pnfs: change lo refcounting to atomic_t
This will be required to allow us to grab reference outside of i_lock.
While we are at it, make put_layout_hdr take the same argument as all the
related functions.
Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index cd99064..32b6646 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -177,34 +177,38 @@
* pNFS client layout cache
*/
+/* Need to hold i_lock if caller does not already hold reference */
static void
-get_layout_hdr_locked(struct pnfs_layout_hdr *lo)
+get_layout_hdr(struct pnfs_layout_hdr *lo)
{
- assert_spin_locked(&lo->plh_inode->i_lock);
- lo->plh_refcount++;
+ atomic_inc(&lo->plh_refcount);
+}
+
+static void
+destroy_layout_hdr(struct pnfs_layout_hdr *lo)
+{
+ dprintk("%s: freeing layout cache %p\n", __func__, lo);
+ BUG_ON(!list_empty(&lo->plh_layouts));
+ NFS_I(lo->plh_inode)->layout = NULL;
+ kfree(lo);
}
static void
put_layout_hdr_locked(struct pnfs_layout_hdr *lo)
{
- assert_spin_locked(&lo->plh_inode->i_lock);
- BUG_ON(lo->plh_refcount == 0);
-
- lo->plh_refcount--;
- if (!lo->plh_refcount) {
- dprintk("%s: freeing layout cache %p\n", __func__, lo);
- BUG_ON(!list_empty(&lo->plh_layouts));
- NFS_I(lo->plh_inode)->layout = NULL;
- kfree(lo);
- }
+ if (atomic_dec_and_test(&lo->plh_refcount))
+ destroy_layout_hdr(lo);
}
void
-put_layout_hdr(struct inode *inode)
+put_layout_hdr(struct pnfs_layout_hdr *lo)
{
- spin_lock(&inode->i_lock);
- put_layout_hdr_locked(NFS_I(inode)->layout);
- spin_unlock(&inode->i_lock);
+ struct inode *inode = lo->plh_inode;
+
+ if (atomic_dec_and_lock(&lo->plh_refcount, &inode->i_lock)) {
+ destroy_layout_hdr(lo);
+ spin_unlock(&inode->i_lock);
+ }
}
static void
@@ -223,7 +227,7 @@
NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg);
/* Matched by get_layout_hdr in pnfs_insert_layout */
- put_layout_hdr(ino);
+ put_layout_hdr(NFS_I(ino)->layout);
}
/* The use of tmp_list is necessary because pnfs_curr_ld->free_lseg
@@ -490,7 +494,7 @@
__func__, lseg, lseg->pls_range.iomode,
lseg->pls_range.offset, lseg->pls_range.length);
}
- get_layout_hdr_locked(lo);
+ get_layout_hdr(lo);
dprintk("%s:Return\n", __func__);
}
@@ -503,7 +507,7 @@
lo = kzalloc(sizeof(struct pnfs_layout_hdr), GFP_KERNEL);
if (!lo)
return NULL;
- lo->plh_refcount = 1;
+ atomic_set(&lo->plh_refcount, 1);
INIT_LIST_HEAD(&lo->plh_layouts);
INIT_LIST_HEAD(&lo->plh_segs);
lo->plh_inode = ino;
@@ -618,7 +622,7 @@
goto out_unlock;
atomic_inc(&lo->plh_outstanding);
- get_layout_hdr_locked(lo);
+ get_layout_hdr(lo);
if (list_empty(&lo->plh_segs)) {
/* The lo must be on the clp list if there is any
* chance of a CB_LAYOUTRECALL(FILE) coming in.
@@ -641,7 +645,7 @@
spin_unlock(&ino->i_lock);
}
atomic_dec(&lo->plh_outstanding);
- put_layout_hdr(ino);
+ put_layout_hdr(lo);
out:
dprintk("%s end, state 0x%lx lseg %p\n", __func__,
nfsi->layout->plh_flags, lseg);
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index 698380d..8aaab56 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -65,7 +65,7 @@
};
struct pnfs_layout_hdr {
- unsigned long plh_refcount;
+ atomic_t plh_refcount;
struct list_head plh_layouts; /* other client layouts */
struct list_head plh_segs; /* layout segments list */
nfs4_stateid plh_stateid;
@@ -147,7 +147,7 @@
int pnfs_layout_process(struct nfs4_layoutget *lgp);
void pnfs_destroy_layout(struct nfs_inode *);
void pnfs_destroy_all_layouts(struct nfs_client *);
-void put_layout_hdr(struct inode *inode);
+void put_layout_hdr(struct pnfs_layout_hdr *lo);
int pnfs_choose_layoutget_stateid(nfs4_stateid *dst,
struct pnfs_layout_hdr *lo,
struct nfs4_state *open_state);
