diff options
Diffstat (limited to 'fs/ntfs/runlist.c')
| -rw-r--r-- | fs/ntfs/runlist.c | 1893 |
1 files changed, 0 insertions, 1893 deletions
diff --git a/fs/ntfs/runlist.c b/fs/ntfs/runlist.c deleted file mode 100644 index 0d448e9881..0000000000 --- a/fs/ntfs/runlist.c +++ /dev/null @@ -1,1893 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-or-later -/* - * runlist.c - NTFS runlist handling code. Part of the Linux-NTFS project. - * - * Copyright (c) 2001-2007 Anton Altaparmakov - * Copyright (c) 2002-2005 Richard Russon - */ - -#include "debug.h" -#include "dir.h" -#include "endian.h" -#include "malloc.h" -#include "ntfs.h" - -/** - * ntfs_rl_mm - runlist memmove - * - * It is up to the caller to serialize access to the runlist @base. - */ -static inline void ntfs_rl_mm(runlist_element *base, int dst, int src, - int size) -{ - if (likely((dst != src) && (size > 0))) - memmove(base + dst, base + src, size * sizeof(*base)); -} - -/** - * ntfs_rl_mc - runlist memory copy - * - * It is up to the caller to serialize access to the runlists @dstbase and - * @srcbase. - */ -static inline void ntfs_rl_mc(runlist_element *dstbase, int dst, - runlist_element *srcbase, int src, int size) -{ - if (likely(size > 0)) - memcpy(dstbase + dst, srcbase + src, size * sizeof(*dstbase)); -} - -/** - * ntfs_rl_realloc - Reallocate memory for runlists - * @rl: original runlist - * @old_size: number of runlist elements in the original runlist @rl - * @new_size: number of runlist elements we need space for - * - * As the runlists grow, more memory will be required. To prevent the - * kernel having to allocate and reallocate large numbers of small bits of - * memory, this function returns an entire page of memory. - * - * It is up to the caller to serialize access to the runlist @rl. - * - * N.B. If the new allocation doesn't require a different number of pages in - * memory, the function will return the original pointer. - * - * On success, return a pointer to the newly allocated, or recycled, memory. - * On error, return -errno. The following error codes are defined: - * -ENOMEM - Not enough memory to allocate runlist array. - * -EINVAL - Invalid parameters were passed in. - */ -static inline runlist_element *ntfs_rl_realloc(runlist_element *rl, - int old_size, int new_size) -{ - runlist_element *new_rl; - - old_size = PAGE_ALIGN(old_size * sizeof(*rl)); - new_size = PAGE_ALIGN(new_size * sizeof(*rl)); - if (old_size == new_size) - return rl; - - new_rl = ntfs_malloc_nofs(new_size); - if (unlikely(!new_rl)) - return ERR_PTR(-ENOMEM); - - if (likely(rl != NULL)) { - if (unlikely(old_size > new_size)) - old_size = new_size; - memcpy(new_rl, rl, old_size); - ntfs_free(rl); - } - return new_rl; -} - -/** - * ntfs_rl_realloc_nofail - Reallocate memory for runlists - * @rl: original runlist - * @old_size: number of runlist elements in the original runlist @rl - * @new_size: number of runlist elements we need space for - * - * As the runlists grow, more memory will be required. To prevent the - * kernel having to allocate and reallocate large numbers of small bits of - * memory, this function returns an entire page of memory. - * - * This function guarantees that the allocation will succeed. It will sleep - * for as long as it takes to complete the allocation. - * - * It is up to the caller to serialize access to the runlist @rl. - * - * N.B. If the new allocation doesn't require a different number of pages in - * memory, the function will return the original pointer. - * - * On success, return a pointer to the newly allocated, or recycled, memory. - * On error, return -errno. The following error codes are defined: - * -ENOMEM - Not enough memory to allocate runlist array. - * -EINVAL - Invalid parameters were passed in. - */ -static inline runlist_element *ntfs_rl_realloc_nofail(runlist_element *rl, - int old_size, int new_size) -{ - runlist_element *new_rl; - - old_size = PAGE_ALIGN(old_size * sizeof(*rl)); - new_size = PAGE_ALIGN(new_size * sizeof(*rl)); - if (old_size == new_size) - return rl; - - new_rl = ntfs_malloc_nofs_nofail(new_size); - BUG_ON(!new_rl); - - if (likely(rl != NULL)) { - if (unlikely(old_size > new_size)) - old_size = new_size; - memcpy(new_rl, rl, old_size); - ntfs_free(rl); - } - return new_rl; -} - -/** - * ntfs_are_rl_mergeable - test if two runlists can be joined together - * @dst: original runlist - * @src: new runlist to test for mergeability with @dst - * - * Test if two runlists can be joined together. For this, their VCNs and LCNs - * must be adjacent. - * - * It is up to the caller to serialize access to the runlists @dst and @src. - * - * Return: true Success, the runlists can be merged. - * false Failure, the runlists cannot be merged. - */ -static inline bool ntfs_are_rl_mergeable(runlist_element *dst, - runlist_element *src) -{ - BUG_ON(!dst); - BUG_ON(!src); - - /* We can merge unmapped regions even if they are misaligned. */ - if ((dst->lcn == LCN_RL_NOT_MAPPED) && (src->lcn == LCN_RL_NOT_MAPPED)) - return true; - /* If the runs are misaligned, we cannot merge them. */ - if ((dst->vcn + dst->length) != src->vcn) - return false; - /* If both runs are non-sparse and contiguous, we can merge them. */ - if ((dst->lcn >= 0) && (src->lcn >= 0) && - ((dst->lcn + dst->length) == src->lcn)) - return true; - /* If we are merging two holes, we can merge them. */ - if ((dst->lcn == LCN_HOLE) && (src->lcn == LCN_HOLE)) - return true; - /* Cannot merge. */ - return false; -} - -/** - * __ntfs_rl_merge - merge two runlists without testing if they can be merged - * @dst: original, destination runlist - * @src: new runlist to merge with @dst - * - * Merge the two runlists, writing into the destination runlist @dst. The - * caller must make sure the runlists can be merged or this will corrupt the - * destination runlist. - * - * It is up to the caller to serialize access to the runlists @dst and @src. - */ -static inline void __ntfs_rl_merge(runlist_element *dst, runlist_element *src) -{ - dst->length += src->length; -} - -/** - * ntfs_rl_append - append a runlist after a given element - * @dst: original runlist to be worked on - * @dsize: number of elements in @dst (including end marker) - * @src: runlist to be inserted into @dst - * @ssize: number of elements in @src (excluding end marker) - * @loc: append the new runlist @src after this element in @dst - * - * Append the runlist @src after element @loc in @dst. Merge the right end of - * the new runlist, if necessary. Adjust the size of the hole before the - * appended runlist. - * - * It is up to the caller to serialize access to the runlists @dst and @src. - * - * On success, return a pointer to the new, combined, runlist. Note, both - * runlists @dst and @src are deallocated before returning so you cannot use - * the pointers for anything any more. (Strictly speaking the returned runlist - * may be the same as @dst but this is irrelevant.) - * - * On error, return -errno. Both runlists are left unmodified. The following - * error codes are defined: - * -ENOMEM - Not enough memory to allocate runlist array. - * -EINVAL - Invalid parameters were passed in. - */ -static inline runlist_element *ntfs_rl_append(runlist_element *dst, - int dsize, runlist_element *src, int ssize, int loc) -{ - bool right = false; /* Right end of @src needs merging. */ - int marker; /* End of the inserted runs. */ - - BUG_ON(!dst); - BUG_ON(!src); - - /* First, check if the right hand end needs merging. */ - if ((loc + 1) < dsize) - right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1); - - /* Space required: @dst size + @src size, less one if we merged. */ - dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - right); - if (IS_ERR(dst)) - return dst; - /* - * We are guaranteed to succeed from here so can start modifying the - * original runlists. - */ - - /* First, merge the right hand end, if necessary. */ - if (right) - __ntfs_rl_merge(src + ssize - 1, dst + loc + 1); - - /* First run after the @src runs that have been inserted. */ - marker = loc + ssize + 1; - - /* Move the tail of @dst out of the way, then copy in @src. */ - ntfs_rl_mm(dst, marker, loc + 1 + right, dsize - (loc + 1 + right)); - ntfs_rl_mc(dst, loc + 1, src, 0, ssize); - - /* Adjust the size of the preceding hole. */ - dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn; - - /* We may have changed the length of the file, so fix the end marker */ - if (dst[marker].lcn == LCN_ENOENT) - dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length; - - return dst; -} - -/** - * ntfs_rl_insert - insert a runlist into another - * @dst: original runlist to be worked on - * @dsize: number of elements in @dst (including end marker) - * @src: new runlist to be inserted - * @ssize: number of elements in @src (excluding end marker) - * @loc: insert the new runlist @src before this element in @dst - * - * Insert the runlist @src before element @loc in the runlist @dst. Merge the - * left end of the new runlist, if necessary. Adjust the size of the hole - * after the inserted runlist. - * - * It is up to the caller to serialize access to the runlists @dst and @src. - * - * On success, return a pointer to the new, combined, runlist. Note, both - * runlists @dst and @src are deallocated before returning so you cannot use - * the pointers for anything any more. (Strictly speaking the returned runlist - * may be the same as @dst but this is irrelevant.) - * - * On error, return -errno. Both runlists are left unmodified. The following - * error codes are defined: - * -ENOMEM - Not enough memory to allocate runlist array. - * -EINVAL - Invalid parameters were passed in. - */ -static inline runlist_element *ntfs_rl_insert(runlist_element *dst, - int dsize, runlist_element *src, int ssize, int loc) -{ - bool left = false; /* Left end of @src needs merging. */ - bool disc = false; /* Discontinuity between @dst and @src. */ - int marker; /* End of the inserted runs. */ - - BUG_ON(!dst); - BUG_ON(!src); - - /* - * disc => Discontinuity between the end of @dst and the start of @src. - * This means we might need to insert a "not mapped" run. - */ - if (loc == 0) - disc = (src[0].vcn > 0); - else { - s64 merged_length; - - left = ntfs_are_rl_mergeable(dst + loc - 1, src); - - merged_length = dst[loc - 1].length; - if (left) - merged_length += src->length; - - disc = (src[0].vcn > dst[loc - 1].vcn + merged_length); - } - /* - * Space required: @dst size + @src size, less one if we merged, plus - * one if there was a discontinuity. - */ - dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left + disc); - if (IS_ERR(dst)) - return dst; - /* - * We are guaranteed to succeed from here so can start modifying the - * original runlist. - */ - if (left) - __ntfs_rl_merge(dst + loc - 1, src); - /* - * First run after the @src runs that have been inserted. - * Nominally, @marker equals @loc + @ssize, i.e. location + number of - * runs in @src. However, if @left, then the first run in @src has - * been merged with one in @dst. And if @disc, then @dst and @src do - * not meet and we need an extra run to fill the gap. - */ - marker = loc + ssize - left + disc; - - /* Move the tail of @dst out of the way, then copy in @src. */ - ntfs_rl_mm(dst, marker, loc, dsize - loc); - ntfs_rl_mc(dst, loc + disc, src, left, ssize - left); - - /* Adjust the VCN of the first run after the insertion... */ - dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length; - /* ... and the length. */ - if (dst[marker].lcn == LCN_HOLE || dst[marker].lcn == LCN_RL_NOT_MAPPED) - dst[marker].length = dst[marker + 1].vcn - dst[marker].vcn; - - /* Writing beyond the end of the file and there is a discontinuity. */ - if (disc) { - if (loc > 0) { - dst[loc].vcn = dst[loc - 1].vcn + dst[loc - 1].length; - dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn; - } else { - dst[loc].vcn = 0; - dst[loc].length = dst[loc + 1].vcn; - } - dst[loc].lcn = LCN_RL_NOT_MAPPED; - } - return dst; -} - -/** - * ntfs_rl_replace - overwrite a runlist element with another runlist - * @dst: original runlist to be worked on - * @dsize: number of elements in @dst (including end marker) - * @src: new runlist to be inserted - * @ssize: number of elements in @src (excluding end marker) - * @loc: index in runlist @dst to overwrite with @src - * - * Replace the runlist element @dst at @loc with @src. Merge the left and - * right ends of the inserted runlist, if necessary. - * - * It is up to the caller to serialize access to the runlists @dst and @src. - * - * On success, return a pointer to the new, combined, runlist. Note, both - * runlists @dst and @src are deallocated before returning so you cannot use - * the pointers for anything any more. (Strictly speaking the returned runlist - * may be the same as @dst but this is irrelevant.) - * - * On error, return -errno. Both runlists are left unmodified. The following - * error codes are defined: - * -ENOMEM - Not enough memory to allocate runlist array. - * -EINVAL - Invalid parameters were passed in. - */ -static inline runlist_element *ntfs_rl_replace(runlist_element *dst, - int dsize, runlist_element *src, int ssize, int loc) -{ - signed delta; - bool left = false; /* Left end of @src needs merging. */ - bool right = false; /* Right end of @src needs merging. */ - int tail; /* Start of tail of @dst. */ - int marker; /* End of the inserted runs. */ - - BUG_ON(!dst); - BUG_ON(!src); - - /* First, see if the left and right ends need merging. */ - if ((loc + 1) < dsize) - right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1); - if (loc > 0) - left = ntfs_are_rl_mergeable(dst + loc - 1, src); - /* - * Allocate some space. We will need less if the left, right, or both - * ends get merged. The -1 accounts for the run being replaced. - */ - delta = ssize - 1 - left - right; - if (delta > 0) { - dst = ntfs_rl_realloc(dst, dsize, dsize + delta); - if (IS_ERR(dst)) - return dst; - } - /* - * We are guaranteed to succeed from here so can start modifying the - * original runlists. - */ - - /* First, merge the left and right ends, if necessary. */ - if (right) - __ntfs_rl_merge(src + ssize - 1, dst + loc + 1); - if (left) - __ntfs_rl_merge(dst + loc - 1, src); - /* - * Offset of the tail of @dst. This needs to be moved out of the way - * to make space for the runs to be copied from @src, i.e. the first - * run of the tail of @dst. - * Nominally, @tail equals @loc + 1, i.e. location, skipping the - * replaced run. However, if @right, then one of @dst's runs is - * already merged into @src. - */ - tail = loc + right + 1; - /* - * First run after the @src runs that have been inserted, i.e. where - * the tail of @dst needs to be moved to. - * Nominally, @marker equals @loc + @ssize, i.e. location + number of - * runs in @src. However, if @left, then the first run in @src has - * been merged with one in @dst. - */ - marker = loc + ssize - left; - - /* Move the tail of @dst out of the way, then copy in @src. */ - ntfs_rl_mm(dst, marker, tail, dsize - tail); - ntfs_rl_mc(dst, loc, src, left, ssize - left); - - /* We may have changed the length of the file, so fix the end marker. */ - if (dsize - tail > 0 && dst[marker].lcn == LCN_ENOENT) - dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length; - return dst; -} - -/** - * ntfs_rl_split - insert a runlist into the centre of a hole - * @dst: original runlist to be worked on - * @dsize: number of elements in @dst (including end marker) - * @src: new runlist to be inserted - * @ssize: number of elements in @src (excluding end marker) - * @loc: index in runlist @dst at which to split and insert @src - * - * Split the runlist @dst at @loc into two and insert @new in between the two - * fragments. No merging of runlists is necessary. Adjust the size of the - * holes either side. - * - * It is up to the caller to serialize access to the runlists @dst and @src. - * - * On success, return a pointer to the new, combined, runlist. Note, both - * runlists @dst and @src are deallocated before returning so you cannot use - * the pointers for anything any more. (Strictly speaking the returned runlist - * may be the same as @dst but this is irrelevant.) - * - * On error, return -errno. Both runlists are left unmodified. The following - * error codes are defined: - * -ENOMEM - Not enough memory to allocate runlist array. - * -EINVAL - Invalid parameters were passed in. - */ -static inline runlist_element *ntfs_rl_split(runlist_element *dst, int dsize, - runlist_element *src, int ssize, int loc) -{ - BUG_ON(!dst); - BUG_ON(!src); - - /* Space required: @dst size + @src size + one new hole. */ - dst = ntfs_rl_realloc(dst, dsize, dsize + ssize + 1); - if (IS_ERR(dst)) - return dst; - /* - * We are guaranteed to succeed from here so can start modifying the - * original runlists. - */ - - /* Move the tail of @dst out of the way, then copy in @src. */ - ntfs_rl_mm(dst, loc + 1 + ssize, loc, dsize - loc); - ntfs_rl_mc(dst, loc + 1, src, 0, ssize); - - /* Adjust the size of the holes either size of @src. */ - dst[loc].length = dst[loc+1].vcn - dst[loc].vcn; - dst[loc+ssize+1].vcn = dst[loc+ssize].vcn + dst[loc+ssize].length; - dst[loc+ssize+1].length = dst[loc+ssize+2].vcn - dst[loc+ssize+1].vcn; - - return dst; -} - -/** - * ntfs_runlists_merge - merge two runlists into one - * @drl: original runlist to be worked on - * @srl: new runlist to be merged into @drl - * - * First we sanity check the two runlists @srl and @drl to make sure that they - * are sensible and can be merged. The runlist @srl must be either after the - * runlist @drl or completely within a hole (or unmapped region) in @drl. - * - * It is up to the caller to serialize access to the runlists @drl and @srl. - * - * Merging of runlists is necessary in two cases: - * 1. When attribute lists are used and a further extent is being mapped. - * 2. When new clusters are allocated to fill a hole or extend a file. - * - * There are four possible ways @srl can be merged. It can: - * - be inserted at the beginning of a hole, - * - split the hole in two and be inserted between the two fragments, - * - be appended at the end of a hole, or it can - * - replace the whole hole. - * It can also be appended to the end of the runlist, which is just a variant - * of the insert case. - * - * On success, return a pointer to the new, combined, runlist. Note, both - * runlists @drl and @srl are deallocated before returning so you cannot use - * the pointers for anything any more. (Strictly speaking the returned runlist - * may be the same as @dst but this is irrelevant.) - * - * On error, return -errno. Both runlists are left unmodified. The following - * error codes are defined: - * -ENOMEM - Not enough memory to allocate runlist array. - * -EINVAL - Invalid parameters were passed in. - * -ERANGE - The runlists overlap and cannot be merged. - */ -runlist_element *ntfs_runlists_merge(runlist_element *drl, - runlist_element *srl) -{ - int di, si; /* Current index into @[ds]rl. */ - int sstart; /* First index with lcn > LCN_RL_NOT_MAPPED. */ - int dins; /* Index into @drl at which to insert @srl. */ - int dend, send; /* Last index into @[ds]rl. */ - int dfinal, sfinal; /* The last index into @[ds]rl with - lcn >= LCN_HOLE. */ - int marker = 0; - VCN marker_vcn = 0; - -#ifdef DEBUG - ntfs_debug("dst:"); - ntfs_debug_dump_runlist(drl); - ntfs_debug("src:"); - ntfs_debug_dump_runlist(srl); -#endif - - /* Check for silly calling... */ - if (unlikely(!srl)) - return drl; - if (IS_ERR(srl) || IS_ERR(drl)) - return ERR_PTR(-EINVAL); - - /* Check for the case where the first mapping is being done now. */ - if (unlikely(!drl)) { - drl = srl; - /* Complete the source runlist if necessary. */ - if (unlikely(drl[0].vcn)) { - /* Scan to the end of the source runlist. */ - for (dend = 0; likely(drl[dend].length); dend++) - ; - dend++; - drl = ntfs_rl_realloc(drl, dend, dend + 1); - if (IS_ERR(drl)) - return drl; - /* Insert start element at the front of the runlist. */ - ntfs_rl_mm(drl, 1, 0, dend); - drl[0].vcn = 0; - drl[0].lcn = LCN_RL_NOT_MAPPED; - drl[0].length = drl[1].vcn; - } - goto finished; - } - - si = di = 0; - - /* Skip any unmapped start element(s) in the source runlist. */ - while (srl[si].length && srl[si].lcn < LCN_HOLE) - si++; - - /* Can't have an entirely unmapped source runlist. */ - BUG_ON(!srl[si].length); - - /* Record the starting points. */ - sstart = si; - - /* - * Skip forward in @drl until we reach the position where @srl needs to - * be inserted. If we reach the end of @drl, @srl just needs to be - * appended to @drl. - */ - for (; drl[di].length; di++) { - if (drl[di].vcn + drl[di].length > srl[sstart].vcn) - break; - } - dins = di; - - /* Sanity check for illegal overlaps. */ - if ((drl[di].vcn == srl[si].vcn) && (drl[di].lcn >= 0) && - (srl[si].lcn >= 0)) { - ntfs_error(NULL, "Run lists overlap. Cannot merge!"); - return ERR_PTR(-ERANGE); - } - - /* Scan to the end of both runlists in order to know their sizes. */ - for (send = si; srl[send].length; send++) - ; - for (dend = di; drl[dend].length; dend++) - ; - - if (srl[send].lcn == LCN_ENOENT) - marker_vcn = srl[marker = send].vcn; - - /* Scan to the last element with lcn >= LCN_HOLE. */ - for (sfinal = send; sfinal >= 0 && srl[sfinal].lcn < LCN_HOLE; sfinal--) - ; - for (dfinal = dend; dfinal >= 0 && drl[dfinal].lcn < LCN_HOLE; dfinal--) - ; - - { - bool start; - bool finish; - int ds = dend + 1; /* Number of elements in drl & srl */ - int ss = sfinal - sstart + 1; - - start = ((drl[dins].lcn < LCN_RL_NOT_MAPPED) || /* End of file */ - (drl[dins].vcn == srl[sstart].vcn)); /* Start of hole */ - finish = ((drl[dins].lcn >= LCN_RL_NOT_MAPPED) && /* End of file */ - ((drl[dins].vcn + drl[dins].length) <= /* End of hole */ - (srl[send - 1].vcn + srl[send - 1].length))); - - /* Or we will lose an end marker. */ - if (finish && !drl[dins].length) - ss++; - if (marker && (drl[dins].vcn + drl[dins].length > srl[send - 1].vcn)) - finish = false; -#if 0 - ntfs_debug("dfinal = %i, dend = %i", dfinal, dend); - ntfs_debug("sstart = %i, sfinal = %i, send = %i", sstart, sfinal, send); - ntfs_debug("start = %i, finish = %i", start, finish); - ntfs_debug("ds = %i, ss = %i, dins = %i", ds, ss, dins); -#endif - if (start) { - if (finish) - drl = ntfs_rl_replace(drl, ds, srl + sstart, ss, dins); - else - drl = ntfs_rl_insert(drl, ds, srl + sstart, ss, dins); - } else { - if (finish) - drl = ntfs_rl_append(drl, ds, srl + sstart, ss, dins); - else - drl = ntfs_rl_split(drl, ds, srl + sstart, ss, dins); - } - if (IS_ERR(drl)) { - ntfs_error(NULL, "Merge failed."); - return drl; - } - ntfs_free(srl); - if (marker) { - ntfs_debug("Triggering marker code."); - for (ds = dend; drl[ds].length; ds++) - ; - /* We only need to care if @srl ended after @drl. */ - if (drl[ds].vcn <= marker_vcn) { - int slots = 0; - - if (drl[ds].vcn == marker_vcn) { - ntfs_debug("Old marker = 0x%llx, replacing " - "with LCN_ENOENT.", - (unsigned long long) - drl[ds].lcn); - drl[ds].lcn = LCN_ENOENT; - goto finished; - } - /* - * We need to create an unmapped runlist element in - * @drl or extend an existing one before adding the - * ENOENT terminator. - */ - if (drl[ds].lcn == LCN_ENOENT) { - ds--; - slots = 1; - } - if (drl[ds].lcn != LCN_RL_NOT_MAPPED) { - /* Add an unmapped runlist element. */ - if (!slots) { - drl = ntfs_rl_realloc_nofail(drl, ds, - ds + 2); - slots = 2; - } - ds++; - /* Need to set vcn if it isn't set already. */ - if (slots != 1) - drl[ds].vcn = drl[ds - 1].vcn + - drl[ds - 1].length; - drl[ds].lcn = LCN_RL_NOT_MAPPED; - /* We now used up a slot. */ - slots--; - } - drl[ds].length = marker_vcn - drl[ds].vcn; - /* Finally add the ENOENT terminator. */ - ds++; - if (!slots) - drl = ntfs_rl_realloc_nofail(drl, ds, ds + 1); - drl[ds].vcn = marker_vcn; - drl[ds].lcn = LCN_ENOENT; - drl[ds].length = (s64)0; - } - } - } - -finished: - /* The merge was completed successfully. */ - ntfs_debug("Merged runlist:"); - ntfs_debug_dump_runlist(drl); - return drl; -} - -/** - * ntfs_mapping_pairs_decompress - convert mapping pairs array to runlist - * @vol: ntfs volume on which the attribute resides - * @attr: attribute record whose mapping pairs array to decompress - * @old_rl: optional runlist in which to insert @attr's runlist - * - * It is up to the caller to serialize access to the runlist @old_rl. - * - * Decompress the attribute @attr's mapping pairs array into a runlist. On - * success, return the decompressed runlist. - * - * If @old_rl is not NULL, decompressed runlist is inserted into the - * appropriate place in @old_rl and the resultant, combined runlist is - * returned. The original @old_rl is deallocated. - * - * On error, return -errno. @old_rl is left unmodified in that case. - * - * The following error codes are defined: - * -ENOMEM - Not enough memory to allocate runlist array. - * -EIO - Corrupt runlist. - * -EINVAL - Invalid parameters were passed in. - * -ERANGE - The two runlists overlap. - * - * FIXME: For now we take the conceptionally simplest approach of creating the - * new runlist disregarding the already existing one and then splicing the - * two into one, if that is possible (we check for overlap and discard the new - * runlist if overlap present before returning ERR_PTR(-ERANGE)). - */ -runlist_element *ntfs_mapping_pairs_decompress(const ntfs_volume *vol, - const ATTR_RECORD *attr, runlist_element *old_rl) -{ - VCN vcn; /* Current vcn. */ - LCN lcn; /* Current lcn. */ - s64 deltaxcn; /* Change in [vl]cn. */ - runlist_element *rl; /* The output runlist. */ - u8 *buf; /* Current position in mapping pairs array. */ - u8 *attr_end; /* End of attribute. */ - int rlsize; /* Size of runlist buffer. */ - u16 rlpos; /* Current runlist position in units of - runlist_elements. */ - u8 b; /* Current byte offset in buf. */ - -#ifdef DEBUG - /* Make sure attr exists and is non-resident. */ - if (!attr || !attr->non_resident || sle64_to_cpu( - attr->data.non_resident.lowest_vcn) < (VCN)0) { - ntfs_error(vol->sb, "Invalid arguments."); - return ERR_PTR(-EINVAL); - } -#endif - /* Start at vcn = lowest_vcn and lcn 0. */ - vcn = sle64_to_cpu(attr->data.non_resident.lowest_vcn); - lcn = 0; - /* Get start of the mapping pairs array. */ - buf = (u8*)attr + le16_to_cpu( - attr->data.non_resident.mapping_pairs_offset); - attr_end = (u8*)attr + le32_to_cpu(attr->length); - if (unlikely(buf < (u8*)attr || buf > attr_end)) { - ntfs_error(vol->sb, "Corrupt attribute."); - return ERR_PTR(-EIO); - } - /* If the mapping pairs array is valid but empty, nothing to do. */ - if (!vcn && !*buf) - return old_rl; - /* Current position in runlist array. */ - rlpos = 0; - /* Allocate first page and set current runlist size to one page. */ - rl = ntfs_malloc_nofs(rlsize = PAGE_SIZE); - if (unlikely(!rl)) - return ERR_PTR(-ENOMEM); - /* Insert unmapped starting element if necessary. */ - if (vcn) { - rl->vcn = 0; - rl->lcn = LCN_RL_NOT_MAPPED; - rl->length = vcn; - rlpos++; - } - while (buf < attr_end && *buf) { - /* - * Allocate more memory if needed, including space for the - * not-mapped and terminator elements. ntfs_malloc_nofs() - * operates on whole pages only. - */ - if (((rlpos + 3) * sizeof(*old_rl)) > rlsize) { - runlist_element *rl2; - - rl2 = ntfs_malloc_nofs(rlsize + (int)PAGE_SIZE); - if (unlikely(!rl2)) { - ntfs_free(rl); - return ERR_PTR(-ENOMEM); - } - memcpy(rl2, rl, rlsize); - ntfs_free(rl); - rl = rl2; - rlsize += PAGE_SIZE; - } - /* Enter the current vcn into the current runlist element. */ - rl[rlpos].vcn = vcn; - /* - * Get the change in vcn, i.e. the run length in clusters. - * Doing it this way ensures that we signextend negative values. - * A negative run length doesn't make any sense, but hey, I - * didn't make up the NTFS specs and Windows NT4 treats the run - * length as a signed value so that's how it is... - */ - b = *buf & 0xf; - if (b) { - if (unlikely(buf + b > attr_end)) - goto io_error; - for (deltaxcn = (s8)buf[b--]; b; b--) - deltaxcn = (deltaxcn << 8) + buf[b]; - } else { /* The length entry is compulsory. */ - ntfs_error(vol->sb, "Missing length entry in mapping " - "pairs array."); - deltaxcn = (s64)-1; - } - /* - * Assume a negative length to indicate data corruption and - * hence clean-up and return NULL. - */ - if (unlikely(deltaxcn < 0)) { - ntfs_error(vol->sb, "Invalid length in mapping pairs " - "array."); - goto err_out; - } - /* - * Enter the current run length into the current runlist - * element. - */ - rl[rlpos].length = deltaxcn; - /* Increment the current vcn by the current run length. */ - vcn += deltaxcn; - /* - * There might be no lcn change at all, as is the case for - * sparse clusters on NTFS 3.0+, in which case we set the lcn - * to LCN_HOLE. - */ - if (!(*buf & 0xf0)) - rl[rlpos].lcn = LCN_HOLE; - else { - /* Get the lcn change which really can be negative. */ - u8 b2 = *buf & 0xf; - b = b2 + ((*buf >> 4) & 0xf); - if (buf + b > attr_end) - goto io_error; - for (deltaxcn = (s8)buf[b--]; b > b2; b--) - deltaxcn = (deltaxcn << 8) + buf[b]; - /* Change the current lcn to its new value. */ - lcn += deltaxcn; -#ifdef DEBUG - /* - * On NTFS 1.2-, apparently can have lcn == -1 to - * indicate a hole. But we haven't verified ourselves - * whether it is really the lcn or the deltaxcn that is - * -1. So if either is found give us a message so we - * can investigate it further! - */ - if (vol->major_ver < 3) { - if (unlikely(deltaxcn == (LCN)-1)) - ntfs_error(vol->sb, "lcn delta == -1"); - if (unlikely(lcn == (LCN)-1)) - ntfs_error(vol->sb, "lcn == -1"); - } -#endif - /* Check lcn is not below -1. */ - if (unlikely(lcn < (LCN)-1)) { - ntfs_error(vol->sb, "Invalid LCN < -1 in " - "mapping pairs array."); - goto err_out; - } - /* Enter the current lcn into the runlist element. */ - rl[rlpos].lcn = lcn; - } - /* Get to the next runlist element. */ - rlpos++; - /* Increment the buffer position to the next mapping pair. */ - buf += (*buf & 0xf) + ((*buf >> 4) & 0xf) + 1; - } - if (unlikely(buf >= attr_end)) - goto io_error; - /* - * If there is a highest_vcn specified, it must be equal to the final - * vcn in the runlist - 1, or something has gone badly wrong. - */ - deltaxcn = sle64_to_cpu(attr->data.non_resident.highest_vcn); - if (unlikely(deltaxcn && vcn - 1 != deltaxcn)) { -mpa_err: - ntfs_error(vol->sb, "Corrupt mapping pairs array in " - "non-resident attribute."); - goto err_out; - } - /* Setup not mapped runlist element if this is the base extent. */ - if (!attr->data.non_resident.lowest_vcn) { - VCN max_cluster; - - max_cluster = ((sle64_to_cpu( - attr->data.non_resident.allocated_size) + - vol->cluster_size - 1) >> - vol->cluster_size_bits) - 1; - /* - * A highest_vcn of zero means this is a single extent - * attribute so simply terminate the runlist with LCN_ENOENT). - */ - if (deltaxcn) { - /* - * If there is a difference between the highest_vcn and - * the highest cluster, the runlist is either corrupt - * or, more likely, there are more extents following - * this one. - */ - if (deltaxcn < max_cluster) { - ntfs_debug("More extents to follow; deltaxcn " - "= 0x%llx, max_cluster = " - "0x%llx", - (unsigned long long)deltaxcn, - (unsigned long long) - max_cluster); - rl[rlpos].vcn = vcn; - vcn += rl[rlpos].length = max_cluster - - deltaxcn; - rl[rlpos].lcn = LCN_RL_NOT_MAPPED; - rlpos++; - } else if (unlikely(deltaxcn > max_cluster)) { - ntfs_error(vol->sb, "Corrupt attribute. " - "deltaxcn = 0x%llx, " - "max_cluster = 0x%llx", - (unsigned long long)deltaxcn, - (unsigned long long) - max_cluster); - goto mpa_err; - } - } - rl[rlpos].lcn = LCN_ENOENT; - } else /* Not the base extent. There may be more extents to follow. */ - rl[rlpos].lcn = LCN_RL_NOT_MAPPED; - - /* Setup terminating runlist element. */ - rl[rlpos].vcn = vcn; - rl[rlpos].length = (s64)0; - /* If no existing runlist was specified, we are done. */ - if (!old_rl) { - ntfs_debug("Mapping pairs array successfully decompressed:"); - ntfs_debug_dump_runlist(rl); - return rl; - } - /* Now combine the new and old runlists checking for overlaps. */ - old_rl = ntfs_runlists_merge(old_rl, rl); - if (!IS_ERR(old_rl)) - return old_rl; - ntfs_free(rl); - ntfs_error(vol->sb, "Failed to merge runlists."); - return old_rl; -io_error: - ntfs_error(vol->sb, "Corrupt attribute."); -err_out: - ntfs_free(rl); - return ERR_PTR(-EIO); -} - -/** - * ntfs_rl_vcn_to_lcn - convert a vcn into a lcn given a runlist - * @rl: runlist to use for conversion - * @vcn: vcn to convert - * - * Convert the virtual cluster number @vcn of an attribute into a logical - * cluster number (lcn) of a device using the runlist @rl to map vcns to their - * corresponding lcns. - * - * It is up to the caller to serialize access to the runlist @rl. - * - * Since lcns must be >= 0, we use negative return codes with special meaning: - * - * Return code Meaning / Description - * ================================================== - * LCN_HOLE Hole / not allocated on disk. - * LCN_RL_NOT_MAPPED This is part of the runlist which has not been - * inserted into the runlist yet. - * LCN_ENOENT There is no such vcn in the attribute. - * - * Locking: - The caller must have locked the runlist (for reading or writing). - * - This function does not touch the lock, nor does it modify the - * runlist. - */ -LCN ntfs_rl_vcn_to_lcn(const runlist_element *rl, const VCN vcn) -{ - int i; - - BUG_ON(vcn < 0); - /* - * If rl is NULL, assume that we have found an unmapped runlist. The - * caller can then attempt to map it and fail appropriately if - * necessary. - */ - if (unlikely(!rl)) - return LCN_RL_NOT_MAPPED; - - /* Catch out of lower bounds vcn. */ - if (unlikely(vcn < rl[0].vcn)) - return LCN_ENOENT; - - for (i = 0; likely(rl[i].length); i++) { - if (unlikely(vcn < rl[i+1].vcn)) { - if (likely(rl[i].lcn >= (LCN)0)) - return rl[i].lcn + (vcn - rl[i].vcn); - return rl[i].lcn; - } - } - /* - * The terminator element is setup to the correct value, i.e. one of - * LCN_HOLE, LCN_RL_NOT_MAPPED, or LCN_ENOENT. - */ - if (likely(rl[i].lcn < (LCN)0)) - return rl[i].lcn; - /* Just in case... We could replace this with BUG() some day. */ - return LCN_ENOENT; -} - -#ifdef NTFS_RW - -/** - * ntfs_rl_find_vcn_nolock - find a vcn in a runlist - * @rl: runlist to search - * @vcn: vcn to find - * - * Find the virtual cluster number @vcn in the runlist @rl and return the - * address of the runlist element containing the @vcn on success. - * - * Return NULL if @rl is NULL or @vcn is in an unmapped part/out of bounds of - * the runlist. - * - * Locking: The runlist must be locked on entry. - */ -runlist_element *ntfs_rl_find_vcn_nolock(runlist_element *rl, const VCN vcn) -{ - BUG_ON(vcn < 0); - if (unlikely(!rl || vcn < rl[0].vcn)) - return NULL; - while (likely(rl->length)) { - if (unlikely(vcn < rl[1].vcn)) { - if (likely(rl->lcn >= LCN_HOLE)) - return rl; - return NULL; - } - rl++; - } - if (likely(rl->lcn == LCN_ENOENT)) - return rl; - return NULL; -} - -/** - * ntfs_get_nr_significant_bytes - get number of bytes needed to store a number - * @n: number for which to get the number of bytes for - * - * Return the number of bytes required to store @n unambiguously as - * a signed number. - * - * This is used in the context of the mapping pairs array to determine how - * many bytes will be needed in the array to store a given logical cluster - * number (lcn) or a specific run length. - * - * Return the number of bytes written. This function cannot fail. - */ -static inline int ntfs_get_nr_significant_bytes(const s64 n) -{ - s64 l = n; - int i; - s8 j; - - i = 0; - do { - l >>= 8; - i++; - } while (l != 0 && l != -1); - j = (n >> 8 * (i - 1)) & 0xff; - /* If the sign bit is wrong, we need an extra byte. */ - if ((n < 0 && j >= 0) || (n > 0 && j < 0)) - i++; - return i; -} - -/** - * 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 - * @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 @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. - * - * If @rl is NULL, just return 1 (for the single terminator byte). - * - * Return the calculated size in bytes on success. On error, return -errno. - * The following error codes are defined: - * -EINVAL - Run list contains unmapped elements. Make sure to only pass - * fully mapped runlists to this function. - * -EIO - The runlist is corrupt. - * - * Locking: @rl must be locked on entry (either for reading or writing), it - * 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 first_vcn, - const VCN last_vcn) -{ - LCN prev_lcn; - int rls; - bool the_end = false; - - BUG_ON(first_vcn < 0); - BUG_ON(last_vcn < -1); - BUG_ON(last_vcn >= 0 && first_vcn > last_vcn); - if (!rl) { - BUG_ON(first_vcn); - BUG_ON(last_vcn > 0); - return 1; - } - /* Skip to runlist element containing @first_vcn. */ - while (rl->length && first_vcn >= rl[1].vcn) - rl++; - 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 (first_vcn > rl->vcn) { - s64 delta, length = rl->length; - - /* We know rl->length != 0 already. */ - 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; - } - delta = first_vcn - rl->vcn; - /* Header byte + length. */ - 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 - * zero space. On earlier NTFS versions we just store the lcn. - * 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 (likely(rl->lcn >= 0 || vol->major_ver < 3)) { - prev_lcn = rl->lcn; - if (likely(rl->lcn >= 0)) - prev_lcn += delta; - /* Change in lcn. */ - rls += ntfs_get_nr_significant_bytes(prev_lcn); - } - /* Go to next runlist element. */ - rl++; - } - /* Do the full runs. */ - 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(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 - * zero space. On earlier NTFS versions we just store the lcn. - * 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 (likely(rl->lcn >= 0 || vol->major_ver < 3)) { - /* Change in lcn. */ - rls += ntfs_get_nr_significant_bytes(rl->lcn - - prev_lcn); - prev_lcn = rl->lcn; - } - } - return rls; -err_out: - if (rl->lcn == LCN_RL_NOT_MAPPED) - rls = -EINVAL; - else - rls = -EIO; - return rls; -} - -/** - * ntfs_write_significant_bytes - write the significant bytes of a number - * @dst: destination buffer to write to - * @dst_max: pointer to last byte of destination buffer for bounds checking - * @n: number whose significant bytes to write - * - * Store in @dst, the minimum bytes of the number @n which are required to - * identify @n unambiguously as a signed number, taking care not to exceed - * @dest_max, the maximum position within @dst to which we are allowed to - * write. - * - * This is used when building the mapping pairs array of a runlist to compress - * a given logical cluster number (lcn) or a specific run length to the minimum - * size possible. - * - * Return the number of bytes written on success. On error, i.e. the - * destination buffer @dst is too small, return -ENOSPC. - */ -static inline int ntfs_write_significant_bytes(s8 *dst, const s8 *dst_max, - const s64 n) -{ - s64 l = n; - int i; - s8 j; - - i = 0; - do { - if (unlikely(dst > dst_max)) - goto err_out; - *dst++ = l & 0xffll; - l >>= 8; - i++; - } while (l != 0 && l != -1); - j = (n >> 8 * (i - 1)) & 0xff; - /* If the sign bit is wrong, we need an extra byte. */ - if (n < 0 && j >= 0) { - if (unlikely(dst > dst_max)) - goto err_out; - i++; - *dst = (s8)-1; - } else if (n > 0 && j < 0) { - if (unlikely(dst > dst_max)) - goto err_out; - i++; - *dst = (s8)0; - } - return i; -err_out: - return -ENOSPC; -} - -/** - * ntfs_mapping_pairs_build - build the mapping pairs array from a runlist - * @vol: ntfs volume (needed for the ntfs version) - * @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 - * @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 - * @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. - * - * On success or -ENOSPC error, if @stop_vcn is not NULL, *@stop_vcn is set to - * the first vcn outside the destination buffer. Note that on error, @dst has - * 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 @first_vcn set to *@stop_vcn. - * - * Return 0 on success and -errno on error. The following error codes are - * defined: - * -EINVAL - Run list contains unmapped elements. Make sure to only pass - * fully mapped runlists to this function. - * -EIO - The runlist is corrupt. - * -ENOSPC - The destination buffer is too small. - * - * Locking: @rl must be locked on entry (either for reading or writing), it - * remains locked throughout, and is left locked upon return. - */ -int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst, - const int dst_len, const runlist_element *rl, - 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(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(first_vcn); - BUG_ON(last_vcn > 0); - if (stop_vcn) - *stop_vcn = 0; - /* Terminator byte. */ - *dst = 0; - return 0; - } - /* Skip to runlist element containing @first_vcn. */ - while (rl->length && first_vcn >= rl[1].vcn) - rl++; - if (unlikely((!rl->length && first_vcn > rl->vcn) || - first_vcn < rl->vcn)) - return -EINVAL; - /* - * @dst_max is used for bounds checking in - * ntfs_write_significant_bytes(). - */ - dst_max = dst + dst_len - 1; - prev_lcn = 0; - /* Do the first partial run if present. */ - if (first_vcn > rl->vcn) { - s64 delta, length = rl->length; - - /* We know rl->length != 0 already. */ - 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; - } - delta = first_vcn - rl->vcn; - /* Write length. */ - len_len = ntfs_write_significant_bytes(dst + 1, dst_max, - length - delta); - if (unlikely(len_len < 0)) - goto size_err; - /* - * 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 - * zero space. On earlier NTFS versions we just write the lcn - * change. FIXME: Do we need to write the lcn change or just - * the lcn in that case? Not sure as I have never seen this - * case on NT4. - We assume that we just need to write the lcn - * change until someone tells us otherwise... (AIA) - */ - if (likely(rl->lcn >= 0 || vol->major_ver < 3)) { - prev_lcn = rl->lcn; - 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 (unlikely(lcn_len < 0)) - goto size_err; - } else - lcn_len = 0; - dst_next = dst + len_len + lcn_len + 1; - if (unlikely(dst_next > dst_max)) - goto size_err; - /* Update header byte. */ - *dst = lcn_len << 4 | len_len; - /* Position at next mapping pairs array element. */ - dst = dst_next; - /* Go to next runlist element. */ - rl++; - } - /* Do the full runs. */ - 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, - length); - if (unlikely(len_len < 0)) - goto size_err; - /* - * 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 - * zero space. On earlier NTFS versions we just write the lcn - * change. FIXME: Do we need to write the lcn change or just - * the lcn in that case? Not sure as I have never seen this - * case on NT4. - We assume that we just need to write the lcn - * change until someone tells us otherwise... (AIA) - */ - 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 (unlikely(lcn_len < 0)) - goto size_err; - prev_lcn = rl->lcn; - } else - lcn_len = 0; - dst_next = dst + len_len + lcn_len + 1; - if (unlikely(dst_next > dst_max)) - goto size_err; - /* Update header byte. */ - *dst = lcn_len << 4 | len_len; - /* Position at next mapping pairs array element. */ - dst = dst_next; - } - /* Success. */ - err = 0; -size_err: - /* Set stop vcn. */ - if (stop_vcn) - *stop_vcn = rl->vcn; - /* Add terminator byte. */ - *dst = 0; - return err; -err_out: - if (rl->lcn == LCN_RL_NOT_MAPPED) - err = -EINVAL; - else - err = -EIO; - return err; -} - -/** - * ntfs_rl_truncate_nolock - truncate a runlist starting at a specified vcn - * @vol: ntfs volume (needed for error output) - * @runlist: runlist to truncate - * @new_length: the new length of the runlist in VCNs - * - * Truncate the runlist described by @runlist as well as the memory buffer - * holding the runlist elements to a length of @new_length VCNs. - * - * If @new_length lies within the runlist, the runlist elements with VCNs of - * @new_length and above are discarded. As a special case if @new_length is - * zero, the runlist is discarded and set to NULL. - * - * If @new_length lies beyond the runlist, a sparse runlist element is added to - * the end of the runlist @runlist or if the last runlist element is a sparse - * one already, this is extended. - * - * Note, no checking is done for unmapped runlist elements. It is assumed that - * the caller has mapped any elements that need to be mapped already. - * - * Return 0 on success and -errno on error. - * - * Locking: The caller must hold @runlist->lock for writing. - */ -int ntfs_rl_truncate_nolock(const ntfs_volume *vol, runlist *const runlist, - const s64 new_length) -{ - runlist_element *rl; - int old_size; - - ntfs_debug("Entering for new_length 0x%llx.", (long long)new_length); - BUG_ON(!runlist); - BUG_ON(new_length < 0); - rl = runlist->rl; - if (!new_length) { - ntfs_debug("Freeing runlist."); - runlist->rl = NULL; - if (rl) - ntfs_free(rl); - return 0; - } - if (unlikely(!rl)) { - /* - * Create a runlist consisting of a sparse runlist element of - * length @new_length followed by a terminator runlist element. - */ - rl = ntfs_malloc_nofs(PAGE_SIZE); - if (unlikely(!rl)) { - ntfs_error(vol->sb, "Not enough memory to allocate " - "runlist element buffer."); - return -ENOMEM; - } - runlist->rl = rl; - rl[1].length = rl->vcn = 0; - rl->lcn = LCN_HOLE; - rl[1].vcn = rl->length = new_length; - rl[1].lcn = LCN_ENOENT; - return 0; - } - BUG_ON(new_length < rl->vcn); - /* Find @new_length in the runlist. */ - while (likely(rl->length && new_length >= rl[1].vcn)) - rl++; - /* - * If not at the end of the runlist we need to shrink it. - * If at the end of the runlist we need to expand it. - */ - if (rl->length) { - runlist_element *trl; - bool is_end; - - ntfs_debug("Shrinking runlist."); - /* Determine the runlist size. */ - trl = rl + 1; - while (likely(trl->length)) - trl++; - old_size = trl - runlist->rl + 1; - /* Truncate the run. */ - rl->length = new_length - rl->vcn; - /* - * If a run was partially truncated, make the following runlist - * element a terminator. - */ - is_end = false; - if (rl->length) { - rl++; - if (!rl->length) - is_end = true; - rl->vcn = new_length; - rl->length = 0; - } - rl->lcn = LCN_ENOENT; - /* Reallocate memory if necessary. */ - if (!is_end) { - int new_size = rl - runlist->rl + 1; - rl = ntfs_rl_realloc(runlist->rl, old_size, new_size); - 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; - } - } else if (likely(/* !rl->length && */ new_length > rl->vcn)) { - ntfs_debug("Expanding runlist."); - /* - * If there is a previous runlist element and it is a sparse - * one, extend it. Otherwise need to add a new, sparse runlist - * element. - */ - if ((rl > runlist->rl) && ((rl - 1)->lcn == LCN_HOLE)) - (rl - 1)->length = new_length - (rl - 1)->vcn; - else { - /* Determine the runlist size. */ - old_size = rl - runlist->rl + 1; - /* Reallocate memory if necessary. */ - rl = ntfs_rl_realloc(runlist->rl, old_size, - old_size + 1); - if (IS_ERR(rl)) { - ntfs_error(vol->sb, "Failed to expand runlist " - "buffer, aborting."); - return PTR_ERR(rl); - } - runlist->rl = rl; - /* - * Set @rl to the same runlist element in the new - * runlist as before in the old runlist. - */ - rl += old_size - 1; - /* Add a new, sparse runlist element. */ - rl->lcn = LCN_HOLE; - rl->length = new_length - rl->vcn; - /* Add a new terminator runlist element. */ - rl++; - rl->length = 0; - } - rl->vcn = new_length; - rl->lcn = LCN_ENOENT; - } else /* if (unlikely(!rl->length && new_length == rl->vcn)) */ { - /* Runlist already has same size as requested. */ - rl->lcn = LCN_ENOENT; - } - ntfs_debug("Done."); - 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) { - 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 */ |