Add an extra option to control the inode identification behaviour, and
make path-based default. The reasoning for this default is that the
current 9pfs already does not re-use inodes even for same qid.path, but
because of the dcache, a file kept open by a process (by e.g. open, or
having the directory as CWD) means that other processes will re-use that
inode. If we identify inode by path by default, this behaviour is
consistent regardless of whether files are kept open or not.
In a future version, if we can negotiate with the server and be sure that
it won't give us duplicate qid.path, the default for those cases can be
qid-based (possibly re-merging commit 724a08450f74 ("fs/9p: simplify iget
to remove unnecessary paths")...?)
Signed-off-by: Tingmao Wang <m@xxxxxxxxxx>
---
fs/9p/v9fs.c | 33 ++++++++++++++++++++++++++++++++-
fs/9p/v9fs.h | 2 ++
2 files changed, 34 insertions(+), 1 deletion(-)
diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index 77e9c4387c1d..487532295a98 100644
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -36,7 +36,7 @@ enum {
/* Options that take integer arguments */
Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
/* String options */
- Opt_uname, Opt_remotename, Opt_cache, Opt_cachetag,
+ Opt_uname, Opt_remotename, Opt_cache, Opt_cachetag, Opt_inodeident,
/* Options that take no arguments */
Opt_nodevmap, Opt_noxattr, Opt_directio, Opt_ignoreqv,
/* Access options */
@@ -63,6 +63,7 @@ static const match_table_t tokens = {
{Opt_access, "access=%s"},
{Opt_posixacl, "posixacl"},
{Opt_locktimeout, "locktimeout=%u"},
+ {Opt_inodeident, "inodeident=%s"},
{Opt_err, NULL}
};
@@ -149,6 +150,15 @@ int v9fs_show_options(struct seq_file *m, struct dentry *root)
if (v9ses->flags & V9FS_NO_XATTR)
seq_puts(m, ",noxattr");
+ switch (v9ses->flags & V9FS_INODE_IDENT_MASK) {
+ case 0:
+ seq_puts(m, ",inodeident=none");
+ break;
+ case V9FS_INODE_IDENT_PATH:
+ seq_puts(m, ",inodeident=path");
+ break;
+ }
+
return p9_show_client_options(m, v9ses->clnt);
}
@@ -369,6 +379,25 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
v9ses->session_lock_timeout = (long)option * HZ;
break;
+ case Opt_inodeident:
+ s = match_strdup(&args[0]);
+ if (!s) {
+ ret = -ENOMEM;
+ p9_debug(P9_DEBUG_ERROR,
+ "problem allocating copy of inodeident arg\n");
+ goto free_and_return;
+ }
+ if (strcmp(s, "none") == 0) {
+ v9ses->flags &= ~V9FS_INODE_IDENT_MASK;
+ } else if (strcmp(s, "path") == 0) {
+ v9ses->flags |= V9FS_INODE_IDENT_PATH;
+ } else {
+ ret = -EINVAL;
+ p9_debug(P9_DEBUG_ERROR, "Unknown inodeident argument %s\n", s);
+ }
+ kfree(s);
+ break;
+
default:
continue;
}
@@ -423,6 +452,8 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
v9ses->flags |= V9FS_PROTO_2000U;
}
+ v9ses->flags |= V9FS_INODE_IDENT_PATH;
+
rc = v9fs_parse_options(v9ses, data);
if (rc < 0)
goto err_clnt;
diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
index 5c85923aa2dd..b4874fdd925e 100644
--- a/fs/9p/v9fs.h
+++ b/fs/9p/v9fs.h
@@ -31,6 +31,8 @@
#define V9FS_ACCESS_MASK V9FS_ACCESS_ANY
#define V9FS_ACL_MASK V9FS_POSIX_ACL
+#define V9FS_INODE_IDENT_MASK (V9FS_INODE_IDENT_PATH)
+
enum p9_session_flags {
V9FS_PROTO_2000U = 0x01,
V9FS_PROTO_2000L = 0x02,
--
2.39.5
