Commit fae5096ad217
"nfsd: assume writeable exportabled filesystems have f_sync"
have remove the checking of f_sync.
Christoph Hellwig suggests, "Warn and refuse the writable export."
I think just covert to a readonly export for !fsync filesystem and
readonly filesystem is reasonable.
For example,
A test directory may be mounted many underlay filesystem (contain
ISO9660, f2fs, etc) frequently. If refuse the writeable export,
for ISO9660 the exports entry must be *(ro,...), but for f2fs
may be *(rw,...). I don't think someone wants change it every time.
Also, I let the message as a dprintk for, an export entry cache will
be dropped without any use in some times, and created in the next use.
If let the message as a warning, there will be many messages that
users maybe think that's a noise or bug.
v2, update the notice message advice from Bruce
just pass svc_exoprt to check_export instead many parameters
a path string for exporting entry is simply than d_path
Signed-off-by: Kinglong Mee <kinglongmee@xxxxxxxxx>
---
fs/nfsd/export.c | 25 ++++++++++++++++++++-----
1 file changed, 20 insertions(+), 5 deletions(-)
diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index 43e109c..5b9527b 100644
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -339,8 +339,10 @@ static struct svc_export *svc_export_update(struct svc_export *new,
struct svc_export *old);
static struct svc_export *svc_export_lookup(struct svc_export *);
-static int check_export(struct inode *inode, int *flags, unsigned char *uuid)
+static int check_export(struct svc_export *exp, char *path_str)
{
+ struct inode *inode = d_inode(exp->ex_path.dentry);
+ int *flags = &exp->ex_flags;
/*
* We currently export only dirs, regular files, and (for v4
@@ -358,6 +360,18 @@ static int check_export(struct inode *inode, int *flags, unsigned char *uuid)
if (*flags & NFSEXP_V4ROOT)
*flags |= NFSEXP_READONLY;
+ /*
+ * Convert to a readonly export for that,
+ * 1. not supported fsync filesystem,
+ * 2. readonly filesystem.
+ */
+ if ((!inode->i_fop->fsync || IS_RDONLY(inode))
+ && !(*flags & NFSEXP_READONLY)) {
+ dprintk("%s %s: exporting read-only.\n", path_str,
+ IS_RDONLY(inode) ? "is read-only" : "has no fsync method");
+ *flags |= NFSEXP_READONLY;
+ }
+
/* There are two requirements on a filesystem to be exportable.
* 1: We must be able to identify the filesystem from a number.
* either a device number (so FS_REQUIRES_DEV needed)
@@ -367,7 +381,7 @@ static int check_export(struct inode *inode, int *flags, unsigned char *uuid)
*/
if (!(inode->i_sb->s_type->fs_flags & FS_REQUIRES_DEV) &&
!(*flags & NFSEXP_FSID) &&
- uuid == NULL) {
+ exp->ex_uuid == NULL) {
dprintk("exp_export: export of non-dev fs without fsid\n");
return -EINVAL;
}
@@ -509,7 +523,7 @@ uuid_parse(char **mesg, char *buf, unsigned char **puuid)
static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
{
/* client path expiry [flags anonuid anongid fsid] */
- char *buf;
+ char *buf, *path_str = NULL;
int len;
int err;
struct auth_domain *dom = NULL;
@@ -544,6 +558,7 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
if (err)
goto out1;
+ path_str = kstrdup(buf, GFP_KERNEL);
exp.ex_client = dom;
exp.cd = cd;
exp.ex_devid_map = NULL;
@@ -599,8 +614,7 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
goto out4;
}
- err = check_export(d_inode(exp.ex_path.dentry), &exp.ex_flags,
- exp.ex_uuid);
+ err = check_export(&exp, path_str);
if (err)
goto out4;
/*
@@ -645,6 +659,7 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
out1:
auth_domain_put(dom);
out:
+ kfree(path_str);
kfree(buf);
return err;
}
--
2.9.3
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
