[PATCH 7/8] lockd: don't attempt blocking locks on nfs reexports
From: J. Bruce Fields <hidden>
Date: 2021-08-20 21:02:18
Subsystem:
filesystems (vfs and infrastructure), kernel nfsd, sunrpc, and lockd servers, nfs, sunrpc, and lockd clients, the rest · Maintainers:
Alexander Viro, Christian Brauner, Chuck Lever, Jeff Layton, Trond Myklebust, Anna Schumaker, Linus Torvalds
From: "J. Bruce Fields" <redacted> As in the v4 case, it doesn't work well to block waiting for a lock on an nfs filesystem. As in the v4 case, that means we're depending on the client to poll. It's probably incorrect to depend on that, but I *think* clients do poll in practice. In any case, it's an improvement over hanging the lockd thread indefinitely as we currently are. Signed-off-by: J. Bruce Fields <redacted> --- fs/lockd/svclock.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index d60e6eea2d57..c99acefb9ec9 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c@@ -31,6 +31,7 @@ #include <linux/lockd/nlm.h> #include <linux/lockd/lockd.h> #include <linux/kthread.h> +#include <linux/exportfs.h> #define NLMDBG_FACILITY NLMDBG_SVCLOCK
@@ -470,18 +471,24 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file, struct nlm_cookie *cookie, int reclaim) { struct nlm_block *block = NULL; + struct inode *inode = nlmsvc_file_inode(file); int error; int mode; + int async_block = 0; __be32 ret; dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n", - nlmsvc_file_inode(file)->i_sb->s_id, - nlmsvc_file_inode(file)->i_ino, + inode->i_sb->s_id, inode->i_ino, lock->fl.fl_type, lock->fl.fl_pid, (long long)lock->fl.fl_start, (long long)lock->fl.fl_end, wait); + if (inode->i_sb->s_export_op->flags & EXPORT_OP_SYNC_LOCKS) { + async_block = wait; + wait = 0; + } + /* Lock file against concurrent access */ mutex_lock(&file->f_mutex); /* Get existing block (in case client is busy-waiting)
@@ -542,7 +549,7 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file, */ if (wait) break; - ret = nlm_lck_denied; + ret = async_block ? nlm_lck_blocked : nlm_lck_denied; goto out; case FILE_LOCK_DEFERRED: if (wait)
--
2.31.1