Re: [PATCH v17 04/10] fs/ntfs3: Add file operations and implementation

Kari Argillander
2021-01-03T21:58:38Z

On Thu, Dec 31, 2020 at 06:23:55PM +0300, Konstantin Komarov wrote:
> This adds file operations and implementation
>
> Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
> ---
> fs/ntfs3/dir.c | 570 ++++++++
> fs/ntfs3/file.c | 1140 ++++++++++++++++
> fs/ntfs3/frecord.c | 3088 ++++++++++++++++++++++++++++++++++++++++++++
> fs/ntfs3/namei.c | 590 +++++++++
> fs/ntfs3/record.c | 614 +++++++++
> fs/ntfs3/run.c | 1254 ++++++++++++++++++
> 6 files changed, 7256 insertions(+)
> create mode 100644 fs/ntfs3/dir.c
> create mode 100644 fs/ntfs3/file.c
> create mode 100644 fs/ntfs3/frecord.c
> create mode 100644 fs/ntfs3/namei.c
> create mode 100644 fs/ntfs3/record.c
> create mode 100644 fs/ntfs3/run.c
>
> diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c

> +int ntfs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
> +{
> + return generic_file_fsync(filp, start, end, datasync);
> +}

Do we have a reson why we implement this if we just use generic. Isn't
it more clear if we use generic fsync straight away?

> +static long ntfs_fallocate(struct file *file, int mode, loff_t vbo, loff_t len)
> +{

> + /* Return error if mode is not supported */
> + if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
> + FALLOC_FL_COLLAPSE_RANGE))
> + return -EOPNOTSUPP;

> +
> + if (mode & FALLOC_FL_PUNCH_HOLE) {

> + } else if (mode & FALLOC_FL_COLLAPSE_RANGE) {

> + } else {
> + /*
> + * normal file: allocate clusters, do not change 'valid' size
> + */
> + err = ntfs_set_size(inode, max(end, i_size));
> + if (err)
> + goto out;
> +
> + if (is_sparsed(ni) || is_compressed(ni)) {
> + CLST vcn_v = ni->i_valid >> sbi->cluster_bits;
> + CLST vcn = vbo >> sbi->cluster_bits;
> + CLST cend = bytes_to_cluster(sbi, end);
> + CLST lcn, clen;
> + bool new;
> +
> + /*
> + * allocate but not zero new clusters (see below comments)
> + * this breaks security (one can read unused on-disk areas)
> + * zeroing these clusters may be too long
> + * may be we should check here for root rights?
> + */
> + for (; vcn < cend; vcn += clen) {
> + err = attr_data_get_block(ni, vcn, cend - vcn,
> + &lcn, &clen, &new);
> + if (err)
> + goto out;
> + if (!new || vcn >= vcn_v)
> + continue;
> +
> + /*
> + * Unwritten area
> + * NTFS is not able to store several unwritten areas
> + * Activate 'ntfs_sparse_cluster' to zero new allocated clusters
> + *
> + * Dangerous in case:
> + * 1G of sparsed clusters + 1 cluster of data =>
> + * valid_size == 1G + 1 cluster
> + * fallocate(1G) will zero 1G and this can be very long
> + * xfstest 016/086 will fail whithout 'ntfs_sparse_cluster'
> + */
> + /*ntfs_sparse_cluster(inode, NULL, vcn,
> + * min(vcn_v - vcn, clen));
> + */
> + }
> + }
> +
> + if (mode & FALLOC_FL_KEEP_SIZE) {

Isn't this hole else already (mode & FALLOC_FL_KEEP_SIZE?

> + ni_lock(ni);
> + /*true - keep preallocated*/
> + err = attr_set_size(ni, ATTR_DATA, NULL, 0,
> + &ni->file.run, i_size, &ni->i_valid,
> + true, NULL);
> + ni_unlock(ni);
> + }
> + }
> +
> + if (!err) {
> + inode->i_ctime = inode->i_mtime = current_time(inode);
> + mark_inode_dirty(inode);
> + }
> +out:
> + if (err == -EFBIG)
> + err = -ENOSPC;
> +
> + inode_unlock(inode);
> + return err;
> +}

> diff --git a/fs/ntfs3/namei.c b/fs/ntfs3/namei.c

> +int mi_get(struct ntfs_sb_info *sbi, CLST rno, struct mft_inode **mi)
> +{
> + int err;
> + struct mft_inode *m = ntfs_alloc(sizeof(struct mft_inode), 1);
> +
> + if (!m)
> + return -ENOMEM;
> +
> + err = mi_init(m, sbi, rno);

If error happend should we just free end exit. Now we call mi_put() to
clean up.

> + if (!err)
> + err = mi_read(m, false);
> +
> + if (err) {
> + mi_put(m);
> + return err;
> + }
> +
> + *mi = m;
> + return 0;
> +}

> +struct ATTRIB *mi_enum_attr(struct mft_inode *mi, struct ATTRIB *attr)
> +{
> + const struct MFT_REC *rec = mi->mrec;
> + u32 used = le32_to_cpu(rec->used);
> + u32 t32, off, asize;
> + u16 t16;
> +
> + if (!attr) {
> + u32 total = le32_to_cpu(rec->total);
> +
> + off = le16_to_cpu(rec->attr_off);
> +
> + if (used > total)
> + goto out;
> +
> + if (off >= used || off < MFTRECORD_FIXUP_OFFSET_1 ||
> + !IsDwordAligned(off)) {
> + goto out;
> + }
> +
> + /* Skip non-resident records */
> + if (!is_rec_inuse(rec))
> + goto out;
> +
> + attr = Add2Ptr(rec, off);
> + } else {
> + /* Check if input attr inside record */
> + off = PtrOffset(rec, attr);
> + if (off >= used)
> + goto out;
> +
> + asize = le32_to_cpu(attr->size);
> + if (asize < SIZEOF_RESIDENT)
> + goto out;
> +
> + attr = Add2Ptr(attr, asize);
> + off += asize;
> + }
> +
> + asize = le32_to_cpu(attr->size);
> +
> + /* Can we use the first field (attr->type) */
> + if (off + 8 > used) {
> + static_assert(QuadAlign(sizeof(enum ATTR_TYPE)) == 8);
> + goto out;
> + }
> +
> + if (attr->type == ATTR_END) {
> + if (used != off + 8)
> + goto out;

This if is not needed if there is return NULL after. But return
NULL might also be bug.

> + return NULL;
> + }
> +
> + t32 = le32_to_cpu(attr->type);
> + if ((t32 & 0xf) || (t32 > 0x100))
> + goto out;
> +
> + /* Check boundary */
> + if (off + asize > used)
> + goto out;
> +
> + /* Check size of attribute */
> + if (!attr->non_res) {
> + if (asize < SIZEOF_RESIDENT)
> + goto out;
> +
> + t16 = le16_to_cpu(attr->res.data_off);
> +
> + if (t16 > asize)
> + goto out;
> +
> + t32 = le32_to_cpu(attr->res.data_size);
> + if (t16 + t32 > asize)
> + goto out;
> +
> + return attr;
> + }
> +
> + /* Check some nonresident fields */
> + if (attr->name_len &&
> + le16_to_cpu(attr->name_off) + sizeof(short) * attr->name_len >
> + le16_to_cpu(attr->nres.run_off)) {
> + goto out;
> + }
> +
> + if (attr->nres.svcn || !is_attr_ext(attr)) {
> + if (asize + 8 < SIZEOF_NONRESIDENT)
> + goto out;
> +
> + if (attr->nres.c_unit)
> + goto out;
> + } else if (asize + 8 < SIZEOF_NONRESIDENT_EX)
> + goto out;
> +
> + return attr;
> +
> +out:
> + return NULL;
> +}

> diff --git a/fs/ntfs3/run.c b/fs/ntfs3/run.c

> +static inline int run_packed_size(const s64 *n)
> +{
> +#ifdef __BIG_ENDIAN

These are whole functions with ifdef. It would be maybe more clear
that there really is whole functions to both endiand.

> + const u8 *p = (const u8 *)n + sizeof(*n) - 1;
> +
> + if (*n >= 0) {
> + if (p[-7] || p[-6] || p[-5] || p[-4])
> + p -= 4;
> + if (p[-3] || p[-2])
> + p -= 2;
> + if (p[-1])
> + p -= 1;
> + if (p[0] & 0x80)
> + p -= 1;
> + } else {
> + if (p[-7] != 0xff || p[-6] != 0xff || p[-5] != 0xff ||
> + p[-4] != 0xff)
> + p -= 4;
> + if (p[-3] != 0xff || p[-2] != 0xff)
> + p -= 2;
> + if (p[-1] != 0xff)
> + p -= 1;
> + if (!(p[0] & 0x80))
> + p -= 1;
> + }
> + return (const u8 *)n + sizeof(*n) - p;

}
#else
static inline int run_packed_size(const s64 *n)
{

Something like this.

> + const u8 *p = (const u8 *)n;
> +
> + if (*n >= 0) {
> + if (p[7] || p[6] || p[5] || p[4])
> + p += 4;
> + if (p[3] || p[2])
> + p += 2;
> + if (p[1])
> + p += 1;
> + if (p[0] & 0x80)
> + p += 1;
> + } else {
> + if (p[7] != 0xff || p[6] != 0xff || p[5] != 0xff ||
> + p[4] != 0xff)
> + p += 4;
> + if (p[3] != 0xff || p[2] != 0xff)
> + p += 2;
> + if (p[1] != 0xff)
> + p += 1;
> + if (!(p[0] & 0x80))
> + p += 1;
> + }
> +
> + return 1 + p - (const u8 *)n;
> +#endif
> +}
> +
> +/*
> + * run_pack
> + *
> + * packs runs into buffer
> + * packed_vcns - how much runs we have packed
> + * packed_size - how much bytes we have used run_buf
> + */
> +int run_pack(const struct runs_tree *run, CLST svcn, CLST len, u8 *run_buf,
> + u32 run_buf_size, CLST *packed_vcns)
> +{
> + CLST next_vcn, vcn, lcn;
> + CLST prev_lcn = 0;
> + CLST evcn1 = svcn + len;
> + int packed_size = 0;
> + size_t i;
> + bool ok;
> + s64 dlcn, len64;
> + int offset_size, size_size, t;
> + const u8 *p;
> +
> + next_vcn = vcn = svcn;
> +
> + *packed_vcns = 0;
> +
> + if (!len)
> + goto out;
> +
> + ok = run_lookup_entry(run, vcn, &lcn, &len, &i);
> +
> + if (!ok)
> + goto error;
> +
> + if (next_vcn != vcn)
> + goto error;
> +
> + for (;;) {
> + /* offset of current fragment relatively to previous fragment */
> + dlcn = 0;

This dlcn

> + next_vcn = vcn + len;
> +
> + if (next_vcn > evcn1)
> + len = evcn1 - vcn;
> +
> + /*
> + * mirror of len, but signed, because run_packed_size()
> + * works with signed int only
> + */
> + len64 = len;
> +
> + /* how much bytes is packed len64 */
> + size_size = run_packed_size(&len64);

Does (s64 *)&len work just fine?

> +
> + /* offset_size - how much bytes is packed dlcn */
> + if (lcn == SPARSE_LCN) {
> + offset_size = 0;

dlcn might be better to live here?

> + } else {
> + /* NOTE: lcn can be less than prev_lcn! */
> + dlcn = (s64)lcn - prev_lcn;
> + offset_size = run_packed_size(&dlcn);
> + prev_lcn = lcn;
> + }
> +
> + t = run_buf_size - packed_size - 2 - offset_size;
> + if (t <= 0)
> + goto out;
> +
> + /* can we store this entire run */
> + if (t < size_size)
> + goto out;
> +
> + if (run_buf) {
> + p = (u8 *)&len64;
> +
> + /* pack run header */
> + run_buf[0] = ((u8)(size_size | (offset_size << 4)));
> + run_buf += 1;
> +
> + /* Pack the length of run */
> + switch (size_size) {
> +#ifdef __BIG_ENDIAN
> + case 8:
> + run_buf[7] = p[0];
> + fallthrough;
> + case 7:
> + run_buf[6] = p[1];
> + fallthrough;
> + case 6:
> + run_buf[5] = p[2];
> + fallthrough;
> + case 5:
> + run_buf[4] = p[3];
> + fallthrough;
> + case 4:
> + run_buf[3] = p[4];
> + fallthrough;
> + case 3:
> + run_buf[2] = p[5];
> + fallthrough;
> + case 2:
> + run_buf[1] = p[6];
> + fallthrough;
> + case 1:
> + run_buf[0] = p[7];
> +#else
> + case 8:
> + run_buf[7] = p[7];
> + fallthrough;
> + case 7:
> + run_buf[6] = p[6];
> + fallthrough;
> + case 6:
> + run_buf[5] = p[5];
> + fallthrough;
> + case 5:
> + run_buf[4] = p[4];
> + fallthrough;
> + case 4:
> + run_buf[3] = p[3];
> + fallthrough;
> + case 3:
> + run_buf[2] = p[2];
> + fallthrough;
> + case 2:
> + run_buf[1] = p[1];
> + fallthrough;
> + case 1:
> + run_buf[0] = p[0];
> +#endif
> + }

Why is this not own function? We use this like 5 places. Also isn't
little endian just memcopy()

> +
> + run_buf += size_size;
> + p = (u8 *)&dlcn;

I think that when we have function for that switch tmp p is not needed
anymore.

> +
> + /* Pack the offset from previous lcn */
> + switch (offset_size) {
> +#ifdef __BIG_ENDIAN
> + case 8:
> + run_buf[7] = p[0];
> + fallthrough;
> + case 7:
> + run_buf[6] = p[1];
> + fallthrough;
> + case 6:
> + run_buf[5] = p[2];
> + fallthrough;
> + case 5:
> + run_buf[4] = p[3];
> + fallthrough;
> + case 4:
> + run_buf[3] = p[4];
> + fallthrough;
> + case 3:
> + run_buf[2] = p[5];
> + fallthrough;
> + case 2:
> + run_buf[1] = p[6];
> + fallthrough;
> + case 1:
> + run_buf[0] = p[7];
> +#else
> + case 8:
> + run_buf[7] = p[7];
> + fallthrough;
> + case 7:
> + run_buf[6] = p[6];
> + fallthrough;
> + case 6:
> + run_buf[5] = p[5];
> + fallthrough;
> + case 5:
> + run_buf[4] = p[4];
> + fallthrough;
> + case 4:
> + run_buf[3] = p[3];
> + fallthrough;
> + case 3:
> + run_buf[2] = p[2];
> + fallthrough;
> + case 2:
> + run_buf[1] = p[1];
> + fallthrough;
> + case 1:
> + run_buf[0] = p[0];
> +#endif
> + }

> +int run_get_highest_vcn(CLST vcn, const u8 *run_buf, u64 *highest_vcn)
> +{

> + /* skip size_size */
> + run += size_size;
> +
> + if (!len)
> + goto error;
> +
> + run += offset_size;

Can this be straight
run += size_size + offset_size;

> +
> +#ifdef NTFS3_64BIT_CLUSTER
> + if ((vcn >> 32) || (len >> 32))
> + goto error;
> +#endif
> + vcn64 += len;
> + }
> +
> + *highest_vcn = vcn64 - 1;
> + return 0;
> +}