[PATCH AUTOSEL 4.19 06/57] 9p locks: add mount option for lock retry interval

Sasha Levin
2019-03-30T01:41:10Z

From: Dinu-Razvan Chis-Serban <justcsdr@gmail.com>

[ Upstream commit 5e172f75e51e3de1b4274146d9b990f803cb5c2a ]

The default P9_LOCK_TIMEOUT can be too long for some users exporting
a local file system to a guest VM (30s), make this configurable at
mount time.

Link: http://lkml.kernel.org/r/1536295827-3181-1-git-send-email-asmadeus@codewreck.org
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=195727
Signed-off-by: Dinu-Razvan Chis-Serban <justcsdr@gmail.com>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/9p/v9fs.c | 21 +++++++++++++++++++++
fs/9p/v9fs.h | 1 +
fs/9p/vfs_file.c | 6 +++++-
3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index 89bac3d2f05b..619128b55837 100644
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -61,6 +61,8 @@ enum {
Opt_cache_loose, Opt_fscache, Opt_mmap,
/* Access options */
Opt_access, Opt_posixacl,
+ /* Lock timeout option */
+ Opt_locktimeout,
/* Error token */
Opt_err
};
@@ -80,6 +82,7 @@ static const match_table_t tokens = {
{Opt_cachetag, "cachetag=%s"},
{Opt_access, "access=%s"},
{Opt_posixacl, "posixacl"},
+ {Opt_locktimeout, "locktimeout=%u"},
{Opt_err, NULL}
};

@@ -187,6 +190,7 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
#ifdef CONFIG_9P_FSCACHE
v9ses->cachetag = NULL;
#endif
+ v9ses->session_lock_timeout = P9_LOCK_TIMEOUT;

if (!opts)
return 0;
@@ -359,6 +363,23 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
#endif
break;

+ case Opt_locktimeout:
+ r = match_int(&args[0], &option);
+ if (r < 0) {
+ p9_debug(P9_DEBUG_ERROR,
+ "integer field, but no integer?\n");
+ ret = r;
+ continue;
+ }
+ if (option < 1) {
+ p9_debug(P9_DEBUG_ERROR,
+ "locktimeout must be a greater than zero integer.\n");
+ ret = -EINVAL;
+ continue;
+ }
+ v9ses->session_lock_timeout = (long)option * HZ;
+ break;
+
default:
continue;
}
diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
index 982e017acadb..129e5243a6bf 100644
--- a/fs/9p/v9fs.h
+++ b/fs/9p/v9fs.h
@@ -116,6 +116,7 @@ struct v9fs_session_info {
struct p9_client *clnt; /* 9p client */
struct list_head slist; /* list of sessions registered with v9fs */
struct rw_semaphore rename_sem;
+ long session_lock_timeout; /* retry interval for blocking locks */
};

/* cache_validity flags */
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index c87e6d6ec069..05454a7e22dc 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -154,6 +154,7 @@ static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl)
uint8_t status = P9_LOCK_ERROR;
int res = 0;
unsigned char fl_type;
+ struct v9fs_session_info *v9ses;

fid = filp->private_data;
BUG_ON(fid == NULL);
@@ -189,6 +190,8 @@ static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl)
if (IS_SETLKW(cmd))
flock.flags = P9_LOCK_FLAGS_BLOCK;

+ v9ses = v9fs_inode2v9ses(file_inode(filp));
+
/*
* if its a blocked request and we get P9_LOCK_BLOCKED as the status
* for lock request, keep on trying
@@ -202,7 +205,8 @@ static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl)
break;
if (status == P9_LOCK_BLOCKED && !IS_SETLKW(cmd))
break;
- if (schedule_timeout_interruptible(P9_LOCK_TIMEOUT) != 0)
+ if (schedule_timeout_interruptible(v9ses->session_lock_timeout)
+ != 0)
break;
/*
* p9_client_lock_dotl overwrites flock.client_id with the
--
2.19.1