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1893 lines
59 KiB
1893 lines
59 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/** |
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* runlist.c - NTFS runlist handling code. Part of the Linux-NTFS project. |
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* |
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* Copyright (c) 2001-2007 Anton Altaparmakov |
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* Copyright (c) 2002-2005 Richard Russon |
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*/ |
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|
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#include "debug.h" |
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#include "dir.h" |
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#include "endian.h" |
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#include "malloc.h" |
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#include "ntfs.h" |
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|
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/** |
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* ntfs_rl_mm - runlist memmove |
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* |
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* It is up to the caller to serialize access to the runlist @base. |
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*/ |
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static inline void ntfs_rl_mm(runlist_element *base, int dst, int src, |
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int size) |
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{ |
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if (likely((dst != src) && (size > 0))) |
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memmove(base + dst, base + src, size * sizeof(*base)); |
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} |
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/** |
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* ntfs_rl_mc - runlist memory copy |
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* |
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* It is up to the caller to serialize access to the runlists @dstbase and |
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* @srcbase. |
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*/ |
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static inline void ntfs_rl_mc(runlist_element *dstbase, int dst, |
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runlist_element *srcbase, int src, int size) |
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{ |
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if (likely(size > 0)) |
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memcpy(dstbase + dst, srcbase + src, size * sizeof(*dstbase)); |
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} |
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|
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/** |
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* ntfs_rl_realloc - Reallocate memory for runlists |
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* @rl: original runlist |
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* @old_size: number of runlist elements in the original runlist @rl |
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* @new_size: number of runlist elements we need space for |
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* |
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* As the runlists grow, more memory will be required. To prevent the |
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* kernel having to allocate and reallocate large numbers of small bits of |
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* memory, this function returns an entire page of memory. |
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* |
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* It is up to the caller to serialize access to the runlist @rl. |
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* |
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* N.B. If the new allocation doesn't require a different number of pages in |
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* memory, the function will return the original pointer. |
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* |
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* On success, return a pointer to the newly allocated, or recycled, memory. |
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* On error, return -errno. The following error codes are defined: |
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* -ENOMEM - Not enough memory to allocate runlist array. |
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* -EINVAL - Invalid parameters were passed in. |
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*/ |
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static inline runlist_element *ntfs_rl_realloc(runlist_element *rl, |
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int old_size, int new_size) |
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{ |
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runlist_element *new_rl; |
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|
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old_size = PAGE_ALIGN(old_size * sizeof(*rl)); |
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new_size = PAGE_ALIGN(new_size * sizeof(*rl)); |
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if (old_size == new_size) |
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return rl; |
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new_rl = ntfs_malloc_nofs(new_size); |
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if (unlikely(!new_rl)) |
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return ERR_PTR(-ENOMEM); |
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|
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if (likely(rl != NULL)) { |
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if (unlikely(old_size > new_size)) |
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old_size = new_size; |
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memcpy(new_rl, rl, old_size); |
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ntfs_free(rl); |
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} |
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return new_rl; |
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} |
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/** |
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* ntfs_rl_realloc_nofail - Reallocate memory for runlists |
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* @rl: original runlist |
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* @old_size: number of runlist elements in the original runlist @rl |
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* @new_size: number of runlist elements we need space for |
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* |
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* As the runlists grow, more memory will be required. To prevent the |
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* kernel having to allocate and reallocate large numbers of small bits of |
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* memory, this function returns an entire page of memory. |
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* |
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* This function guarantees that the allocation will succeed. It will sleep |
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* for as long as it takes to complete the allocation. |
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* |
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* It is up to the caller to serialize access to the runlist @rl. |
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* |
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* N.B. If the new allocation doesn't require a different number of pages in |
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* memory, the function will return the original pointer. |
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* |
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* On success, return a pointer to the newly allocated, or recycled, memory. |
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* On error, return -errno. The following error codes are defined: |
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* -ENOMEM - Not enough memory to allocate runlist array. |
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* -EINVAL - Invalid parameters were passed in. |
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*/ |
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static inline runlist_element *ntfs_rl_realloc_nofail(runlist_element *rl, |
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int old_size, int new_size) |
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{ |
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runlist_element *new_rl; |
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|
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old_size = PAGE_ALIGN(old_size * sizeof(*rl)); |
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new_size = PAGE_ALIGN(new_size * sizeof(*rl)); |
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if (old_size == new_size) |
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return rl; |
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new_rl = ntfs_malloc_nofs_nofail(new_size); |
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BUG_ON(!new_rl); |
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|
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if (likely(rl != NULL)) { |
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if (unlikely(old_size > new_size)) |
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old_size = new_size; |
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memcpy(new_rl, rl, old_size); |
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ntfs_free(rl); |
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} |
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return new_rl; |
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} |
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/** |
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* ntfs_are_rl_mergeable - test if two runlists can be joined together |
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* @dst: original runlist |
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* @src: new runlist to test for mergeability with @dst |
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* |
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* Test if two runlists can be joined together. For this, their VCNs and LCNs |
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* must be adjacent. |
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* |
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* It is up to the caller to serialize access to the runlists @dst and @src. |
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* |
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* Return: true Success, the runlists can be merged. |
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* false Failure, the runlists cannot be merged. |
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*/ |
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static inline bool ntfs_are_rl_mergeable(runlist_element *dst, |
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runlist_element *src) |
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{ |
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BUG_ON(!dst); |
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BUG_ON(!src); |
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/* We can merge unmapped regions even if they are misaligned. */ |
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if ((dst->lcn == LCN_RL_NOT_MAPPED) && (src->lcn == LCN_RL_NOT_MAPPED)) |
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return true; |
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/* If the runs are misaligned, we cannot merge them. */ |
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if ((dst->vcn + dst->length) != src->vcn) |
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return false; |
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/* If both runs are non-sparse and contiguous, we can merge them. */ |
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if ((dst->lcn >= 0) && (src->lcn >= 0) && |
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((dst->lcn + dst->length) == src->lcn)) |
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return true; |
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/* If we are merging two holes, we can merge them. */ |
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if ((dst->lcn == LCN_HOLE) && (src->lcn == LCN_HOLE)) |
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return true; |
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/* Cannot merge. */ |
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return false; |
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} |
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/** |
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* __ntfs_rl_merge - merge two runlists without testing if they can be merged |
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* @dst: original, destination runlist |
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* @src: new runlist to merge with @dst |
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* |
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* Merge the two runlists, writing into the destination runlist @dst. The |
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* caller must make sure the runlists can be merged or this will corrupt the |
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* destination runlist. |
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* |
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* It is up to the caller to serialize access to the runlists @dst and @src. |
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*/ |
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static inline void __ntfs_rl_merge(runlist_element *dst, runlist_element *src) |
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{ |
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dst->length += src->length; |
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} |
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/** |
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* ntfs_rl_append - append a runlist after a given element |
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* @dst: original runlist to be worked on |
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* @dsize: number of elements in @dst (including end marker) |
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* @src: runlist to be inserted into @dst |
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* @ssize: number of elements in @src (excluding end marker) |
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* @loc: append the new runlist @src after this element in @dst |
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* |
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* Append the runlist @src after element @loc in @dst. Merge the right end of |
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* the new runlist, if necessary. Adjust the size of the hole before the |
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* appended runlist. |
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* |
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* It is up to the caller to serialize access to the runlists @dst and @src. |
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* |
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* On success, return a pointer to the new, combined, runlist. Note, both |
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* runlists @dst and @src are deallocated before returning so you cannot use |
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* the pointers for anything any more. (Strictly speaking the returned runlist |
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* may be the same as @dst but this is irrelevant.) |
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* |
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* On error, return -errno. Both runlists are left unmodified. The following |
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* error codes are defined: |
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* -ENOMEM - Not enough memory to allocate runlist array. |
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* -EINVAL - Invalid parameters were passed in. |
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*/ |
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static inline runlist_element *ntfs_rl_append(runlist_element *dst, |
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int dsize, runlist_element *src, int ssize, int loc) |
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{ |
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bool right = false; /* Right end of @src needs merging. */ |
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int marker; /* End of the inserted runs. */ |
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BUG_ON(!dst); |
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BUG_ON(!src); |
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/* First, check if the right hand end needs merging. */ |
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if ((loc + 1) < dsize) |
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right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1); |
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/* Space required: @dst size + @src size, less one if we merged. */ |
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dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - right); |
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if (IS_ERR(dst)) |
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return dst; |
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/* |
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* We are guaranteed to succeed from here so can start modifying the |
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* original runlists. |
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*/ |
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/* First, merge the right hand end, if necessary. */ |
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if (right) |
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__ntfs_rl_merge(src + ssize - 1, dst + loc + 1); |
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|
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/* First run after the @src runs that have been inserted. */ |
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marker = loc + ssize + 1; |
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/* Move the tail of @dst out of the way, then copy in @src. */ |
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ntfs_rl_mm(dst, marker, loc + 1 + right, dsize - (loc + 1 + right)); |
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ntfs_rl_mc(dst, loc + 1, src, 0, ssize); |
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/* Adjust the size of the preceding hole. */ |
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dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn; |
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/* We may have changed the length of the file, so fix the end marker */ |
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if (dst[marker].lcn == LCN_ENOENT) |
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dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length; |
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return dst; |
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} |
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/** |
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* ntfs_rl_insert - insert a runlist into another |
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* @dst: original runlist to be worked on |
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* @dsize: number of elements in @dst (including end marker) |
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* @src: new runlist to be inserted |
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* @ssize: number of elements in @src (excluding end marker) |
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* @loc: insert the new runlist @src before this element in @dst |
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* |
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* Insert the runlist @src before element @loc in the runlist @dst. Merge the |
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* left end of the new runlist, if necessary. Adjust the size of the hole |
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* after the inserted runlist. |
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* |
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* It is up to the caller to serialize access to the runlists @dst and @src. |
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* |
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* On success, return a pointer to the new, combined, runlist. Note, both |
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* runlists @dst and @src are deallocated before returning so you cannot use |
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* the pointers for anything any more. (Strictly speaking the returned runlist |
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* may be the same as @dst but this is irrelevant.) |
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* |
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* On error, return -errno. Both runlists are left unmodified. The following |
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* error codes are defined: |
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* -ENOMEM - Not enough memory to allocate runlist array. |
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* -EINVAL - Invalid parameters were passed in. |
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*/ |
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static inline runlist_element *ntfs_rl_insert(runlist_element *dst, |
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int dsize, runlist_element *src, int ssize, int loc) |
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{ |
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bool left = false; /* Left end of @src needs merging. */ |
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bool disc = false; /* Discontinuity between @dst and @src. */ |
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int marker; /* End of the inserted runs. */ |
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BUG_ON(!dst); |
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BUG_ON(!src); |
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/* |
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* disc => Discontinuity between the end of @dst and the start of @src. |
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* This means we might need to insert a "not mapped" run. |
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*/ |
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if (loc == 0) |
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disc = (src[0].vcn > 0); |
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else { |
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s64 merged_length; |
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left = ntfs_are_rl_mergeable(dst + loc - 1, src); |
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merged_length = dst[loc - 1].length; |
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if (left) |
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merged_length += src->length; |
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disc = (src[0].vcn > dst[loc - 1].vcn + merged_length); |
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} |
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/* |
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* Space required: @dst size + @src size, less one if we merged, plus |
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* one if there was a discontinuity. |
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*/ |
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dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left + disc); |
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if (IS_ERR(dst)) |
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return dst; |
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/* |
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* We are guaranteed to succeed from here so can start modifying the |
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* original runlist. |
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*/ |
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if (left) |
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__ntfs_rl_merge(dst + loc - 1, src); |
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/* |
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* First run after the @src runs that have been inserted. |
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* Nominally, @marker equals @loc + @ssize, i.e. location + number of |
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* runs in @src. However, if @left, then the first run in @src has |
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* been merged with one in @dst. And if @disc, then @dst and @src do |
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* not meet and we need an extra run to fill the gap. |
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*/ |
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marker = loc + ssize - left + disc; |
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|
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/* Move the tail of @dst out of the way, then copy in @src. */ |
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ntfs_rl_mm(dst, marker, loc, dsize - loc); |
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ntfs_rl_mc(dst, loc + disc, src, left, ssize - left); |
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|
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/* Adjust the VCN of the first run after the insertion... */ |
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dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length; |
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/* ... and the length. */ |
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if (dst[marker].lcn == LCN_HOLE || dst[marker].lcn == LCN_RL_NOT_MAPPED) |
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dst[marker].length = dst[marker + 1].vcn - dst[marker].vcn; |
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|
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/* Writing beyond the end of the file and there is a discontinuity. */ |
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if (disc) { |
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if (loc > 0) { |
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dst[loc].vcn = dst[loc - 1].vcn + dst[loc - 1].length; |
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dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn; |
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} else { |
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dst[loc].vcn = 0; |
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dst[loc].length = dst[loc + 1].vcn; |
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} |
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dst[loc].lcn = LCN_RL_NOT_MAPPED; |
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} |
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return dst; |
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} |
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|
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/** |
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* ntfs_rl_replace - overwrite a runlist element with another runlist |
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* @dst: original runlist to be worked on |
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* @dsize: number of elements in @dst (including end marker) |
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* @src: new runlist to be inserted |
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* @ssize: number of elements in @src (excluding end marker) |
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* @loc: index in runlist @dst to overwrite with @src |
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* |
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* Replace the runlist element @dst at @loc with @src. Merge the left and |
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* right ends of the inserted runlist, if necessary. |
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* |
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* It is up to the caller to serialize access to the runlists @dst and @src. |
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* |
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* On success, return a pointer to the new, combined, runlist. Note, both |
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* runlists @dst and @src are deallocated before returning so you cannot use |
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* the pointers for anything any more. (Strictly speaking the returned runlist |
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* may be the same as @dst but this is irrelevant.) |
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* |
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* On error, return -errno. Both runlists are left unmodified. The following |
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* error codes are defined: |
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* -ENOMEM - Not enough memory to allocate runlist array. |
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* -EINVAL - Invalid parameters were passed in. |
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*/ |
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static inline runlist_element *ntfs_rl_replace(runlist_element *dst, |
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int dsize, runlist_element *src, int ssize, int loc) |
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{ |
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signed delta; |
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bool left = false; /* Left end of @src needs merging. */ |
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bool right = false; /* Right end of @src needs merging. */ |
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int tail; /* Start of tail of @dst. */ |
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int marker; /* End of the inserted runs. */ |
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|
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BUG_ON(!dst); |
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BUG_ON(!src); |
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|
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/* First, see if the left and right ends need merging. */ |
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if ((loc + 1) < dsize) |
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right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1); |
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if (loc > 0) |
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left = ntfs_are_rl_mergeable(dst + loc - 1, src); |
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/* |
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* Allocate some space. We will need less if the left, right, or both |
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* ends get merged. The -1 accounts for the run being replaced. |
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*/ |
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delta = ssize - 1 - left - right; |
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if (delta > 0) { |
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dst = ntfs_rl_realloc(dst, dsize, dsize + delta); |
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if (IS_ERR(dst)) |
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return dst; |
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} |
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/* |
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* We are guaranteed to succeed from here so can start modifying the |
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* original runlists. |
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*/ |
|
|
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/* First, merge the left and right ends, if necessary. */ |
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if (right) |
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__ntfs_rl_merge(src + ssize - 1, dst + loc + 1); |
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if (left) |
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__ntfs_rl_merge(dst + loc - 1, src); |
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/* |
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* Offset of the tail of @dst. This needs to be moved out of the way |
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* to make space for the runs to be copied from @src, i.e. the first |
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* run of the tail of @dst. |
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* Nominally, @tail equals @loc + 1, i.e. location, skipping the |
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* replaced run. However, if @right, then one of @dst's runs is |
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* already merged into @src. |
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*/ |
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tail = loc + right + 1; |
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/* |
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* First run after the @src runs that have been inserted, i.e. where |
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* the tail of @dst needs to be moved to. |
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* Nominally, @marker equals @loc + @ssize, i.e. location + number of |
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* runs in @src. However, if @left, then the first run in @src has |
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* been merged with one in @dst. |
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*/ |
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marker = loc + ssize - left; |
|
|
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/* Move the tail of @dst out of the way, then copy in @src. */ |
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ntfs_rl_mm(dst, marker, tail, dsize - tail); |
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ntfs_rl_mc(dst, loc, src, left, ssize - left); |
|
|
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/* We may have changed the length of the file, so fix the end marker. */ |
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if (dsize - tail > 0 && dst[marker].lcn == LCN_ENOENT) |
|
dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length; |
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return dst; |
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} |
|
|
|
/** |
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* ntfs_rl_split - insert a runlist into the centre of a hole |
|
* @dst: original runlist to be worked on |
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* @dsize: number of elements in @dst (including end marker) |
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* @src: new runlist to be inserted |
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* @ssize: number of elements in @src (excluding end marker) |
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* @loc: index in runlist @dst at which to split and insert @src |
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* |
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* Split the runlist @dst at @loc into two and insert @new in between the two |
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* fragments. No merging of runlists is necessary. Adjust the size of the |
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* holes either side. |
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* |
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* 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, |
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runlist_element *src, int ssize, int loc) |
|
{ |
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BUG_ON(!dst); |
|
BUG_ON(!src); |
|
|
|
/* Space required: @dst size + @src size + one new hole. */ |
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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); |
|
|
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/* 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; |
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dst[loc+ssize+1].length = dst[loc+ssize+2].vcn - dst[loc+ssize+1].vcn; |
|
|
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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 |
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* are sensible and can be merged. The runlist @srl must be either after the |
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* runlist @drl or completely within a hole (or unmapped region) in @drl. |
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* |
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* 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 */
|
|
|