| /** |
| * runlist.c - NTFS runlist handling code. Part of the Linux-NTFS project. |
| * |
| * Copyright (c) 2001-2005 Anton Altaparmakov |
| * Copyright (c) 2002 Richard Russon |
| * |
| * This program/include file is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License as published |
| * by the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program/include file is distributed in the hope that it will be |
| * useful, but WITHOUT ANY WARRANTY; without even the implied warranty |
| * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program (in the main directory of the Linux-NTFS |
| * distribution in the file COPYING); if not, write to the Free Software |
| * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| */ |
| |
| #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); |
| |
| if ((dst->lcn < 0) || (src->lcn < 0)) { /* Are we merging holes? */ |
| if (dst->lcn == LCN_HOLE && src->lcn == LCN_HOLE) |
| return TRUE; |
| return FALSE; |
| } |
| if ((dst->lcn + dst->length) != src->lcn) /* Are the runs contiguous? */ |
| return FALSE; |
| if ((dst->vcn + dst->length) != src->vcn) /* Are the runs misaligned? */ |
| return FALSE; |
| |
| return TRUE; |
| } |
| |
| /** |
| * __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; |
| int magic; |
| |
| BUG_ON(!dst); |
| BUG_ON(!src); |
| |
| /* First, check if the right hand end needs merging. */ |
| 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); |
| |
| magic = loc + ssize; |
| |
| /* Move the tail of @dst out of the way, then copy in @src. */ |
| ntfs_rl_mm(dst, magic + 1, 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[magic + 1].lcn == LCN_ENOENT) |
| dst[magic + 1].vcn = dst[magic].vcn + dst[magic].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; |
| BOOL disc = FALSE; /* Discontinuity */ |
| BOOL hole = FALSE; /* Following a hole */ |
| int magic; |
| |
| 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 hole. |
| * hole => @dst ends with a hole or an unmapped region which we can |
| * extend to match the discontinuity. */ |
| 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); |
| if (disc) |
| hole = (dst[loc - 1].lcn == LCN_HOLE); |
| } |
| |
| /* Space required: @dst size + @src size, less one if we merged, plus |
| * one if there was a discontinuity, less one for a trailing hole. */ |
| dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left + disc - hole); |
| 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); |
| |
| magic = loc + ssize - left + disc - hole; |
| |
| /* Move the tail of @dst out of the way, then copy in @src. */ |
| ntfs_rl_mm(dst, magic, loc, dsize - loc); |
| ntfs_rl_mc(dst, loc + disc - hole, src, left, ssize - left); |
| |
| /* Adjust the VCN of the last run ... */ |
| if (dst[magic].lcn <= LCN_HOLE) |
| dst[magic].vcn = dst[magic - 1].vcn + dst[magic - 1].length; |
| /* ... and the length. */ |
| if (dst[magic].lcn == LCN_HOLE || dst[magic].lcn == LCN_RL_NOT_MAPPED) |
| dst[magic].length = dst[magic + 1].vcn - dst[magic].vcn; |
| |
| /* Writing beyond the end of the file and there's a discontinuity. */ |
| if (disc) { |
| if (hole) |
| dst[loc - 1].length = dst[loc].vcn - dst[loc - 1].vcn; |
| else { |
| 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; |
| } |
| |
| magic += hole; |
| |
| if (dst[magic].lcn == LCN_ENOENT) |
| dst[magic].vcn = dst[magic - 1].vcn + |
| dst[magic - 1].length; |
| } |
| 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) |
| { |
| BOOL left = FALSE; |
| BOOL right; |
| int magic; |
| |
| BUG_ON(!dst); |
| BUG_ON(!src); |
| |
| /* First, merge the left and right ends, if necessary. */ |
| 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'll need less if the left, right, or both |
| * ends were merged. */ |
| dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left - right); |
| if (IS_ERR(dst)) |
| return dst; |
| /* |
| * We are guaranteed to succeed from here so can start modifying the |
| * original runlists. |
| */ |
| if (right) |
| __ntfs_rl_merge(src + ssize - 1, dst + loc + 1); |
| if (left) |
| __ntfs_rl_merge(dst + loc - 1, src); |
| |
| /* FIXME: What does this mean? (AIA) */ |
| magic = loc + ssize - left; |
| |
| /* Move the tail of @dst out of the way, then copy in @src. */ |
| ntfs_rl_mm(dst, magic, loc + right + 1, dsize - loc - right - 1); |
| ntfs_rl_mc(dst, loc, src, left, ssize - left); |
| |
| /* We may have changed the length of the file, so fix the end marker */ |
| if (dst[magic].lcn == LCN_ENOENT) |
| dst[magic].vcn = dst[magic - 1].vcn + dst[magic - 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++) |
| ; |
| 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'll lose an end marker */ |
| if (start && finish && (drl[dins].length == 0)) |
| 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); |
| } |
| /* 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 (likely(!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 minumum |
| * 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 |
| * @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. |
| * |
| * 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. |
| * |
| * 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 (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; |
| } |
| |
| #endif /* NTFS_RW */ |