On 2020/6/5 12:27, Daeho Jeong wrote: > From: Daeho Jeong <[email protected]> > > Added a new ioctl to send discard commands to whole data area of > a regular file for security reason.
I guess this interface is introduced for security key destruction, if I'm right, however, IIRC, discard(erase) semantics in eMMC/UFS spec won't guarantee that data which was discard could be zeroed out, so after discard, the key still have risk of exposure. So instead, should we use sb_issue_zeroout()? Thanks, > > Signed-off-by: Daeho Jeong <[email protected]> > --- > fs/f2fs/f2fs.h | 1 + > fs/f2fs/file.c | 129 +++++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 130 insertions(+) > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index c812fb8e2d9c..9ae81d0fefa0 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -434,6 +434,7 @@ static inline bool __has_cursum_space(struct f2fs_journal > *journal, > _IOR(F2FS_IOCTL_MAGIC, 18, __u64) > #define F2FS_IOC_RESERVE_COMPRESS_BLOCKS \ > _IOR(F2FS_IOCTL_MAGIC, 19, __u64) > +#define F2FS_IOC_TRIM_FILE _IO(F2FS_IOCTL_MAGIC, 20) > > #define F2FS_IOC_GET_VOLUME_NAME FS_IOC_GETFSLABEL > #define F2FS_IOC_SET_VOLUME_NAME FS_IOC_SETFSLABEL > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > index dfa1ac2d751a..58507bb5649c 100644 > --- a/fs/f2fs/file.c > +++ b/fs/f2fs/file.c > @@ -3749,6 +3749,132 @@ static int f2fs_reserve_compress_blocks(struct file > *filp, unsigned long arg) > return ret; > } > > +static int f2fs_trim_file(struct file *filp) > +{ > + struct inode *inode = file_inode(filp); > + struct f2fs_sb_info *sbi = F2FS_I_SB(inode); > + struct address_space *mapping = inode->i_mapping; > + struct bio *bio = NULL; > + struct block_device *prev_bdev = NULL; > + loff_t file_size; > + pgoff_t index, pg_start = 0, pg_end; > + block_t prev_block = 0, len = 0; > + int ret = 0; > + > + if (!f2fs_hw_support_discard(sbi)) > + return -EOPNOTSUPP; > + > + if (!S_ISREG(inode->i_mode) || f2fs_is_atomic_file(inode) || > + f2fs_compressed_file(inode)) > + return -EINVAL; > + > + if (f2fs_readonly(sbi->sb)) > + return -EROFS; > + > + ret = mnt_want_write_file(filp); > + if (ret) > + return ret; > + > + inode_lock(inode); > + > + file_size = i_size_read(inode); > + if (!file_size) > + goto err; > + pg_end = (pgoff_t)round_up(file_size, PAGE_SIZE) >> PAGE_SHIFT; > + > + ret = f2fs_convert_inline_inode(inode); > + if (ret) > + goto err; > + > + down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); > + down_write(&F2FS_I(inode)->i_mmap_sem); > + > + ret = filemap_write_and_wait(mapping); > + if (ret) > + goto out; > + > + truncate_inode_pages(mapping, 0); > + > + for (index = pg_start; index < pg_end;) { > + struct dnode_of_data dn; > + unsigned int end_offset; > + > + set_new_dnode(&dn, inode, NULL, NULL, 0); > + ret = f2fs_get_dnode_of_data(&dn, index, LOOKUP_NODE); > + if (ret) > + goto out; > + > + end_offset = ADDRS_PER_PAGE(dn.node_page, inode); > + if (pg_end < end_offset + index) > + end_offset = pg_end - index; > + > + for (; dn.ofs_in_node < end_offset; > + dn.ofs_in_node++, index++) { > + struct block_device *cur_bdev; > + block_t blkaddr = f2fs_data_blkaddr(&dn); > + > + if (__is_valid_data_blkaddr(blkaddr)) { > + if (!f2fs_is_valid_blkaddr(F2FS_I_SB(inode), > + blkaddr, DATA_GENERIC_ENHANCE)) { > + ret = -EFSCORRUPTED; > + goto out; > + } > + } else > + continue; > + > + cur_bdev = f2fs_target_device(sbi, blkaddr, NULL); > + if (f2fs_is_multi_device(sbi)) { > + int i = f2fs_target_device_index(sbi, blkaddr); > + > + blkaddr -= FDEV(i).start_blk; > + } > + > + if (len) { > + if (prev_bdev == cur_bdev && > + blkaddr == prev_block + len) { > + len++; > + } else { > + ret = __blkdev_issue_discard(prev_bdev, > + SECTOR_FROM_BLOCK(prev_block), > + SECTOR_FROM_BLOCK(len), > + GFP_NOFS, 0, &bio); > + if (ret) > + goto out; > +> + len = 0; > + } > + } > + > + if (!len) { > + prev_bdev = cur_bdev; > + prev_block = blkaddr; > + len = 1; > + } > + } > + > + f2fs_put_dnode(&dn); > + } > + > + if (len) > + ret = __blkdev_issue_discard(prev_bdev, > + SECTOR_FROM_BLOCK(prev_block), > + SECTOR_FROM_BLOCK(len), > + GFP_NOFS, 0, &bio); > +out: > + if (bio) { > + ret = submit_bio_wait(bio); > + bio_put(bio); > + } > + > + up_write(&F2FS_I(inode)->i_mmap_sem); > + up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); > +err: > + inode_unlock(inode); > + mnt_drop_write_file(filp); > + > + return ret; > +} > + > long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) > { > if (unlikely(f2fs_cp_error(F2FS_I_SB(file_inode(filp))))) > @@ -3835,6 +3961,8 @@ long f2fs_ioctl(struct file *filp, unsigned int cmd, > unsigned long arg) > return f2fs_release_compress_blocks(filp, arg); > case F2FS_IOC_RESERVE_COMPRESS_BLOCKS: > return f2fs_reserve_compress_blocks(filp, arg); > + case F2FS_IOC_TRIM_FILE: > + return f2fs_trim_file(filp); > default: > return -ENOTTY; > } > @@ -4004,6 +4132,7 @@ long f2fs_compat_ioctl(struct file *file, unsigned int > cmd, unsigned long arg) > case F2FS_IOC_GET_COMPRESS_BLOCKS: > case F2FS_IOC_RELEASE_COMPRESS_BLOCKS: > case F2FS_IOC_RESERVE_COMPRESS_BLOCKS: > + case F2FS_IOC_TRIM_FILE: > break; > default: > return -ENOIOCTLCMD; > _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
