diff options
Diffstat (limited to 'fs/ntfs')
| -rw-r--r-- | fs/ntfs/ChangeLog | 2 | ||||
| -rw-r--r-- | fs/ntfs/runlist.c | 284 | ||||
| -rw-r--r-- | fs/ntfs/runlist.h | 3 |
3 files changed, 289 insertions, 0 deletions
diff --git a/fs/ntfs/ChangeLog b/fs/ntfs/ChangeLog index 79d9899b3b0..39dca6dced1 100644 --- a/fs/ntfs/ChangeLog +++ b/fs/ntfs/ChangeLog @@ -53,6 +53,8 @@ ToDo/Notes: pointing this out. - Change ntfs_rl_truncate_nolock() to throw away the runlist if the new length is zero. + - Add runlist.[hc]::ntfs_rl_punch_nolock() which punches a caller + specified hole into a runlist. 2.1.23 - Implement extension of resident files and make writing safe as well as many bug fixes, cleanups, and enhancements... diff --git a/fs/ntfs/runlist.c b/fs/ntfs/runlist.c index 539fa2b7f36..f5b2ac92908 100644 --- a/fs/ntfs/runlist.c +++ b/fs/ntfs/runlist.c @@ -1601,4 +1601,288 @@ int ntfs_rl_truncate_nolock(const ntfs_volume *vol, runlist *const runlist, return 0; } +/** + * ntfs_rl_punch_nolock - punch a hole into a runlist + * @vol: ntfs volume (needed for error output) + * @runlist: runlist to punch a hole into + * @start: starting VCN of the hole to be created + * @length: size of the hole to be created in units of clusters + * + * Punch a hole into the runlist @runlist starting at VCN @start and of size + * @length clusters. + * + * Return 0 on success and -errno on error, in which case @runlist has not been + * modified. + * + * If @start and/or @start + @length are outside the runlist return error code + * -ENOENT. + * + * If the runlist contains unmapped or error elements between @start and @start + * + @length return error code -EINVAL. + * + * Locking: The caller must hold @runlist->lock for writing. + */ +int ntfs_rl_punch_nolock(const ntfs_volume *vol, runlist *const runlist, + const VCN start, const s64 length) +{ + const VCN end = start + length; + s64 delta; + runlist_element *rl, *rl_end, *rl_real_end, *trl; + int old_size; + BOOL lcn_fixup = FALSE; + + ntfs_debug("Entering for start 0x%llx, length 0x%llx.", + (long long)start, (long long)length); + BUG_ON(!runlist); + BUG_ON(start < 0); + BUG_ON(length < 0); + BUG_ON(end < 0); + rl = runlist->rl; + if (unlikely(!rl)) { + if (likely(!start && !length)) + return 0; + return -ENOENT; + } + /* Find @start in the runlist. */ + while (likely(rl->length && start >= rl[1].vcn)) + rl++; + rl_end = rl; + /* Find @end in the runlist. */ + while (likely(rl_end->length && end >= rl_end[1].vcn)) { + /* Verify there are no unmapped or error elements. */ + if (unlikely(rl_end->lcn < LCN_HOLE)) + return -EINVAL; + rl_end++; + } + /* Check the last element. */ + if (unlikely(rl_end->length && rl_end->lcn < LCN_HOLE)) + return -EINVAL; + /* This covers @start being out of bounds, too. */ + if (!rl_end->length && end > rl_end->vcn) + return -ENOENT; + if (!length) + return 0; + if (!rl->length) + return -ENOENT; + rl_real_end = rl_end; + /* Determine the runlist size. */ + while (likely(rl_real_end->length)) + rl_real_end++; + old_size = rl_real_end - runlist->rl + 1; + /* If @start is in a hole simply extend the hole. */ + if (rl->lcn == LCN_HOLE) { + /* + * If both @start and @end are in the same sparse run, we are + * done. + */ + if (end <= rl[1].vcn) { + ntfs_debug("Done (requested hole is already sparse)."); + return 0; + } +extend_hole: + /* Extend the hole. */ + rl->length = end - rl->vcn; + /* If @end is in a hole, merge it with the current one. */ + if (rl_end->lcn == LCN_HOLE) { + rl_end++; + rl->length = rl_end->vcn - rl->vcn; + } + /* We have done the hole. Now deal with the remaining tail. */ + rl++; + /* Cut out all runlist elements up to @end. */ + if (rl < rl_end) + memmove(rl, rl_end, (rl_real_end - rl_end + 1) * + sizeof(*rl)); + /* Adjust the beginning of the tail if necessary. */ + if (end > rl->vcn) { + s64 delta = end - rl->vcn; + rl->vcn = end; + rl->length -= delta; + /* Only adjust the lcn if it is real. */ + if (rl->lcn >= 0) + rl->lcn += delta; + } +shrink_allocation: + /* Reallocate memory if the allocation changed. */ + if (rl < rl_end) { + rl = ntfs_rl_realloc(runlist->rl, old_size, + old_size - (rl_end - rl)); + if (IS_ERR(rl)) + ntfs_warning(vol->sb, "Failed to shrink " + "runlist buffer. This just " + "wastes a bit of memory " + "temporarily so we ignore it " + "and return success."); + else + runlist->rl = rl; + } + ntfs_debug("Done (extend hole)."); + return 0; + } + /* + * If @start is at the beginning of a run things are easier as there is + * no need to split the first run. + */ + if (start == rl->vcn) { + /* + * @start is at the beginning of a run. + * + * If the previous run is sparse, extend its hole. + * + * If @end is not in the same run, switch the run to be sparse + * and extend the newly created hole. + * + * Thus both of these cases reduce the problem to the above + * case of "@start is in a hole". + */ + if (rl > runlist->rl && (rl - 1)->lcn == LCN_HOLE) { + rl--; + goto extend_hole; + } + if (end >= rl[1].vcn) { + rl->lcn = LCN_HOLE; + goto extend_hole; + } + /* + * The final case is when @end is in the same run as @start. + * For this need to split the run into two. One run for the + * sparse region between the beginning of the old run, i.e. + * @start, and @end and one for the remaining non-sparse + * region, i.e. between @end and the end of the old run. + */ + trl = ntfs_rl_realloc(runlist->rl, old_size, old_size + 1); + if (IS_ERR(trl)) + goto enomem_out; + old_size++; + if (runlist->rl != trl) { + rl = trl + (rl - runlist->rl); + rl_end = trl + (rl_end - runlist->rl); + rl_real_end = trl + (rl_real_end - runlist->rl); + runlist->rl = trl; + } +split_end: + /* Shift all the runs up by one. */ + memmove(rl + 1, rl, (rl_real_end - rl + 1) * sizeof(*rl)); + /* Finally, setup the two split runs. */ + rl->lcn = LCN_HOLE; + rl->length = length; + rl++; + rl->vcn += length; + /* Only adjust the lcn if it is real. */ + if (rl->lcn >= 0 || lcn_fixup) + rl->lcn += length; + rl->length -= length; + ntfs_debug("Done (split one)."); + return 0; + } + /* + * @start is neither in a hole nor at the beginning of a run. + * + * If @end is in a hole, things are easier as simply truncating the run + * @start is in to end at @start - 1, deleting all runs after that up + * to @end, and finally extending the beginning of the run @end is in + * to be @start is all that is needed. + */ + if (rl_end->lcn == LCN_HOLE) { + /* Truncate the run containing @start. */ + rl->length = start - rl->vcn; + rl++; + /* Cut out all runlist elements up to @end. */ + if (rl < rl_end) + memmove(rl, rl_end, (rl_real_end - rl_end + 1) * + sizeof(*rl)); + /* Extend the beginning of the run @end is in to be @start. */ + rl->vcn = start; + rl->length = rl[1].vcn - start; + goto shrink_allocation; + } + /* + * If @end is not in a hole there are still two cases to distinguish. + * Either @end is or is not in the same run as @start. + * + * The second case is easier as it can be reduced to an already solved + * problem by truncating the run @start is in to end at @start - 1. + * Then, if @end is in the next run need to split the run into a sparse + * run followed by a non-sparse run (already covered above) and if @end + * is not in the next run switching it to be sparse, again reduces the + * problem to the already covered case of "@start is in a hole". + */ + if (end >= rl[1].vcn) { + /* + * If @end is not in the next run, reduce the problem to the + * case of "@start is in a hole". + */ + if (rl[1].length && end >= rl[2].vcn) { + /* Truncate the run containing @start. */ + rl->length = start - rl->vcn; + rl++; + rl->vcn = start; + rl->lcn = LCN_HOLE; + goto extend_hole; + } + trl = ntfs_rl_realloc(runlist->rl, old_size, old_size + 1); + if (IS_ERR(trl)) + goto enomem_out; + old_size++; + if (runlist->rl != trl) { + rl = trl + (rl - runlist->rl); + rl_end = trl + (rl_end - runlist->rl); + rl_real_end = trl + (rl_real_end - runlist->rl); + runlist->rl = trl; + } + /* Truncate the run containing @start. */ + rl->length = start - rl->vcn; + rl++; + /* + * @end is in the next run, reduce the problem to the case + * where "@start is at the beginning of a run and @end is in + * the same run as @start". + */ + delta = rl->vcn - start; + rl->vcn = start; + if (rl->lcn >= 0) { + rl->lcn -= delta; + /* Need this in case the lcn just became negative. */ + lcn_fixup = TRUE; + } + rl->length += delta; + goto split_end; + } + /* + * The first case from above, i.e. @end is in the same run as @start. + * We need to split the run into three. One run for the non-sparse + * region between the beginning of the old run and @start, one for the + * sparse region between @start and @end, and one for the remaining + * non-sparse region, i.e. between @end and the end of the old run. + */ + trl = ntfs_rl_realloc(runlist->rl, old_size, old_size + 2); + if (IS_ERR(trl)) + goto enomem_out; + old_size += 2; + if (runlist->rl != trl) { + rl = trl + (rl - runlist->rl); + rl_end = trl + (rl_end - runlist->rl); + rl_real_end = trl + (rl_real_end - runlist->rl); + runlist->rl = trl; + } + /* Shift all the runs up by two. */ + memmove(rl + 2, rl, (rl_real_end - rl + 1) * sizeof(*rl)); + /* Finally, setup the three split runs. */ + rl->length = start - rl->vcn; + rl++; + rl->vcn = start; + rl->lcn = LCN_HOLE; + rl->length = length; + rl++; + delta = end - rl->vcn; + rl->vcn = end; + rl->lcn += delta; + rl->length -= delta; + ntfs_debug("Done (split both)."); + return 0; +enomem_out: + ntfs_error(vol->sb, "Not enough memory to extend runlist buffer."); + return -ENOMEM; +} + #endif /* NTFS_RW */ diff --git a/fs/ntfs/runlist.h b/fs/ntfs/runlist.h index aa0ee6540e7..47728fbb610 100644 --- a/fs/ntfs/runlist.h +++ b/fs/ntfs/runlist.h @@ -94,6 +94,9 @@ extern int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst, extern int ntfs_rl_truncate_nolock(const ntfs_volume *vol, runlist *const runlist, const s64 new_length); +int ntfs_rl_punch_nolock(const ntfs_volume *vol, runlist *const runlist, + const VCN start, const s64 length); + #endif /* NTFS_RW */ #endif /* _LINUX_NTFS_RUNLIST_H */ |