configfs updates for 5.4:
- fix a symlink deadlock (Al Viro) - various cleanups (Al Viro, me) -----BEGIN PGP SIGNATURE----- iQI/BAABCgApFiEEgdbnc3r/njty3Iq9D55TZVIEUYMFAl2CSaILHGhjaEBsc3Qu ZGUACgkQD55TZVIEUYMpLBAAmwYW2g9wlNcKdZs0k0Pqn7sGyOErInaRKsS+TP6N Ds6CYpU9B1uETL1K46f45QnOJh7fWudMTPY8TISJh/XYrREmmRcCqS1Fh+VZvAFK 7sjhgP70+ZJEIX4xaixqUnCyNNSHJJwvhDN/BDDiiv1CgJjiZH5jkAV2Nb4dCnyE IDAeMvWNUYo+H35hclatd3vB79p+GUOaJnYszQ7LUxfH+WPyliw1PAJDeeZS3u9w uq7v8o3+1iKt3o1IGKaPVWKUgzS3RuqFYhdueyJ/xPCWI9NMx3DoT2FuOcvTQwT2 eoEd6hyJJLUc2MTHpjlytryfkEUTzGJQz3Rvc59O/RQG17evlugPOcWblWQwAJKW 9PuHIrLus7FmRSazUVGaEdAveVHFupZ7Qh+cUfGUzXlWwdAYldbOnt+TBF4zgOU8 +/sCk+Zy2hpjx1uY+0h7+dRDCGrgICf/xwoGpsg2uhvY+8ng017wUMNeZYEuWKOJ NeqqqP6vCQ8nfljitL8X0XtVSvCri1hSPUJ44adwAah1N/h6uk/N40bkYLPhhC3y PPvuVbBsEmGy6rYMkGp7kVuUmSWLs3+WEE0lUfYI73XDGK8dviJawxd+WAF25Y9o Z0VfNL4jphT2mS/oSmRbn+7Ukwm7jr9IwpM8OA0SDBKKFyFEv0yMloKK+BdBwyxg 6XE= =H208 -----END PGP SIGNATURE----- Merge tag 'configfs-for-5.4' of git://git.infradead.org/users/hch/configfs Pull configfs updates from Christoph Hellwig: - fix a symlink deadlock (Al Viro) - various cleanups (Al Viro, me) * tag 'configfs-for-5.4' of git://git.infradead.org/users/hch/configfs: configfs: calculate the symlink target only once configfs: make configfs_create() return inode configfs: factor dirent removal into helpers configfs: fix a deadlock in configfs_symlink()
This commit is contained in:
Linus Torvalds
commit
c9fe5630da
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@ -34,7 +34,7 @@ struct configfs_dirent {
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int s_dependent_count;
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struct list_head s_sibling;
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struct list_head s_children;
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struct list_head s_links;
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int s_links;
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void * s_element;
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int s_type;
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umode_t s_mode;
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@ -66,7 +66,7 @@ extern struct kmem_cache *configfs_dir_cachep;
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extern int configfs_is_root(struct config_item *item);
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extern struct inode * configfs_new_inode(umode_t mode, struct configfs_dirent *, struct super_block *);
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extern int configfs_create(struct dentry *, umode_t mode, void (*init)(struct inode *));
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extern struct inode *configfs_create(struct dentry *, umode_t mode);
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extern int configfs_create_file(struct config_item *, const struct configfs_attribute *);
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extern int configfs_create_bin_file(struct config_item *,
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@ -84,7 +84,6 @@ extern int configfs_setattr(struct dentry *dentry, struct iattr *iattr);
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extern struct dentry *configfs_pin_fs(void);
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extern void configfs_release_fs(void);
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extern struct rw_semaphore configfs_rename_sem;
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extern const struct file_operations configfs_dir_operations;
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extern const struct file_operations configfs_file_operations;
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extern const struct file_operations configfs_bin_file_operations;
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@ -97,14 +96,8 @@ extern int configfs_symlink(struct inode *dir, struct dentry *dentry,
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const char *symname);
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extern int configfs_unlink(struct inode *dir, struct dentry *dentry);
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struct configfs_symlink {
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struct list_head sl_list;
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struct config_item *sl_target;
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};
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extern int configfs_create_link(struct configfs_symlink *sl,
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struct dentry *parent,
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struct dentry *dentry);
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int configfs_create_link(struct configfs_dirent *target, struct dentry *parent,
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struct dentry *dentry, char *body);
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static inline struct config_item * to_item(struct dentry * dentry)
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{
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@ -132,11 +125,7 @@ static inline struct config_item *configfs_get_config_item(struct dentry *dentry
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spin_lock(&dentry->d_lock);
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if (!d_unhashed(dentry)) {
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struct configfs_dirent * sd = dentry->d_fsdata;
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if (sd->s_type & CONFIGFS_ITEM_LINK) {
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struct configfs_symlink * sl = sd->s_element;
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item = config_item_get(sl->sl_target);
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} else
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item = config_item_get(sd->s_element);
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item = config_item_get(sd->s_element);
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}
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spin_unlock(&dentry->d_lock);
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@ -22,7 +22,6 @@
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#include <linux/configfs.h>
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#include "configfs_internal.h"
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DECLARE_RWSEM(configfs_rename_sem);
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/*
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* Protects mutations of configfs_dirent linkage together with proper i_mutex
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* Also protects mutations of symlinks linkage to target configfs_dirent
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@ -191,7 +190,6 @@ static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *paren
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return ERR_PTR(-ENOMEM);
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atomic_set(&sd->s_count, 1);
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INIT_LIST_HEAD(&sd->s_links);
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INIT_LIST_HEAD(&sd->s_children);
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sd->s_element = element;
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sd->s_type = type;
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@ -253,30 +251,16 @@ int configfs_make_dirent(struct configfs_dirent * parent_sd,
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return 0;
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}
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static void init_dir(struct inode * inode)
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static void configfs_remove_dirent(struct dentry *dentry)
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{
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inode->i_op = &configfs_dir_inode_operations;
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inode->i_fop = &configfs_dir_operations;
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struct configfs_dirent *sd = dentry->d_fsdata;
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/* directory inodes start off with i_nlink == 2 (for "." entry) */
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inc_nlink(inode);
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}
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static void configfs_init_file(struct inode * inode)
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{
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inode->i_size = PAGE_SIZE;
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inode->i_fop = &configfs_file_operations;
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}
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static void configfs_init_bin_file(struct inode *inode)
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{
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inode->i_size = 0;
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inode->i_fop = &configfs_bin_file_operations;
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}
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static void init_symlink(struct inode * inode)
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{
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inode->i_op = &configfs_symlink_inode_operations;
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if (!sd)
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return;
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spin_lock(&configfs_dirent_lock);
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list_del_init(&sd->s_sibling);
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spin_unlock(&configfs_dirent_lock);
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configfs_put(sd);
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}
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/**
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@ -294,6 +278,7 @@ static int configfs_create_dir(struct config_item *item, struct dentry *dentry,
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int error;
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umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
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struct dentry *p = dentry->d_parent;
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struct inode *inode;
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BUG_ON(!item);
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@ -308,20 +293,24 @@ static int configfs_create_dir(struct config_item *item, struct dentry *dentry,
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return error;
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configfs_set_dir_dirent_depth(p->d_fsdata, dentry->d_fsdata);
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error = configfs_create(dentry, mode, init_dir);
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if (!error) {
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inc_nlink(d_inode(p));
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item->ci_dentry = dentry;
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} else {
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struct configfs_dirent *sd = dentry->d_fsdata;
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if (sd) {
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spin_lock(&configfs_dirent_lock);
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list_del_init(&sd->s_sibling);
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spin_unlock(&configfs_dirent_lock);
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configfs_put(sd);
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}
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}
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return error;
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inode = configfs_create(dentry, mode);
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if (IS_ERR(inode))
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goto out_remove;
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inode->i_op = &configfs_dir_inode_operations;
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inode->i_fop = &configfs_dir_operations;
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/* directory inodes start off with i_nlink == 2 (for "." entry) */
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inc_nlink(inode);
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d_instantiate(dentry, inode);
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/* already hashed */
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dget(dentry); /* pin directory dentries in core */
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inc_nlink(d_inode(p));
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item->ci_dentry = dentry;
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return 0;
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out_remove:
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configfs_remove_dirent(dentry);
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return PTR_ERR(inode);
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}
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/*
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@ -362,41 +351,40 @@ int configfs_dirent_is_ready(struct configfs_dirent *sd)
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return ret;
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}
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int configfs_create_link(struct configfs_symlink *sl,
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struct dentry *parent,
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struct dentry *dentry)
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int configfs_create_link(struct configfs_dirent *target, struct dentry *parent,
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struct dentry *dentry, char *body)
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{
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int err = 0;
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umode_t mode = S_IFLNK | S_IRWXUGO;
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struct configfs_dirent *p = parent->d_fsdata;
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struct inode *inode;
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err = configfs_make_dirent(p, dentry, sl, mode,
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CONFIGFS_ITEM_LINK, p->s_frag);
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if (!err) {
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err = configfs_create(dentry, mode, init_symlink);
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if (err) {
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struct configfs_dirent *sd = dentry->d_fsdata;
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if (sd) {
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spin_lock(&configfs_dirent_lock);
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list_del_init(&sd->s_sibling);
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spin_unlock(&configfs_dirent_lock);
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configfs_put(sd);
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}
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}
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}
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return err;
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err = configfs_make_dirent(p, dentry, target, mode, CONFIGFS_ITEM_LINK,
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p->s_frag);
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if (err)
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return err;
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inode = configfs_create(dentry, mode);
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if (IS_ERR(inode))
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goto out_remove;
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inode->i_link = body;
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inode->i_op = &configfs_symlink_inode_operations;
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d_instantiate(dentry, inode);
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dget(dentry); /* pin link dentries in core */
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return 0;
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out_remove:
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configfs_remove_dirent(dentry);
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return PTR_ERR(inode);
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}
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static void remove_dir(struct dentry * d)
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{
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struct dentry * parent = dget(d->d_parent);
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struct configfs_dirent * sd;
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sd = d->d_fsdata;
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spin_lock(&configfs_dirent_lock);
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list_del_init(&sd->s_sibling);
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spin_unlock(&configfs_dirent_lock);
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configfs_put(sd);
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configfs_remove_dirent(d);
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if (d_really_is_positive(d))
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simple_rmdir(d_inode(parent),d);
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@ -437,20 +425,27 @@ static void configfs_remove_dir(struct config_item * item)
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static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry)
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{
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struct configfs_attribute * attr = sd->s_element;
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int error;
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struct inode *inode;
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spin_lock(&configfs_dirent_lock);
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dentry->d_fsdata = configfs_get(sd);
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sd->s_dentry = dentry;
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spin_unlock(&configfs_dirent_lock);
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error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG,
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(sd->s_type & CONFIGFS_ITEM_BIN_ATTR) ?
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configfs_init_bin_file :
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configfs_init_file);
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if (error)
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inode = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG);
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if (IS_ERR(inode)) {
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configfs_put(sd);
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return error;
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return PTR_ERR(inode);
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}
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if (sd->s_type & CONFIGFS_ITEM_BIN_ATTR) {
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inode->i_size = 0;
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inode->i_fop = &configfs_bin_file_operations;
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} else {
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inode->i_size = PAGE_SIZE;
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inode->i_fop = &configfs_file_operations;
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}
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d_add(dentry, inode);
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return 0;
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}
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static struct dentry * configfs_lookup(struct inode *dir,
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@ -520,7 +515,7 @@ static int configfs_detach_prep(struct dentry *dentry, struct dentry **wait)
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parent_sd->s_type |= CONFIGFS_USET_DROPPING;
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ret = -EBUSY;
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if (!list_empty(&parent_sd->s_links))
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if (parent_sd->s_links)
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goto out;
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ret = 0;
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@ -1578,44 +1573,6 @@ const struct inode_operations configfs_root_inode_operations = {
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.setattr = configfs_setattr,
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};
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#if 0
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int configfs_rename_dir(struct config_item * item, const char *new_name)
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{
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int error = 0;
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struct dentry * new_dentry, * parent;
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if (!strcmp(config_item_name(item), new_name))
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return -EINVAL;
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if (!item->parent)
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return -EINVAL;
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down_write(&configfs_rename_sem);
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parent = item->parent->dentry;
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inode_lock(d_inode(parent));
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new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
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if (!IS_ERR(new_dentry)) {
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if (d_really_is_negative(new_dentry)) {
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error = config_item_set_name(item, "%s", new_name);
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if (!error) {
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d_add(new_dentry, NULL);
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d_move(item->dentry, new_dentry);
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}
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else
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d_delete(new_dentry);
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} else
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error = -EEXIST;
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dput(new_dentry);
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}
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inode_unlock(d_inode(parent));
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up_write(&configfs_rename_sem);
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return error;
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}
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#endif
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static int configfs_dir_open(struct inode *inode, struct file *file)
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{
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struct dentry * dentry = file->f_path.dentry;
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|
|
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@ -164,41 +164,27 @@ static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
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|||
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#endif /* CONFIG_LOCKDEP */
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|
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int configfs_create(struct dentry * dentry, umode_t mode, void (*init)(struct inode *))
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struct inode *configfs_create(struct dentry *dentry, umode_t mode)
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{
|
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int error = 0;
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struct inode *inode = NULL;
|
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struct configfs_dirent *sd;
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struct inode *p_inode;
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||||
|
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if (!dentry)
|
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return -ENOENT;
|
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return ERR_PTR(-ENOENT);
|
||||
|
||||
if (d_really_is_positive(dentry))
|
||||
return -EEXIST;
|
||||
return ERR_PTR(-EEXIST);
|
||||
|
||||
sd = dentry->d_fsdata;
|
||||
inode = configfs_new_inode(mode, sd, dentry->d_sb);
|
||||
if (!inode)
|
||||
return -ENOMEM;
|
||||
return ERR_PTR(-ENOMEM);
|
||||
|
||||
p_inode = d_inode(dentry->d_parent);
|
||||
p_inode->i_mtime = p_inode->i_ctime = current_time(p_inode);
|
||||
configfs_set_inode_lock_class(sd, inode);
|
||||
|
||||
init(inode);
|
||||
if (S_ISDIR(mode) || S_ISLNK(mode)) {
|
||||
/*
|
||||
* ->symlink(), ->mkdir(), configfs_register_subsystem() or
|
||||
* create_default_group() - already hashed.
|
||||
*/
|
||||
d_instantiate(dentry, inode);
|
||||
dget(dentry); /* pin link and directory dentries in core */
|
||||
} else {
|
||||
/* ->lookup() */
|
||||
d_add(dentry, inode);
|
||||
}
|
||||
return error;
|
||||
return inode;
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
|
|||
|
|
@ -28,9 +28,18 @@ static struct vfsmount *configfs_mount = NULL;
|
|||
struct kmem_cache *configfs_dir_cachep;
|
||||
static int configfs_mnt_count = 0;
|
||||
|
||||
|
||||
static void configfs_free_inode(struct inode *inode)
|
||||
{
|
||||
if (S_ISLNK(inode->i_mode))
|
||||
kfree(inode->i_link);
|
||||
free_inode_nonrcu(inode);
|
||||
}
|
||||
|
||||
static const struct super_operations configfs_ops = {
|
||||
.statfs = simple_statfs,
|
||||
.drop_inode = generic_delete_inode,
|
||||
.free_inode = configfs_free_inode,
|
||||
};
|
||||
|
||||
static struct config_group configfs_root_group = {
|
||||
|
|
|
|||
|
|
@ -55,41 +55,63 @@ static void fill_item_path(struct config_item * item, char * buffer, int length)
|
|||
}
|
||||
}
|
||||
|
||||
static int configfs_get_target_path(struct config_item *item,
|
||||
struct config_item *target, char *path)
|
||||
{
|
||||
int depth, size;
|
||||
char *s;
|
||||
|
||||
depth = item_depth(item);
|
||||
size = item_path_length(target) + depth * 3 - 1;
|
||||
if (size > PATH_MAX)
|
||||
return -ENAMETOOLONG;
|
||||
|
||||
pr_debug("%s: depth = %d, size = %d\n", __func__, depth, size);
|
||||
|
||||
for (s = path; depth--; s += 3)
|
||||
strcpy(s,"../");
|
||||
|
||||
fill_item_path(target, path, size);
|
||||
pr_debug("%s: path = '%s'\n", __func__, path);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int create_link(struct config_item *parent_item,
|
||||
struct config_item *item,
|
||||
struct dentry *dentry)
|
||||
{
|
||||
struct configfs_dirent *target_sd = item->ci_dentry->d_fsdata;
|
||||
struct configfs_symlink *sl;
|
||||
char *body;
|
||||
int ret;
|
||||
|
||||
ret = -ENOENT;
|
||||
if (!configfs_dirent_is_ready(target_sd))
|
||||
goto out;
|
||||
ret = -ENOMEM;
|
||||
sl = kmalloc(sizeof(struct configfs_symlink), GFP_KERNEL);
|
||||
if (sl) {
|
||||
spin_lock(&configfs_dirent_lock);
|
||||
if (target_sd->s_type & CONFIGFS_USET_DROPPING) {
|
||||
spin_unlock(&configfs_dirent_lock);
|
||||
kfree(sl);
|
||||
return -ENOENT;
|
||||
}
|
||||
sl->sl_target = config_item_get(item);
|
||||
list_add(&sl->sl_list, &target_sd->s_links);
|
||||
spin_unlock(&configfs_dirent_lock);
|
||||
ret = configfs_create_link(sl, parent_item->ci_dentry,
|
||||
dentry);
|
||||
if (ret) {
|
||||
spin_lock(&configfs_dirent_lock);
|
||||
list_del_init(&sl->sl_list);
|
||||
spin_unlock(&configfs_dirent_lock);
|
||||
config_item_put(item);
|
||||
kfree(sl);
|
||||
}
|
||||
}
|
||||
return -ENOENT;
|
||||
|
||||
out:
|
||||
body = kzalloc(PAGE_SIZE, GFP_KERNEL);
|
||||
if (!body)
|
||||
return -ENOMEM;
|
||||
|
||||
configfs_get(target_sd);
|
||||
spin_lock(&configfs_dirent_lock);
|
||||
if (target_sd->s_type & CONFIGFS_USET_DROPPING) {
|
||||
spin_unlock(&configfs_dirent_lock);
|
||||
configfs_put(target_sd);
|
||||
kfree(body);
|
||||
return -ENOENT;
|
||||
}
|
||||
target_sd->s_links++;
|
||||
spin_unlock(&configfs_dirent_lock);
|
||||
ret = configfs_get_target_path(item, item, body);
|
||||
if (!ret)
|
||||
ret = configfs_create_link(target_sd, parent_item->ci_dentry,
|
||||
dentry, body);
|
||||
if (ret) {
|
||||
spin_lock(&configfs_dirent_lock);
|
||||
target_sd->s_links--;
|
||||
spin_unlock(&configfs_dirent_lock);
|
||||
configfs_put(target_sd);
|
||||
kfree(body);
|
||||
}
|
||||
return ret;
|
||||
}
|
||||
|
||||
|
|
@ -131,9 +153,8 @@ int configfs_symlink(struct inode *dir, struct dentry *dentry, const char *symna
|
|||
* Fake invisibility if dir belongs to a group/default groups hierarchy
|
||||
* being attached
|
||||
*/
|
||||
ret = -ENOENT;
|
||||
if (!configfs_dirent_is_ready(sd))
|
||||
goto out;
|
||||
return -ENOENT;
|
||||
|
||||
parent_item = configfs_get_config_item(dentry->d_parent);
|
||||
type = parent_item->ci_type;
|
||||
|
|
@ -143,11 +164,42 @@ int configfs_symlink(struct inode *dir, struct dentry *dentry, const char *symna
|
|||
!type->ct_item_ops->allow_link)
|
||||
goto out_put;
|
||||
|
||||
/*
|
||||
* This is really sick. What they wanted was a hybrid of
|
||||
* link(2) and symlink(2) - they wanted the target resolved
|
||||
* at syscall time (as link(2) would've done), be a directory
|
||||
* (which link(2) would've refused to do) *AND* be a deep
|
||||
* fucking magic, making the target busy from rmdir POV.
|
||||
* symlink(2) is nothing of that sort, and the locking it
|
||||
* gets matches the normal symlink(2) semantics. Without
|
||||
* attempts to resolve the target (which might very well
|
||||
* not even exist yet) done prior to locking the parent
|
||||
* directory. This perversion, OTOH, needs to resolve
|
||||
* the target, which would lead to obvious deadlocks if
|
||||
* attempted with any directories locked.
|
||||
*
|
||||
* Unfortunately, that garbage is userland ABI and we should've
|
||||
* said "no" back in 2005. Too late now, so we get to
|
||||
* play very ugly games with locking.
|
||||
*
|
||||
* Try *ANYTHING* of that sort in new code, and you will
|
||||
* really regret it. Just ask yourself - what could a BOFH
|
||||
* do to me and do I want to find it out first-hand?
|
||||
*
|
||||
* AV, a thoroughly annoyed bastard.
|
||||
*/
|
||||
inode_unlock(dir);
|
||||
ret = get_target(symname, &path, &target_item, dentry->d_sb);
|
||||
inode_lock(dir);
|
||||
if (ret)
|
||||
goto out_put;
|
||||
|
||||
ret = type->ct_item_ops->allow_link(parent_item, target_item);
|
||||
if (dentry->d_inode || d_unhashed(dentry))
|
||||
ret = -EEXIST;
|
||||
else
|
||||
ret = inode_permission(dir, MAY_WRITE | MAY_EXEC);
|
||||
if (!ret)
|
||||
ret = type->ct_item_ops->allow_link(parent_item, target_item);
|
||||
if (!ret) {
|
||||
mutex_lock(&configfs_symlink_mutex);
|
||||
ret = create_link(parent_item, target_item, dentry);
|
||||
|
|
@ -162,15 +214,12 @@ int configfs_symlink(struct inode *dir, struct dentry *dentry, const char *symna
|
|||
|
||||
out_put:
|
||||
config_item_put(parent_item);
|
||||
|
||||
out:
|
||||
return ret;
|
||||
}
|
||||
|
||||
int configfs_unlink(struct inode *dir, struct dentry *dentry)
|
||||
{
|
||||
struct configfs_dirent *sd = dentry->d_fsdata;
|
||||
struct configfs_symlink *sl;
|
||||
struct configfs_dirent *sd = dentry->d_fsdata, *target_sd;
|
||||
struct config_item *parent_item;
|
||||
const struct config_item_type *type;
|
||||
int ret;
|
||||
|
|
@ -179,7 +228,7 @@ int configfs_unlink(struct inode *dir, struct dentry *dentry)
|
|||
if (!(sd->s_type & CONFIGFS_ITEM_LINK))
|
||||
goto out;
|
||||
|
||||
sl = sd->s_element;
|
||||
target_sd = sd->s_element;
|
||||
|
||||
parent_item = configfs_get_config_item(dentry->d_parent);
|
||||
type = parent_item->ci_type;
|
||||
|
|
@ -193,21 +242,18 @@ int configfs_unlink(struct inode *dir, struct dentry *dentry)
|
|||
|
||||
/*
|
||||
* drop_link() must be called before
|
||||
* list_del_init(&sl->sl_list), so that the order of
|
||||
* decrementing target's ->s_links, so that the order of
|
||||
* drop_link(this, target) and drop_item(target) is preserved.
|
||||
*/
|
||||
if (type && type->ct_item_ops &&
|
||||
type->ct_item_ops->drop_link)
|
||||
type->ct_item_ops->drop_link(parent_item,
|
||||
sl->sl_target);
|
||||
target_sd->s_element);
|
||||
|
||||
spin_lock(&configfs_dirent_lock);
|
||||
list_del_init(&sl->sl_list);
|
||||
target_sd->s_links--;
|
||||
spin_unlock(&configfs_dirent_lock);
|
||||
|
||||
/* Put reference from create_link() */
|
||||
config_item_put(sl->sl_target);
|
||||
kfree(sl);
|
||||
configfs_put(target_sd);
|
||||
|
||||
config_item_put(parent_item);
|
||||
|
||||
|
|
@ -217,79 +263,8 @@ int configfs_unlink(struct inode *dir, struct dentry *dentry)
|
|||
return ret;
|
||||
}
|
||||
|
||||
static int configfs_get_target_path(struct config_item * item, struct config_item * target,
|
||||
char *path)
|
||||
{
|
||||
char * s;
|
||||
int depth, size;
|
||||
|
||||
depth = item_depth(item);
|
||||
size = item_path_length(target) + depth * 3 - 1;
|
||||
if (size > PATH_MAX)
|
||||
return -ENAMETOOLONG;
|
||||
|
||||
pr_debug("%s: depth = %d, size = %d\n", __func__, depth, size);
|
||||
|
||||
for (s = path; depth--; s += 3)
|
||||
strcpy(s,"../");
|
||||
|
||||
fill_item_path(target, path, size);
|
||||
pr_debug("%s: path = '%s'\n", __func__, path);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int configfs_getlink(struct dentry *dentry, char * path)
|
||||
{
|
||||
struct config_item *item, *target_item;
|
||||
int error = 0;
|
||||
|
||||
item = configfs_get_config_item(dentry->d_parent);
|
||||
if (!item)
|
||||
return -EINVAL;
|
||||
|
||||
target_item = configfs_get_config_item(dentry);
|
||||
if (!target_item) {
|
||||
config_item_put(item);
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
down_read(&configfs_rename_sem);
|
||||
error = configfs_get_target_path(item, target_item, path);
|
||||
up_read(&configfs_rename_sem);
|
||||
|
||||
config_item_put(item);
|
||||
config_item_put(target_item);
|
||||
return error;
|
||||
|
||||
}
|
||||
|
||||
static const char *configfs_get_link(struct dentry *dentry,
|
||||
struct inode *inode,
|
||||
struct delayed_call *done)
|
||||
{
|
||||
char *body;
|
||||
int error;
|
||||
|
||||
if (!dentry)
|
||||
return ERR_PTR(-ECHILD);
|
||||
|
||||
body = kzalloc(PAGE_SIZE, GFP_KERNEL);
|
||||
if (!body)
|
||||
return ERR_PTR(-ENOMEM);
|
||||
|
||||
error = configfs_getlink(dentry, body);
|
||||
if (!error) {
|
||||
set_delayed_call(done, kfree_link, body);
|
||||
return body;
|
||||
}
|
||||
|
||||
kfree(body);
|
||||
return ERR_PTR(error);
|
||||
}
|
||||
|
||||
const struct inode_operations configfs_symlink_inode_operations = {
|
||||
.get_link = configfs_get_link,
|
||||
.get_link = simple_get_link,
|
||||
.setattr = configfs_setattr,
|
||||
};
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue