hostfs: don't keep a field in each inode when we are using it only in root
Al Viro [Sun, 6 Jun 2010 21:53:01 +0000 (17:53 -0400)]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/hostfs/hostfs_kern.c

index fab5f5a..7e67504 100644 (file)
@@ -19,7 +19,6 @@
 #include "kern.h"
 
 struct hostfs_inode_info {
-       char *host_filename;
        int fd;
        fmode_t mode;
        struct inode vfs_inode;
@@ -103,7 +102,7 @@ static char *dentry_name(struct dentry *dentry, int extra)
                parent = parent->d_parent;
        }
 
-       root = HOSTFS_I(parent->d_inode)->host_filename;
+       root = parent->d_sb->s_fs_info;
        len += strlen(root);
        name = kmalloc(len + extra + 1, GFP_KERNEL);
        if (name == NULL)
@@ -266,7 +265,7 @@ int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf)
        long long f_files;
        long long f_ffree;
 
-       err = do_statfs(HOSTFS_I(dentry->d_sb->s_root->d_inode)->host_filename,
+       err = do_statfs(dentry->d_sb->s_fs_info,
                        &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files,
                        &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid),
                        &sf->f_namelen, sf->f_spare);
@@ -285,13 +284,10 @@ static struct inode *hostfs_alloc_inode(struct super_block *sb)
 {
        struct hostfs_inode_info *hi;
 
-       hi = kmalloc(sizeof(*hi), GFP_KERNEL);
+       hi = kzalloc(sizeof(*hi), GFP_KERNEL);
        if (hi == NULL)
                return NULL;
-
-       *hi = ((struct hostfs_inode_info) { .host_filename      = NULL,
-                                           .fd                 = -1,
-                                           .mode               = 0 });
+       hi->fd = -1;
        inode_init_once(&hi->vfs_inode);
        return &hi->vfs_inode;
 }
@@ -308,14 +304,12 @@ static void hostfs_evict_inode(struct inode *inode)
 
 static void hostfs_destroy_inode(struct inode *inode)
 {
-       kfree(HOSTFS_I(inode)->host_filename);
        kfree(HOSTFS_I(inode));
 }
 
 static int hostfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 {
-       struct inode *root = vfs->mnt_sb->s_root->d_inode;
-       const char *root_path = HOSTFS_I(root)->host_filename;
+       const char *root_path = vfs->mnt_sb->s_fs_info;
        size_t offset = strlen(root_ino) + 1;
 
        if (strlen(root_path) > offset)
@@ -978,8 +972,8 @@ static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
                req_root = "";
 
        err = -ENOMEM;
-       host_root_path = kmalloc(strlen(root_ino) + 1
-                                + strlen(req_root) + 1, GFP_KERNEL);
+       sb->s_fs_info = host_root_path =
+               kmalloc(strlen(root_ino) + strlen(req_root) + 2, GFP_KERNEL);
        if (host_root_path == NULL)
                goto out;
 
@@ -988,20 +982,13 @@ static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
        root_inode = hostfs_iget(sb);
        if (IS_ERR(root_inode)) {
                err = PTR_ERR(root_inode);
-               goto out_free;
+               goto out;
        }
 
        err = init_inode(root_inode, NULL);
        if (err)
                goto out_put;
 
-       HOSTFS_I(root_inode)->host_filename = host_root_path;
-       /*
-        * Avoid that in the error path, iput(root_inode) frees again
-        * host_root_path through hostfs_destroy_inode!
-        */
-       host_root_path = NULL;
-
        err = -ENOMEM;
        sb->s_root = d_alloc_root(root_inode);
        if (sb->s_root == NULL)
@@ -1019,8 +1006,6 @@ static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
 
 out_put:
        iput(root_inode);
-out_free:
-       kfree(host_root_path);
 out:
        return err;
 }
@@ -1032,11 +1017,17 @@ static int hostfs_read_sb(struct file_system_type *type,
        return get_sb_nodev(type, flags, data, hostfs_fill_sb_common, mnt);
 }
 
+static void hostfs_kill_sb(struct super_block *s)
+{
+       kill_anon_super(s);
+       kfree(s->s_fs_info);
+}
+
 static struct file_system_type hostfs_type = {
        .owner          = THIS_MODULE,
        .name           = "hostfs",
        .get_sb         = hostfs_read_sb,
-       .kill_sb        = kill_anon_super,
+       .kill_sb        = hostfs_kill_sb,
        .fs_flags       = 0,
 };