diff options
| -rw-r--r-- | fs/Makefile | 3 | ||||
| -rw-r--r-- | fs/remap_range.c | 97 | ||||
| -rw-r--r-- | include/linux/fs.h | 2 | ||||
| -rw-r--r-- | mm/filemap.c | 81 |
4 files changed, 102 insertions, 81 deletions
diff --git a/fs/Makefile b/fs/Makefile index 1c7b0e3f6daa..7173350739c5 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -13,7 +13,8 @@ obj-y := open.o read_write.o file_table.o super.o \ seq_file.o xattr.o libfs.o fs-writeback.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 + fs_types.o fs_context.o fs_parser.o fsopen.o init.o \ + remap_range.o ifeq ($(CONFIG_BLOCK),y) obj-y += buffer.o block_dev.o direct-io.o mpage.o diff --git a/fs/remap_range.c b/fs/remap_range.c new file mode 100644 index 000000000000..f0a8c7065d5b --- /dev/null +++ b/fs/remap_range.c @@ -0,0 +1,97 @@ +// 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. + */ +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; +} diff --git a/include/linux/fs.h b/include/linux/fs.h index 7519ae003a08..eea754a8dd67 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3012,6 +3012,8 @@ extern ssize_t generic_write_checks(struct kiocb *, struct iov_iter *); extern int generic_remap_checks(struct file *file_in, loff_t pos_in, struct file *file_out, loff_t pos_out, loff_t *count, unsigned int remap_flags); +extern int generic_write_check_limits(struct file *file, loff_t pos, + loff_t *count); extern int generic_file_rw_checks(struct file *file_in, struct file *file_out); extern int generic_copy_file_checks(struct file *file_in, loff_t pos_in, struct file *file_out, loff_t pos_out, diff --git a/mm/filemap.c b/mm/filemap.c index 99c49eeae71b..cf20e5aeb11b 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -3098,8 +3098,7 @@ EXPORT_SYMBOL(read_cache_page_gfp); * LFS limits. If pos is under the limit it becomes a short access. If it * exceeds the limit we return -EFBIG. */ -static int generic_write_check_limits(struct file *file, loff_t pos, - loff_t *count) +int generic_write_check_limits(struct file *file, loff_t pos, loff_t *count) { struct inode *inode = file->f_mapping->host; loff_t max_size = inode->i_sb->s_maxbytes; @@ -3162,84 +3161,6 @@ inline ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from) EXPORT_SYMBOL(generic_write_checks); /* - * 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. - */ -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; -} - - -/* * Performs common checks before doing a file copy/clone * from @file_in to @file_out. */ |