diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/kernfs/dir.c | 988 | ||||
| -rw-r--r-- | fs/kernfs/kernfs-internal.h | 17 | ||||
| -rw-r--r-- | fs/sysfs/dir.c | 986 | ||||
| -rw-r--r-- | fs/sysfs/sysfs.h | 13 |
4 files changed, 1005 insertions, 999 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index 1061602ce81a..a4ca4de3cb21 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -7,3 +7,991 @@ * * This file is released under the GPLv2. */ + +#include <linux/fs.h> +#include <linux/namei.h> +#include <linux/idr.h> +#include <linux/slab.h> +#include <linux/security.h> +#include <linux/hash.h> + +#include "kernfs-internal.h" + +DEFINE_MUTEX(sysfs_mutex); + +#define to_sysfs_dirent(X) rb_entry((X), struct sysfs_dirent, s_rb) + +static DEFINE_SPINLOCK(sysfs_ino_lock); +static DEFINE_IDA(sysfs_ino_ida); + +/** + * sysfs_name_hash + * @name: Null terminated string to hash + * @ns: Namespace tag to hash + * + * Returns 31 bit hash of ns + name (so it fits in an off_t ) + */ +static unsigned int sysfs_name_hash(const char *name, const void *ns) +{ + unsigned long hash = init_name_hash(); + unsigned int len = strlen(name); + while (len--) + hash = partial_name_hash(*name++, hash); + hash = (end_name_hash(hash) ^ hash_ptr((void *)ns, 31)); + hash &= 0x7fffffffU; + /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */ + if (hash < 1) + hash += 2; + if (hash >= INT_MAX) + hash = INT_MAX - 1; + return hash; +} + +static int sysfs_name_compare(unsigned int hash, const char *name, + const void *ns, const struct sysfs_dirent *sd) +{ + if (hash != sd->s_hash) + return hash - sd->s_hash; + if (ns != sd->s_ns) + return ns - sd->s_ns; + return strcmp(name, sd->s_name); +} + +static int sysfs_sd_compare(const struct sysfs_dirent *left, + const struct sysfs_dirent *right) +{ + return sysfs_name_compare(left->s_hash, left->s_name, left->s_ns, + right); +} + +/** + * sysfs_link_sibling - link sysfs_dirent into sibling rbtree + * @sd: sysfs_dirent of interest + * + * Link @sd into its sibling rbtree which starts from + * sd->s_parent->s_dir.children. + * + * Locking: + * mutex_lock(sysfs_mutex) + * + * RETURNS: + * 0 on susccess -EEXIST on failure. + */ +static int sysfs_link_sibling(struct sysfs_dirent *sd) +{ + struct rb_node **node = &sd->s_parent->s_dir.children.rb_node; + struct rb_node *parent = NULL; + + if (sysfs_type(sd) == SYSFS_DIR) + sd->s_parent->s_dir.subdirs++; + + while (*node) { + struct sysfs_dirent *pos; + int result; + + pos = to_sysfs_dirent(*node); + parent = *node; + result = sysfs_sd_compare(sd, pos); + if (result < 0) + node = &pos->s_rb.rb_left; + else if (result > 0) + node = &pos->s_rb.rb_right; + else + return -EEXIST; + } + /* add new node and rebalance the tree */ + rb_link_node(&sd->s_rb, parent, node); + rb_insert_color(&sd->s_rb, &sd->s_parent->s_dir.children); + return 0; +} + +/** + * sysfs_unlink_sibling - unlink sysfs_dirent from sibling rbtree + * @sd: sysfs_dirent of interest + * + * Unlink @sd from its sibling rbtree which starts from + * sd->s_parent->s_dir.children. + * + * Locking: + * mutex_lock(sysfs_mutex) + */ +static void sysfs_unlink_sibling(struct sysfs_dirent *sd) +{ + if (sysfs_type(sd) == SYSFS_DIR) + sd->s_parent->s_dir.subdirs--; + + rb_erase(&sd->s_rb, &sd->s_parent->s_dir.children); +} + +/** + * sysfs_get_active - get an active reference to sysfs_dirent + * @sd: sysfs_dirent to get an active reference to + * + * Get an active reference of @sd. This function is noop if @sd + * is NULL. + * + * RETURNS: + * Pointer to @sd on success, NULL on failure. + */ +struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd) +{ + if (unlikely(!sd)) + return NULL; + + if (!atomic_inc_unless_negative(&sd->s_active)) + return NULL; + + if (sd->s_flags & SYSFS_FLAG_LOCKDEP) + rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_); + return sd; +} + +/** + * sysfs_put_active - put an active reference to sysfs_dirent + * @sd: sysfs_dirent to put an active reference to + * + * Put an active reference to @sd. This function is noop if @sd + * is NULL. + */ +void sysfs_put_active(struct sysfs_dirent *sd) +{ + int v; + + if (unlikely(!sd)) + return; + + if (sd->s_flags & SYSFS_FLAG_LOCKDEP) + rwsem_release(&sd->dep_map, 1, _RET_IP_); + v = atomic_dec_return(&sd->s_active); + if (likely(v != SD_DEACTIVATED_BIAS)) + return; + + /* atomic_dec_return() is a mb(), we'll always see the updated + * sd->u.completion. + */ + complete(sd->u.completion); +} + +/** + * sysfs_deactivate - deactivate sysfs_dirent + * @sd: sysfs_dirent to deactivate + * + * Deny new active references and drain existing ones. + */ +static void sysfs_deactivate(struct sysfs_dirent *sd) +{ + DECLARE_COMPLETION_ONSTACK(wait); + int v; + + BUG_ON(!(sd->s_flags & SYSFS_FLAG_REMOVED)); + + if (!(sysfs_type(sd) & SYSFS_ACTIVE_REF)) + return; + + sd->u.completion = (void *)&wait; + + rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_); + /* atomic_add_return() is a mb(), put_active() will always see + * the updated sd->u.completion. + */ + v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active); + + if (v != SD_DEACTIVATED_BIAS) { + lock_contended(&sd->dep_map, _RET_IP_); + wait_for_completion(&wait); + } + + lock_acquired(&sd->dep_map, _RET_IP_); + rwsem_release(&sd->dep_map, 1, _RET_IP_); +} + +static int sysfs_alloc_ino(unsigned int *pino) +{ + int ino, rc; + + retry: + spin_lock(&sysfs_ino_lock); + rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino); + spin_unlock(&sysfs_ino_lock); + + if (rc == -EAGAIN) { + if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL)) + goto retry; + rc = -ENOMEM; + } + + *pino = ino; + return rc; +} + +static void sysfs_free_ino(unsigned int ino) +{ + spin_lock(&sysfs_ino_lock); + ida_remove(&sysfs_ino_ida, ino); + spin_unlock(&sysfs_ino_lock); +} + +/** + * kernfs_get - get a reference count on a sysfs_dirent + * @sd: the target sysfs_dirent + */ +void kernfs_get(struct sysfs_dirent *sd) +{ + if (sd) { + WARN_ON(!atomic_read(&sd->s_count)); + atomic_inc(&sd->s_count); + } +} +EXPORT_SYMBOL_GPL(kernfs_get); + +/** + * kernfs_put - put a reference count on a sysfs_dirent + * @sd: the target sysfs_dirent + * + * Put a reference count of @sd and destroy it if it reached zero. + */ +void kernfs_put(struct sysfs_dirent *sd) +{ + struct sysfs_dirent *parent_sd; + + if (!sd || !atomic_dec_and_test(&sd->s_count)) + return; + repeat: + /* Moving/renaming is always done while holding reference. + * sd->s_parent won't change beneath us. + */ + parent_sd = sd->s_parent; + + WARN(!(sd->s_flags & SYSFS_FLAG_REMOVED), + "sysfs: free using entry: %s/%s\n", + parent_sd ? parent_sd->s_name : "", sd->s_name); + + if (sysfs_type(sd) == SYSFS_KOBJ_LINK) + kernfs_put(sd->s_symlink.target_sd); + if (sysfs_type(sd) & SYSFS_COPY_NAME) + kfree(sd->s_name); + if (sd->s_iattr && sd->s_iattr->ia_secdata) + security_release_secctx(sd->s_iattr->ia_secdata, + sd->s_iattr->ia_secdata_len); + kfree(sd->s_iattr); + sysfs_free_ino(sd->s_ino); + kmem_cache_free(sysfs_dir_cachep, sd); + + sd = parent_sd; + if (sd && atomic_dec_and_test(&sd->s_count)) + goto repeat; +} +EXPORT_SYMBOL_GPL(kernfs_put); + +static int sysfs_dentry_delete(const struct dentry *dentry) +{ + struct sysfs_dirent *sd = dentry->d_fsdata; + return !(sd && !(sd->s_flags & SYSFS_FLAG_REMOVED)); +} + +static int sysfs_dentry_revalidate(struct dentry *dentry, unsigned int flags) +{ + struct sysfs_dirent *sd; + + if (flags & LOOKUP_RCU) + return -ECHILD; + + sd = dentry->d_fsdata; + mutex_lock(&sysfs_mutex); + + /* The sysfs dirent has been deleted */ + if (sd->s_flags & SYSFS_FLAG_REMOVED) + goto out_bad; + + /* The sysfs dirent has been moved? */ + if (dentry->d_parent->d_fsdata != sd->s_parent) + goto out_bad; + + /* The sysfs dirent has been renamed */ + if (strcmp(dentry->d_name.name, sd->s_name) != 0) + goto out_bad; + + /* The sysfs dirent has been moved to a different namespace */ + if (sd->s_parent && (sd->s_parent->s_flags & SYSFS_FLAG_NS) && + sysfs_info(dentry->d_sb)->ns != sd->s_ns) + goto out_bad; + + mutex_unlock(&sysfs_mutex); +out_valid: + return 1; +out_bad: + /* Remove the dentry from the dcache hashes. + * If this is a deleted dentry we use d_drop instead of d_delete + * so sysfs doesn't need to cope with negative dentries. + * + * If this is a dentry that has simply been renamed we + * use d_drop to remove it from the dcache lookup on its + * old parent. If this dentry persists later when a lookup + * is performed at its new name the dentry will be readded + * to the dcache hashes. + */ + mutex_unlock(&sysfs_mutex); + + /* If we have submounts we must allow the vfs caches + * to lie about the state of the filesystem to prevent + * leaks and other nasty things. + */ + if (check_submounts_and_drop(dentry) != 0) + goto out_valid; + + return 0; +} + +static void sysfs_dentry_release(struct dentry *dentry) +{ + kernfs_put(dentry->d_fsdata); +} + +const struct dentry_operations sysfs_dentry_ops = { + .d_revalidate = sysfs_dentry_revalidate, + .d_delete = sysfs_dentry_delete, + .d_release = sysfs_dentry_release, +}; + +struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type) +{ + char *dup_name = NULL; + struct sysfs_dirent *sd; + + if (type & SYSFS_COPY_NAME) { + name = dup_name = kstrdup(name, GFP_KERNEL); + if (!name) + return NULL; + } + + sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL); + if (!sd) + goto err_out1; + + if (sysfs_alloc_ino(&sd->s_ino)) + goto err_out2; + + atomic_set(&sd->s_count, 1); + atomic_set(&sd->s_active, 0); + + sd->s_name = name; + sd->s_mode = mode; + sd->s_flags = type | SYSFS_FLAG_REMOVED; + + return sd; + + err_out2: + kmem_cache_free(sysfs_dir_cachep, sd); + err_out1: + kfree(dup_name); + return NULL; +} + +/** + * sysfs_addrm_start - prepare for sysfs_dirent add/remove + * @acxt: pointer to sysfs_addrm_cxt to be used + * + * This function is called when the caller is about to add or remove + * sysfs_dirent. This function acquires sysfs_mutex. @acxt is used + * to keep and pass context to other addrm functions. + * + * LOCKING: + * Kernel thread context (may sleep). sysfs_mutex is locked on + * return. + */ +void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt) + __acquires(sysfs_mutex) +{ + memset(acxt, 0, sizeof(*acxt)); + + mutex_lock(&sysfs_mutex); +} + +/** + * sysfs_add_one - add sysfs_dirent to parent without warning + * @acxt: addrm context to use + * @sd: sysfs_dirent to be added + * @parent_sd: the parent sysfs_dirent to add @sd to + * + * Get @parent_sd and set @sd->s_parent to it and increment nlink of + * the parent inode if @sd is a directory and link into the children + * list of the parent. + * + * This function should be called between calls to + * sysfs_addrm_start() and sysfs_addrm_finish() and should be + * passed the same @acxt as passed to sysfs_addrm_start(). + * + * LOCKING: + * Determined by sysfs_addrm_start(). + * + * RETURNS: + * 0 on success, -EEXIST if entry with the given name already + * exists. + */ +int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd, + struct sysfs_dirent *parent_sd) +{ + bool has_ns = parent_sd->s_flags & SYSFS_FLAG_NS; + struct sysfs_inode_attrs *ps_iattr; + int ret; + + if (has_ns != (bool)sd->s_ns) { + WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n", + has_ns ? "required" : "invalid", + parent_sd->s_name, sd->s_name); + return -EINVAL; + } + + if (sysfs_type(parent_sd) != SYSFS_DIR) + return -EINVAL; + + sd->s_hash = sysfs_name_hash(sd->s_name, sd->s_ns); + sd->s_parent = parent_sd; + kernfs_get(parent_sd); + + ret = sysfs_link_sibling(sd); + if (ret) + return ret; + + /* Update timestamps on the parent */ + ps_iattr = parent_sd->s_iattr; + if (ps_iattr) { + struct iattr *ps_iattrs = &ps_iattr->ia_iattr; + ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME; + } + + /* Mark the entry added into directory tree */ + sd->s_flags &= ~SYSFS_FLAG_REMOVED; + + return 0; +} + +/** + * sysfs_remove_one - remove sysfs_dirent from parent + * @acxt: addrm context to use + * @sd: sysfs_dirent to be removed + * + * Mark @sd removed and drop nlink of parent inode if @sd is a + * directory. @sd is unlinked from the children list. + * + * This function should be called between calls to + * sysfs_addrm_start() and sysfs_addrm_finish() and should be + * passed the same @acxt as passed to sysfs_addrm_start(). + * + * LOCKING: + * Determined by sysfs_addrm_start(). + */ +static void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, + struct sysfs_dirent *sd) +{ + struct sysfs_inode_attrs *ps_iattr; + + /* + * Removal can be called multiple times on the same node. Only the + * first invocation is effective and puts the base ref. + */ + if (sd->s_flags & SYSFS_FLAG_REMOVED) + return; + + sysfs_unlink_sibling(sd); + + /* Update timestamps on the parent */ + ps_iattr = sd->s_parent->s_iattr; + if (ps_iattr) { + struct iattr *ps_iattrs = &ps_iattr->ia_iattr; + ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME; + } + + sd->s_flags |= SYSFS_FLAG_REMOVED; + sd->u.removed_list = acxt->removed; + acxt->removed = sd; +} + +/** + * sysfs_addrm_finish - finish up sysfs_dirent add/remove + * @acxt: addrm context to finish up + * + * Finish up sysfs_dirent add/remove. Resources acquired by + * sysfs_addrm_start() are released and removed sysfs_dirents are + * cleaned up. + * + * LOCKING: + * sysfs_mutex is released. + */ +void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt) + __releases(sysfs_mutex) +{ + /* release resources acquired by sysfs_addrm_start() */ + mutex_unlock(&sysfs_mutex); + + /* kill removed sysfs_dirents */ + while (acxt->removed) { + struct sysfs_dirent *sd = acxt->removed; + + acxt->removed = sd->u.removed_list; + + sysfs_deactivate(sd); + sysfs_unmap_bin_file(sd); + kernfs_put(sd); + } +} + +/** + * kernfs_find_ns - find sysfs_dirent with the given name + * @parent: sysfs_dirent to search under + * @name: name to look for + * @ns: the namespace tag to use + * + * Look for sysfs_dirent with name @name under @parent. Returns pointer to + * the found sysfs_dirent on success, %NULL on failure. + */ +static struct sysfs_dirent *kernfs_find_ns(struct sysfs_dirent *parent, + const unsigned char *name, + const void *ns) +{ + struct rb_node *node = parent->s_dir.children.rb_node; + bool has_ns = parent->s_flags & SYSFS_FLAG_NS; + unsigned int hash; + + lockdep_assert_held(&sysfs_mutex); + + if (has_ns != (bool)ns) { + WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n", + has_ns ? "required" : "invalid", + parent->s_name, name); + return NULL; + } + + hash = sysfs_name_hash(name, ns); + while (node) { + struct sysfs_dirent *sd; + int result; + + sd = to_sysfs_dirent(node); + result = sysfs_name_compare(hash, name, ns, sd); + if (result < 0) + node = node->rb_left; + else if (result > 0) + node = node->rb_right; + else + return sd; + } + return NULL; +} + +/** + * kernfs_find_and_get_ns - find and get sysfs_dirent with the given name + * @parent: sysfs_dirent to search under + * @name: name to look for + * @ns: the namespace tag to use + * + * Look for sysfs_dirent with name @name under @parent and get a reference + * if found. This function may sleep and returns pointer to the found + * sysfs_dirent on success, %NULL on failure. + */ +struct sysfs_dirent *kernfs_find_and_get_ns(struct sysfs_dirent *parent, + const char *name, const void *ns) +{ + struct sysfs_dirent *sd; + + mutex_lock(&sysfs_mutex); + sd = kernfs_find_ns(parent, name, ns); + kernfs_get(sd); + mutex_unlock(&sysfs_mutex); + + return sd; +} +EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns); + +/** + * kernfs_create_dir_ns - create a directory + * @parent: parent in which to create a new directory + * @name: name of the new directory + * @priv: opaque data associated with the new directory + * @ns: optional namespace tag of the directory + * + * Returns the created node on success, ERR_PTR() value on failure. + */ +struct sysfs_dirent *kernfs_create_dir_ns(struct sysfs_dirent *parent, + const char *name, void *priv, + const void *ns) +{ + umode_t mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; + struct sysfs_addrm_cxt acxt; + struct sysfs_dirent *sd; + int rc; + + /* allocate */ + sd = sysfs_new_dirent(name, mode, SYSFS_DIR); + if (!sd) + return ERR_PTR(-ENOMEM); + + sd->s_ns = ns; + sd->priv = priv; + + /* link in */ + sysfs_addrm_start(&acxt); + rc = sysfs_add_one(&acxt, sd, parent); + sysfs_addrm_finish(&acxt); + + if (!rc) + return sd; + + kernfs_put(sd); + return ERR_PTR(rc); +} + +static struct dentry *sysfs_lookup(struct inode *dir, struct dentry *dentry, + unsigned int flags) +{ + struct dentry *ret = NULL; + struct dentry *parent = dentry->d_parent; + struct sysfs_dirent *parent_sd = parent->d_fsdata; + struct sysfs_dirent *sd; + struct inode *inode; + const void *ns = NULL; + + mutex_lock(&sysfs_mutex); + + if (parent_sd->s_flags & SYSFS_FLAG_NS) + ns = sysfs_info(dir->i_sb)->ns; + + sd = kernfs_find_ns(parent_sd, dentry->d_name.name, ns); + + /* no such entry */ + if (!sd) { + ret = ERR_PTR(-ENOENT); + goto out_unlock; + } + kernfs_get(sd); + dentry->d_fsdata = sd; + + /* attach dentry and inode */ + inode = sysfs_get_inode(dir->i_sb, sd); + if (!inode) { + ret = ERR_PTR(-ENOMEM); + goto out_unlock; + } + + /* instantiate and hash dentry */ + ret = d_materialise_unique(dentry, inode); + out_unlock: + mutex_unlock(&sysfs_mutex); + return ret; +} + +const struct inode_operations sysfs_dir_inode_operations = { + .lookup = sysfs_lookup, + .permission = sysfs_permission, + .setattr = sysfs_setattr, + .getattr = sysfs_getattr, + .setxattr = sysfs_setxattr, +}; + +static struct sysfs_dirent *sysfs_leftmost_descendant(struct sysfs_dirent *pos) +{ + struct sysfs_dirent *last; + + while (true) { + struct rb_node *rbn; + + last = pos; + + if (sysfs_type(pos) != SYSFS_DIR) + break; + + rbn = rb_first(&pos->s_dir.children); + if (!rbn) + break; + + pos = to_sysfs_dirent(rbn); + } + + return last; +} + +/** + * sysfs_next_descendant_post - find the next descendant for post-order walk + * @pos: the current position (%NULL to initiate traversal) + * @root: sysfs_dirent whose descendants to walk + * + * Find the next descendant to visit for post-order traversal of @root's + * descendants. @root is included in the iteration and the last node to be + * visited. + */ +static struct sysfs_dirent *sysfs_next_descendant_post(struct sysfs_dirent *pos, + struct sysfs_dirent *root) +{ + struct rb_node *rbn; + + lockdep_assert_held(&sysfs_mutex); + + /* if first iteration, visit leftmost descendant which may be root */ + if (!pos) + return sysfs_leftmost_descendant(root); + + /* if we visited @root, we're done */ + if (pos == root) + return NULL; + + /* if there's an unvisited sibling, visit its leftmost descendant */ + rbn = rb_next(&pos->s_rb); + if (rbn) + return sysfs_leftmost_descendant(to_sysfs_dirent(rbn)); + + /* no sibling left, visit parent */ + return pos->s_parent; +} + +static void __kernfs_remove(struct sysfs_addrm_cxt *acxt, + struct sysfs_dirent *sd) +{ + struct sysfs_dirent *pos, *next; + + if (!sd) + return; + + pr_debug("sysfs %s: removing\n", sd->s_name); + + next = NULL; + do { + pos = next; + next = sysfs_next_descendant_post(pos, sd); + if (pos) + sysfs_remove_one(acxt, pos); + } while (next); +} + +/** + * kernfs_remove - remove a sysfs_dirent recursively + * @sd: the sysfs_dirent to remove + * + * Remove @sd along with all its subdirectories and files. + */ +void kernfs_remove(struct sysfs_dirent *sd) +{ + struct sysfs_addrm_cxt acxt; + + sysfs_addrm_start(&acxt); + __kernfs_remove(&acxt, sd); + sysfs_addrm_finish(&acxt); +} + +/** + * kernfs_remove_by_name_ns - find a sysfs_dirent by name and remove it + * @dir_sd: parent of the target + * @name: name of the sysfs_dirent to remove + * @ns: namespace tag of the sysfs_dirent to remove + * + * Look for the sysfs_dirent with @name and @ns under @dir_sd and remove + * it. Returns 0 on success, -ENOENT if such entry doesn't exist. + */ +int kernfs_remove_by_name_ns(struct sysfs_dirent *dir_sd, const char *name, + const void *ns) +{ + struct sysfs_addrm_cxt acxt; + struct sysfs_dirent *sd; + + if (!dir_sd) { + WARN(1, KERN_WARNING "sysfs: can not remove '%s', no directory\n", + name); + return -ENOENT; + } + + sysfs_addrm_start(&acxt); + + sd = kernfs_find_ns(dir_sd, name, ns); + if (sd) + __kernfs_remove(&acxt, sd); + + sysfs_addrm_finish(&acxt); + + if (sd) + return 0; + else + return -ENOENT; +} + +/** + * kernfs_rename_ns - move and rename a kernfs_node + * @sd: target node + * @new_parent: new parent to put @sd under + * @new_name: new name + * @new_ns: new namespace tag + */ +int kernfs_rename_ns(struct sysfs_dirent *sd, struct sysfs_dirent *new_parent, + const char *new_name, const void *new_ns) +{ + int error; + + mutex_lock(&sysfs_mutex); + + error = 0; + if ((sd->s_parent == new_parent) && (sd->s_ns == new_ns) && + (strcmp(sd->s_name, new_name) == 0)) + goto out; /* nothing to rename */ + + error = -EEXIST; + if (kernfs_find_ns(new_parent, new_name, new_ns)) + goto out; + + /* rename sysfs_dirent */ + if (strcmp(sd->s_name, new_name) != 0) { + error = -ENOMEM; + new_name = kstrdup(new_name, GFP_KERNEL); + if (!new_name) + goto out; + + kfree(sd->s_name); + sd->s_name = new_name; + } + + /* + * Move to the appropriate place in the appropriate directories rbtree. + */ + sysfs_unlink_sibling(sd); + kernfs_get(new_parent); + kernfs_put(sd->s_parent); + sd->s_ns = new_ns; + sd->s_hash = sysfs_name_hash(sd->s_name, sd->s_ns); + sd->s_parent = new_parent; + sysfs_link_sibling(sd); + + error = 0; + out: + mutex_unlock(&sysfs_mutex); + return error; +} + +/** + * kernfs_enable_ns - enable namespace under a directory + * @sd: directory of interest, should be empty + * + * This is to be called right after @sd is created to enable namespace + * under it. All children of @sd must have non-NULL namespace tags and + * only the ones which match the super_block's tag will be visible. + */ +void kernfs_enable_ns(struct sysfs_dirent *sd) +{ + WARN_ON_ONCE(sysfs_type(sd) != SYSFS_DIR); + WARN_ON_ONCE(!RB_EMPTY_ROOT(&sd->s_dir.children)); + sd->s_flags |= SYSFS_FLAG_NS; +} + +/* Relationship between s_mode and the DT_xxx types */ +static inline unsigned char dt_type(struct sysfs_dirent *sd) +{ + return (sd->s_mode >> 12) & 15; +} + +static int sysfs_dir_release(struct inode *inode, struct file *filp) +{ + kernfs_put(filp->private_data); + return 0; +} + +static struct sysfs_dirent *sysfs_dir_pos(const void *ns, + struct sysfs_dirent *parent_sd, loff_t hash, struct sysfs_dirent *pos) +{ + if (pos) { + int valid = !(pos->s_flags & SYSFS_FLAG_REMOVED) && + pos->s_parent == parent_sd && + hash == pos->s_hash; + kernfs_put(pos); + if (!valid) + pos = NULL; + } + if (!pos && (hash > 1) && (hash < INT_MAX)) { + struct rb_node *node = parent_sd->s_dir.children.rb_node; + while (node) { + pos = to_sysfs_dirent(node); + + if (hash < pos->s_hash) + node = node->rb_left; + else if (hash > pos->s_hash) + node = node->rb_right; + else + break; + } + } + /* Skip over entries in the wrong namespace */ + while (pos && pos->s_ns != ns) { + struct rb_node *node = rb_next(&pos->s_rb); + if (!node) + pos = NULL; + else + pos = to_sysfs_dirent(node); + } + return pos; +} + +static struct sysfs_dirent *sysfs_dir_next_pos(const void *ns, + struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos) +{ + pos = sysfs_dir_pos(ns, parent_sd, ino, pos); + if (pos) + do { + struct rb_node *node = rb_next(&pos->s_rb); + if (!node) + pos = NULL; + else + pos = to_sysfs_dirent(node); + } while (pos && pos->s_ns != ns); + return pos; +} + +static int sysfs_readdir(struct file *file, struct dir_context *ctx) +{ + struct dentry *dentry = file->f_path.dentry; + struct sysfs_dirent *parent_sd = dentry->d_fsdata; + struct sysfs_dirent *pos = file->private_data; + const void *ns = NULL; + + if (!dir_emit_dots(file, ctx)) + return 0; + mutex_lock(&sysfs_mutex); + + if (parent_sd->s_flags & SYSFS_FLAG_NS) + ns = sysfs_info(dentry->d_sb)->ns; + + for (pos = sysfs_dir_pos(ns, parent_sd, ctx->pos, pos); + pos; + pos = sysfs_dir_next_pos(ns, parent_sd, ctx->pos, pos)) { + const char *name = pos->s_name; + unsigned int type = dt_type(pos); + int len = strlen(name); + ino_t ino = pos->s_ino; + + ctx->pos = pos->s_hash; + file->private_data = pos; + kernfs_get(pos); + + mutex_unlock(&sysfs_mutex); + if (!dir_emit(ctx, name, len, ino, type)) + return 0; + mutex_lock(&sysfs_mutex); + } + mutex_unlock(&sysfs_mutex); + file->private_data = NULL; + ctx->pos = INT_MAX; + return 0; +} + +static loff_t sysfs_dir_llseek(struct file *file, loff_t offset, int whence) +{ + struct inode *inode = file_inode(file); + loff_t ret; + + mutex_lock(&inode->i_mutex); + ret = generic_file_llseek(file, offset, whence); + mutex_unlock(&inode->i_mutex); + + return ret; +} + +const struct file_operations sysfs_dir_operations = { + .read = generic_read_dir, + .iterate = sysfs_readdir, + .release = sysfs_dir_release, + .llseek = sysfs_dir_llseek, +}; diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h index 933ac8d5d07a..31f0dbe1881b 100644 --- a/fs/kernfs/kernfs-internal.h +++ b/fs/kernfs/kernfs-internal.h @@ -14,6 +14,7 @@ #include <linux/lockdep.h> #include <linux/fs.h> #include <linux/rbtree.h> +#include <linux/mutex.h> #include <linux/kernfs.h> @@ -125,4 +126,20 @@ int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags); int sysfs_inode_init(void); +/* + * dir.c + */ +extern struct mutex sysfs_mutex; +extern const struct dentry_operations sysfs_dentry_ops; +extern const struct file_operations sysfs_dir_operations; +extern const struct inode_operations sysfs_dir_inode_operations; + +struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd); +void sysfs_put_active(struct sysfs_dirent *sd); +void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt); +int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd, + struct sysfs_dirent *parent_sd); +void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt); +struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type); + #endif /* __KERNFS_INTERNAL_H */ diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index 0d806efcc9a6..e5c4e7118050 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -13,468 +13,12 @@ #undef DEBUG #include <linux/fs.h> -#include <linux/mount.h> -#include <linux/module.h> #include <linux/kobject.h> -#include <linux/namei.h> -#include <linux/idr.h> -#include <linux/completion.h> -#include <linux/mutex.h> #include <linux/slab.h> -#include <linux/security.h> -#include <linux/hash.h> #include "sysfs.h" -DEFINE_MUTEX(sysfs_mutex); DEFINE_SPINLOCK(sysfs_symlink_target_lock); -#define to_sysfs_dirent(X) rb_entry((X), struct sysfs_dirent, s_rb) - -static DEFINE_SPINLOCK(sysfs_ino_lock); -static DEFINE_IDA(sysfs_ino_ida); - -/** - * sysfs_name_hash - * @name: Null terminated string to hash - * @ns: Namespace tag to hash - * - * Returns 31 bit hash of ns + name (so it fits in an off_t ) - */ -static unsigned int sysfs_name_hash(const char *name, const void *ns) -{ - unsigned long hash = init_name_hash(); - unsigned int len = strlen(name); - while (len--) - hash = partial_name_hash(*name++, hash); - hash = (end_name_hash(hash) ^ hash_ptr((void *)ns, 31)); - hash &= 0x7fffffffU; - /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */ - if (hash < 1) - hash += 2; - if (hash >= INT_MAX) - hash = INT_MAX - 1; - return hash; -} - -static int sysfs_name_compare(unsigned int hash, const char *name, - const void *ns, const struct sysfs_dirent *sd) -{ - if (hash != sd->s_hash) - return hash - sd->s_hash; - if (ns != sd->s_ns) - return ns - sd->s_ns; - return strcmp(name, sd->s_name); -} - -static int sysfs_sd_compare(const struct sysfs_dirent *left, - const struct sysfs_dirent *right) -{ - return sysfs_name_compare(left->s_hash, left->s_name, left->s_ns, - right); -} - -/** - * sysfs_link_sibling - link sysfs_dirent into sibling rbtree - * @sd: sysfs_dirent of interest - * - * Link @sd into its sibling rbtree which starts from - * sd->s_parent->s_dir.children. - * - * Locking: - * mutex_lock(sysfs_mutex) - * - * RETURNS: - * 0 on susccess -EEXIST on failure. - */ -static int sysfs_link_sibling(struct sysfs_dirent *sd) -{ - struct rb_node **node = &sd->s_parent->s_dir.children.rb_node; - struct rb_node *parent = NULL; - - if (sysfs_type(sd) == SYSFS_DIR) - sd->s_parent->s_dir.subdirs++; - - while (*node) { - struct sysfs_dirent *pos; - int result; - - pos = to_sysfs_dirent(*node); - parent = *node; - result = sysfs_sd_compare(sd, pos); - if (result < 0) - node = &pos->s_rb.rb_left; - else if (result > 0) - node = &pos->s_rb.rb_right; - else - return -EEXIST; - } - /* add new node and rebalance the tree */ - rb_link_node(&sd->s_rb, parent, node); - rb_insert_color(&sd->s_rb, &sd->s_parent->s_dir.children); - return 0; -} - -/** - * sysfs_unlink_sibling - unlink sysfs_dirent from sibling rbtree - * @sd: sysfs_dirent of interest - * - * Unlink @sd from its sibling rbtree which starts from - * sd->s_parent->s_dir.children. - * - * Locking: - * mutex_lock(sysfs_mutex) - */ -static void sysfs_unlink_sibling(struct sysfs_dirent *sd) -{ - if (sysfs_type(sd) == SYSFS_DIR) - sd->s_parent->s_dir.subdirs--; - - rb_erase(&sd->s_rb, &sd->s_parent->s_dir.children); -} - -/** - * sysfs_get_active - get an active reference to sysfs_dirent - * @sd: sysfs_dirent to get an active reference to - * - * Get an active reference of @sd. This function is noop if @sd - * is NULL. - * - * RETURNS: - * Pointer to @sd on success, NULL on failure. - */ -struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd) -{ - if (unlikely(!sd)) - return NULL; - - if (!atomic_inc_unless_negative(&sd->s_active)) - return NULL; - - if (sd->s_flags & SYSFS_FLAG_LOCKDEP) - rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_); - return sd; -} - -/** - * sysfs_put_active - put an active reference to sysfs_dirent - * @sd: sysfs_dirent to put an active reference to - * - * Put an active reference to @sd. This function is noop if @sd - * is NULL. - */ -void sysfs_put_active(struct sysfs_dirent *sd) -{ - int v; - - if (unlikely(!sd)) - return; - - if (sd->s_flags & SYSFS_FLAG_LOCKDEP) - rwsem_release(&sd->dep_map, 1, _RET_IP_); - v = atomic_dec_return(&sd->s_active); - if (likely(v != SD_DEACTIVATED_BIAS)) - return; - - /* atomic_dec_return() is a mb(), we'll always see the updated - * sd->u.completion. - */ - complete(sd->u.completion); -} - -/** - * sysfs_deactivate - deactivate sysfs_dirent - * @sd: sysfs_dirent to deactivate - * - * Deny new active references and drain existing ones. - */ -static void sysfs_deactivate(struct sysfs_dirent *sd) -{ - DECLARE_COMPLETION_ONSTACK(wait); - int v; - - BUG_ON(!(sd->s_flags & SYSFS_FLAG_REMOVED)); - - if (!(sysfs_type(sd) & SYSFS_ACTIVE_REF)) - return; - - sd->u.completion = (void *)&wait; - - rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_); - /* atomic_add_return() is a mb(), put_active() will always see - * the updated sd->u.completion. - */ - v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active); - - if (v != SD_DEACTIVATED_BIAS) { - lock_contended(&sd->dep_map, _RET_IP_); - wait_for_completion(&wait); - } - - lock_acquired(&sd->dep_map, _RET_IP_); - rwsem_release(&sd->dep_map, 1, _RET_IP_); -} - -static int sysfs_alloc_ino(unsigned int *pino) -{ - int ino, rc; - - retry: - spin_lock(&sysfs_ino_lock); - rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino); - spin_unlock(&sysfs_ino_lock); - - if (rc == -EAGAIN) { - if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL)) - goto retry; - rc = -ENOMEM; - } - - *pino = ino; - return rc; -} - -static void sysfs_free_ino(unsigned int ino) -{ - spin_lock(&sysfs_ino_lock); - ida_remove(&sysfs_ino_ida, ino); - spin_unlock(&sysfs_ino_lock); -} - -/** - * kernfs_get - get a reference count on a sysfs_dirent - * @sd: the target sysfs_dirent - */ -void kernfs_get(struct sysfs_dirent *sd) -{ - if (sd) { - WARN_ON(!atomic_read(&sd->s_count)); - atomic_inc(&sd->s_count); - } -} -EXPORT_SYMBOL_GPL(kernfs_get); - -/** - * kernfs_put - put a reference count on a sysfs_dirent - * @sd: the target sysfs_dirent - * - * Put a reference count of @sd and destroy it if it reached zero. - */ -void kernfs_put(struct sysfs_dirent *sd) -{ - struct sysfs_dirent *parent_sd; - - if (!sd || !atomic_dec_and_test(&sd->s_count)) - return; - repeat: - /* Moving/renaming is always done while holding reference. - * sd->s_parent won't change beneath us. - */ - parent_sd = sd->s_parent; - - WARN(!(sd->s_flags & SYSFS_FLAG_REMOVED), - "sysfs: free using entry: %s/%s\n", - parent_sd ? parent_sd->s_name : "", sd->s_name); - - if (sysfs_type(sd) == SYSFS_KOBJ_LINK) - kernfs_put(sd->s_symlink.target_sd); - if (sysfs_type(sd) & SYSFS_COPY_NAME) - kfree(sd->s_name); - if (sd->s_iattr && sd->s_iattr->ia_secdata) - security_release_secctx(sd->s_iattr->ia_secdata, - sd->s_iattr->ia_secdata_len); - kfree(sd->s_iattr); - sysfs_free_ino(sd->s_ino); - kmem_cache_free(sysfs_dir_cachep, sd); - - sd = parent_sd; - if (sd && atomic_dec_and_test(&sd->s_count)) - goto repeat; -} -EXPORT_SYMBOL_GPL(kernfs_put); - -static int sysfs_dentry_delete(const struct dentry *dentry) -{ - struct sysfs_dirent *sd = dentry->d_fsdata; - return !(sd && !(sd->s_flags & SYSFS_FLAG_REMOVED)); -} - -static int sysfs_dentry_revalidate(struct dentry *dentry, unsigned int flags) -{ - struct sysfs_dirent *sd; - - if (flags & LOOKUP_RCU) - return -ECHILD; - - sd = dentry->d_fsdata; - mutex_lock(&sysfs_mutex); - - /* The sysfs dirent has been deleted */ - if (sd->s_flags & SYSFS_FLAG_REMOVED) - goto out_bad; - - /* The sysfs dirent has been moved? */ - if (dentry->d_parent->d_fsdata != sd->s_parent) - goto out_bad; - - /* The sysfs dirent has been renamed */ - if (strcmp(dentry->d_name.name, sd->s_name) != 0) - goto out_bad; - - /* The sysfs dirent has been moved to a different namespace */ - if (sd->s_parent && (sd->s_parent->s_flags & SYSFS_FLAG_NS) && - sysfs_info(dentry->d_sb)->ns != sd->s_ns) - goto out_bad; - - mutex_unlock(&sysfs_mutex); -out_valid: - return 1; -out_bad: - /* Remove the dentry from the dcache hashes. - * If this is a deleted dentry we use d_drop instead of d_delete - * so sysfs doesn't need to cope with negative dentries. - * - * If this is a dentry that has simply been renamed we - * use d_drop to remove it from the dcache lookup on its - * old parent. If this dentry persists later when a lookup - * is performed at its new name the dentry will be readded - * to the dcache hashes. - */ - mutex_unlock(&sysfs_mutex); - - /* If we have submounts we must allow the vfs caches - * to lie about the state of the filesystem to prevent - * leaks and other nasty things. - */ - if (check_submounts_and_drop(dentry) != 0) - goto out_valid; - - return 0; -} - -static void sysfs_dentry_release(struct dentry *dentry) -{ - kernfs_put(dentry->d_fsdata); -} - -const struct dentry_operations sysfs_dentry_ops = { - .d_revalidate = sysfs_dentry_revalidate, - .d_delete = sysfs_dentry_delete, - .d_release = sysfs_dentry_release, -}; - -struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type) -{ - char *dup_name = NULL; - struct sysfs_dirent *sd; - - if (type & SYSFS_COPY_NAME) { - name = dup_name = kstrdup(name, GFP_KERNEL); - if (!name) - return NULL; - } - - sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL); - if (!sd) - goto err_out1; - - if (sysfs_alloc_ino(&sd->s_ino)) - goto err_out2; - - atomic_set(&sd->s_count, 1); - atomic_set(&sd->s_active, 0); - - sd->s_name = name; - sd->s_mode = mode; - sd->s_flags = type | SYSFS_FLAG_REMOVED; - - return sd; - - err_out2: - kmem_cache_free(sysfs_dir_cachep, sd); - err_out1: - kfree(dup_name); - return NULL; -} - -/** - * sysfs_addrm_start - prepare for sysfs_dirent add/remove - * @acxt: pointer to sysfs_addrm_cxt to be used - * - * This function is called when the caller is about to add or remove - * sysfs_dirent. This function acquires sysfs_mutex. @acxt is used - * to keep and pass context to other addrm functions. - * - * LOCKING: - * Kernel thread context (may sleep). sysfs_mutex is locked on - * return. - */ -void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt) - __acquires(sysfs_mutex) -{ - memset(acxt, 0, sizeof(*acxt)); - - mutex_lock(&sysfs_mutex); -} - -/** - * sysfs_add_one - add sysfs_dirent to parent without warning - * @acxt: addrm context to use - * @sd: sysfs_dirent to be added - * @parent_sd: the parent sysfs_dirent to add @sd to - * - * Get @parent_sd and set @sd->s_parent to it and increment nlink of - * the parent inode if @sd is a directory and link into the children - * list of the parent. - * - * This function should be called between calls to - * sysfs_addrm_start() and sysfs_addrm_finish() and should be - * passed the same @acxt as passed to sysfs_addrm_start(). - * - * LOCKING: - * Determined by sysfs_addrm_start(). - * - * RETURNS: - * 0 on success, -EEXIST if entry with the given name already - * exists. - */ -int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd, - struct sysfs_dirent *parent_sd) -{ - bool has_ns = parent_sd->s_flags & SYSFS_FLAG_NS; - struct sysfs_inode_attrs *ps_iattr; - int ret; - - if (has_ns != (bool)sd->s_ns) { - WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n", - has_ns ? "required" : "invalid", - parent_sd->s_name, sd->s_name); - return -EINVAL; - } - - if (sysfs_type(parent_sd) != SYSFS_DIR) - return -EINVAL; - - sd->s_hash = sysfs_name_hash(sd->s_name, sd->s_ns); - sd->s_parent = parent_sd; - kernfs_get(parent_sd); - - ret = sysfs_link_sibling(sd); - if (ret) - return ret; - - /* Update timestamps on the parent */ - ps_iattr = parent_sd->s_iattr; - if (ps_iattr) { - struct iattr *ps_iattrs = &ps_iattr->ia_iattr; - ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME; - } - - /* Mark the entry added into directory tree */ - sd->s_flags &= ~SYSFS_FLAG_REMOVED; - - return 0; -} - /** * sysfs_pathname - return full path to sysfs dirent * @sd: sysfs_dirent whose path we want @@ -511,181 +55,6 @@ void sysfs_warn_dup(struct sysfs_dirent *parent, const char *name) } /** - * sysfs_remove_one - remove sysfs_dirent from parent - * @acxt: addrm context to use - * @sd: sysfs_dirent to be removed - * - * Mark @sd removed and drop nlink of parent inode if @sd is a - * directory. @sd is unlinked from the children list. - * - * This function should be called between calls to - * sysfs_addrm_start() and sysfs_addrm_finish() and should be - * passed the same @acxt as passed to sysfs_addrm_start(). - * - * LOCKING: - * Determined by sysfs_addrm_start(). - */ -static void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, - struct sysfs_dirent *sd) -{ - struct sysfs_inode_attrs *ps_iattr; - - /* - * Removal can be called multiple times on the same node. Only the - * first invocation is effective and puts the base ref. - */ - if (sd->s_flags & SYSFS_FLAG_REMOVED) - return; - - sysfs_unlink_sibling(sd); - - /* Update timestamps on the parent */ - ps_iattr = sd->s_parent->s_iattr; - if (ps_iattr) { - struct iattr *ps_iattrs = &ps_iattr->ia_iattr; - ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME; - } - - sd->s_flags |= SYSFS_FLAG_REMOVED; - sd->u.removed_list = acxt->removed; - acxt->removed = sd; -} - -/** - * sysfs_addrm_finish - finish up sysfs_dirent add/remove - * @acxt: addrm context to finish up - * - * Finish up sysfs_dirent add/remove. Resources acquired by - * sysfs_addrm_start() are released and removed sysfs_dirents are - * cleaned up. - * - * LOCKING: - * sysfs_mutex is released. - */ -void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt) - __releases(sysfs_mutex) -{ - /* release resources acquired by sysfs_addrm_start() */ - mutex_unlock(&sysfs_mutex); - - /* kill removed sysfs_dirents */ - while (acxt->removed) { - struct sysfs_dirent *sd = acxt->removed; - - acxt->removed = sd->u.removed_list; - - sysfs_deactivate(sd); - sysfs_unmap_bin_file(sd); - kernfs_put(sd); - } -} - -/** - * kernfs_find_ns - find sysfs_dirent with the given name - * @parent: sysfs_dirent to search under - * @name: name to look for - * @ns: the namespace tag to use - * - * Look for sysfs_dirent with name @name under @parent. Returns pointer to - * the found sysfs_dirent on success, %NULL on failure. - */ -static struct sysfs_dirent *kernfs_find_ns(struct sysfs_dirent *parent, - const unsigned char *name, - const void *ns) -{ - struct rb_node *node = parent->s_dir.children.rb_node; - bool has_ns = parent->s_flags & SYSFS_FLAG_NS; - unsigned int hash; - - lockdep_assert_held(&sysfs_mutex); - - if (has_ns != (bool)ns) { - WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n", - has_ns ? "required" : "invalid", - parent->s_name, name); - return NULL; - } - - hash = sysfs_name_hash(name, ns); - while (node) { - struct sysfs_dirent *sd; - int result; - - sd = to_sysfs_dirent(node); - result = sysfs_name_compare(hash, name, ns, sd); - if (result < 0) - node = node->rb_left; - else if (result > 0) - node = node->rb_right; - else - return sd; - } - return NULL; -} - -/** - * kernfs_find_and_get_ns - find and get sysfs_dirent with the given name - * @parent: sysfs_dirent to search under - * @name: name to look for - * @ns: the namespace tag to use - * - * Look for sysfs_dirent with name @name under @parent and get a reference - * if found. This function may sleep and returns pointer to the found - * sysfs_dirent on success, %NULL on failure. - */ -struct sysfs_dirent *kernfs_find_and_get_ns(struct sysfs_dirent *parent, - const char *name, const void *ns) -{ - struct sysfs_dirent *sd; - - mutex_lock(&sysfs_mutex); - sd = kernfs_find_ns(parent, name, ns); - kernfs_get(sd); - mutex_unlock(&sysfs_mutex); - - return sd; -} -EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns); - -/** - * kernfs_create_dir_ns - create a directory - * @parent: parent in which to create a new directory - * @name: name of the new directory - * @priv: opaque data associated with the new directory - * @ns: optional namespace tag of the directory - * - * Returns the created node on success, ERR_PTR() value on failure. - */ -struct sysfs_dirent *kernfs_create_dir_ns(struct sysfs_dirent *parent, - const char *name, void *priv, - const void *ns) -{ - umode_t mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; - struct sysfs_addrm_cxt acxt; - struct sysfs_dirent *sd; - int rc; - - /* allocate */ - sd = sysfs_new_dirent(name, mode, SYSFS_DIR); - if (!sd) - return ERR_PTR(-ENOMEM); - - sd->s_ns = ns; - sd->priv = priv; - - /* link in */ - sysfs_addrm_start(&acxt); - rc = sysfs_add_one(&acxt, sd, parent); - sysfs_addrm_finish(&acxt); - - if (!rc) - return sd; - - kernfs_put(sd); - return ERR_PTR(rc); -} - -/** * sysfs_create_dir_ns - create a directory for an object with a namespace tag * @kobj: object we're creating directory for * @ns: the namespace tag to use @@ -715,177 +84,6 @@ int sysfs_create_dir_ns(struct kobject *kobj, const void *ns) return 0; } -static struct dentry *sysfs_lookup(struct inode *dir, struct dentry *dentry, - unsigned int flags) -{ - struct dentry *ret = NULL; - struct dentry *parent = dentry->d_parent; - struct sysfs_dirent *parent_sd = parent->d_fsdata; - struct sysfs_dirent *sd; - struct inode *inode; - const void *ns = NULL; - - mutex_lock(&sysfs_mutex); - - if (parent_sd->s_flags & SYSFS_FLAG_NS) - ns = sysfs_info(dir->i_sb)->ns; - - sd = kernfs_find_ns(parent_sd, dentry->d_name.name, ns); - - /* no such entry */ - if (!sd) { - ret = ERR_PTR(-ENOENT); - goto out_unlock; - } - kernfs_get(sd); - dentry->d_fsdata = sd; - - /* attach dentry and inode */ - inode = sysfs_get_inode(dir->i_sb, sd); - if (!inode) { - ret = ERR_PTR(-ENOMEM); - goto out_unlock; - } - - /* instantiate and hash dentry */ - ret = d_materialise_unique(dentry, inode); - out_unlock: - mutex_unlock(&sysfs_mutex); - return ret; -} - -const struct inode_operations sysfs_dir_inode_operations = { - .lookup = sysfs_lookup, - .permission = sysfs_permission, - .setattr = sysfs_setattr, - .getattr = sysfs_getattr, - .setxattr = sysfs_setxattr, -}; - -static struct sysfs_dirent *sysfs_leftmost_descendant(struct sysfs_dirent *pos) -{ - struct sysfs_dirent *last; - - while (true) { - struct rb_node *rbn; - - last = pos; - - if (sysfs_type(pos) != SYSFS_DIR) - break; - - rbn = rb_first(&pos->s_dir.children); - if (!rbn) - break; - - pos = to_sysfs_dirent(rbn); - } - - return last; -} - -/** - * sysfs_next_descendant_post - find the next descendant for post-order walk - * @pos: the current position (%NULL to initiate traversal) - * @root: sysfs_dirent whose descendants to walk - * - * Find the next descendant to visit for post-order traversal of @root's - * descendants. @root is included in the iteration and the last node to be - * visited. - */ -static struct sysfs_dirent *sysfs_next_descendant_post(struct sysfs_dirent *pos, - struct sysfs_dirent *root) -{ - struct rb_node *rbn; - - lockdep_assert_held(&sysfs_mutex); - - /* if first iteration, visit leftmost descendant which may be root */ - if (!pos) - return sysfs_leftmost_descendant(root); - - /* if we visited @root, we're done */ - if (pos == root) - return NULL; - - /* if there's an unvisited sibling, visit its leftmost descendant */ - rbn = rb_next(&pos->s_rb); - if (rbn) - return sysfs_leftmost_descendant(to_sysfs_dirent(rbn)); - - /* no sibling left, visit parent */ - return pos->s_parent; -} - -static void __kernfs_remove(struct sysfs_addrm_cxt *acxt, - struct sysfs_dirent *sd) -{ - struct sysfs_dirent *pos, *next; - - if (!sd) - return; - - pr_debug("sysfs %s: removing\n", sd->s_name); - - next = NULL; - do { - pos = next; - next = sysfs_next_descendant_post(pos, sd); - if (pos) - sysfs_remove_one(acxt, pos); - } while (next); -} - -/** - * kernfs_remove - remove a sysfs_dirent recursively - * @sd: the sysfs_dirent to remove - * - * Remove @sd along with all its subdirectories and files. - */ -void kernfs_remove(struct sysfs_dirent *sd) -{ - struct sysfs_addrm_cxt acxt; - - sysfs_addrm_start(&acxt); - __kernfs_remove(&acxt, sd); - sysfs_addrm_finish(&acxt); -} - -/** - * kernfs_remove_by_name_ns - find a sysfs_dirent by name and remove it - * @dir_sd: parent of the target - * @name: name of the sysfs_dirent to remove - * @ns: namespace tag of the sysfs_dirent to remove - * - * Look for the sysfs_dirent with @name and @ns under @dir_sd and remove - * it. Returns 0 on success, -ENOENT if such entry doesn't exist. - */ -int kernfs_remove_by_name_ns(struct sysfs_dirent *dir_sd, const char *name, - const void *ns) -{ - struct sysfs_addrm_cxt acxt; - struct sysfs_dirent *sd; - - if (!dir_sd) { - WARN(1, KERN_WARNING "sysfs: can not remove '%s', no directory\n", - name); - return -ENOENT; - } - - sysfs_addrm_start(&acxt); - - sd = kernfs_find_ns(dir_sd, name, ns); - if (sd) - __kernfs_remove(&acxt, sd); - - sysfs_addrm_finish(&acxt); - - if (sd) - return 0; - else - return -ENOENT; -} - /** * sysfs_remove_dir - remove an object's directory. * @kobj: object. @@ -920,57 +118,6 @@ void sysfs_remove_dir(struct kobject *kobj) } } -/** - * kernfs_rename_ns - move and rename a kernfs_node - * @sd: target node - * @new_parent: new parent to put @sd under - * @new_name: new name - * @new_ns: new namespace tag - */ -int kernfs_rename_ns(struct sysfs_dirent *sd, struct sysfs_dirent *new_parent, - const char *new_name, const void *new_ns) -{ - int error; - - mutex_lock(&sysfs_mutex); - - error = 0; - if ((sd->s_parent == new_parent) && (sd->s_ns == new_ns) && - (strcmp(sd->s_name, new_name) == 0)) - goto out; /* nothing to rename */ - - error = -EEXIST; - if (kernfs_find_ns(new_parent, new_name, new_ns)) - goto out; - - /* rename sysfs_dirent */ - if (strcmp(sd->s_name, new_name) != 0) { - error = -ENOMEM; - new_name = kstrdup(new_name, GFP_KERNEL); - if (!new_name) - goto out; - - kfree(sd->s_name); - sd->s_name = new_name; - } - - /* - * Move to the appropriate place in the appropriate directories rbtree. - */ - sysfs_unlink_sibling(sd); - kernfs_get(new_parent); - kernfs_put(sd->s_parent); - sd->s_ns = new_ns; - sd->s_hash = sysfs_name_hash(sd->s_name, sd->s_ns); - sd->s_parent = new_parent; - sysfs_link_sibling(sd); - - error = 0; - out: - mutex_unlock(&sysfs_mutex); - return error; -} - int sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name, const void *new_ns) { @@ -991,136 +138,3 @@ int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj, return kernfs_rename_ns(sd, new_parent_sd, sd->s_name, new_ns); } - -/** - * kernfs_enable_ns - enable namespace under a directory - * @sd: directory of interest, should be empty - * - * This is to be called right after @sd is created to enable namespace - * under it. All children of @sd must have non-NULL namespace tags and - * only the ones which match the super_block's tag will be visible. - */ -void kernfs_enable_ns(struct sysfs_dirent *sd) -{ - WARN_ON_ONCE(sysfs_type(sd) != SYSFS_DIR); - WARN_ON_ONCE(!RB_EMPTY_ROOT(&sd->s_dir.children)); - sd->s_flags |= SYSFS_FLAG_NS; -} - -/* Relationship between s_mode and the DT_xxx types */ -static inline unsigned char dt_type(struct sysfs_dirent *sd) -{ - return (sd->s_mode >> 12) & 15; -} - -static int sysfs_dir_release(struct inode *inode, struct file *filp) -{ - kernfs_put(filp->private_data); - return 0; -} - -static struct sysfs_dirent *sysfs_dir_pos(const void *ns, - struct sysfs_dirent *parent_sd, loff_t hash, struct sysfs_dirent *pos) -{ - if (pos) { - int valid = !(pos->s_flags & SYSFS_FLAG_REMOVED) && - pos->s_parent == parent_sd && - hash == pos->s_hash; - kernfs_put(pos); - if (!valid) - pos = NULL; - } - if (!pos && (hash > 1) && (hash < INT_MAX)) { - struct rb_node *node = parent_sd->s_dir.children.rb_node; - while (node) { - pos = to_sysfs_dirent(node); - - if (hash < pos->s_hash) - node = node->rb_left; - else if (hash > pos->s_hash) - node = node->rb_right; - else - break; - } - } - /* Skip over entries in the wrong namespace */ - while (pos && pos->s_ns != ns) { - struct rb_node *node = rb_next(&pos->s_rb); - if (!node) - pos = NULL; - else - pos = to_sysfs_dirent(node); - } - return pos; -} - -static struct sysfs_dirent *sysfs_dir_next_pos(const void *ns, - struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos) -{ - pos = sysfs_dir_pos(ns, parent_sd, ino, pos); - if (pos) - do { - struct rb_node *node = rb_next(&pos->s_rb); - if (!node) - pos = NULL; - else - pos = to_sysfs_dirent(node); - } while (pos && pos->s_ns != ns); - return pos; -} - -static int sysfs_readdir(struct file *file, struct dir_context *ctx) -{ - struct dentry *dentry = file->f_path.dentry; - struct sysfs_dirent *parent_sd = dentry->d_fsdata; - struct sysfs_dirent *pos = file->private_data; - const void *ns = NULL; - - if (!dir_emit_dots(file, ctx)) - return 0; - mutex_lock(&sysfs_mutex); - - if (parent_sd->s_flags & SYSFS_FLAG_NS) - ns = sysfs_info(dentry->d_sb)->ns; - - for (pos = sysfs_dir_pos(ns, parent_sd, ctx->pos, pos); - pos; - pos = sysfs_dir_next_pos(ns, parent_sd, ctx->pos, pos)) { - const char *name = pos->s_name; - unsigned int type = dt_type(pos); - int len = strlen(name); - ino_t ino = pos->s_ino; - - ctx->pos = pos->s_hash; - file->private_data = pos; - kernfs_get(pos); - - mutex_unlock(&sysfs_mutex); - if (!dir_emit(ctx, name, len, ino, type)) - return 0; - mutex_lock(&sysfs_mutex); - } - mutex_unlock(&sysfs_mutex); - file->private_data = NULL; - ctx->pos = INT_MAX; - return 0; -} - -static loff_t sysfs_dir_llseek(struct file *file, loff_t offset, int whence) -{ - struct inode *inode = file_inode(file); - loff_t ret; - - mutex_lock(&inode->i_mutex); - ret = generic_file_llseek(file, offset, whence); - mutex_unlock(&inode->i_mutex); - - return ret; -} - -const struct file_operations sysfs_dir_operations = { - .read = generic_read_dir, - .iterate = sysfs_readdir, - .release = sysfs_dir_release, - .llseek = sysfs_dir_llseek, -}; diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h index 93c1910783fc..972b4a4a5f90 100644 --- a/fs/sysfs/sysfs.h +++ b/fs/sysfs/sysfs.h @@ -34,22 +34,9 @@ extern struct kmem_cache *sysfs_dir_cachep; /* * dir.c */ -extern struct mutex sysfs_mutex; extern spinlock_t sysfs_symlink_target_lock; -extern const struct dentry_operations sysfs_dentry_ops; -extern const struct file_operations sysfs_dir_operations; -extern const struct inode_operations sysfs_dir_inode_operations; - -struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd); -void sysfs_put_active(struct sysfs_dirent *sd); -void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt); void sysfs_warn_dup(struct sysfs_dirent *parent, const char *name); -int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd, - struct sysfs_dirent *parent_sd); -void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt); - -struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type); /* * file.c |