[PATCH] FUSE - mount options

This patch adds miscellaneous mount options to the FUSE filesystem.

The following mount options are added:

 o default_permissions:  check permissions with generic_permission()
 o allow_other:          allow other users to access files
 o allow_root:           allow root to access files
 o kernel_cache:         don't invalidate page cache on open

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 38 insertions, 39 deletions

diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index f229d6962643..458c62ca0fec 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -15,7 +15,6 @@
 #include <linux/seq_file.h>
 #include <linux/init.h>
 #include <linux/module.h>
-#include <linux/moduleparam.h>
 #include <linux/parser.h>
 #include <linux/statfs.h>
 
@@ -25,11 +24,6 @@ MODULE_LICENSE("GPL");
 
 spinlock_t fuse_lock;
 static kmem_cache_t *fuse_inode_cachep;
-static int mount_count;
-
-static int mount_max = 1000;
-module_param(mount_max, int, 0644);
-MODULE_PARM_DESC(mount_max, "Maximum number of FUSE mounts allowed, if -1 then unlimited (default: 1000)");
 
 #define FUSE_SUPER_MAGIC 0x65735546
 
@@ -37,6 +31,7 @@ struct fuse_mount_data {
         int fd;
         unsigned rootmode;
         unsigned user_id;
+        unsigned flags;
 };
 
 static struct inode *fuse_alloc_inode(struct super_block *sb)
@@ -89,8 +84,8 @@ void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
 
 static void fuse_clear_inode(struct inode *inode)
 {
-        struct fuse_conn *fc = get_fuse_conn(inode);
-        if (fc) {
+        if (inode->i_sb->s_flags & MS_ACTIVE) {
+                struct fuse_conn *fc = get_fuse_conn(inode);
                 struct fuse_inode *fi = get_fuse_inode(inode);
                 fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup);
                 fi->forget_req = NULL;
@@ -195,14 +190,19 @@ static void fuse_put_super(struct super_block *sb)
 {
         struct fuse_conn *fc = get_fuse_conn_super(sb);
 
+        down_write(&fc->sbput_sem);
+        while (!list_empty(&fc->background))
+                fuse_release_background(list_entry(fc->background.next,
+                                                   struct fuse_req, bg_entry));
+
         spin_lock(&fuse_lock);
-        mount_count --;
-        fc->sb = NULL;
+        fc->mounted = 0;
         fc->user_id = 0;
+        fc->flags = 0;
         /* Flush all readers on this fs */
         wake_up_all(&fc->waitq);
+        up_write(&fc->sbput_sem);
         fuse_release_conn(fc);
-        *get_fuse_conn_super_p(sb) = NULL;
         spin_unlock(&fuse_lock);
 }
 
@@ -249,7 +249,6 @@ enum {
         OPT_USER_ID,
         OPT_DEFAULT_PERMISSIONS,
         OPT_ALLOW_OTHER,
-        OPT_ALLOW_ROOT,
         OPT_KERNEL_CACHE,
         OPT_ERR
 };
@@ -260,7 +259,6 @@ static match_table_t tokens = {
         {OPT_USER_ID,                   "user_id=%u"},
         {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
         {OPT_ALLOW_OTHER,               "allow_other"},
-        {OPT_ALLOW_ROOT,                "allow_root"},
         {OPT_KERNEL_CACHE,              "kernel_cache"},
         {OPT_ERR,                       NULL}
 };
@@ -298,6 +296,18 @@ static int parse_fuse_opt(char *opt, struct fuse_mount_data *d)
                         d->user_id = value;
                         break;
 
+                case OPT_DEFAULT_PERMISSIONS:
+                        d->flags |= FUSE_DEFAULT_PERMISSIONS;
+                        break;
+
+                case OPT_ALLOW_OTHER:
+                        d->flags |= FUSE_ALLOW_OTHER;
+                        break;
+
+                case OPT_KERNEL_CACHE:
+                        d->flags |= FUSE_KERNEL_CACHE;
+                        break;
+
                 default:
                         return 0;
                 }
@@ -313,6 +323,12 @@ static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
         struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
 
         seq_printf(m, ",user_id=%u", fc->user_id);
+        if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
+                seq_puts(m, ",default_permissions");
+        if (fc->flags & FUSE_ALLOW_OTHER)
+                seq_puts(m, ",allow_other");
+        if (fc->flags & FUSE_KERNEL_CACHE)
+                seq_puts(m, ",kernel_cache");
         return 0;
 }
 
@@ -330,7 +346,8 @@ static void free_conn(struct fuse_conn *fc)
 /* Must be called with the fuse lock held */
 void fuse_release_conn(struct fuse_conn *fc)
 {
-        if (!fc->sb && !fc->file)
+        fc->count--;
+        if (!fc->count)
                 free_conn(fc);
 }
 
@@ -342,14 +359,13 @@ static struct fuse_conn *new_conn(void)
         if (fc != NULL) {
                 int i;
                 memset(fc, 0, sizeof(*fc));
-                fc->sb = NULL;
-                fc->file = NULL;
-                fc->user_id = 0;
                 init_waitqueue_head(&fc->waitq);
                 INIT_LIST_HEAD(&fc->pending);
                 INIT_LIST_HEAD(&fc->processing);
                 INIT_LIST_HEAD(&fc->unused_list);
+                INIT_LIST_HEAD(&fc->background);
                 sema_init(&fc->outstanding_sem, 0);
+                init_rwsem(&fc->sbput_sem);
                 for (i = 0; i < FUSE_MAX_OUTSTANDING; i++) {
                         struct fuse_req *req = fuse_request_alloc();
                         if (!req) {
@@ -380,8 +396,10 @@ static struct fuse_conn *get_conn(struct file *file, struct super_block *sb)
                 fc = ERR_PTR(-EINVAL);
         } else {
                 file->private_data = fc;
-                fc->sb = sb;
-                fc->file = file;
+                *get_fuse_conn_super_p(sb) = fc;
+                fc->mounted = 1;
+                fc->connected = 1;
+                fc->count = 2;
         }
         spin_unlock(&fuse_lock);
         return fc;
@@ -407,17 +425,6 @@ static struct super_operations fuse_super_operations = {
         .show_options   = fuse_show_options,
 };
 
-static int inc_mount_count(void)
-{
-        int success = 0;
-        spin_lock(&fuse_lock);
-        mount_count ++;
-        if (mount_max == -1 || mount_count <= mount_max)
-                success = 1;
-        spin_unlock(&fuse_lock);
-        return success;
-}
-
 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 {
         struct fuse_conn *fc;
@@ -444,14 +451,9 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
         if (IS_ERR(fc))
                 return PTR_ERR(fc);
 
+        fc->flags = d.flags;
         fc->user_id = d.user_id;
 
-        *get_fuse_conn_super_p(sb) = fc;
-
-        err = -ENFILE;
-        if (!inc_mount_count() && current->uid != 0)
-                goto err;
-
         err = -ENOMEM;
         root = get_root_inode(sb, d.rootmode);
         if (root == NULL)
@@ -467,11 +469,8 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 
  err:
         spin_lock(&fuse_lock);
-        mount_count --;
-        fc->sb = NULL;
         fuse_release_conn(fc);
         spin_unlock(&fuse_lock);
-        *get_fuse_conn_super_p(sb) = NULL;
         return err;
 }