f2fs: add F2FS_IOC_SEC_TRIM_FILE ioctl

Added a new ioctl to send discard commands or/and zero out
to selected data area of a regular file for security reason.

The way of handling range.len of F2FS_IOC_SEC_TRIM_FILE:
1. Added -1 value support for range.len to secure trim the whole blocks
   starting from range.start regardless of i_size.
2. If the end of the range passes over the end of file, it means until
   the end of file (i_size).
3. ignored the case of that range.len is zero to prevent the function
   from making end_addr zero and triggering different behaviour of
   the function.

Signed-off-by: Daeho Jeong <daehojeong@google.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 163fd5f..3d9dd32 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -430,6 +430,8 @@ 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_SEC_TRIM_FILE         _IOW(F2FS_IOCTL_MAGIC, 20,      \
+                                               struct f2fs_sectrim_range)
 
 /*
  * should be same as XFS_IOC_GOINGDOWN.
@@ -442,6 +444,13 @@ static inline bool __has_cursum_space(struct f2fs_journal *journal,
 #define F2FS_GOING_DOWN_METAFLUSH      0x3     /* going down with meta flush */
 #define F2FS_GOING_DOWN_NEED_FSCK      0x4     /* going down to trigger fsck */
 
+/*
+ * Flags used by F2FS_IOC_SEC_TRIM_FILE
+ */
+#define F2FS_TRIM_FILE_DISCARD         0x1     /* send discard command */
+#define F2FS_TRIM_FILE_ZEROOUT         0x2     /* zero out */
+#define F2FS_TRIM_FILE_MASK            0x3
+
 struct f2fs_gc_range {
        u32 sync;
        u64 start;
@@ -465,6 +474,12 @@ struct f2fs_flush_device {
        u32 segments;           /* # of segments to flush */
 };
 
+struct f2fs_sectrim_range {
+       u64 start;
+       u64 len;
+       u64 flags;
+};
+
 /* for inline stuff */
 #define DEF_INLINE_RESERVED_SIZE       1
 static inline int get_extra_isize(struct inode *inode);

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 521987c..cc7f567 100644 (file)
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -21,6 +21,7 @@
 #include <linux/uuid.h>
 #include <linux/file.h>
 #include <linux/nls.h>
+#include <linux/sched/signal.h>
 
 #include "f2fs.h"
 #include "node.h"
@@ -3759,6 +3760,193 @@ out:
        return ret;
 }
 
+static int f2fs_secure_erase(struct block_device *bdev, struct inode *inode,
+               pgoff_t off, block_t block, block_t len, u32 flags)
+{
+       struct request_queue *q = bdev_get_queue(bdev);
+       sector_t sector = SECTOR_FROM_BLOCK(block);
+       sector_t nr_sects = SECTOR_FROM_BLOCK(len);
+       int ret = 0;
+
+       if (!q)
+               return -ENXIO;
+
+       if (flags & F2FS_TRIM_FILE_DISCARD)
+               ret = blkdev_issue_discard(bdev, sector, nr_sects, GFP_NOFS,
+                                               blk_queue_secure_erase(q) ?
+                                               BLKDEV_DISCARD_SECURE : 0);
+
+       if (!ret && (flags & F2FS_TRIM_FILE_ZEROOUT)) {
+               if (IS_ENCRYPTED(inode))
+                       ret = fscrypt_zeroout_range(inode, off, block, len);
+               else
+                       ret = blkdev_issue_zeroout(bdev, sector, nr_sects,
+                                       GFP_NOFS, 0);
+       }
+
+       return ret;
+}
+
+static int f2fs_sec_trim_file(struct file *filp, unsigned long arg)
+{
+       struct inode *inode = file_inode(filp);
+       struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+       struct address_space *mapping = inode->i_mapping;
+       struct block_device *prev_bdev = NULL;
+       struct f2fs_sectrim_range range;
+       pgoff_t index, pg_end, prev_index = 0;
+       block_t prev_block = 0, len = 0;
+       loff_t end_addr;
+       bool to_end = false;
+       int ret = 0;
+
+       if (!(filp->f_mode & FMODE_WRITE))
+               return -EBADF;
+
+       if (copy_from_user(&range, (struct f2fs_sectrim_range __user *)arg,
+                               sizeof(range)))
+               return -EFAULT;
+
+       if (range.flags == 0 || (range.flags & ~F2FS_TRIM_FILE_MASK) ||
+                       !S_ISREG(inode->i_mode))
+               return -EINVAL;
+
+       if (((range.flags & F2FS_TRIM_FILE_DISCARD) &&
+                       !f2fs_hw_support_discard(sbi)) ||
+                       ((range.flags & F2FS_TRIM_FILE_ZEROOUT) &&
+                        IS_ENCRYPTED(inode) && f2fs_is_multi_device(sbi)))
+               return -EOPNOTSUPP;
+
+       file_start_write(filp);
+       inode_lock(inode);
+
+       if (f2fs_is_atomic_file(inode) || f2fs_compressed_file(inode) ||
+                       range.start >= inode->i_size) {
+               ret = -EINVAL;
+               goto err;
+       }
+
+       if (range.len == 0)
+               goto err;
+
+       if (inode->i_size - range.start > range.len) {
+               end_addr = range.start + range.len;
+       } else {
+               end_addr = range.len == (u64)-1 ?
+                       sbi->sb->s_maxbytes : inode->i_size;
+               to_end = true;
+       }
+
+       if (!IS_ALIGNED(range.start, F2FS_BLKSIZE) ||
+                       (!to_end && !IS_ALIGNED(end_addr, F2FS_BLKSIZE))) {
+               ret = -EINVAL;
+               goto err;
+       }
+
+       index = F2FS_BYTES_TO_BLK(range.start);
+       pg_end = DIV_ROUND_UP(end_addr, F2FS_BLKSIZE);
+
+       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_range(mapping, range.start,
+                       to_end ? LLONG_MAX : end_addr - 1);
+       if (ret)
+               goto out;
+
+       truncate_inode_pages_range(mapping, range.start,
+                       to_end ? -1 : end_addr - 1);
+
+       while (index < pg_end) {
+               struct dnode_of_data dn;
+               pgoff_t end_offset, count;
+               int i;
+
+               set_new_dnode(&dn, inode, NULL, NULL, 0);
+               ret = f2fs_get_dnode_of_data(&dn, index, LOOKUP_NODE);
+               if (ret) {
+                       if (ret == -ENOENT) {
+                               index = f2fs_get_next_page_offset(&dn, index);
+                               continue;
+                       }
+                       goto out;
+               }
+
+               end_offset = ADDRS_PER_PAGE(dn.node_page, inode);
+               count = min(end_offset - dn.ofs_in_node, pg_end - index);
+               for (i = 0; i < count; i++, index++, dn.ofs_in_node++) {
+                       struct block_device *cur_bdev;
+                       block_t blkaddr = f2fs_data_blkaddr(&dn);
+
+                       if (!__is_valid_data_blkaddr(blkaddr))
+                               continue;
+
+                       if (!f2fs_is_valid_blkaddr(sbi, blkaddr,
+                                               DATA_GENERIC_ENHANCE)) {
+                               ret = -EFSCORRUPTED;
+                               f2fs_put_dnode(&dn);
+                               goto out;
+                       }
+
+                       cur_bdev = f2fs_target_device(sbi, blkaddr, NULL);
+                       if (f2fs_is_multi_device(sbi)) {
+                               int di = f2fs_target_device_index(sbi, blkaddr);
+
+                               blkaddr -= FDEV(di).start_blk;
+                       }
+
+                       if (len) {
+                               if (prev_bdev == cur_bdev &&
+                                               index == prev_index + len &&
+                                               blkaddr == prev_block + len) {
+                                       len++;
+                               } else {
+                                       ret = f2fs_secure_erase(prev_bdev,
+                                               inode, prev_index, prev_block,
+                                               len, range.flags);
+                                       if (ret) {
+                                               f2fs_put_dnode(&dn);
+                                               goto out;
+                                       }
+
+                                       len = 0;
+                               }
+                       }
+
+                       if (!len) {
+                               prev_bdev = cur_bdev;
+                               prev_index = index;
+                               prev_block = blkaddr;
+                               len = 1;
+                       }
+               }
+
+               f2fs_put_dnode(&dn);
+
+               if (fatal_signal_pending(current)) {
+                       ret = -EINTR;
+                       goto out;
+               }
+               cond_resched();
+       }
+
+       if (len)
+               ret = f2fs_secure_erase(prev_bdev, inode, prev_index,
+                               prev_block, len, range.flags);
+out:
+       up_write(&F2FS_I(inode)->i_mmap_sem);
+       up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
+err:
+       inode_unlock(inode);
+       file_end_write(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)))))
@@ -3845,6 +4033,8 @@ 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_SEC_TRIM_FILE:
+               return f2fs_sec_trim_file(filp, arg);
        default:
                return -ENOTTY;
        }
@@ -4014,6 +4204,7 @@ 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_SEC_TRIM_FILE:
                break;
        default:
                return -ENOIOCTLCMD;