[PATCH v2 3/3] NFSv4.1: Add a helper pnfs_commit_and_return_layout

Trond Myklebust
2013-03-21T14:13:07Z

In order to be able to safely return the layout in nfs4_proc_setattr,
we need to block new uses of the layout, wait for all outstanding
users of the layout to complete, commit the layout and then return it.

This patch adds a helper in order to do all this safely.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Boaz Harrosh <bharrosh@panasas.com>
---
fs/nfs/nfs4proc.c | 2 +-
fs/nfs/pnfs.c | 27 +++++++++++++++++++++++++++
fs/nfs/pnfs.h | 6 ++++++
3 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 6ccdd4f..26431cf 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2632,7 +2632,7 @@ nfs4_proc_setattr(struct dentry *dentry, struct nfs_fattr *fattr,
int status;

if (pnfs_ld_layoutret_on_setattr(inode))
- pnfs_return_layout(inode);
+ pnfs_commit_and_return_layout(inode);

nfs_fattr_init(fattr);

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index b9d0682..2b5d98e 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -866,6 +866,33 @@ out:
}
EXPORT_SYMBOL_GPL(_pnfs_return_layout);

+int
+pnfs_commit_and_return_layout(struct inode *inode)
+{
+ struct pnfs_layout_hdr *lo;
+ int ret;
+
+ spin_lock(&inode->i_lock);
+ lo = NFS_I(inode)->layout;
+ if (lo == NULL) {
+ spin_unlock(&inode->i_lock);
+ return 0;
+ }
+ pnfs_get_layout_hdr(lo);
+ /* Block new layoutgets and read/write to ds */
+ lo->plh_block_lgets++;
+ spin_unlock(&inode->i_lock);
+ filemap_fdatawait(inode->i_mapping);
+ ret = pnfs_layoutcommit_inode(inode, true);
+ if (ret == 0)
+ ret = _pnfs_return_layout(inode);
+ spin_lock(&inode->i_lock);
+ lo->plh_block_lgets--;
+ spin_unlock(&inode->i_lock);
+ pnfs_put_layout_hdr(lo);
+ return ret;
+}
+
bool pnfs_roc(struct inode *ino)
{
struct pnfs_layout_hdr *lo;
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index 94ba804..f5f8a47 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -219,6 +219,7 @@ void pnfs_set_layoutcommit(struct nfs_write_data *wdata);
void pnfs_cleanup_layoutcommit(struct nfs4_layoutcommit_data *data);
int pnfs_layoutcommit_inode(struct inode *inode, bool sync);
int _pnfs_return_layout(struct inode *);
+int pnfs_commit_and_return_layout(struct inode *);
void pnfs_ld_write_done(struct nfs_write_data *);
void pnfs_ld_read_done(struct nfs_read_data *);
struct pnfs_layout_segment *pnfs_update_layout(struct inode *ino,
@@ -407,6 +408,11 @@ static inline int pnfs_return_layout(struct inode *ino)
return 0;
}

+static inline int pnfs_commit_and_return_layout(struct inode *inode)
+{
+ return 0;
+}
+
static inline bool
pnfs_ld_layoutret_on_setattr(struct inode *inode)
{
--
1.8.1.4