in case the clone should be allowed. + */ +static int generic_remap_checks(struct file *file_in, loff_t pos_in, + struct file *file_out, loff_t pos_out, + loff_t *req_count, unsigned int remap_flags) +{ + struct inode *inode_in = file_in->f_mapping->host; + struct inode *inode_out = file_out->f_mapping->host; + uint64_t count = *req_count; + uint64_t bcount; + loff_t size_in, size_out; + loff_t bs = inode_out->i_sb->s_blocksize; + int ret; + + /* The start of both ranges must be aligned to an fs block. */ + if (!IS_ALIGNED(pos_in, bs) || !IS_ALIGNED(pos_out, bs)) + return -EINVAL; + + /* Ensure offsets don't wrap. */ + if (pos_in + count < pos_in || pos_out + count < pos_out) + return -EINVAL; + + size_in = i_size_read(inode_in); + size_out = i_size_read(inode_out); + + /* Dedupe requires both ranges to be within EOF. */ + if ((remap_flags & REMAP_FILE_DEDUP) && + (pos_in >= size_in || pos_in + count > size_in || + pos_out >= size_out || pos_out + count > size_out)) + return -EINVAL; + + /* Ensure the infile range is within the infile. */ + if (pos_in >= size_in) + return -EINVAL; + count = min(count, size_in - (uint64_t)pos_in); + + ret = generic_write_check_limits(file_out, pos_out, &count); + if (ret) + return ret; + + /* + * If the user wanted us to link to the infile's EOF, round up to the + * next block boundary for this check. + * + * Otherwise, make sure the count is also block-aligned, having + * already confirmed the starting offsets' block alignment. + */ + if (pos_in + count == size_in) { + bcount = ALIGN(size_in, bs) - pos_in; + } else { + if (!IS_ALIGNED(count, bs)) + count = ALIGN_DOWN(count, bs); + bcount = count; + } + + /* Don't allow overlapped cloning within the same file. */ + if (inode_in == inode_out && + pos_out + bcount > pos_in && + pos_out < pos_in + bcount) + return -EINVAL; + + /* + * We shortened the request but the caller can't deal with that, so + * bounce the request back to userspace. + */ + if (*req_count != count && !(remap_flags & REMAP_FILE_CAN_SHORTEN)) + return -EINVAL; + + *req_count = count; + return 0; +} + +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); |