diff options
Diffstat (limited to 'fs/sysfs/dir.c')
| -rw-r--r-- | fs/sysfs/dir.c | 101 |
1 files changed, 71 insertions, 30 deletions
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index 1b5643407a9..9fc8558fd86 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -14,7 +14,7 @@ #include <asm/semaphore.h> #include "sysfs.h" -DECLARE_RWSEM(sysfs_rename_sem); +DEFINE_MUTEX(sysfs_mutex); spinlock_t sysfs_assoc_lock = SPIN_LOCK_UNLOCKED; static spinlock_t sysfs_ino_lock = SPIN_LOCK_UNLOCKED; @@ -28,7 +28,7 @@ static DEFINE_IDA(sysfs_ino_ida); * sd->s_parent->s_children. * * Locking: - * mutex_lock(sd->s_parent->dentry->d_inode->i_mutex) + * mutex_lock(sysfs_mutex) */ static void sysfs_link_sibling(struct sysfs_dirent *sd) { @@ -47,7 +47,7 @@ static void sysfs_link_sibling(struct sysfs_dirent *sd) * sd->s_parent->s_children. * * Locking: - * mutex_lock(sd->s_parent->dentry->d_inode->i_mutex) + * mutex_lock(sysfs_mutex) */ static void sysfs_unlink_sibling(struct sysfs_dirent *sd) { @@ -215,6 +215,9 @@ void release_sysfs_dirent(struct sysfs_dirent * sd) struct sysfs_dirent *parent_sd; repeat: + /* Moving/renaming is always done while holding reference. + * sd->s_parent won't change beneath us. + */ parent_sd = sd->s_parent; if (sysfs_type(sd) == SYSFS_KOBJ_LINK) @@ -291,6 +294,17 @@ struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type) return NULL; } +/** + * sysfs_attach_dentry - associate sysfs_dirent with dentry + * @sd: target sysfs_dirent + * @dentry: dentry to associate + * + * Associate @sd with @dentry. This is protected by + * sysfs_assoc_lock to avoid race with sysfs_d_iput(). + * + * LOCKING: + * mutex_lock(sysfs_mutex) + */ static void sysfs_attach_dentry(struct sysfs_dirent *sd, struct dentry *dentry) { dentry->d_op = &sysfs_dentry_ops; @@ -304,6 +318,17 @@ static void sysfs_attach_dentry(struct sysfs_dirent *sd, struct dentry *dentry) d_rehash(dentry); } +/** + * sysfs_attach_dirent - attach sysfs_dirent to its parent and dentry + * @sd: sysfs_dirent to attach + * @parent_sd: parent to attach to (optional) + * @dentry: dentry to be associated to @sd (optional) + * + * Attach @sd to @parent_sd and/or @dentry. Both are optional. + * + * LOCKING: + * mutex_lock(sysfs_mutex) + */ void sysfs_attach_dirent(struct sysfs_dirent *sd, struct sysfs_dirent *parent_sd, struct dentry *dentry) { @@ -324,7 +349,7 @@ void sysfs_attach_dirent(struct sysfs_dirent *sd, * Look for sysfs_dirent with name @name under @parent_sd. * * LOCKING: - * mutex_lock(parent->i_mutex) + * mutex_lock(sysfs_mutex) * * RETURNS: * Pointer to sysfs_dirent if found, NULL if not. @@ -349,7 +374,7 @@ struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd, * it if found. * * LOCKING: - * Kernel thread context (may sleep) + * Kernel thread context (may sleep). Grabs sysfs_mutex. * * RETURNS: * Pointer to sysfs_dirent if found, NULL if not. @@ -359,10 +384,10 @@ struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd, { struct sysfs_dirent *sd; - mutex_lock(&parent_sd->s_dentry->d_inode->i_mutex); + mutex_lock(&sysfs_mutex); sd = sysfs_find_dirent(parent_sd, name); sysfs_get(sd); - mutex_unlock(&parent_sd->s_dentry->d_inode->i_mutex); + mutex_unlock(&sysfs_mutex); return sd; } @@ -408,14 +433,20 @@ static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd, } /* link in */ + mutex_lock(&sysfs_mutex); + error = -EEXIST; - if (sysfs_find_dirent(parent_sd, name)) + if (sysfs_find_dirent(parent_sd, name)) { + mutex_unlock(&sysfs_mutex); goto out_iput; + } sysfs_instantiate(dentry, inode); inc_nlink(parent->d_inode); sysfs_attach_dirent(sd, parent_sd, dentry); + mutex_unlock(&sysfs_mutex); + *p_sd = sd; error = 0; goto out_unlock; /* pin directory dentry in core */ @@ -493,6 +524,8 @@ static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry, if (!inode) return ERR_PTR(-ENOMEM); + mutex_lock(&sysfs_mutex); + if (inode->i_state & I_NEW) { /* initialize inode according to type */ switch (sysfs_type(sd)) { @@ -516,6 +549,8 @@ static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry, sysfs_instantiate(dentry, inode); sysfs_attach_dentry(sd, dentry); + mutex_unlock(&sysfs_mutex); + return NULL; } @@ -526,17 +561,13 @@ const struct inode_operations sysfs_dir_inode_operations = { static void remove_dir(struct sysfs_dirent *sd) { - struct dentry *parent = sd->s_parent->s_dentry; - - mutex_lock(&parent->d_inode->i_mutex); - + mutex_lock(&sysfs_mutex); sysfs_unlink_sibling(sd); sd->s_flags |= SYSFS_FLAG_REMOVED; + mutex_unlock(&sysfs_mutex); pr_debug(" o %s removing done\n", sd->s_name); - mutex_unlock(&parent->d_inode->i_mutex); - sysfs_drop_dentry(sd); sysfs_deactivate(sd); sysfs_put(sd); @@ -552,15 +583,12 @@ static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd) { struct sysfs_dirent *removed = NULL; struct sysfs_dirent **pos; - struct dentry *dir; if (!dir_sd) return; - dir = dir_sd->s_dentry; - pr_debug("sysfs %s: removing dir\n", dir_sd->s_name); - mutex_lock(&dir->d_inode->i_mutex); + mutex_lock(&sysfs_mutex); pos = &dir_sd->s_children; while (*pos) { struct sysfs_dirent *sd = *pos; @@ -573,7 +601,7 @@ static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd) } else pos = &(*pos)->s_sibling; } - mutex_unlock(&dir->d_inode->i_mutex); + mutex_unlock(&sysfs_mutex); while (removed) { struct sysfs_dirent *sd = removed; @@ -621,7 +649,6 @@ int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd, if (!new_parent_sd) return -EFAULT; - down_write(&sysfs_rename_sem); mutex_lock(&new_parent->d_inode->i_mutex); new_dentry = lookup_one_len(new_name, new_parent, strlen(new_name)); @@ -661,12 +688,16 @@ int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd, d_add(new_dentry, NULL); d_move(sd->s_dentry, new_dentry); + mutex_lock(&sysfs_mutex); + sysfs_unlink_sibling(sd); sysfs_get(new_parent_sd); sysfs_put(sd->s_parent); sd->s_parent = new_parent_sd; sysfs_link_sibling(sd); + mutex_unlock(&sysfs_mutex); + error = 0; goto out_unlock; @@ -678,7 +709,6 @@ int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd, dput(new_dentry); out_unlock: mutex_unlock(&new_parent->d_inode->i_mutex); - up_write(&sysfs_rename_sem); return error; } @@ -717,12 +747,15 @@ again: dput(new_dentry); /* Remove from old parent's list and insert into new parent's list. */ + mutex_lock(&sysfs_mutex); + sysfs_unlink_sibling(sd); sysfs_get(new_parent_sd); sysfs_put(sd->s_parent); sd->s_parent = new_parent_sd; sysfs_link_sibling(sd); + mutex_unlock(&sysfs_mutex); out: mutex_unlock(&new_parent_dentry->d_inode->i_mutex); mutex_unlock(&old_parent_dentry->d_inode->i_mutex); @@ -736,11 +769,12 @@ static int sysfs_dir_open(struct inode *inode, struct file *file) struct sysfs_dirent * parent_sd = dentry->d_fsdata; struct sysfs_dirent * sd; - mutex_lock(&dentry->d_inode->i_mutex); sd = sysfs_new_dirent("_DIR_", 0, 0); - if (sd) + if (sd) { + mutex_lock(&sysfs_mutex); sysfs_attach_dirent(sd, parent_sd, NULL); - mutex_unlock(&dentry->d_inode->i_mutex); + mutex_unlock(&sysfs_mutex); + } file->private_data = sd; return sd ? 0 : -ENOMEM; @@ -748,12 +782,11 @@ static int sysfs_dir_open(struct inode *inode, struct file *file) static int sysfs_dir_close(struct inode *inode, struct file *file) { - struct dentry * dentry = file->f_path.dentry; struct sysfs_dirent * cursor = file->private_data; - mutex_lock(&dentry->d_inode->i_mutex); + mutex_lock(&sysfs_mutex); sysfs_unlink_sibling(cursor); - mutex_unlock(&dentry->d_inode->i_mutex); + mutex_unlock(&sysfs_mutex); release_sysfs_dirent(cursor); @@ -794,6 +827,8 @@ static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir) i++; /* fallthrough */ default: + mutex_lock(&sysfs_mutex); + pos = &parent_sd->s_children; while (*pos != cursor) pos = &(*pos)->s_sibling; @@ -826,6 +861,8 @@ static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir) /* put cursor back in */ cursor->s_sibling = *pos; *pos = cursor; + + mutex_unlock(&sysfs_mutex); } return 0; } @@ -834,7 +871,6 @@ static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin) { struct dentry * dentry = file->f_path.dentry; - mutex_lock(&dentry->d_inode->i_mutex); switch (origin) { case 1: offset += file->f_pos; @@ -842,10 +878,11 @@ static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin) if (offset >= 0) break; default: - mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); return -EINVAL; } if (offset != file->f_pos) { + mutex_lock(&sysfs_mutex); + file->f_pos = offset; if (file->f_pos >= 2) { struct sysfs_dirent *sd = dentry->d_fsdata; @@ -866,8 +903,10 @@ static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin) cursor->s_sibling = *pos; *pos = cursor; } + + mutex_unlock(&sysfs_mutex); } - mutex_unlock(&dentry->d_inode->i_mutex); + return offset; } @@ -933,7 +972,9 @@ struct sysfs_dirent *sysfs_create_shadow_dir(struct kobject *kobj) sd->s_elem.dir.kobj = kobj; /* point to parent_sd but don't attach to it */ sd->s_parent = sysfs_get(parent_sd); + mutex_lock(&sysfs_mutex); sysfs_attach_dirent(sd, NULL, shadow); + mutex_unlock(&sysfs_mutex); d_instantiate(shadow, igrab(inode)); inc_nlink(inode); |