Re: [V9fs-developer] [PATCH] fs/9p: Fix invalid mount options/args

From: Venkateswararao Jujjuri
Date: Sun May 08 2011 - 13:51:52 EST


On 05/06/2011 05:54 AM, Prem Karat wrote:
fs/9p: Fix invalid mount options/args

Without this fix, if any invalid mount options/args are passed while mouting the 9p fs,
no error (-EINVAL) is returned and default arg value is assigned.

This fix returns -EINVAL when an invalid arguement is found while parsing mount options.
Prem, Thanks for the patch.
Quick question..any reason why you have a new function for cache, and in-line here?

Thanks,
JV
Signed-off-by: Prem Karat<prem.karat@xxxxxxxxxxxxxxxxxx>
---
fs/9p/v9fs.c | 43 ++++++++++++++++++++++++++++++++++---------
1 files changed, 34 insertions(+), 9 deletions(-)

diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index c82b017..033c23e 100644
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -78,6 +78,25 @@ static const match_table_t tokens = {
{Opt_err, NULL}
};

+/* Interpret mount options for cache mode */
+static int get_cache_mode(char *s)
+{
+ int version = -EINVAL;
+
+ if (!strcmp(s, "loose")) {
+ version = CACHE_LOOSE;
+ P9_DPRINTK(P9_DEBUG_9P, "Cache mode: loose\n");
+ } else if (!strcmp(s, "fscache")) {
+ version = CACHE_FSCACHE;
+ P9_DPRINTK(P9_DEBUG_9P, "Cache mode: fscache\n");
+ } else if (!strcmp(s, "none")) {
+ version = CACHE_NONE;
+ P9_DPRINTK(P9_DEBUG_9P, "Cache mode: none\n");
+ } else
+ printk(KERN_INFO "9p: Unknown Cache mode %s.\n", s);
+ return version;
+}
+
/**
* v9fs_parse_options - parse mount options into session structure
* @v9ses: existing v9fs session information
@@ -97,7 +116,7 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
/* setup defaults */
v9ses->afid = ~0;
v9ses->debug = 0;
- v9ses->cache = 0;
+ v9ses->cache = CACHE_NONE;
#ifdef CONFIG_9P_FSCACHE
v9ses->cachetag = NULL;
#endif
@@ -171,13 +190,13 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
"problem allocating copy of cache arg\n");
goto free_and_return;
}
+ ret = get_cache_mode(s);
+ if (ret == -EINVAL) {
+ kfree(s);
+ goto free_and_return;
+ }

- if (strcmp(s, "loose") == 0)
- v9ses->cache = CACHE_LOOSE;
- else if (strcmp(s, "fscache") == 0)
- v9ses->cache = CACHE_FSCACHE;
- else
- v9ses->cache = CACHE_NONE;
+ v9ses->cache = ret;
kfree(s);
break;

@@ -200,9 +219,15 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
} else {
v9ses->flags |= V9FS_ACCESS_SINGLE;
v9ses->uid = simple_strtoul(s,&e, 10);
- if (*e != '\0')
- v9ses->uid = ~0;
+ if (*e != '\0') {
+ ret = -EINVAL;
+ printk(KERN_INFO "9p: Unknown access "
+ "argument %s.\n", s);
+ kfree(s);
+ goto free_and_return;


+ }
}
+
kfree(s);
break;


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