From b065556a7d1a9205403db77a318a5c5aa530e701 Mon Sep 17 00:00:00 2001 From: Tao Ma Date: Thu, 8 Apr 2010 16:33:02 +0800 Subject: [PATCH] ocfs2: make ocfs2_adjust_resv_from_alloc simple. When we allocate some bits from the reservation, we always allocate from the r_start(see ocfs2_resmap_resv_bits). So there should be no reason to check between r_start and start. And I don't think we will change this behaviour later by allocating from some bits after r_start. Why not make ocfs2_adjust_resv_from_alloc simple for now? The only chance we have to adjust the reservation is when we haven't reached the end. With this patch, the function is more readable. Note: btw, this patch also fixes an original bug in the function which I haven't found before. if (end < ocfs2_resv_end(resv)) rhs = end - ocfs2_resv_end(resv); This code is of course buggy. ;) Signed-off-by: Tao Ma Acked-by: Mark Fasheh Signed-off-by: Joel Becker --- fs/ocfs2/reservations.c | 32 ++++++++++++-------------------- fs/ocfs2/reservations.h | 3 ++- 2 files changed, 14 insertions(+), 21 deletions(-) diff --git a/fs/ocfs2/reservations.c b/fs/ocfs2/reservations.c index 6497bcc00fa5..cb813ef98846 100644 --- a/fs/ocfs2/reservations.c +++ b/fs/ocfs2/reservations.c @@ -408,7 +408,7 @@ ocfs2_find_resv_lhs(struct ocfs2_reservation_map *resmap, unsigned int goal) * The start value of *rstart is insignificant. * * This function searches the bitmap range starting at search_start - * with length csearch_len for a set of contiguous free bits. We try + * with length search_len for a set of contiguous free bits. We try * to find up to 'wanted' bits, but can sometimes return less. * * Returns the length of allocation, 0 if no free bits are found. @@ -778,38 +778,28 @@ static void struct ocfs2_alloc_reservation *resv, unsigned int start, unsigned int end) { - unsigned int lhs = 0, rhs = 0; + unsigned int rhs = 0; + unsigned int old_end = ocfs2_resv_end(resv); - BUG_ON(start < resv->r_start); + BUG_ON(start != resv->r_start || old_end < end); /* * Completely used? We can remove it then. */ - if (ocfs2_resv_end(resv) <= end && resv->r_start >= start) { + if (old_end == end) { __ocfs2_resv_discard(resmap, resv); return; } - if (end < ocfs2_resv_end(resv)) - rhs = end - ocfs2_resv_end(resv); - - if (start > resv->r_start) - lhs = start - resv->r_start; + rhs = old_end - end; /* - * This should have been trapped above. At the very least, rhs - * should be non zero. + * This should have been trapped above. */ - BUG_ON(rhs == 0 && lhs == 0); + BUG_ON(rhs == 0); - if (rhs >= lhs) { - unsigned int old_end = ocfs2_resv_end(resv); - - resv->r_start = end + 1; - resv->r_len = old_end - resv->r_start + 1; - } else { - resv->r_len = start - resv->r_start; - } + resv->r_start = end + 1; + resv->r_len = old_end - resv->r_start + 1; } void ocfs2_resmap_claimed_bits(struct ocfs2_reservation_map *resmap, @@ -824,6 +814,8 @@ void ocfs2_resmap_claimed_bits(struct ocfs2_reservation_map *resmap, if (resv == NULL) return; + BUG_ON(cstart != resv->r_start); + spin_lock(&resv_lock); mlog(0, "claim bits: cstart: %u cend: %u clen: %u r_start: %u " diff --git a/fs/ocfs2/reservations.h b/fs/ocfs2/reservations.h index 25b0c0e31e91..1e49cc29d06c 100644 --- a/fs/ocfs2/reservations.h +++ b/fs/ocfs2/reservations.h @@ -149,7 +149,8 @@ int ocfs2_resmap_resv_bits(struct ocfs2_reservation_map *resmap, * reservation. But we must always call this function when bits are claimed. * Internally, the reservations code will use this information to mark the * reservations bitmap. If resv is passed, it's next allocation window will be - * calculated. + * calculated. It also expects that 'cstart' is the same as we passed back + * from ocfs2_resmap_resv_bits(). */ void ocfs2_resmap_claimed_bits(struct ocfs2_reservation_map *resmap, struct ocfs2_alloc_reservation *resv,