From 51225039f3cf9d250596d1344494b293274b9169 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 14 Jun 2007 04:27:25 +0900 Subject: [PATCH] sysfs: make directory dentries and inodes reclaimable This patch makes dentries and inodes for sysfs directories reclaimable. * sysfs_notify() is modified to walk sysfs_dirent tree instead of dentry tree. * sysfs_update_file() and sysfs_chmod_file() use sysfs_get_dentry() to grab the victim dentry. * sysfs_rename_dir() and sysfs_move_dir() grab all dentries using sysfs_get_dentry() on startup. * Dentries for all shadowed directories are pinned in memory to serve as lookup start point. Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/dir.c | 231 +++++++++++++++++++++++------------------- fs/sysfs/file.c | 134 +++++++++++------------- fs/sysfs/mount.c | 2 +- fs/sysfs/sysfs.h | 1 + include/linux/sysfs.h | 1 - 5 files changed, 187 insertions(+), 182 deletions(-) diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index 98721129610..aee966c44aa 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -568,10 +568,10 @@ static void sysfs_drop_dentry(struct sysfs_dirent *sd) spin_unlock(&dcache_lock); spin_unlock(&sysfs_assoc_lock); - dput(dentry); - /* XXX: unpin if directory, this will go away soon */ - if (sysfs_type(sd) == SYSFS_DIR) + /* dentries for shadowed inodes are pinned, unpin */ + if (dentry && sysfs_is_shadowed_inode(dentry->d_inode)) dput(dentry); + dput(dentry); /* adjust nlink and update timestamp */ inode = ilookup(sysfs_sb, sd->s_ino); @@ -686,69 +686,29 @@ struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd, static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd, const char *name, struct sysfs_dirent **p_sd) { - struct dentry *parent = parent_sd->s_dentry; - struct sysfs_addrm_cxt acxt; - int error; umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; - struct dentry *dentry; - struct inode *inode; + struct sysfs_addrm_cxt acxt; struct sysfs_dirent *sd; - sysfs_addrm_start(&acxt, parent_sd); - /* allocate */ - dentry = lookup_one_len(name, parent, strlen(name)); - if (IS_ERR(dentry)) { - error = PTR_ERR(dentry); - goto out_finish; - } - - error = -EEXIST; - if (dentry->d_inode) - goto out_dput; - - error = -ENOMEM; sd = sysfs_new_dirent(name, mode, SYSFS_DIR); if (!sd) - goto out_drop; + return -ENOMEM; sd->s_elem.dir.kobj = kobj; - inode = sysfs_get_inode(sd); - if (!inode) - goto out_sput; - - if (inode->i_state & I_NEW) { - inode->i_op = &sysfs_dir_inode_operations; - inode->i_fop = &sysfs_dir_operations; - /* directory inodes start off with i_nlink == 2 (for ".") */ - inc_nlink(inode); - } - /* link in */ - error = -EEXIST; - if (sysfs_find_dirent(parent_sd, name)) - goto out_iput; - - sysfs_add_one(&acxt, sd); - sysfs_link_sibling(sd); - sysfs_instantiate(dentry, inode); - sysfs_attach_dentry(sd, dentry); - - *p_sd = sd; - error = 0; - goto out_finish; /* pin directory dentry in core */ + sysfs_addrm_start(&acxt, parent_sd); + if (!sysfs_find_dirent(parent_sd, name)) { + sysfs_add_one(&acxt, sd); + sysfs_link_sibling(sd); + } + if (sysfs_addrm_finish(&acxt)) { + *p_sd = sd; + return 0; + } - out_iput: - iput(inode); - out_sput: sysfs_put(sd); - out_drop: - d_drop(dentry); - out_dput: - dput(dentry); - out_finish: - sysfs_addrm_finish(&acxt); - return error; + return -EEXIST; } int sysfs_create_subdir(struct kobject *kobj, const char *name, @@ -785,6 +745,17 @@ int sysfs_create_dir(struct kobject *kobj, return error; } +static int sysfs_count_nlink(struct sysfs_dirent *sd) +{ + struct sysfs_dirent *child; + int nr = 0; + + for (child = sd->s_children; child; child = child->s_sibling) + if (sysfs_type(child) == SYSFS_DIR) + nr++; + return nr + 2; +} + static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) { @@ -795,7 +766,7 @@ static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry, int found = 0; for (sd = parent_sd->s_children; sd; sd = sd->s_sibling) { - if ((sysfs_type(sd) & SYSFS_NOT_PINNED) && + if (sysfs_type(sd) && !strcmp(sd->s_name, dentry->d_name.name)) { found = 1; break; @@ -816,6 +787,11 @@ static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry, if (inode->i_state & I_NEW) { /* initialize inode according to type */ switch (sysfs_type(sd)) { + case SYSFS_DIR: + inode->i_op = &sysfs_dir_inode_operations; + inode->i_fop = &sysfs_dir_operations; + inode->i_nlink = sysfs_count_nlink(sd); + break; case SYSFS_KOBJ_ATTR: inode->i_size = PAGE_SIZE; inode->i_fop = &sysfs_file_operations; @@ -876,7 +852,7 @@ static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd) while (*pos) { struct sysfs_dirent *sd = *pos; - if (sysfs_type(sd) && (sysfs_type(sd) & SYSFS_NOT_PINNED)) { + if (sysfs_type(sd) && sysfs_type(sd) != SYSFS_DIR) { *pos = sd->s_sibling; sd->s_sibling = NULL; sysfs_remove_one(&acxt, sd); @@ -912,14 +888,25 @@ int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd, const char *new_name) { struct sysfs_dirent *sd = kobj->sd; - struct dentry *new_parent = new_parent_sd->s_dentry; - struct dentry *new_dentry; - char *dup_name; + struct dentry *new_parent = NULL; + struct dentry *old_dentry = NULL, *new_dentry = NULL; + const char *dup_name = NULL; int error; - if (!new_parent_sd) - return -EFAULT; + /* get dentries */ + old_dentry = sysfs_get_dentry(sd); + if (IS_ERR(old_dentry)) { + error = PTR_ERR(old_dentry); + goto out_dput; + } + + new_parent = sysfs_get_dentry(new_parent_sd); + if (IS_ERR(new_parent)) { + error = PTR_ERR(new_parent); + goto out_dput; + } + /* lock new_parent and get dentry for new name */ mutex_lock(&new_parent->d_inode->i_mutex); new_dentry = lookup_one_len(new_name, new_parent, strlen(new_name)); @@ -933,14 +920,14 @@ int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd, * shadows of the same directory */ error = -EINVAL; - if (sd->s_parent->s_dentry->d_inode != new_parent->d_inode || + if (old_dentry->d_parent->d_inode != new_parent->d_inode || new_dentry->d_parent->d_inode != new_parent->d_inode || - new_dentry == sd->s_dentry) - goto out_dput; + old_dentry == new_dentry) + goto out_unlock; error = -EEXIST; if (new_dentry->d_inode) - goto out_dput; + goto out_unlock; /* rename kobject and sysfs_dirent */ error = -ENOMEM; @@ -950,9 +937,9 @@ int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd, error = kobject_set_name(kobj, "%s", new_name); if (error) - goto out_free; + goto out_drop; - kfree(sd->s_name); + dup_name = sd->s_name; sd->s_name = new_name; /* move under the new parent */ @@ -972,45 +959,58 @@ int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd, error = 0; goto out_unlock; - out_free: - kfree(dup_name); out_drop: d_drop(new_dentry); - out_dput: - dput(new_dentry); out_unlock: mutex_unlock(&new_parent->d_inode->i_mutex); + out_dput: + kfree(dup_name); + dput(new_parent); + dput(old_dentry); + dput(new_dentry); return error; } -int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent) +int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj) { - struct dentry *old_parent_dentry, *new_parent_dentry, *new_dentry; - struct sysfs_dirent *new_parent_sd, *sd; + struct sysfs_dirent *sd = kobj->sd; + struct sysfs_dirent *new_parent_sd; + struct dentry *old_parent, *new_parent = NULL; + struct dentry *old_dentry = NULL, *new_dentry = NULL; int error; - old_parent_dentry = kobj->parent ? - kobj->parent->sd->s_dentry : sysfs_mount->mnt_sb->s_root; - new_parent_dentry = new_parent ? - new_parent->sd->s_dentry : sysfs_mount->mnt_sb->s_root; + BUG_ON(!sd->s_parent); + new_parent_sd = new_parent_kobj->sd ? new_parent_kobj->sd : &sysfs_root; + + /* get dentries */ + old_dentry = sysfs_get_dentry(sd); + if (IS_ERR(old_dentry)) { + error = PTR_ERR(old_dentry); + goto out_dput; + } + old_parent = sd->s_parent->s_dentry; + + new_parent = sysfs_get_dentry(new_parent_sd); + if (IS_ERR(new_parent)) { + error = PTR_ERR(new_parent); + goto out_dput; + } - if (old_parent_dentry->d_inode == new_parent_dentry->d_inode) - return 0; /* nothing to move */ + if (old_parent->d_inode == new_parent->d_inode) { + error = 0; + goto out_dput; /* nothing to move */ + } again: - mutex_lock(&old_parent_dentry->d_inode->i_mutex); - if (!mutex_trylock(&new_parent_dentry->d_inode->i_mutex)) { - mutex_unlock(&old_parent_dentry->d_inode->i_mutex); + mutex_lock(&old_parent->d_inode->i_mutex); + if (!mutex_trylock(&new_parent->d_inode->i_mutex)) { + mutex_unlock(&old_parent->d_inode->i_mutex); goto again; } - new_parent_sd = new_parent_dentry->d_fsdata; - sd = kobj->sd; - - new_dentry = lookup_one_len(kobj->name, new_parent_dentry, - strlen(kobj->name)); + new_dentry = lookup_one_len(kobj->name, new_parent, strlen(kobj->name)); if (IS_ERR(new_dentry)) { error = PTR_ERR(new_dentry); - goto out; + goto out_unlock; } else error = 0; d_add(new_dentry, NULL); @@ -1027,10 +1027,14 @@ again: 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); + out_unlock: + mutex_unlock(&new_parent->d_inode->i_mutex); + mutex_unlock(&old_parent->d_inode->i_mutex); + out_dput: + dput(new_parent); + dput(old_dentry); + dput(new_dentry); return error; } @@ -1191,12 +1195,20 @@ static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin) int sysfs_make_shadowed_dir(struct kobject *kobj, void * (*follow_link)(struct dentry *, struct nameidata *)) { + struct dentry *dentry; struct inode *inode; struct inode_operations *i_op; - inode = kobj->sd->s_dentry->d_inode; - if (inode->i_op != &sysfs_dir_inode_operations) + /* get dentry for @kobj->sd, dentry of a shadowed dir is pinned */ + dentry = sysfs_get_dentry(kobj->sd); + if (IS_ERR(dentry)) + return PTR_ERR(dentry); + + inode = dentry->d_inode; + if (inode->i_op != &sysfs_dir_inode_operations) { + dput(dentry); return -EINVAL; + } i_op = kmalloc(sizeof(*i_op), GFP_KERNEL); if (!i_op) @@ -1223,17 +1235,23 @@ int sysfs_make_shadowed_dir(struct kobject *kobj, struct sysfs_dirent *sysfs_create_shadow_dir(struct kobject *kobj) { - struct dentry *dir = kobj->sd->s_dentry; - struct inode *inode = dir->d_inode; - struct dentry *parent = dir->d_parent; - struct sysfs_dirent *parent_sd = parent->d_fsdata; - struct dentry *shadow; + struct sysfs_dirent *parent_sd = kobj->sd->s_parent; + struct dentry *dir, *parent, *shadow; + struct inode *inode; struct sysfs_dirent *sd; struct sysfs_addrm_cxt acxt; + dir = sysfs_get_dentry(kobj->sd); + if (IS_ERR(dir)) { + sd = (void *)dir; + goto out; + } + parent = dir->d_parent; + + inode = dir->d_inode; sd = ERR_PTR(-EINVAL); if (!sysfs_is_shadowed_inode(inode)) - goto out; + goto out_dput; shadow = d_alloc(parent, &dir->d_name); if (!shadow) @@ -1258,12 +1276,15 @@ struct sysfs_dirent *sysfs_create_shadow_dir(struct kobject *kobj) dget(shadow); /* Extra count - pin the dentry in core */ -out: - return sd; -nomem: + goto out_dput; + + nomem: dput(shadow); sd = ERR_PTR(-ENOMEM); - goto out; + out_dput: + dput(dir); + out: + return sd; } /** diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 69bacf1db59..cc497994b2a 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -362,43 +362,22 @@ static unsigned int sysfs_poll(struct file *filp, poll_table *wait) return POLLERR|POLLPRI; } - -static struct dentry *step_down(struct dentry *dir, const char * name) +void sysfs_notify(struct kobject *k, char *dir, char *attr) { - struct dentry * de; - - if (dir == NULL || dir->d_inode == NULL) - return NULL; - - mutex_lock(&dir->d_inode->i_mutex); - de = lookup_one_len(name, dir, strlen(name)); - mutex_unlock(&dir->d_inode->i_mutex); - dput(dir); - if (IS_ERR(de)) - return NULL; - if (de->d_inode == NULL) { - dput(de); - return NULL; - } - return de; -} + struct sysfs_dirent *sd = k->sd; -void sysfs_notify(struct kobject * k, char *dir, char *attr) -{ - struct dentry *de = k->sd->s_dentry; - if (de) - dget(de); - if (de && dir) - de = step_down(de, dir); - if (de && attr) - de = step_down(de, attr); - if (de) { - struct sysfs_dirent * sd = de->d_fsdata; - if (sd) - atomic_inc(&sd->s_event); + mutex_lock(&sysfs_mutex); + + if (sd && dir) + sd = sysfs_find_dirent(sd, dir); + if (sd && attr) + sd = sysfs_find_dirent(sd, attr); + if (sd) { + atomic_inc(&sd->s_event); wake_up_interruptible(&k->poll); - dput(de); } + + mutex_unlock(&sysfs_mutex); } EXPORT_SYMBOL_GPL(sysfs_notify); @@ -485,30 +464,31 @@ EXPORT_SYMBOL_GPL(sysfs_add_file_to_group); */ int sysfs_update_file(struct kobject * kobj, const struct attribute * attr) { - struct dentry *dir = kobj->sd->s_dentry; - struct dentry * victim; - int res = -ENOENT; - - mutex_lock(&dir->d_inode->i_mutex); - victim = lookup_one_len(attr->name, dir, strlen(attr->name)); - if (!IS_ERR(victim)) { - /* make sure dentry is really there */ - if (victim->d_inode && - (victim->d_parent->d_inode == dir->d_inode)) { - victim->d_inode->i_mtime = CURRENT_TIME; - fsnotify_modify(victim); - res = 0; - } else - d_drop(victim); - - /** - * Drop the reference acquired from lookup_one_len() above. - */ - dput(victim); + struct sysfs_dirent *victim_sd = NULL; + struct dentry *victim = NULL; + int rc; + + rc = -ENOENT; + victim_sd = sysfs_get_dirent(kobj->sd, attr->name); + if (!victim_sd) + goto out; + + victim = sysfs_get_dentry(victim_sd); + if (IS_ERR(victim)) { + rc = PTR_ERR(victim); + victim = NULL; + goto out; } - mutex_unlock(&dir->d_inode->i_mutex); - return res; + mutex_lock(&victim->d_inode->i_mutex); + victim->d_inode->i_mtime = CURRENT_TIME; + fsnotify_modify(victim); + mutex_unlock(&victim->d_inode->i_mutex); + rc = 0; + out: + dput(victim); + sysfs_put(victim_sd); + return rc; } @@ -521,30 +501,34 @@ int sysfs_update_file(struct kobject * kobj, const struct attribute * attr) */ int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode) { - struct dentry *dir = kobj->sd->s_dentry; - struct dentry *victim; + struct sysfs_dirent *victim_sd = NULL; + struct dentry *victim = NULL; struct inode * inode; struct iattr newattrs; - int res = -ENOENT; - - mutex_lock(&dir->d_inode->i_mutex); - victim = lookup_one_len(attr->name, dir, strlen(attr->name)); - if (!IS_ERR(victim)) { - if (victim->d_inode && - (victim->d_parent->d_inode == dir->d_inode)) { - inode = victim->d_inode; - mutex_lock(&inode->i_mutex); - newattrs.ia_mode = (mode & S_IALLUGO) | - (inode->i_mode & ~S_IALLUGO); - newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; - res = notify_change(victim, &newattrs); - mutex_unlock(&inode->i_mutex); - } - dput(victim); + int rc; + + rc = -ENOENT; + victim_sd = sysfs_get_dirent(kobj->sd, attr->name); + if (!victim_sd) + goto out; + + victim = sysfs_get_dentry(victim_sd); + if (IS_ERR(victim)) { + rc = PTR_ERR(victim); + victim = NULL; + goto out; } - mutex_unlock(&dir->d_inode->i_mutex); - return res; + inode = victim->d_inode; + mutex_lock(&inode->i_mutex); + newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); + newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; + rc = notify_change(victim, &newattrs); + mutex_unlock(&inode->i_mutex); + out: + dput(victim); + sysfs_put(victim_sd); + return rc; } EXPORT_SYMBOL_GPL(sysfs_chmod_file); diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c index 078537e5d69..402cc356203 100644 --- a/fs/sysfs/mount.c +++ b/fs/sysfs/mount.c @@ -24,7 +24,7 @@ static const struct super_operations sysfs_ops = { .drop_inode = sysfs_delete_inode, }; -static struct sysfs_dirent sysfs_root = { +struct sysfs_dirent sysfs_root = { .s_count = ATOMIC_INIT(1), .s_flags = SYSFS_ROOT, .s_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO, diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h index 72530dc666f..6a37f2386a8 100644 --- a/fs/sysfs/sysfs.h +++ b/fs/sysfs/sysfs.h @@ -52,6 +52,7 @@ struct sysfs_addrm_cxt { }; extern struct vfsmount * sysfs_mount; +extern struct sysfs_dirent sysfs_root; extern struct kmem_cache *sysfs_dir_cachep; extern struct dentry *sysfs_get_dentry(struct sysfs_dirent *sd); diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index 4c43030fae5..2f58ca1af77 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -81,7 +81,6 @@ struct sysfs_ops { #define SYSFS_KOBJ_ATTR 0x0004 #define SYSFS_KOBJ_BIN_ATTR 0x0008 #define SYSFS_KOBJ_LINK 0x0020 -#define SYSFS_NOT_PINNED (SYSFS_KOBJ_ATTR | SYSFS_KOBJ_BIN_ATTR | SYSFS_KOBJ_LINK) #define SYSFS_COPY_NAME (SYSFS_DIR | SYSFS_KOBJ_LINK) #define SYSFS_FLAG_MASK ~SYSFS_TYPE_MASK -- 2.20.1