Messages in this thread | | | From | Daeho Jeong <> | Date | Fri, 12 Jun 2020 07:49:12 +0900 | Subject | Re: [f2fs-dev] [PATCH v2] f2fs: add F2FS_IOC_SEC_TRIM_FILE ioctl |
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2020년 6월 12일 (금) 오전 1:27, Eric Biggers <ebiggers@kernel.org>님이 작성: > > On Thu, Jun 11, 2020 at 12:16:52PM +0900, Daeho Jeong wrote: > > + 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 = f2fs_secure_erase(prev_bdev, > > + prev_block, len, flags); > > + if (ret) > > + goto out; > > + > > + len = 0; > > + } > > + } > > + > > + if (!len) { > > + prev_bdev = cur_bdev; > > + prev_block = blkaddr; > > + len = 1; > > + } > > + } > > + > > + f2fs_put_dnode(&dn); > > + } > > This loop processes the entire file, which may be very large. So it could take > a very long time to execute. > > It should at least use the following to make the task killable and preemptible: > > if (fatal_signal_pending(current)) { > err = -EINTR; > goto out; > } > cond_resched(); >
Good point!
> Also, perhaps this ioctl should be made incremental, i.e. take in an > (offset, length) like pwrite()? > > - Eric
Discard and Zeroing will be treated in a unit of block, which is 4KB in F2FS case. Do you really need the (offset, length) option here even if the unit is a 4KB block? I guess this option might make the user even inconvenienced to use this ioctl, because they have to bear 4KB alignment in mind.
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