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authorAl Viro <viro@zeniv.linux.org.uk>2019-09-11 10:00:01 +0300
committerChristoph Hellwig <hch@lst.de>2019-09-11 13:46:14 +0300
commite9c03af21cc7e5723d4f1e90fe45d2cdccb70dc7 (patch)
treea6daaac424c8aa5a827de19a2b21ea9a8636de04 /fs/configfs
parent2743c515a1239bb96028bddafef87c0a486f4361 (diff)
downloadlinux-e9c03af21cc7e5723d4f1e90fe45d2cdccb70dc7.tar.xz
configfs: calculate the symlink target only once
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'fs/configfs')
-rw-r--r--fs/configfs/configfs_internal.h19
-rw-r--r--fs/configfs/dir.c52
-rw-r--r--fs/configfs/mount.c9
-rw-r--r--fs/configfs/symlink.c164
4 files changed, 73 insertions, 171 deletions
diff --git a/fs/configfs/configfs_internal.h b/fs/configfs/configfs_internal.h
index c1f2125acf94..22dce2d35a4b 100644
--- a/fs/configfs/configfs_internal.h
+++ b/fs/configfs/configfs_internal.h
@@ -34,7 +34,7 @@ struct configfs_dirent {
int s_dependent_count;
struct list_head s_sibling;
struct list_head s_children;
- struct list_head s_links;
+ int s_links;
void * s_element;
int s_type;
umode_t s_mode;
@@ -84,7 +84,6 @@ extern int configfs_setattr(struct dentry *dentry, struct iattr *iattr);
extern struct dentry *configfs_pin_fs(void);
extern void configfs_release_fs(void);
-extern struct rw_semaphore configfs_rename_sem;
extern const struct file_operations configfs_dir_operations;
extern const struct file_operations configfs_file_operations;
extern const struct file_operations configfs_bin_file_operations;
@@ -97,14 +96,8 @@ extern int configfs_symlink(struct inode *dir, struct dentry *dentry,
const char *symname);
extern int configfs_unlink(struct inode *dir, struct dentry *dentry);
-struct configfs_symlink {
- struct list_head sl_list;
- struct config_item *sl_target;
-};
-
-extern int configfs_create_link(struct configfs_symlink *sl,
- struct dentry *parent,
- struct dentry *dentry);
+int configfs_create_link(struct configfs_dirent *target, struct dentry *parent,
+ struct dentry *dentry, char *body);
static inline struct config_item * to_item(struct dentry * dentry)
{
@@ -132,11 +125,7 @@ static inline struct config_item *configfs_get_config_item(struct dentry *dentry
spin_lock(&dentry->d_lock);
if (!d_unhashed(dentry)) {
struct configfs_dirent * sd = dentry->d_fsdata;
- if (sd->s_type & CONFIGFS_ITEM_LINK) {
- struct configfs_symlink * sl = sd->s_element;
- item = config_item_get(sl->sl_target);
- } else
- item = config_item_get(sd->s_element);
+ item = config_item_get(sd->s_element);
}
spin_unlock(&dentry->d_lock);
diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index 728d1f1ee6a9..cf7b7e1d5bd7 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -22,7 +22,6 @@
#include <linux/configfs.h>
#include "configfs_internal.h"
-DECLARE_RWSEM(configfs_rename_sem);
/*
* Protects mutations of configfs_dirent linkage together with proper i_mutex
* Also protects mutations of symlinks linkage to target configfs_dirent
@@ -191,7 +190,6 @@ static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *paren
return ERR_PTR(-ENOMEM);
atomic_set(&sd->s_count, 1);
- INIT_LIST_HEAD(&sd->s_links);
INIT_LIST_HEAD(&sd->s_children);
sd->s_element = element;
sd->s_type = type;
@@ -353,17 +351,16 @@ int configfs_dirent_is_ready(struct configfs_dirent *sd)
return ret;
}
-int configfs_create_link(struct configfs_symlink *sl,
- struct dentry *parent,
- struct dentry *dentry)
+int configfs_create_link(struct configfs_dirent *target, struct dentry *parent,
+ struct dentry *dentry, char *body)
{
int err = 0;
umode_t mode = S_IFLNK | S_IRWXUGO;
struct configfs_dirent *p = parent->d_fsdata;
struct inode *inode;
- err = configfs_make_dirent(p, dentry, sl, mode,
- CONFIGFS_ITEM_LINK, p->s_frag);
+ err = configfs_make_dirent(p, dentry, target, mode, CONFIGFS_ITEM_LINK,
+ p->s_frag);
if (err)
return err;
@@ -371,6 +368,7 @@ int configfs_create_link(struct configfs_symlink *sl,
if (IS_ERR(inode))
goto out_remove;
+ inode->i_link = body;
inode->i_op = &configfs_symlink_inode_operations;
d_instantiate(dentry, inode);
dget(dentry); /* pin link dentries in core */
@@ -517,7 +515,7 @@ static int configfs_detach_prep(struct dentry *dentry, struct dentry **wait)
parent_sd->s_type |= CONFIGFS_USET_DROPPING;
ret = -EBUSY;
- if (!list_empty(&parent_sd->s_links))
+ if (parent_sd->s_links)
goto out;
ret = 0;
@@ -1575,44 +1573,6 @@ const struct inode_operations configfs_root_inode_operations = {
.setattr = configfs_setattr,
};
-#if 0
-int configfs_rename_dir(struct config_item * item, const char *new_name)
-{
- int error = 0;
- struct dentry * new_dentry, * parent;
-
- if (!strcmp(config_item_name(item), new_name))
- return -EINVAL;
-
- if (!item->parent)
- return -EINVAL;
-
- down_write(&configfs_rename_sem);
- parent = item->parent->dentry;
-
- inode_lock(d_inode(parent));
-
- new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
- if (!IS_ERR(new_dentry)) {
- if (d_really_is_negative(new_dentry)) {
- error = config_item_set_name(item, "%s", new_name);
- if (!error) {
- d_add(new_dentry, NULL);
- d_move(item->dentry, new_dentry);
- }
- else
- d_delete(new_dentry);
- } else
- error = -EEXIST;
- dput(new_dentry);
- }
- inode_unlock(d_inode(parent));
- up_write(&configfs_rename_sem);
-
- return error;
-}
-#endif
-
static int configfs_dir_open(struct inode *inode, struct file *file)
{
struct dentry * dentry = file->f_path.dentry;
diff --git a/fs/configfs/mount.c b/fs/configfs/mount.c
index 55438dd58189..0c6e8cf61953 100644
--- a/fs/configfs/mount.c
+++ b/fs/configfs/mount.c
@@ -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 = {
diff --git a/fs/configfs/symlink.c b/fs/configfs/symlink.c
index f3881e4caedd..dc5dbf6a81d7 100644
--- a/fs/configfs/symlink.c
+++ b/fs/configfs/symlink.c
@@ -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) {
+ return -ENOENT;
+
+ 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);
- 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);
+ 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);
- }
+ configfs_put(target_sd);
+ kfree(body);
}
-
-out:
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;
@@ -193,15 +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;
@@ -210,7 +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;
@@ -224,21 +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);
@@ -248,79 +263,8 @@ out:
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,
};