diff options
Diffstat (limited to 'fs/ntfs/runlist.c')
| -rw-r--r-- | fs/ntfs/runlist.c | 167 |
1 files changed, 117 insertions, 50 deletions
diff --git a/fs/ntfs/runlist.c b/fs/ntfs/runlist.c index 396d767..758855b 100644 --- a/fs/ntfs/runlist.c +++ b/fs/ntfs/runlist.c @@ -1048,10 +1048,17 @@ static inline int ntfs_get_nr_significant_bytes(const s64 n) * ntfs_get_size_for_mapping_pairs - get bytes needed for mapping pairs array * @vol: ntfs volume (needed for the ntfs version) * @rl: locked runlist to determine the size of the mapping pairs of - * @start_vcn: vcn at which to start the mapping pairs array + * @first_vcn: first vcn which to include in the mapping pairs array + * @last_vcn: last vcn which to include in the mapping pairs array * * Walk the locked runlist @rl and calculate the size in bytes of the mapping - * pairs array corresponding to the runlist @rl, starting at vcn @start_vcn. + * pairs array corresponding to the runlist @rl, starting at vcn @first_vcn and + * finishing with vcn @last_vcn. + * + * A @last_vcn of -1 means end of runlist and in that case the size of the + * mapping pairs array corresponding to the runlist starting at vcn @first_vcn + * and finishing at the end of the runlist is determined. + * * This for example allows us to allocate a buffer of the right size when * building the mapping pairs array. * @@ -1067,34 +1074,50 @@ static inline int ntfs_get_nr_significant_bytes(const s64 n) * remains locked throughout, and is left locked upon return. */ int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol, - const runlist_element *rl, const VCN start_vcn) + const runlist_element *rl, const VCN first_vcn, + const VCN last_vcn) { LCN prev_lcn; int rls; + BOOL the_end = FALSE; - BUG_ON(start_vcn < 0); + BUG_ON(first_vcn < 0); + BUG_ON(last_vcn < -1); + BUG_ON(last_vcn >= 0 && first_vcn > last_vcn); if (!rl) { - BUG_ON(start_vcn); + BUG_ON(first_vcn); + BUG_ON(last_vcn > 0); return 1; } - /* Skip to runlist element containing @start_vcn. */ - while (rl->length && start_vcn >= rl[1].vcn) + /* Skip to runlist element containing @first_vcn. */ + while (rl->length && first_vcn >= rl[1].vcn) rl++; - if ((!rl->length && start_vcn > rl->vcn) || start_vcn < rl->vcn) + if (unlikely((!rl->length && first_vcn > rl->vcn) || + first_vcn < rl->vcn)) return -EINVAL; prev_lcn = 0; /* Always need the termining zero byte. */ rls = 1; /* Do the first partial run if present. */ - if (start_vcn > rl->vcn) { - s64 delta; + if (first_vcn > rl->vcn) { + s64 delta, length = rl->length; /* We know rl->length != 0 already. */ - if (rl->length < 0 || rl->lcn < LCN_HOLE) + if (unlikely(length < 0 || rl->lcn < LCN_HOLE)) goto err_out; - delta = start_vcn - rl->vcn; + /* + * If @stop_vcn is given and finishes inside this run, cap the + * run length. + */ + if (unlikely(last_vcn >= 0 && rl[1].vcn > last_vcn)) { + s64 s1 = last_vcn + 1; + if (unlikely(rl[1].vcn > s1)) + length = s1 - rl->vcn; + the_end = TRUE; + } + delta = first_vcn - rl->vcn; /* Header byte + length. */ - rls += 1 + ntfs_get_nr_significant_bytes(rl->length - delta); + rls += 1 + ntfs_get_nr_significant_bytes(length - delta); /* * If the logical cluster number (lcn) denotes a hole and we * are on NTFS 3.0+, we don't store it at all, i.e. we need @@ -1102,9 +1125,9 @@ int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol, * Note: this assumes that on NTFS 1.2-, holes are stored with * an lcn of -1 and not a delta_lcn of -1 (unless both are -1). */ - if (rl->lcn >= 0 || vol->major_ver < 3) { + if (likely(rl->lcn >= 0 || vol->major_ver < 3)) { prev_lcn = rl->lcn; - if (rl->lcn >= 0) + if (likely(rl->lcn >= 0)) prev_lcn += delta; /* Change in lcn. */ rls += ntfs_get_nr_significant_bytes(prev_lcn); @@ -1113,11 +1136,23 @@ int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol, rl++; } /* Do the full runs. */ - for (; rl->length; rl++) { - if (rl->length < 0 || rl->lcn < LCN_HOLE) + for (; rl->length && !the_end; rl++) { + s64 length = rl->length; + + if (unlikely(length < 0 || rl->lcn < LCN_HOLE)) goto err_out; + /* + * If @stop_vcn is given and finishes inside this run, cap the + * run length. + */ + if (unlikely(last_vcn >= 0 && rl[1].vcn > last_vcn)) { + s64 s1 = last_vcn + 1; + if (unlikely(rl[1].vcn > s1)) + length = s1 - rl->vcn; + the_end = TRUE; + } /* Header byte + length. */ - rls += 1 + ntfs_get_nr_significant_bytes(rl->length); + rls += 1 + ntfs_get_nr_significant_bytes(length); /* * If the logical cluster number (lcn) denotes a hole and we * are on NTFS 3.0+, we don't store it at all, i.e. we need @@ -1125,7 +1160,7 @@ int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol, * Note: this assumes that on NTFS 1.2-, holes are stored with * an lcn of -1 and not a delta_lcn of -1 (unless both are -1). */ - if (rl->lcn >= 0 || vol->major_ver < 3) { + if (likely(rl->lcn >= 0 || vol->major_ver < 3)) { /* Change in lcn. */ rls += ntfs_get_nr_significant_bytes(rl->lcn - prev_lcn); @@ -1168,7 +1203,7 @@ static inline int ntfs_write_significant_bytes(s8 *dst, const s8 *dst_max, i = 0; do { - if (dst > dst_max) + if (unlikely(dst > dst_max)) goto err_out; *dst++ = l & 0xffll; l >>= 8; @@ -1177,12 +1212,12 @@ static inline int ntfs_write_significant_bytes(s8 *dst, const s8 *dst_max, j = (n >> 8 * (i - 1)) & 0xff; /* If the sign bit is wrong, we need an extra byte. */ if (n < 0 && j >= 0) { - if (dst > dst_max) + if (unlikely(dst > dst_max)) goto err_out; i++; *dst = (s8)-1; } else if (n > 0 && j < 0) { - if (dst > dst_max) + if (unlikely(dst > dst_max)) goto err_out; i++; *dst = (s8)0; @@ -1198,13 +1233,18 @@ err_out: * @dst: destination buffer to which to write the mapping pairs array * @dst_len: size of destination buffer @dst in bytes * @rl: locked runlist for which to build the mapping pairs array - * @start_vcn: vcn at which to start the mapping pairs array + * @first_vcn: first vcn which to include in the mapping pairs array + * @last_vcn: last vcn which to include in the mapping pairs array * @stop_vcn: first vcn outside destination buffer on success or -ENOSPC * * Create the mapping pairs array from the locked runlist @rl, starting at vcn - * @start_vcn and save the array in @dst. @dst_len is the size of @dst in - * bytes and it should be at least equal to the value obtained by calling - * ntfs_get_size_for_mapping_pairs(). + * @first_vcn and finishing with vcn @last_vcn and save the array in @dst. + * @dst_len is the size of @dst in bytes and it should be at least equal to the + * value obtained by calling ntfs_get_size_for_mapping_pairs(). + * + * A @last_vcn of -1 means end of runlist and in that case the mapping pairs + * array corresponding to the runlist starting at vcn @first_vcn and finishing + * at the end of the runlist is created. * * If @rl is NULL, just write a single terminator byte to @dst. * @@ -1213,7 +1253,7 @@ err_out: * been filled with all the mapping pairs that will fit, thus it can be treated * as partial success, in that a new attribute extent needs to be created or * the next extent has to be used and the mapping pairs build has to be - * continued with @start_vcn set to *@stop_vcn. + * continued with @first_vcn set to *@stop_vcn. * * Return 0 on success and -errno on error. The following error codes are * defined: @@ -1227,27 +1267,32 @@ err_out: */ int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst, const int dst_len, const runlist_element *rl, - const VCN start_vcn, VCN *const stop_vcn) + const VCN first_vcn, const VCN last_vcn, VCN *const stop_vcn) { LCN prev_lcn; s8 *dst_max, *dst_next; int err = -ENOSPC; + BOOL the_end = FALSE; s8 len_len, lcn_len; - BUG_ON(start_vcn < 0); + BUG_ON(first_vcn < 0); + BUG_ON(last_vcn < -1); + BUG_ON(last_vcn >= 0 && first_vcn > last_vcn); BUG_ON(dst_len < 1); if (!rl) { - BUG_ON(start_vcn); + BUG_ON(first_vcn); + BUG_ON(last_vcn > 0); if (stop_vcn) *stop_vcn = 0; /* Terminator byte. */ *dst = 0; return 0; } - /* Skip to runlist element containing @start_vcn. */ - while (rl->length && start_vcn >= rl[1].vcn) + /* Skip to runlist element containing @first_vcn. */ + while (rl->length && first_vcn >= rl[1].vcn) rl++; - if ((!rl->length && start_vcn > rl->vcn) || start_vcn < rl->vcn) + if (unlikely((!rl->length && first_vcn > rl->vcn) || + first_vcn < rl->vcn)) return -EINVAL; /* * @dst_max is used for bounds checking in @@ -1256,17 +1301,27 @@ int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst, dst_max = dst + dst_len - 1; prev_lcn = 0; /* Do the first partial run if present. */ - if (start_vcn > rl->vcn) { - s64 delta; + if (first_vcn > rl->vcn) { + s64 delta, length = rl->length; /* We know rl->length != 0 already. */ - if (rl->length < 0 || rl->lcn < LCN_HOLE) + if (unlikely(length < 0 || rl->lcn < LCN_HOLE)) goto err_out; - delta = start_vcn - rl->vcn; + /* + * If @stop_vcn is given and finishes inside this run, cap the + * run length. + */ + if (unlikely(last_vcn >= 0 && rl[1].vcn > last_vcn)) { + s64 s1 = last_vcn + 1; + if (unlikely(rl[1].vcn > s1)) + length = s1 - rl->vcn; + the_end = TRUE; + } + delta = first_vcn - rl->vcn; /* Write length. */ len_len = ntfs_write_significant_bytes(dst + 1, dst_max, - rl->length - delta); - if (len_len < 0) + length - delta); + if (unlikely(len_len < 0)) goto size_err; /* * If the logical cluster number (lcn) denotes a hole and we @@ -1277,19 +1332,19 @@ int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst, * case on NT4. - We assume that we just need to write the lcn * change until someone tells us otherwise... (AIA) */ - if (rl->lcn >= 0 || vol->major_ver < 3) { + if (likely(rl->lcn >= 0 || vol->major_ver < 3)) { prev_lcn = rl->lcn; - if (rl->lcn >= 0) + if (likely(rl->lcn >= 0)) prev_lcn += delta; /* Write change in lcn. */ lcn_len = ntfs_write_significant_bytes(dst + 1 + len_len, dst_max, prev_lcn); - if (lcn_len < 0) + if (unlikely(lcn_len < 0)) goto size_err; } else lcn_len = 0; dst_next = dst + len_len + lcn_len + 1; - if (dst_next > dst_max) + if (unlikely(dst_next > dst_max)) goto size_err; /* Update header byte. */ *dst = lcn_len << 4 | len_len; @@ -1299,13 +1354,25 @@ int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst, rl++; } /* Do the full runs. */ - for (; rl->length; rl++) { - if (rl->length < 0 || rl->lcn < LCN_HOLE) + for (; rl->length && !the_end; rl++) { + s64 length = rl->length; + + if (unlikely(length < 0 || rl->lcn < LCN_HOLE)) goto err_out; + /* + * If @stop_vcn is given and finishes inside this run, cap the + * run length. + */ + if (unlikely(last_vcn >= 0 && rl[1].vcn > last_vcn)) { + s64 s1 = last_vcn + 1; + if (unlikely(rl[1].vcn > s1)) + length = s1 - rl->vcn; + the_end = TRUE; + } /* Write length. */ len_len = ntfs_write_significant_bytes(dst + 1, dst_max, - rl->length); - if (len_len < 0) + length); + if (unlikely(len_len < 0)) goto size_err; /* * If the logical cluster number (lcn) denotes a hole and we @@ -1316,17 +1383,17 @@ int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst, * case on NT4. - We assume that we just need to write the lcn * change until someone tells us otherwise... (AIA) */ - if (rl->lcn >= 0 || vol->major_ver < 3) { + if (likely(rl->lcn >= 0 || vol->major_ver < 3)) { /* Write change in lcn. */ lcn_len = ntfs_write_significant_bytes(dst + 1 + len_len, dst_max, rl->lcn - prev_lcn); - if (lcn_len < 0) + if (unlikely(lcn_len < 0)) goto size_err; prev_lcn = rl->lcn; } else lcn_len = 0; dst_next = dst + len_len + lcn_len + 1; - if (dst_next > dst_max) + if (unlikely(dst_next > dst_max)) goto size_err; /* Update header byte. */ *dst = lcn_len << 4 | len_len; |
