libfs: simple_follow_link()

let "fast" symlinks store the pointer to the body into ->i_link and
use simple_follow_link for ->follow_link()

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/inode.c b/fs/inode.c
index ea37cd1..952fb48 100644 (file)
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -152,6 +152,7 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
        inode->i_pipe = NULL;
        inode->i_bdev = NULL;
        inode->i_cdev = NULL;
+       inode->i_link = NULL;
        inode->i_rdev = 0;
        inode->dirtied_when = 0;
 

diff --git a/fs/libfs.c b/fs/libfs.c
index cb1fb4b..72e4e01 100644 (file)
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -1093,3 +1093,16 @@ simple_nosetlease(struct file *filp, long arg, struct file_lock **flp,
        return -EINVAL;
 }
 EXPORT_SYMBOL(simple_nosetlease);
+
+void *simple_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+       nd_set_link(nd, d_inode(dentry)->i_link);
+       return NULL;
+}
+EXPORT_SYMBOL(simple_follow_link);
+
+const struct inode_operations simple_symlink_inode_operations = {
+       .follow_link = simple_follow_link,
+       .readlink = generic_readlink
+};
+EXPORT_SYMBOL(simple_symlink_inode_operations);

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 35ec87e..0ac758f 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -656,6 +656,7 @@ struct inode {
                struct pipe_inode_info  *i_pipe;
                struct block_device     *i_bdev;
                struct cdev             *i_cdev;
+               char                    *i_link;
        };
 
        __u32                   i_generation;
@@ -2721,6 +2722,8 @@ void __inode_sub_bytes(struct inode *inode, loff_t bytes);
 void inode_sub_bytes(struct inode *inode, loff_t bytes);
 loff_t inode_get_bytes(struct inode *inode);
 void inode_set_bytes(struct inode *inode, loff_t bytes);
+void *simple_follow_link(struct dentry *, struct nameidata *);
+extern const struct inode_operations simple_symlink_inode_operations;
 
 extern int iterate_dir(struct file *, struct dir_context *);