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NFS: Error when mounting the same filesystem with different options

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Unless the user sets the NFS_MOUNT_NOSHAREDCACHE mount flag, we should
return EBUSY if the filesystem is already mounted on a superblock that
has set conflicting mount options.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust 2007-05-16 16:53:28 -04:00
parent 75180df2ed
commit 275a5d24bf
1 changed files with 42 additions and 1 deletions
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43
fs/nfs/super.c
View File

@ -1317,7 +1317,9 @@ static int nfs_compare_super(struct super_block *sb, void *data)
{
struct nfs_server *server = data, *old = NFS_SB(sb);
if (old->nfs_client != server->nfs_client)
if (memcmp(&old->nfs_client->cl_addr,
&server->nfs_client->cl_addr,
sizeof(old->nfs_client->cl_addr)) != 0)
return 0;
/* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
if (old->flags & NFS_MOUNT_UNSHARED)
@ -1327,6 +1329,39 @@ static int nfs_compare_super(struct super_block *sb, void *data)
return 1;
}
#define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS)
static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
{
const struct nfs_server *a = s->s_fs_info;
const struct rpc_clnt *clnt_a = a->client;
const struct rpc_clnt *clnt_b = b->client;
if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
goto Ebusy;
if (a->nfs_client != b->nfs_client)
goto Ebusy;
if (a->flags != b->flags)
goto Ebusy;
if (a->wsize != b->wsize)
goto Ebusy;
if (a->rsize != b->rsize)
goto Ebusy;
if (a->acregmin != b->acregmin)
goto Ebusy;
if (a->acregmax != b->acregmax)
goto Ebusy;
if (a->acdirmin != b->acdirmin)
goto Ebusy;
if (a->acdirmax != b->acdirmax)
goto Ebusy;
if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
goto Ebusy;
return 0;
Ebusy:
return -EBUSY;
}
static int nfs_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
{
@ -1361,8 +1396,11 @@ static int nfs_get_sb(struct file_system_type *fs_type,
}
if (s->s_fs_info != server) {
error = nfs_compare_mount_options(s, server, flags);
nfs_free_server(server);
server = NULL;
if (error < 0)
goto error_splat_super;
}
if (!s->s_root) {
@ -1442,8 +1480,11 @@ static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
}
if (s->s_fs_info != server) {
error = nfs_compare_mount_options(s, server, flags);
nfs_free_server(server);
server = NULL;
if (error < 0)
goto error_splat_super;
}
if (!s->s_root) {