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@xxxxxxxxxx>
---
fs/nfs/pnfs.c | 50 ++++++++++++++++++++++++++++----------------------
fs/nfs/pnfs.h | 4 ++--
2 files changed, 30 insertions(+), 24 deletions(-)
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 8dbe90c..f49d288 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -177,34 +177,40 @@ EXPORT_SYMBOL_GPL(pnfs_unregister_layoutdriver);
* 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->inode->i_lock);
- lo->refcount++;
+ atomic_inc(&lo->plh_refcount);
}
static void
-put_layout_hdr_locked(struct pnfs_layout_hdr *lo)
+destroy_layout_hdr(struct pnfs_layout_hdr *lo)
{
- assert_spin_locked(&lo->inode->i_lock);
- BUG_ON(lo->refcount == 0);
+ dprintk("%s: freeing layout cache %p\n", __func__, lo);
+ BUG_ON(!list_empty(&lo->layouts));
+ NFS_I(lo->inode)->layout = NULL;
+ kfree(lo);
+}
- lo->refcount--;
- if (!lo->refcount) {
- dprintk("%s: freeing layout cache %p\n", __func__, lo);
- BUG_ON(!list_empty(&lo->layouts));
- NFS_I(lo->inode)->layout = NULL;
- kfree(lo);
- }
+static void
+put_layout_hdr_locked(struct pnfs_layout_hdr *lo)
+{
+ BUG_ON(atomic_read(&lo->plh_refcount) == 0);
+ 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->inode;
+
+ BUG_ON(atomic_read(&lo->plh_refcount) == 0);
+ if (atomic_dec_and_lock(&lo->plh_refcount, &inode->i_lock)) {
+ destroy_layout_hdr(lo);
+ spin_unlock(&inode->i_lock);
+ }
}
static void
@@ -224,7 +230,7 @@ static void free_lseg(struct pnfs_layout_segment *lseg)
BUG_ON(atomic_read(&lseg->pls_refcount) != 0);
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
@@ -484,7 +490,7 @@ pnfs_insert_layout(struct pnfs_layout_hdr *lo,
__func__, lseg, lseg->range.iomode,
lseg->range.offset, lseg->range.length);
}
- get_layout_hdr_locked(lo);
+ get_layout_hdr(lo);
dprintk("%s:Return\n", __func__);
}
@@ -497,7 +503,7 @@ alloc_init_layout_hdr(struct inode *ino)
lo = kzalloc(sizeof(struct pnfs_layout_hdr), GFP_KERNEL);
if (!lo)
return NULL;
- lo->refcount = 1;
+ atomic_set(&lo->plh_refcount, 1);
INIT_LIST_HEAD(&lo->layouts);
INIT_LIST_HEAD(&lo->segs);
lo->inode = ino;
@@ -612,7 +618,7 @@ pnfs_update_layout(struct inode *ino,
goto out_unlock;
atomic_inc(&lo->plh_outstanding);
- get_layout_hdr_locked(lo);
+ get_layout_hdr(lo);
if (list_empty(&lo->segs)) {
/* The lo must be on the clp list if there is any
* chance of a CB_LAYOUTRECALL(FILE) coming in.
@@ -635,7 +641,7 @@ pnfs_update_layout(struct inode *ino,
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 0b8070f..3cf6856 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -65,7 +65,7 @@ struct pnfs_layoutdriver_type {
};
struct pnfs_layout_hdr {
- unsigned long refcount;
+ atomic_t plh_refcount;
struct list_head layouts; /* other client layouts */
struct list_head segs; /* layout segments list */
nfs4_stateid stateid;
@@ -147,7 +147,7 @@ void unset_pnfs_layoutdriver(struct nfs_server *);
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);
--
1.7.2.1
--
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