diff options
Diffstat (limited to 'fs/ntfs/runlist.c')
| -rw-r--r-- | fs/ntfs/runlist.c | 55 |
1 files changed, 33 insertions, 22 deletions
diff --git a/fs/ntfs/runlist.c b/fs/ntfs/runlist.c index e2665d011d7..061b5ff6b73 100644 --- a/fs/ntfs/runlist.c +++ b/fs/ntfs/runlist.c @@ -158,17 +158,21 @@ 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 == LCN_HOLE && src->lcn == LCN_HOLE) - return TRUE; + /* We can merge unmapped regions even if they are misaligned. */ + if ((dst->lcn == LCN_RL_NOT_MAPPED) && (src->lcn == LCN_RL_NOT_MAPPED)) + return TRUE; + /* If the runs are misaligned, we cannot merge them. */ + if ((dst->vcn + dst->length) != src->vcn) return FALSE; - } - if ((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; + /* If both runs are non-sparse and contiguous, we can merge them. */ + if ((dst->lcn >= 0) && (src->lcn >= 0) && + ((dst->lcn + dst->length) == src->lcn)) + return TRUE; + /* If we are merging two holes, we can merge them. */ + if ((dst->lcn == LCN_HOLE) && (src->lcn == LCN_HOLE)) + return TRUE; + /* Cannot merge. */ + return FALSE; } /** @@ -214,14 +218,15 @@ static inline void __ntfs_rl_merge(runlist_element *dst, runlist_element *src) static inline runlist_element *ntfs_rl_append(runlist_element *dst, int dsize, runlist_element *src, int ssize, int loc) { - BOOL right; /* Right end of @src needs merging. */ - int marker; /* End of the inserted runs. */ + BOOL right = FALSE; /* Right end of @src needs merging. */ + int marker; /* End of the inserted runs. */ BUG_ON(!dst); BUG_ON(!src); /* First, check if the right hand end needs merging. */ - right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1); + if ((loc + 1) < dsize) + right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1); /* Space required: @dst size + @src size, less one if we merged. */ dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - right); @@ -377,20 +382,21 @@ static inline runlist_element *ntfs_rl_replace(runlist_element *dst, int dsize, runlist_element *src, int ssize, int loc) { BOOL left = FALSE; /* Left end of @src needs merging. */ - BOOL right; /* Right end of @src needs merging. */ + BOOL right = FALSE; /* Right end of @src needs merging. */ int tail; /* Start of tail of @dst. */ int marker; /* End of the inserted runs. */ BUG_ON(!dst); BUG_ON(!src); - /* First, merge the left and right ends, if necessary. */ - right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1); + /* First, see if the left and right ends need merging. */ + if ((loc + 1) < dsize) + right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1); if (loc > 0) left = ntfs_are_rl_mergeable(dst + loc - 1, src); /* * Allocate some space. We will need less if the left, right, or both - * ends were merged. + * ends get merged. */ dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left - right); if (IS_ERR(dst)) @@ -399,21 +405,26 @@ static inline runlist_element *ntfs_rl_replace(runlist_element *dst, * We are guaranteed to succeed from here so can start modifying the * original runlists. */ + + /* First, merge the left and right ends, if necessary. */ if (right) __ntfs_rl_merge(src + ssize - 1, dst + loc + 1); if (left) __ntfs_rl_merge(dst + loc - 1, src); /* - * First run of @dst that needs to be moved out of the way to make - * space for the runs to be copied from @src, i.e. the first run of the - * tail of @dst. + * Offset of the tail of @dst. This needs to be moved out of the way + * to make space for the runs to be copied from @src, i.e. the first + * run of the tail of @dst. + * Nominally, @tail equals @loc + 1, i.e. location, skipping the + * replaced run. However, if @right, then one of @dst's runs is + * already merged into @src. */ tail = loc + right + 1; /* * First run after the @src runs that have been inserted, i.e. where * the tail of @dst needs to be moved to. - * Nominally, marker equals @loc + @ssize, i.e. location + number of - * runs in @src). However, if @left, then the first run in @src has + * Nominally, @marker equals @loc + @ssize, i.e. location + number of + * runs in @src. However, if @left, then the first run in @src has * been merged with one in @dst. */ marker = loc + ssize - left; |