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From: Alexander Aring <aahringo@redhat.com>
To: linux-nfs@vger.kernel.org
Cc: cluster-devel@redhat.com, ocfs2-devel@lists.linux.dev,
	linux-fsdevel@vger.kernel.org, teigland@redhat.com,
	rpeterso@redhat.com, agruenba@redhat.com,
	trond.myklebust@hammerspace.com, anna@kernel.org,
	chuck.lever@oracle.com, jlayton@kernel.org
Subject: [RFCv2 3/7] lockd: introduce safe async lock op
Date: Mon, 14 Aug 2023 17:11:12 -0400	[thread overview]
Message-ID: <20230814211116.3224759-4-aahringo@redhat.com> (raw)
In-Reply-To: <20230814211116.3224759-1-aahringo@redhat.com>

This patch reverts mostly commit 40595cdc93ed ("nfs: block notification
on fs with its own ->lock") and introduces an EXPORT_OP_SAFE_ASYNC_LOCK
export flag to signal that the "own ->lock" implementation supports
async lock requests. The only main user is DLM that is used by GFS2 and
OCFS2 filesystem. Those implement their own lock() implementation and
return FILE_LOCK_DEFERRED as return value. Since commit 40595cdc93ed
("nfs: block notification on fs with its own ->lock") the DLM
implementation were never updated. This patch should prepare for DLM
to set the EXPORT_OP_SAFE_ASYNC_LOCK export flag and update the DLM
plock implementation regarding to it.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
 fs/lockd/svclock.c       |  5 ++---
 fs/nfsd/nfs4state.c      | 13 ++++++++++---
 include/linux/exportfs.h |  8 ++++++++
 3 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index 1e74a578d7de..b8bd2b841ee1 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -449,9 +449,7 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
 	    struct nlm_host *host, struct nlm_lock *lock, int wait,
 	    struct nlm_cookie *cookie, int reclaim)
 {
-#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 	struct inode		*inode = nlmsvc_file_inode(file);
-#endif
 	struct nlm_block	*block = NULL;
 	int			error;
 	int			mode;
@@ -465,7 +463,8 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
 				(long long)lock->fl.fl_end,
 				wait);
 
-	if (nlmsvc_file_file(file)->f_op->lock) {
+	if (!export_op_support_safe_async_lock(inode->i_sb->s_export_op,
+					       nlmsvc_file_file(file)->f_op)) {
 		async_block = wait;
 		wait = 0;
 	}
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 3aefbad4cc09..14ca06424ff1 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -7430,6 +7430,7 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	struct nfsd4_blocked_lock *nbl = NULL;
 	struct file_lock *file_lock = NULL;
 	struct file_lock *conflock = NULL;
+	struct super_block *sb;
 	__be32 status = 0;
 	int lkflg;
 	int err;
@@ -7451,6 +7452,7 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 		dprintk("NFSD: nfsd4_lock: permission denied!\n");
 		return status;
 	}
+	sb = cstate->current_fh.fh_dentry->d_sb;
 
 	if (lock->lk_is_new) {
 		if (nfsd4_has_session(cstate))
@@ -7502,7 +7504,9 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	fp = lock_stp->st_stid.sc_file;
 	switch (lock->lk_type) {
 		case NFS4_READW_LT:
-			if (nfsd4_has_session(cstate))
+			if (nfsd4_has_session(cstate) ||
+			    export_op_support_safe_async_lock(sb->s_export_op,
+							      nf->nf_file->f_op))
 				fl_flags |= FL_SLEEP;
 			fallthrough;
 		case NFS4_READ_LT:
@@ -7514,7 +7518,9 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 			fl_type = F_RDLCK;
 			break;
 		case NFS4_WRITEW_LT:
-			if (nfsd4_has_session(cstate))
+			if (nfsd4_has_session(cstate) ||
+			    export_op_support_safe_async_lock(sb->s_export_op,
+							      nf->nf_file->f_op))
 				fl_flags |= FL_SLEEP;
 			fallthrough;
 		case NFS4_WRITE_LT:
@@ -7542,7 +7548,8 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	 * for file locks), so don't attempt blocking lock notifications
 	 * on those filesystems:
 	 */
-	if (nf->nf_file->f_op->lock)
+	if (!export_op_support_safe_async_lock(sb->s_export_op,
+					       nf->nf_file->f_op))
 		fl_flags &= ~FL_SLEEP;
 
 	nbl = find_or_allocate_block(lock_sop, &fp->fi_fhandle, nn);
diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index 11fbd0ee1370..10358a93cdc1 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -3,6 +3,7 @@
 #define LINUX_EXPORTFS_H 1
 
 #include <linux/types.h>
+#include <linux/fs.h>
 
 struct dentry;
 struct iattr;
@@ -224,9 +225,16 @@ struct export_operations {
 						  atomic attribute updates
 						*/
 #define EXPORT_OP_FLUSH_ON_CLOSE	(0x20) /* fs flushes file data on close */
+#define EXPORT_OP_SAFE_ASYNC_LOCK	(0x40) /* fs can do async lock request */
 	unsigned long	flags;
 };
 
+static inline bool export_op_support_safe_async_lock(const struct export_operations *export_ops,
+						     const struct file_operations *f_op)
+{
+	return (export_ops->flags & EXPORT_OP_SAFE_ASYNC_LOCK) || !f_op->lock;
+}
+
 extern int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid,
 				    int *max_len, struct inode *parent,
 				    int flags);
-- 
2.31.1


  parent reply	other threads:[~2023-08-14 21:11 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-14 21:11 [RFCv2 0/7] fs: nfs: async lock request changes Alexander Aring
2023-08-14 21:11 ` [RFCv2 1/7] lockd: fix race in async lock request handling Alexander Aring
2023-08-15 17:49   ` Jeff Layton
2023-08-15 18:21     ` Jeff Layton
2023-08-17 18:39       ` Alexander Aring
2023-08-17 18:36     ` Alexander Aring
2023-08-14 21:11 ` [RFCv2 2/7] lockd: FILE_LOCK_DEFERRED only on FL_SLEEP Alexander Aring
2023-08-16 11:37   ` Jeff Layton
2023-08-17  1:40     ` Alexander Aring
2023-08-14 21:11 ` Alexander Aring [this message]
2023-08-16 11:43   ` [RFCv2 3/7] lockd: introduce safe async lock op Jeff Layton
2023-08-14 21:11 ` [RFCv2 4/7] locks: update lock callback documentation Alexander Aring
2023-08-16 12:01   ` Jeff Layton
2023-08-17  1:23     ` Alexander Aring
2023-08-14 21:11 ` [RFCv2 5/7] dlm: use fl_owner from lockd Alexander Aring
2023-08-16 12:02   ` Jeff Layton
2023-08-14 21:11 ` [RFCv2 6/7] dlm: use FL_SLEEP to check if blocking request Alexander Aring
2023-08-16 13:07   ` Jeff Layton
2023-08-17  1:19     ` Alexander Aring
2023-08-17 11:27       ` Jeff Layton
2023-08-17 13:02         ` Alexander Aring
2023-08-14 21:11 ` [RFCv2 7/7] dlm: implement EXPORT_OP_SAFE_ASYNC_LOCK Alexander Aring

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