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authorDavid Teigland <teigland@redhat.com>2007-04-02 13:12:55 -0400
committerSteven Whitehouse <swhiteho@redhat.com>2007-05-01 04:11:15 -0400
commitce03f12b37c0bd81ad707d3642241cc55c944711 (patch)
tree11f6eba9b44a29d0c203c99c47d351152d25529a /fs/dlm
parent72c2be776bd6eec5186e316e6d9dd4aab78d314d (diff)
[DLM] change lkid format
A lock id is a uint32 and is used as an opaque reference to the lock. For userland apps, the lkid is passed up, through libdlm, as the return value from a write() on the dlm device. This created a problem when the high bit was 1, making the lkid look like an error. This is fixed by changing how the lkid is composed. The low 16 bits identified the hash bucket for the lock and the high 16 bits were a per-bucket counter (which eventually hit 0x8000 causing the problem). These are simply swapped around; the number of hash table buckets is far below 0x8000, making all lkid's positive when viewed as signed. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Diffstat (limited to 'fs/dlm')
-rw-r--r--fs/dlm/lock.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 9d26b3a39671..eac54d230fdc 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -580,7 +580,7 @@ static int create_lkb(struct dlm_ls *ls, struct dlm_lkb **lkb_ret)
580 /* counter can roll over so we must verify lkid is not in use */ 580 /* counter can roll over so we must verify lkid is not in use */
581 581
582 while (lkid == 0) { 582 while (lkid == 0) {
583 lkid = bucket | (ls->ls_lkbtbl[bucket].counter++ << 16); 583 lkid = (bucket << 16) | ls->ls_lkbtbl[bucket].counter++;
584 584
585 list_for_each_entry(tmp, &ls->ls_lkbtbl[bucket].list, 585 list_for_each_entry(tmp, &ls->ls_lkbtbl[bucket].list,
586 lkb_idtbl_list) { 586 lkb_idtbl_list) {
@@ -601,8 +601,8 @@ static int create_lkb(struct dlm_ls *ls, struct dlm_lkb **lkb_ret)
601 601
602static struct dlm_lkb *__find_lkb(struct dlm_ls *ls, uint32_t lkid) 602static struct dlm_lkb *__find_lkb(struct dlm_ls *ls, uint32_t lkid)
603{ 603{
604 uint16_t bucket = lkid & 0xFFFF;
605 struct dlm_lkb *lkb; 604 struct dlm_lkb *lkb;
605 uint16_t bucket = (lkid >> 16);
606 606
607 list_for_each_entry(lkb, &ls->ls_lkbtbl[bucket].list, lkb_idtbl_list) { 607 list_for_each_entry(lkb, &ls->ls_lkbtbl[bucket].list, lkb_idtbl_list) {
608 if (lkb->lkb_id == lkid) 608 if (lkb->lkb_id == lkid)
@@ -614,7 +614,7 @@ static struct dlm_lkb *__find_lkb(struct dlm_ls *ls, uint32_t lkid)
614static int find_lkb(struct dlm_ls *ls, uint32_t lkid, struct dlm_lkb **lkb_ret) 614static int find_lkb(struct dlm_ls *ls, uint32_t lkid, struct dlm_lkb **lkb_ret)
615{ 615{
616 struct dlm_lkb *lkb; 616 struct dlm_lkb *lkb;
617 uint16_t bucket = lkid & 0xFFFF; 617 uint16_t bucket = (lkid >> 16);
618 618
619 if (bucket >= ls->ls_lkbtbl_size) 619 if (bucket >= ls->ls_lkbtbl_size)
620 return -EBADSLT; 620 return -EBADSLT;
@@ -644,7 +644,7 @@ static void kill_lkb(struct kref *kref)
644 644
645static int __put_lkb(struct dlm_ls *ls, struct dlm_lkb *lkb) 645static int __put_lkb(struct dlm_ls *ls, struct dlm_lkb *lkb)
646{ 646{
647 uint16_t bucket = lkb->lkb_id & 0xFFFF; 647 uint16_t bucket = (lkb->lkb_id >> 16);
648 648
649 write_lock(&ls->ls_lkbtbl[bucket].lock); 649 write_lock(&ls->ls_lkbtbl[bucket].lock);
650 if (kref_put(&lkb->lkb_ref, kill_lkb)) { 650 if (kref_put(&lkb->lkb_ref, kill_lkb)) {