diff options
Diffstat (limited to 'fs/read_write.c')
| -rw-r--r-- | fs/read_write.c | 977 |
1 files changed, 178 insertions, 799 deletions
diff --git a/fs/read_write.c b/fs/read_write.c index d3428189f36b..75f764b43418 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -419,27 +419,42 @@ static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, lo return ret; } +static int warn_unsupported(struct file *file, const char *op) +{ + pr_warn_ratelimited( + "kernel %s not supported for file %pD4 (pid: %d comm: %.20s)\n", + op, file, current->pid, current->comm); + return -EINVAL; +} + ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos) { - mm_segment_t old_fs = get_fs(); + struct kvec iov = { + .iov_base = buf, + .iov_len = min_t(size_t, count, MAX_RW_COUNT), + }; + struct kiocb kiocb; + struct iov_iter iter; ssize_t ret; if (WARN_ON_ONCE(!(file->f_mode & FMODE_READ))) return -EINVAL; if (!(file->f_mode & FMODE_CAN_READ)) return -EINVAL; + /* + * Also fail if ->read_iter and ->read are both wired up as that + * implies very convoluted semantics. + */ + if (unlikely(!file->f_op->read_iter || file->f_op->read)) + return warn_unsupported(file, "read"); - if (count > MAX_RW_COUNT) - count = MAX_RW_COUNT; - set_fs(KERNEL_DS); - if (file->f_op->read) - ret = file->f_op->read(file, (void __user *)buf, count, pos); - else if (file->f_op->read_iter) - ret = new_sync_read(file, (void __user *)buf, count, pos); - else - ret = -EINVAL; - set_fs(old_fs); + init_sync_kiocb(&kiocb, file); + kiocb.ki_pos = pos ? *pos : 0; + iov_iter_kvec(&iter, READ, &iov, 1, iov.iov_len); + ret = file->f_op->read_iter(&kiocb, &iter); if (ret > 0) { + if (pos) + *pos = kiocb.ki_pos; fsnotify_access(file); add_rchar(current, ret); } @@ -510,28 +525,32 @@ static ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t /* caller is responsible for file_start_write/file_end_write */ ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t *pos) { - mm_segment_t old_fs; - const char __user *p; + struct kvec iov = { + .iov_base = (void *)buf, + .iov_len = min_t(size_t, count, MAX_RW_COUNT), + }; + struct kiocb kiocb; + struct iov_iter iter; ssize_t ret; if (WARN_ON_ONCE(!(file->f_mode & FMODE_WRITE))) return -EBADF; if (!(file->f_mode & FMODE_CAN_WRITE)) return -EINVAL; + /* + * Also fail if ->write_iter and ->write are both wired up as that + * implies very convoluted semantics. + */ + if (unlikely(!file->f_op->write_iter || file->f_op->write)) + return warn_unsupported(file, "write"); - old_fs = get_fs(); - set_fs(KERNEL_DS); - p = (__force const char __user *)buf; - if (count > MAX_RW_COUNT) - count = MAX_RW_COUNT; - if (file->f_op->write) - ret = file->f_op->write(file, p, count, pos); - else if (file->f_op->write_iter) - ret = new_sync_write(file, p, count, pos); - else - ret = -EINVAL; - set_fs(old_fs); + init_sync_kiocb(&kiocb, file); + kiocb.ki_pos = pos ? *pos : 0; + iov_iter_kvec(&iter, WRITE, &iov, 1, iov.iov_len); + ret = file->f_op->write_iter(&kiocb, &iter); if (ret > 0) { + if (pos) + *pos = kiocb.ki_pos; fsnotify_modify(file); add_wchar(current, ret); } @@ -760,185 +779,6 @@ static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter, return ret; } -/** - * rw_copy_check_uvector() - Copy an array of &struct iovec from userspace - * into the kernel and check that it is valid. - * - * @type: One of %CHECK_IOVEC_ONLY, %READ, or %WRITE. - * @uvector: Pointer to the userspace array. - * @nr_segs: Number of elements in userspace array. - * @fast_segs: Number of elements in @fast_pointer. - * @fast_pointer: Pointer to (usually small on-stack) kernel array. - * @ret_pointer: (output parameter) Pointer to a variable that will point to - * either @fast_pointer, a newly allocated kernel array, or NULL, - * depending on which array was used. - * - * This function copies an array of &struct iovec of @nr_segs from - * userspace into the kernel and checks that each element is valid (e.g. - * it does not point to a kernel address or cause overflow by being too - * large, etc.). - * - * As an optimization, the caller may provide a pointer to a small - * on-stack array in @fast_pointer, typically %UIO_FASTIOV elements long - * (the size of this array, or 0 if unused, should be given in @fast_segs). - * - * @ret_pointer will always point to the array that was used, so the - * caller must take care not to call kfree() on it e.g. in case the - * @fast_pointer array was used and it was allocated on the stack. - * - * Return: The total number of bytes covered by the iovec array on success - * or a negative error code on error. - */ -ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector, - unsigned long nr_segs, unsigned long fast_segs, - struct iovec *fast_pointer, - struct iovec **ret_pointer) -{ - unsigned long seg; - ssize_t ret; - struct iovec *iov = fast_pointer; - - /* - * SuS says "The readv() function *may* fail if the iovcnt argument - * was less than or equal to 0, or greater than {IOV_MAX}. Linux has - * traditionally returned zero for zero segments, so... - */ - if (nr_segs == 0) { - ret = 0; - goto out; - } - - /* - * First get the "struct iovec" from user memory and - * verify all the pointers - */ - if (nr_segs > UIO_MAXIOV) { - ret = -EINVAL; - goto out; - } - if (nr_segs > fast_segs) { - iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); - if (iov == NULL) { - ret = -ENOMEM; - goto out; - } - } - if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) { - ret = -EFAULT; - goto out; - } - - /* - * According to the Single Unix Specification we should return EINVAL - * if an element length is < 0 when cast to ssize_t or if the - * total length would overflow the ssize_t return value of the - * system call. - * - * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the - * overflow case. - */ - ret = 0; - for (seg = 0; seg < nr_segs; seg++) { - void __user *buf = iov[seg].iov_base; - ssize_t len = (ssize_t)iov[seg].iov_len; - - /* see if we we're about to use an invalid len or if - * it's about to overflow ssize_t */ - if (len < 0) { - ret = -EINVAL; - goto out; - } - if (type >= 0 - && unlikely(!access_ok(buf, len))) { - ret = -EFAULT; - goto out; - } - if (len > MAX_RW_COUNT - ret) { - len = MAX_RW_COUNT - ret; - iov[seg].iov_len = len; - } - ret += len; - } -out: - *ret_pointer = iov; - return ret; -} - -#ifdef CONFIG_COMPAT -ssize_t compat_rw_copy_check_uvector(int type, - const struct compat_iovec __user *uvector, unsigned long nr_segs, - unsigned long fast_segs, struct iovec *fast_pointer, - struct iovec **ret_pointer) -{ - compat_ssize_t tot_len; - struct iovec *iov = *ret_pointer = fast_pointer; - ssize_t ret = 0; - int seg; - - /* - * SuS says "The readv() function *may* fail if the iovcnt argument - * was less than or equal to 0, or greater than {IOV_MAX}. Linux has - * traditionally returned zero for zero segments, so... - */ - if (nr_segs == 0) - goto out; - - ret = -EINVAL; - if (nr_segs > UIO_MAXIOV) - goto out; - if (nr_segs > fast_segs) { - ret = -ENOMEM; - iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); - if (iov == NULL) - goto out; - } - *ret_pointer = iov; - - ret = -EFAULT; - if (!access_ok(uvector, nr_segs*sizeof(*uvector))) - goto out; - - /* - * Single unix specification: - * We should -EINVAL if an element length is not >= 0 and fitting an - * ssize_t. - * - * In Linux, the total length is limited to MAX_RW_COUNT, there is - * no overflow possibility. - */ - tot_len = 0; - ret = -EINVAL; - for (seg = 0; seg < nr_segs; seg++) { - compat_uptr_t buf; - compat_ssize_t len; - - if (__get_user(len, &uvector->iov_len) || - __get_user(buf, &uvector->iov_base)) { - ret = -EFAULT; - goto out; - } - if (len < 0) /* size_t not fitting in compat_ssize_t .. */ - goto out; - if (type >= 0 && - !access_ok(compat_ptr(buf), len)) { - ret = -EFAULT; - goto out; - } - if (len > MAX_RW_COUNT - tot_len) - len = MAX_RW_COUNT - tot_len; - tot_len += len; - iov->iov_base = compat_ptr(buf); - iov->iov_len = (compat_size_t) len; - uvector++; - iov++; - } - ret = tot_len; - -out: - return ret; -} -#endif - static ssize_t do_iter_read(struct file *file, struct iov_iter *iter, loff_t *pos, rwf_t flags) { @@ -1068,7 +908,7 @@ ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos, } EXPORT_SYMBOL(vfs_iter_write); -ssize_t vfs_readv(struct file *file, const struct iovec __user *vec, +static ssize_t vfs_readv(struct file *file, const struct iovec __user *vec, unsigned long vlen, loff_t *pos, rwf_t flags) { struct iovec iovstack[UIO_FASTIOV]; @@ -1255,224 +1095,93 @@ SYSCALL_DEFINE6(pwritev2, unsigned long, fd, const struct iovec __user *, vec, return do_pwritev(fd, vec, vlen, pos, flags); } +/* + * Various compat syscalls. Note that they all pretend to take a native + * iovec - import_iovec will properly treat those as compat_iovecs based on + * in_compat_syscall(). + */ #ifdef CONFIG_COMPAT -static size_t compat_readv(struct file *file, - const struct compat_iovec __user *vec, - unsigned long vlen, loff_t *pos, rwf_t flags) -{ - struct iovec iovstack[UIO_FASTIOV]; - struct iovec *iov = iovstack; - struct iov_iter iter; - ssize_t ret; - - ret = compat_import_iovec(READ, vec, vlen, UIO_FASTIOV, &iov, &iter); - if (ret >= 0) { - ret = do_iter_read(file, &iter, pos, flags); - kfree(iov); - } - if (ret > 0) - add_rchar(current, ret); - inc_syscr(current); - return ret; -} - -static size_t do_compat_readv(compat_ulong_t fd, - const struct compat_iovec __user *vec, - compat_ulong_t vlen, rwf_t flags) -{ - struct fd f = fdget_pos(fd); - ssize_t ret; - loff_t pos; - - if (!f.file) - return -EBADF; - pos = f.file->f_pos; - ret = compat_readv(f.file, vec, vlen, &pos, flags); - if (ret >= 0) - f.file->f_pos = pos; - fdput_pos(f); - return ret; - -} - -COMPAT_SYSCALL_DEFINE3(readv, compat_ulong_t, fd, - const struct compat_iovec __user *,vec, - compat_ulong_t, vlen) -{ - return do_compat_readv(fd, vec, vlen, 0); -} - -static long do_compat_preadv64(unsigned long fd, - const struct compat_iovec __user *vec, - unsigned long vlen, loff_t pos, rwf_t flags) -{ - struct fd f; - ssize_t ret; - - if (pos < 0) - return -EINVAL; - f = fdget(fd); - if (!f.file) - return -EBADF; - ret = -ESPIPE; - if (f.file->f_mode & FMODE_PREAD) - ret = compat_readv(f.file, vec, vlen, &pos, flags); - fdput(f); - return ret; -} - #ifdef __ARCH_WANT_COMPAT_SYS_PREADV64 COMPAT_SYSCALL_DEFINE4(preadv64, unsigned long, fd, - const struct compat_iovec __user *,vec, + const struct iovec __user *, vec, unsigned long, vlen, loff_t, pos) { - return do_compat_preadv64(fd, vec, vlen, pos, 0); + return do_preadv(fd, vec, vlen, pos, 0); } #endif COMPAT_SYSCALL_DEFINE5(preadv, compat_ulong_t, fd, - const struct compat_iovec __user *,vec, + const struct iovec __user *, vec, compat_ulong_t, vlen, u32, pos_low, u32, pos_high) { loff_t pos = ((loff_t)pos_high << 32) | pos_low; - return do_compat_preadv64(fd, vec, vlen, pos, 0); + return do_preadv(fd, vec, vlen, pos, 0); } #ifdef __ARCH_WANT_COMPAT_SYS_PREADV64V2 COMPAT_SYSCALL_DEFINE5(preadv64v2, unsigned long, fd, - const struct compat_iovec __user *,vec, + const struct iovec __user *, vec, unsigned long, vlen, loff_t, pos, rwf_t, flags) { if (pos == -1) - return do_compat_readv(fd, vec, vlen, flags); - - return do_compat_preadv64(fd, vec, vlen, pos, flags); + return do_readv(fd, vec, vlen, flags); + return do_preadv(fd, vec, vlen, pos, flags); } #endif COMPAT_SYSCALL_DEFINE6(preadv2, compat_ulong_t, fd, - const struct compat_iovec __user *,vec, + const struct iovec __user *, vec, compat_ulong_t, vlen, u32, pos_low, u32, pos_high, rwf_t, flags) { loff_t pos = ((loff_t)pos_high << 32) | pos_low; if (pos == -1) - return do_compat_readv(fd, vec, vlen, flags); - - return do_compat_preadv64(fd, vec, vlen, pos, flags); -} - -static size_t compat_writev(struct file *file, - const struct compat_iovec __user *vec, - unsigned long vlen, loff_t *pos, rwf_t flags) -{ - struct iovec iovstack[UIO_FASTIOV]; - struct iovec *iov = iovstack; - struct iov_iter iter; - ssize_t ret; - - ret = compat_import_iovec(WRITE, vec, vlen, UIO_FASTIOV, &iov, &iter); - if (ret >= 0) { - file_start_write(file); - ret = do_iter_write(file, &iter, pos, flags); - file_end_write(file); - kfree(iov); - } - if (ret > 0) - add_wchar(current, ret); - inc_syscw(current); - return ret; -} - -static size_t do_compat_writev(compat_ulong_t fd, - const struct compat_iovec __user* vec, - compat_ulong_t vlen, rwf_t flags) -{ - struct fd f = fdget_pos(fd); - ssize_t ret; - loff_t pos; - - if (!f.file) - return -EBADF; - pos = f.file->f_pos; - ret = compat_writev(f.file, vec, vlen, &pos, flags); - if (ret >= 0) - f.file->f_pos = pos; - fdput_pos(f); - return ret; -} - -COMPAT_SYSCALL_DEFINE3(writev, compat_ulong_t, fd, - const struct compat_iovec __user *, vec, - compat_ulong_t, vlen) -{ - return do_compat_writev(fd, vec, vlen, 0); -} - -static long do_compat_pwritev64(unsigned long fd, - const struct compat_iovec __user *vec, - unsigned long vlen, loff_t pos, rwf_t flags) -{ - struct fd f; - ssize_t ret; - - if (pos < 0) - return -EINVAL; - f = fdget(fd); - if (!f.file) - return -EBADF; - ret = -ESPIPE; - if (f.file->f_mode & FMODE_PWRITE) - ret = compat_writev(f.file, vec, vlen, &pos, flags); - fdput(f); - return ret; + return do_readv(fd, vec, vlen, flags); + return do_preadv(fd, vec, vlen, pos, flags); } #ifdef __ARCH_WANT_COMPAT_SYS_PWRITEV64 COMPAT_SYSCALL_DEFINE4(pwritev64, unsigned long, fd, - const struct compat_iovec __user *,vec, + const struct iovec __user *, vec, unsigned long, vlen, loff_t, pos) { - return do_compat_pwritev64(fd, vec, vlen, pos, 0); + return do_pwritev(fd, vec, vlen, pos, 0); } #endif COMPAT_SYSCALL_DEFINE5(pwritev, compat_ulong_t, fd, - const struct compat_iovec __user *,vec, + const struct iovec __user *,vec, compat_ulong_t, vlen, u32, pos_low, u32, pos_high) { loff_t pos = ((loff_t)pos_high << 32) | pos_low; - return do_compat_pwritev64(fd, vec, vlen, pos, 0); + return do_pwritev(fd, vec, vlen, pos, 0); } #ifdef __ARCH_WANT_COMPAT_SYS_PWRITEV64V2 COMPAT_SYSCALL_DEFINE5(pwritev64v2, unsigned long, fd, - const struct compat_iovec __user *,vec, + const struct iovec __user *, vec, unsigned long, vlen, loff_t, pos, rwf_t, flags) { if (pos == -1) - return do_compat_writev(fd, vec, vlen, flags); - - return do_compat_pwritev64(fd, vec, vlen, pos, flags); + return do_writev(fd, vec, vlen, flags); + return do_pwritev(fd, vec, vlen, pos, flags); } #endif COMPAT_SYSCALL_DEFINE6(pwritev2, compat_ulong_t, fd, - const struct compat_iovec __user *,vec, + const struct iovec __user *,vec, compat_ulong_t, vlen, u32, pos_low, u32, pos_high, rwf_t, flags) { loff_t pos = ((loff_t)pos_high << 32) | pos_low; if (pos == -1) - return do_compat_writev(fd, vec, vlen, flags); - - return do_compat_pwritev64(fd, vec, vlen, pos, flags); + return do_writev(fd, vec, vlen, flags); + return do_pwritev(fd, vec, vlen, pos, flags); } - -#endif +#endif /* CONFIG_COMPAT */ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos, size_t count, loff_t max) @@ -1702,6 +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. @@ -1833,475 +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. + * 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 int generic_remap_check_len(struct inode *inode_in, - struct inode *inode_out, - loff_t pos_out, - loff_t *len, - unsigned int remap_flags) +int generic_write_check_limits(struct file *file, loff_t pos, loff_t *count) { - 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); + 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; - - 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 (!(file->f_flags & O_LARGEFILE)) + max_size = MAX_NON_LFS; - if (!same) - break; + if (unlikely(pos >= max_size)) + return -EFBIG; - srcoff += cmp_len; - destoff += cmp_len; - len -= cmp_len; - } + *count = min(*count, max_size - pos); - *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); |