NFSv4.1: lseg refcounting
Prepare put_lseg and get_lseg to be called from the pNFS I/O code.
Pull common code from pnfs_lseg_locked to call from pnfs_lseg.
Inline pnfs_lseg_locked into it's only caller.
Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 7d031cd..3afa82e 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -230,32 +230,41 @@
put_layout_hdr(NFS_I(ino)->layout);
}
-/* The use of tmp_list is necessary because pnfs_curr_ld->free_lseg
- * could sleep, so must be called outside of the lock.
- * Returns 1 if object was removed, otherwise return 0.
- */
-static int
-put_lseg_locked(struct pnfs_layout_segment *lseg,
- struct list_head *tmp_list)
+static void
+put_lseg_common(struct pnfs_layout_segment *lseg)
{
+ struct inode *inode = lseg->pls_layout->plh_inode;
+
+ BUG_ON(test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
+ list_del_init(&lseg->pls_list);
+ if (list_empty(&lseg->pls_layout->plh_segs)) {
+ set_bit(NFS_LAYOUT_DESTROYED, &lseg->pls_layout->plh_flags);
+ /* Matched by initial refcount set in alloc_init_layout_hdr */
+ put_layout_hdr_locked(lseg->pls_layout);
+ }
+ rpc_wake_up(&NFS_SERVER(inode)->roc_rpcwaitq);
+}
+
+static void
+put_lseg(struct pnfs_layout_segment *lseg)
+{
+ struct inode *inode;
+
+ if (!lseg)
+ return;
+
dprintk("%s: lseg %p ref %d valid %d\n", __func__, lseg,
atomic_read(&lseg->pls_refcount),
test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
- if (atomic_dec_and_test(&lseg->pls_refcount)) {
- struct inode *ino = lseg->pls_layout->plh_inode;
+ inode = lseg->pls_layout->plh_inode;
+ if (atomic_dec_and_lock(&lseg->pls_refcount, &inode->i_lock)) {
+ LIST_HEAD(free_me);
- BUG_ON(test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
- list_del(&lseg->pls_list);
- if (list_empty(&lseg->pls_layout->plh_segs)) {
- set_bit(NFS_LAYOUT_DESTROYED, &lseg->pls_layout->plh_flags);
- /* Matched by initial refcount set in alloc_init_layout_hdr */
- put_layout_hdr_locked(lseg->pls_layout);
- }
- rpc_wake_up(&NFS_SERVER(ino)->roc_rpcwaitq);
- list_add(&lseg->pls_list, tmp_list);
- return 1;
+ put_lseg_common(lseg);
+ list_add(&lseg->pls_list, &free_me);
+ spin_unlock(&inode->i_lock);
+ pnfs_free_lseg_list(&free_me);
}
- return 0;
}
static bool
@@ -276,7 +285,13 @@
* list. It will now be removed when all
* outstanding io is finished.
*/
- rv = put_lseg_locked(lseg, tmp_list);
+ dprintk("%s: lseg %p ref %d\n", __func__, lseg,
+ atomic_read(&lseg->pls_refcount));
+ if (atomic_dec_and_test(&lseg->pls_refcount)) {
+ put_lseg_common(lseg);
+ list_add(&lseg->pls_list, tmp_list);
+ rv = 1;
+ }
}
return rv;
}
@@ -689,7 +704,7 @@
list_for_each_entry(lseg, &lo->plh_segs, pls_list) {
if (test_bit(NFS_LSEG_VALID, &lseg->pls_flags) &&
is_matching_lseg(lseg, iomode)) {
- ret = lseg;
+ ret = get_lseg(lseg);
break;
}
if (cmp_layout(iomode, lseg->pls_range.iomode) > 0)
@@ -769,6 +784,7 @@
out:
dprintk("%s end, state 0x%lx lseg %p\n", __func__,
nfsi->layout ? nfsi->layout->plh_flags : -1, lseg);
+ put_lseg(lseg); /* STUB - callers currently ignore return value */
return lseg;
out_unlock:
spin_unlock(&ino->i_lock);
@@ -821,7 +837,7 @@
}
init_lseg(lo, lseg);
lseg->pls_range = res->range;
- *lgp->lsegpp = lseg;
+ *lgp->lsegpp = get_lseg(lseg);
pnfs_insert_layout(lo, lseg);
if (res->return_on_close) {