diff options
Diffstat (limited to 'fs/ntfs/runlist.c')
| -rw-r--r-- | fs/ntfs/runlist.c | 111 |
1 files changed, 81 insertions, 30 deletions
diff --git a/fs/ntfs/runlist.c b/fs/ntfs/runlist.c index 8438fb1da219..396d767c2cab 100644 --- a/fs/ntfs/runlist.c +++ b/fs/ntfs/runlist.c @@ -1,7 +1,7 @@ /** * runlist.c - NTFS runlist handling code. Part of the Linux-NTFS project. * - * Copyright (c) 2001-2004 Anton Altaparmakov + * Copyright (c) 2001-2005 Anton Altaparmakov * Copyright (c) 2002 Richard Russon * * This program/include file is free software; you can redistribute it and/or @@ -59,7 +59,7 @@ static inline void ntfs_rl_mc(runlist_element *dstbase, int dst, * * 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 and entire page of memory. + * memory, this function returns an entire page of memory. * * It is up to the caller to serialize access to the runlist @rl. * @@ -113,8 +113,11 @@ static inline BOOL ntfs_are_rl_mergeable(runlist_element *dst, BUG_ON(!dst); BUG_ON(!src); - if ((dst->lcn < 0) || (src->lcn < 0)) /* Are we merging holes? */ + 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? */ @@ -855,30 +858,42 @@ mpa_err: if (!attr->data.non_resident.lowest_vcn) { VCN max_cluster; - max_cluster = (sle64_to_cpu( + max_cluster = ((sle64_to_cpu( attr->data.non_resident.allocated_size) + vol->cluster_size - 1) >> - vol->cluster_size_bits; + vol->cluster_size_bits) - 1; /* - * 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. + * A highest_vcn of zero means this is a single extent + * attribute so simply terminate the runlist with LCN_ENOENT). */ - 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; + 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. */ @@ -918,17 +933,18 @@ err_out: * * It is up to the caller to serialize access to the runlist @rl. * - * Since lcns must be >= 0, we use negative return values with special meaning: + * Since lcns must be >= 0, we use negative return codes with special meaning: * - * Return value Meaning / Description + * Return code Meaning / Description * ================================================== - * -1 = LCN_HOLE Hole / not allocated on disk. - * -2 = LCN_RL_NOT_MAPPED This is part of the runlist which has not been - * inserted into the runlist yet. - * -3 = LCN_ENOENT There is no such vcn in the attribute. + * 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. + * - 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) { @@ -964,6 +980,39 @@ LCN ntfs_rl_vcn_to_lcn(const runlist_element *rl, const VCN vcn) 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 @@ -1436,3 +1485,5 @@ int ntfs_rl_truncate_nolock(const ntfs_volume *vol, runlist *const runlist, ntfs_debug("Done."); return 0; } + +#endif /* NTFS_RW */ |