Convert coda to fs_context.  Note this is slightly tricky as coda currently
only has a binary mount data interface.  This is handled through the
parse_monolithic hook.

Also add a more conventional interface with a parameter named "fd" that
takes an fd that refers to a coda psdev, thereby specifying the index to
use.

Signed-off-by: David Howells <dhowe...@redhat.com>
cc: Jan Harkes <jahar...@cs.cmu.edu>
cc: c...@cs.cmu.edu
---

 fs/coda/inode.c |  171 +++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 116 insertions(+), 55 deletions(-)

diff --git a/fs/coda/inode.c b/fs/coda/inode.c
index 97424cf206c0..aaed68ba960b 100644
--- a/fs/coda/inode.c
+++ b/fs/coda/inode.c
@@ -2,9 +2,9 @@
 /*
  * Super block/filesystem wide operations
  *
- * Copyright (C) 1996 Peter J. Braam <br...@maths.ox.ac.uk> and 
- * Michael Callahan <calla...@maths.ox.ac.uk> 
- * 
+ * Copyright (C) 1996 Peter J. Braam <br...@maths.ox.ac.uk> and
+ * Michael Callahan <calla...@maths.ox.ac.uk>
+ *
  * Rewritten for Linux 2.1.  Peter Braam <br...@cs.cmu.edu>
  * Copyright (C) Carnegie Mellon University
  */
@@ -24,6 +24,8 @@
 #include <linux/pid_namespace.h>
 #include <linux/uaccess.h>
 #include <linux/fs.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
 #include <linux/vmalloc.h>
 
 #include <linux/coda.h>
@@ -93,10 +95,10 @@ void coda_destroy_inodecache(void)
        kmem_cache_destroy(coda_inode_cachep);
 }
 
-static int coda_remount(struct super_block *sb, int *flags, char *data)
+static int coda_reconfigure(struct fs_context *fc)
 {
-       sync_filesystem(sb);
-       *flags |= SB_NOATIME;
+       sync_filesystem(fc->root->d_sb);
+       fc->sb_flags |= SB_NOATIME;
        return 0;
 }
 
@@ -108,78 +110,111 @@ static const struct super_operations 
coda_super_operations =
        .evict_inode    = coda_evict_inode,
        .put_super      = coda_put_super,
        .statfs         = coda_statfs,
-       .remount_fs     = coda_remount,
 };
 
-static int get_device_index(struct coda_mount_data *data)
+struct coda_fs_context {
+       int     idx;
+};
+
+enum {
+       Opt_fd,
+};
+
+static const struct fs_parameter_spec coda_param_specs[] = {
+       fsparam_fd      ("fd",                          Opt_fd),
+       {}
+};
+
+static const struct fs_parameter_description coda_fs_parameters = {
+       .name           = "coda",
+       .specs          = coda_param_specs,
+};
+
+static int coda_parse_fd(struct fs_context *fc, int fd)
 {
+       struct coda_fs_context *ctx = fc->fs_private;
        struct fd f;
        struct inode *inode;
        int idx;
 
-       if (data == NULL) {
-               pr_warn("%s: Bad mount data\n", __func__);
-               return -1;
-       }
-
-       if (data->version != CODA_MOUNT_VERSION) {
-               pr_warn("%s: Bad mount version\n", __func__);
-               return -1;
-       }
-
-       f = fdget(data->fd);
+       f = fdget(fd);
        if (!f.file)
-               goto Ebadf;
+               return -EBADF;
+
        inode = file_inode(f.file);
        if (!S_ISCHR(inode->i_mode) || imajor(inode) != CODA_PSDEV_MAJOR) {
                fdput(f);
-               goto Ebadf;
+               return invalf(fc, "code: Not coda psdev");
        }
 
        idx = iminor(inode);
        fdput(f);
 
-       if (idx < 0 || idx >= MAX_CODADEVS) {
-               pr_warn("%s: Bad minor number\n", __func__);
-               return -1;
+       if (idx < 0 || idx >= MAX_CODADEVS)
+               return invalf(fc, "coda: Bad minor number");
+       ctx->idx = idx;
+       return 0;
+}
+
+static int coda_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+       struct fs_parse_result result;
+       int opt;
+
+       opt = fs_parse(fc, &coda_fs_parameters, param, &result);
+       if (opt < 0)
+               return opt;
+
+       switch (opt) {
+       case Opt_fd:
+               return coda_parse_fd(fc, result.uint_32);
+       }
+
+       return 0;
+}
+
+/*
+ * Parse coda's binary mount data form.  We ignore any errors and go with index
+ * 0 if we get one for backward compatibility.
+ */
+static int coda_parse_monolithic(struct fs_context *fc, void *_data)
+{
+       struct coda_mount_data *data = _data;
+
+       if (!data) {
+               invalf(fc, "coda: Bad mount data");
+               return 0;
+       }
+       if (data->version != CODA_MOUNT_VERSION) {
+               invalf(fc, "coda: Bad mount version");
+               return 0;
        }
 
-       return idx;
-Ebadf:
-       pr_warn("%s: Bad file\n", __func__);
-       return -1;
+       coda_parse_fd(fc, data->fd);
+       return 0;
 }
 
-static int coda_fill_super(struct super_block *sb, void *data, int silent)
+static int coda_fill_super(struct super_block *sb, struct fs_context *fc)
 {
+       struct coda_fs_context *ctx = fc->fs_private;
        struct inode *root = NULL;
        struct venus_comm *vc;
        struct CodaFid fid;
        int error;
-       int idx;
 
-       if (task_active_pid_ns(current) != &init_pid_ns)
-               return -EINVAL;
+       infof(fc, "coda: device index: %i\n", ctx->idx);
 
-       idx = get_device_index((struct coda_mount_data *) data);
-
-       /* Ignore errors in data, for backward compatibility */
-       if(idx == -1)
-               idx = 0;
-       
-       pr_info("%s: device index: %i\n", __func__,  idx);
-
-       vc = &coda_comms[idx];
+       vc = &coda_comms[ctx->idx];
        mutex_lock(&vc->vc_mutex);
 
        if (!vc->vc_inuse) {
-               pr_warn("%s: No pseudo device\n", __func__);
+               errorf(fc, "coda: No pseudo device");
                error = -EINVAL;
                goto unlock_out;
        }
 
        if (vc->vc_sb) {
-               pr_warn("%s: Device already mounted\n", __func__);
+               errorf(fc, "coda: Device already mounted");
                error = -EBUSY;
                goto unlock_out;
        }
@@ -207,7 +242,7 @@ static int coda_fill_super(struct super_block *sb, void 
*data, int silent)
                goto error;
        }
        pr_info("%s: rootfid is %s\n", __func__, coda_f2s(&fid));
-       
+
        /* make root inode */
         root = coda_cnode_make(&fid, sb);
         if (IS_ERR(root)) {
@@ -215,7 +250,7 @@ static int coda_fill_super(struct super_block *sb, void 
*data, int silent)
                pr_warn("Failure of coda_cnode_make for root: error %d\n",
                        error);
                goto error;
-       } 
+       }
 
        pr_info("%s: rootinode is %ld dev %s\n",
                __func__, root->i_ino, root->i_sb->s_id);
@@ -268,7 +303,7 @@ int coda_setattr(struct dentry *de, struct iattr *iattr)
        struct coda_vattr vattr;
        int error;
 
-       memset(&vattr, 0, sizeof(vattr)); 
+       memset(&vattr, 0, sizeof(vattr));
 
        inode->i_ctime = current_time(inode);
        coda_iattr_to_vattr(iattr, &vattr);
@@ -278,7 +313,7 @@ int coda_setattr(struct dentry *de, struct iattr *iattr)
        error = venus_setattr(inode->i_sb, coda_i2f(inode), &vattr);
 
        if (!error) {
-               coda_vattr_to_iattr(inode, &vattr); 
+               coda_vattr_to_iattr(inode, &vattr);
                coda_cache_clear_inode(inode);
        }
        return error;
@@ -293,7 +328,7 @@ const struct inode_operations coda_file_inode_operations = {
 static int coda_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
        int error;
-       
+
        error = venus_statfs(dentry, buf);
 
        if (error) {
@@ -310,23 +345,49 @@ static int coda_statfs(struct dentry *dentry, struct 
kstatfs *buf)
        buf->f_bsize = 4096;
        buf->f_namelen = CODA_MAXNAMLEN;
 
-       return 0; 
+       return 0;
 }
 
-/* init_coda: used by filesystems.c to register coda */
+static int coda_get_tree(struct fs_context *fc)
+{
+       if (task_active_pid_ns(current) != &init_pid_ns)
+               return -EINVAL;
+
+       return vfs_get_super(fc, vfs_get_independent_super, coda_fill_super);
+}
+
+static void coda_free_fc(struct fs_context *fc)
+{
+       kfree(fc->fs_private);
+}
 
-static struct dentry *coda_mount(struct file_system_type *fs_type,
-       int flags, const char *dev_name, void *data)
+static const struct fs_context_operations coda_context_ops = {
+       .free           = coda_free_fc,
+       .parse_param    = coda_parse_param,
+       .parse_monolithic = coda_parse_monolithic,
+       .get_tree       = coda_get_tree,
+       .reconfigure    = coda_reconfigure,
+};
+
+static int coda_init_fs_context(struct fs_context *fc)
 {
-       return mount_nodev(fs_type, flags, data, coda_fill_super);
+       struct coda_fs_context *ctx;
+
+       ctx = kzalloc(sizeof(struct coda_fs_context), GFP_KERNEL);
+       if (!ctx)
+               return -ENOMEM;
+
+       fc->fs_private = ctx;
+       fc->ops = &coda_context_ops;
+       return 0;
 }
 
 struct file_system_type coda_fs_type = {
        .owner          = THIS_MODULE,
        .name           = "coda",
-       .mount          = coda_mount,
+       .init_fs_context = coda_init_fs_context,
+       .parameters     = &coda_fs_parameters,
        .kill_sb        = kill_anon_super,
        .fs_flags       = FS_BINARY_MOUNTDATA,
 };
 MODULE_ALIAS_FS("coda");
-

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