From e6f810759505bc86c009854b82cc495ffd8eb020 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Thu, 24 Jan 2008 18:14:34 -0500 Subject: NFS: Add an asynchronous delegreturn operation for use in nfs_clear_inode Otherwise, there is a potential deadlock if the last dput() from an NFSv4 close() or other asynchronous operation leads to nfs_clear_inode calling the synchronous delegreturn. Signed-off-by: Trond Myklebust --- fs/nfs/delegation.c | 29 +++++++++++++++++++++++++---- 1 file changed, 25 insertions(+), 4 deletions(-) (limited to 'fs/nfs/delegation.c') diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c index b03dcd8403f..2dead8d1dd5 100644 --- a/fs/nfs/delegation.c +++ b/fs/nfs/delegation.c @@ -174,11 +174,11 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct return status; } -static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation) +static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync) { int res = 0; - res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid); + res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync); nfs_free_delegation(delegation); return res; } @@ -208,7 +208,7 @@ static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegat up_read(&clp->cl_sem); nfs_msync_inode(inode); - return nfs_do_return_delegation(inode, delegation); + return nfs_do_return_delegation(inode, delegation, 1); } static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid) @@ -228,6 +228,27 @@ nomatch: return NULL; } +/* + * This function returns the delegation without reclaiming opens + * or protecting against delegation reclaims. + * It is therefore really only safe to be called from + * nfs4_clear_inode() + */ +void nfs_inode_return_delegation_noreclaim(struct inode *inode) +{ + struct nfs_client *clp = NFS_SERVER(inode)->nfs_client; + struct nfs_inode *nfsi = NFS_I(inode); + struct nfs_delegation *delegation; + + if (rcu_dereference(nfsi->delegation) != NULL) { + spin_lock(&clp->cl_lock); + delegation = nfs_detach_delegation_locked(nfsi, NULL); + spin_unlock(&clp->cl_lock); + if (delegation != NULL) + nfs_do_return_delegation(inode, delegation, 0); + } +} + int nfs_inode_return_delegation(struct inode *inode) { struct nfs_client *clp = NFS_SERVER(inode)->nfs_client; @@ -388,7 +409,7 @@ static int recall_thread(void *data) nfs_msync_inode(inode); if (delegation != NULL) - nfs_do_return_delegation(inode, delegation); + nfs_do_return_delegation(inode, delegation, 1); iput(inode); module_put_and_exit(0); } -- cgit v1.2.3