diff options
Diffstat (limited to 'fs/configfs')
| -rw-r--r-- | fs/configfs/configfs_internal.h | 15 | ||||
| -rw-r--r-- | fs/configfs/dir.c | 168 | ||||
| -rw-r--r-- | fs/configfs/file.c | 294 | ||||
| -rw-r--r-- | fs/configfs/symlink.c | 33 |
4 files changed, 314 insertions, 196 deletions
diff --git a/fs/configfs/configfs_internal.h b/fs/configfs/configfs_internal.h index ccc31fa6f1a7..16eb59adf5aa 100644 --- a/fs/configfs/configfs_internal.h +++ b/fs/configfs/configfs_internal.h @@ -34,6 +34,15 @@ #include <linux/list.h> #include <linux/spinlock.h> +struct configfs_fragment { + atomic_t frag_count; + struct rw_semaphore frag_sem; + bool frag_dead; +}; + +void put_fragment(struct configfs_fragment *); +struct configfs_fragment *get_fragment(struct configfs_fragment *); + struct configfs_dirent { atomic_t s_count; int s_dependent_count; @@ -48,6 +57,7 @@ struct configfs_dirent { #ifdef CONFIG_LOCKDEP int s_depth; #endif + struct configfs_fragment *s_frag; }; #define CONFIGFS_ROOT 0x0001 @@ -75,8 +85,8 @@ extern int configfs_create(struct dentry *, umode_t mode, void (*init)(struct in extern int configfs_create_file(struct config_item *, const struct configfs_attribute *); extern int configfs_create_bin_file(struct config_item *, const struct configfs_bin_attribute *); -extern int configfs_make_dirent(struct configfs_dirent *, - struct dentry *, void *, umode_t, int); +extern int configfs_make_dirent(struct configfs_dirent *, struct dentry *, + void *, umode_t, int, struct configfs_fragment *); extern int configfs_dirent_is_ready(struct configfs_dirent *); extern void configfs_hash_and_remove(struct dentry * dir, const char * name); @@ -151,6 +161,7 @@ static inline void release_configfs_dirent(struct configfs_dirent * sd) { if (!(sd->s_type & CONFIGFS_ROOT)) { kfree(sd->s_iattr); + put_fragment(sd->s_frag); kmem_cache_free(configfs_dir_cachep, sd); } } diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c index d2a1a79fa324..c2ef617d2f97 100644 --- a/fs/configfs/dir.c +++ b/fs/configfs/dir.c @@ -58,15 +58,13 @@ static void configfs_d_iput(struct dentry * dentry, if (sd) { /* Coordinate with configfs_readdir */ spin_lock(&configfs_dirent_lock); - /* Coordinate with configfs_attach_attr where will increase - * sd->s_count and update sd->s_dentry to new allocated one. - * Only set sd->dentry to null when this dentry is the only - * sd owner. - * If not do so, configfs_d_iput may run just after - * configfs_attach_attr and set sd->s_dentry to null - * even it's still in use. + /* + * Set sd->s_dentry to null only when this dentry is the one + * that is going to be killed. Otherwise configfs_d_iput may + * run just after configfs_attach_attr and set sd->s_dentry to + * NULL even it's still in use. */ - if (atomic_read(&sd->s_count) <= 2) + if (sd->s_dentry == dentry) sd->s_dentry = NULL; spin_unlock(&configfs_dirent_lock); @@ -166,11 +164,38 @@ configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd) #endif /* CONFIG_LOCKDEP */ +static struct configfs_fragment *new_fragment(void) +{ + struct configfs_fragment *p; + + p = kmalloc(sizeof(struct configfs_fragment), GFP_KERNEL); + if (p) { + atomic_set(&p->frag_count, 1); + init_rwsem(&p->frag_sem); + p->frag_dead = false; + } + return p; +} + +void put_fragment(struct configfs_fragment *frag) +{ + if (frag && atomic_dec_and_test(&frag->frag_count)) + kfree(frag); +} + +struct configfs_fragment *get_fragment(struct configfs_fragment *frag) +{ + if (likely(frag)) + atomic_inc(&frag->frag_count); + return frag; +} + /* * Allocates a new configfs_dirent and links it to the parent configfs_dirent */ static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *parent_sd, - void *element, int type) + void *element, int type, + struct configfs_fragment *frag) { struct configfs_dirent * sd; @@ -190,6 +215,7 @@ static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *paren kmem_cache_free(configfs_dir_cachep, sd); return ERR_PTR(-ENOENT); } + sd->s_frag = get_fragment(frag); list_add(&sd->s_sibling, &parent_sd->s_children); spin_unlock(&configfs_dirent_lock); @@ -224,11 +250,11 @@ static int configfs_dirent_exists(struct configfs_dirent *parent_sd, int configfs_make_dirent(struct configfs_dirent * parent_sd, struct dentry * dentry, void * element, - umode_t mode, int type) + umode_t mode, int type, struct configfs_fragment *frag) { struct configfs_dirent * sd; - sd = configfs_new_dirent(parent_sd, element, type); + sd = configfs_new_dirent(parent_sd, element, type, frag); if (IS_ERR(sd)) return PTR_ERR(sd); @@ -275,7 +301,8 @@ static void init_symlink(struct inode * inode) * until it is validated by configfs_dir_set_ready() */ -static int configfs_create_dir(struct config_item *item, struct dentry *dentry) +static int configfs_create_dir(struct config_item *item, struct dentry *dentry, + struct configfs_fragment *frag) { int error; umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; @@ -288,7 +315,8 @@ static int configfs_create_dir(struct config_item *item, struct dentry *dentry) return error; error = configfs_make_dirent(p->d_fsdata, dentry, item, mode, - CONFIGFS_DIR | CONFIGFS_USET_CREATING); + CONFIGFS_DIR | CONFIGFS_USET_CREATING, + frag); if (unlikely(error)) return error; @@ -353,9 +381,10 @@ int configfs_create_link(struct configfs_symlink *sl, { int err = 0; umode_t mode = S_IFLNK | S_IRWXUGO; + struct configfs_dirent *p = parent->d_fsdata; - err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode, - CONFIGFS_ITEM_LINK); + err = configfs_make_dirent(p, dentry, sl, mode, + CONFIGFS_ITEM_LINK, p->s_frag); if (!err) { err = configfs_create(dentry, mode, init_symlink); if (err) { @@ -614,7 +643,8 @@ static int populate_attrs(struct config_item *item) static int configfs_attach_group(struct config_item *parent_item, struct config_item *item, - struct dentry *dentry); + struct dentry *dentry, + struct configfs_fragment *frag); static void configfs_detach_group(struct config_item *item); static void detach_groups(struct config_group *group) @@ -662,7 +692,8 @@ static void detach_groups(struct config_group *group) * try using vfs_mkdir. Just a thought. */ static int create_default_group(struct config_group *parent_group, - struct config_group *group) + struct config_group *group, + struct configfs_fragment *frag) { int ret; struct configfs_dirent *sd; @@ -678,7 +709,7 @@ static int create_default_group(struct config_group *parent_group, d_add(child, NULL); ret = configfs_attach_group(&parent_group->cg_item, - &group->cg_item, child); + &group->cg_item, child, frag); if (!ret) { sd = child->d_fsdata; sd->s_type |= CONFIGFS_USET_DEFAULT; @@ -692,13 +723,14 @@ static int create_default_group(struct config_group *parent_group, return ret; } -static int populate_groups(struct config_group *group) +static int populate_groups(struct config_group *group, + struct configfs_fragment *frag) { struct config_group *new_group; int ret = 0; list_for_each_entry(new_group, &group->default_groups, group_entry) { - ret = create_default_group(group, new_group); + ret = create_default_group(group, new_group, frag); if (ret) { detach_groups(group); break; @@ -812,11 +844,12 @@ static void link_group(struct config_group *parent_group, struct config_group *g */ static int configfs_attach_item(struct config_item *parent_item, struct config_item *item, - struct dentry *dentry) + struct dentry *dentry, + struct configfs_fragment *frag) { int ret; - ret = configfs_create_dir(item, dentry); + ret = configfs_create_dir(item, dentry, frag); if (!ret) { ret = populate_attrs(item); if (ret) { @@ -846,12 +879,13 @@ static void configfs_detach_item(struct config_item *item) static int configfs_attach_group(struct config_item *parent_item, struct config_item *item, - struct dentry *dentry) + struct dentry *dentry, + struct configfs_fragment *frag) { int ret; struct configfs_dirent *sd; - ret = configfs_attach_item(parent_item, item, dentry); + ret = configfs_attach_item(parent_item, item, dentry, frag); if (!ret) { sd = dentry->d_fsdata; sd->s_type |= CONFIGFS_USET_DIR; @@ -867,7 +901,7 @@ static int configfs_attach_group(struct config_item *parent_item, */ inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD); configfs_adjust_dir_dirent_depth_before_populate(sd); - ret = populate_groups(to_config_group(item)); + ret = populate_groups(to_config_group(item), frag); if (ret) { configfs_detach_item(item); d_inode(dentry)->i_flags |= S_DEAD; @@ -1262,6 +1296,7 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode struct configfs_dirent *sd; struct config_item_type *type; struct module *subsys_owner = NULL, *new_item_owner = NULL; + struct configfs_fragment *frag; char *name; sd = dentry->d_parent->d_fsdata; @@ -1280,6 +1315,12 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode goto out; } + frag = new_fragment(); + if (!frag) { + ret = -ENOMEM; + goto out; + } + /* Get a working ref for the duration of this function */ parent_item = configfs_get_config_item(dentry->d_parent); type = parent_item->ci_type; @@ -1382,9 +1423,9 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode spin_unlock(&configfs_dirent_lock); if (group) - ret = configfs_attach_group(parent_item, item, dentry); + ret = configfs_attach_group(parent_item, item, dentry, frag); else - ret = configfs_attach_item(parent_item, item, dentry); + ret = configfs_attach_item(parent_item, item, dentry, frag); spin_lock(&configfs_dirent_lock); sd->s_type &= ~CONFIGFS_USET_IN_MKDIR; @@ -1421,6 +1462,7 @@ out_put: * reference. */ config_item_put(parent_item); + put_fragment(frag); out: return ret; @@ -1432,6 +1474,7 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry) struct config_item *item; struct configfs_subsystem *subsys; struct configfs_dirent *sd; + struct configfs_fragment *frag; struct module *subsys_owner = NULL, *dead_item_owner = NULL; int ret; @@ -1489,6 +1532,16 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry) } } while (ret == -EAGAIN); + frag = sd->s_frag; + if (down_write_killable(&frag->frag_sem)) { + spin_lock(&configfs_dirent_lock); + configfs_detach_rollback(dentry); + spin_unlock(&configfs_dirent_lock); + return -EINTR; + } + frag->frag_dead = true; + up_write(&frag->frag_sem); + /* Get a working ref for the duration of this function */ item = configfs_get_config_item(dentry); @@ -1589,7 +1642,7 @@ static int configfs_dir_open(struct inode *inode, struct file *file) */ err = -ENOENT; if (configfs_dirent_is_ready(parent_sd)) { - file->private_data = configfs_new_dirent(parent_sd, NULL, 0); + file->private_data = configfs_new_dirent(parent_sd, NULL, 0, NULL); if (IS_ERR(file->private_data)) err = PTR_ERR(file->private_data); else @@ -1745,8 +1798,13 @@ int configfs_register_group(struct config_group *parent_group, { struct configfs_subsystem *subsys = parent_group->cg_subsys; struct dentry *parent; + struct configfs_fragment *frag; int ret; + frag = new_fragment(); + if (!frag) + return -ENOMEM; + mutex_lock(&subsys->su_mutex); link_group(parent_group, group); mutex_unlock(&subsys->su_mutex); @@ -1754,13 +1812,22 @@ int configfs_register_group(struct config_group *parent_group, parent = parent_group->cg_item.ci_dentry; inode_lock_nested(d_inode(parent), I_MUTEX_PARENT); - ret = create_default_group(parent_group, group); - if (!ret) { - spin_lock(&configfs_dirent_lock); - configfs_dir_set_ready(group->cg_item.ci_dentry->d_fsdata); - spin_unlock(&configfs_dirent_lock); - } + ret = create_default_group(parent_group, group, frag); + if (ret) + goto err_out; + + spin_lock(&configfs_dirent_lock); + configfs_dir_set_ready(group->cg_item.ci_dentry->d_fsdata); + spin_unlock(&configfs_dirent_lock); inode_unlock(d_inode(parent)); + put_fragment(frag); + return 0; +err_out: + inode_unlock(d_inode(parent)); + mutex_lock(&subsys->su_mutex); + unlink_group(group); + mutex_unlock(&subsys->su_mutex); + put_fragment(frag); return ret; } EXPORT_SYMBOL(configfs_register_group); @@ -1776,16 +1843,12 @@ void configfs_unregister_group(struct config_group *group) struct configfs_subsystem *subsys = group->cg_subsys; struct dentry *dentry = group->cg_item.ci_dentry; struct dentry *parent = group->cg_item.ci_parent->ci_dentry; + struct configfs_dirent *sd = dentry->d_fsdata; + struct configfs_fragment *frag = sd->s_frag; - mutex_lock(&subsys->su_mutex); - if (!group->cg_item.ci_parent->ci_group) { - /* - * The parent has already been unlinked and detached - * due to a rmdir. - */ - goto unlink_group; - } - mutex_unlock(&subsys->su_mutex); + down_write(&frag->frag_sem); + frag->frag_dead = true; + up_write(&frag->frag_sem); inode_lock_nested(d_inode(parent), I_MUTEX_PARENT); spin_lock(&configfs_dirent_lock); @@ -1801,7 +1864,6 @@ void configfs_unregister_group(struct config_group *group) dput(dentry); mutex_lock(&subsys->su_mutex); -unlink_group: unlink_group(group); mutex_unlock(&subsys->su_mutex); } @@ -1858,10 +1920,17 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys) struct dentry *dentry; struct dentry *root; struct configfs_dirent *sd; + struct configfs_fragment *frag; + + frag = new_fragment(); + if (!frag) + return -ENOMEM; root = configfs_pin_fs(); - if (IS_ERR(root)) + if (IS_ERR(root)) { + put_fragment(frag); return PTR_ERR(root); + } if (!group->cg_item.ci_name) group->cg_item.ci_name = group->cg_item.ci_namebuf; @@ -1877,7 +1946,7 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys) d_add(dentry, NULL); err = configfs_attach_group(sd->s_element, &group->cg_item, - dentry); + dentry, frag); if (err) { BUG_ON(d_inode(dentry)); d_drop(dentry); @@ -1895,6 +1964,7 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys) unlink_group(group); configfs_release_fs(); } + put_fragment(frag); return err; } @@ -1904,12 +1974,18 @@ void configfs_unregister_subsystem(struct configfs_subsystem *subsys) struct config_group *group = &subsys->su_group; struct dentry *dentry = group->cg_item.ci_dentry; struct dentry *root = dentry->d_sb->s_root; + struct configfs_dirent *sd = dentry->d_fsdata; + struct configfs_fragment *frag = sd->s_frag; if (dentry->d_parent != root) { pr_err("Tried to unregister non-subsystem!\n"); return; } + down_write(&frag->frag_sem); + frag->frag_dead = true; + up_write(&frag->frag_sem); + inode_lock_nested(d_inode(root), I_MUTEX_PARENT); inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD); diff --git a/fs/configfs/file.c b/fs/configfs/file.c index 2c6312db8516..7285440bc62e 100644 --- a/fs/configfs/file.c +++ b/fs/configfs/file.c @@ -53,40 +53,44 @@ struct configfs_buffer { bool write_in_progress; char *bin_buffer; int bin_buffer_size; + int cb_max_size; + struct config_item *item; + struct module *owner; + union { + struct configfs_attribute *attr; + struct configfs_bin_attribute *bin_attr; + }; }; +static inline struct configfs_fragment *to_frag(struct file *file) +{ + struct configfs_dirent *sd = file->f_path.dentry->d_fsdata; -/** - * fill_read_buffer - allocate and fill buffer from item. - * @dentry: dentry pointer. - * @buffer: data buffer for file. - * - * Allocate @buffer->page, if it hasn't been already, then call the - * config_item's show() method to fill the buffer with this attribute's - * data. - * This is called only once, on the file's first read. - */ -static int fill_read_buffer(struct dentry * dentry, struct configfs_buffer * buffer) + return sd->s_frag; +} + +static int fill_read_buffer(struct file *file, struct configfs_buffer *buffer) { - struct configfs_attribute * attr = to_attr(dentry); - struct config_item * item = to_item(dentry->d_parent); - int ret = 0; - ssize_t count; + struct configfs_fragment *frag = to_frag(file); + ssize_t count = -ENOENT; if (!buffer->page) buffer->page = (char *) get_zeroed_page(GFP_KERNEL); if (!buffer->page) return -ENOMEM; - count = attr->show(item, buffer->page); - - BUG_ON(count > (ssize_t)SIMPLE_ATTR_SIZE); - if (count >= 0) { - buffer->needs_read_fill = 0; - buffer->count = count; - } else - ret = count; - return ret; + down_read(&frag->frag_sem); + if (!frag->frag_dead) + count = buffer->attr->show(buffer->item, buffer->page); + up_read(&frag->frag_sem); + + if (count < 0) + return count; + if (WARN_ON_ONCE(count > (ssize_t)SIMPLE_ATTR_SIZE)) + return -EIO; + buffer->needs_read_fill = 0; + buffer->count = count; + return 0; } /** @@ -111,12 +115,13 @@ static int fill_read_buffer(struct dentry * dentry, struct configfs_buffer * buf static ssize_t configfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) { - struct configfs_buffer * buffer = file->private_data; + struct configfs_buffer *buffer = file->private_data; ssize_t retval = 0; mutex_lock(&buffer->mutex); if (buffer->needs_read_fill) { - if ((retval = fill_read_buffer(file->f_path.dentry,buffer))) + retval = fill_read_buffer(file, buffer); + if (retval) goto out; } pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n", @@ -152,10 +157,8 @@ static ssize_t configfs_read_bin_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) { + struct configfs_fragment *frag = to_frag(file); struct configfs_buffer *buffer = file->private_data; - struct dentry *dentry = file->f_path.dentry; - struct config_item *item = to_item(dentry->d_parent); - struct configfs_bin_attribute *bin_attr = to_bin_attr(dentry); ssize_t retval = 0; ssize_t len = min_t(size_t, count, PAGE_SIZE); @@ -166,18 +169,23 @@ configfs_read_bin_file(struct file *file, char __user *buf, retval = -ETXTBSY; goto out; } - buffer->read_in_progress = 1; + buffer->read_in_progress = true; if (buffer->needs_read_fill) { /* perform first read with buf == NULL to get extent */ - len = bin_attr->read(item, NULL, 0); + down_read(&frag->frag_sem); + if (!frag->frag_dead) + len = buffer->bin_attr->read(buffer->item, NULL, 0); + else + len = -ENOENT; + up_read(&frag->frag_sem); if (len <= 0) { retval = len; goto out; } /* do not exceed the maximum value */ - if (bin_attr->cb_max_size && len > bin_attr->cb_max_size) { + if (buffer->cb_max_size && len > buffer->cb_max_size) { retval = -EFBIG; goto out; } @@ -190,7 +198,13 @@ configfs_read_bin_file(struct file *file, char __user *buf, buffer->bin_buffer_size = len; /* perform second read to fill buffer */ - len = bin_attr->read(item, buffer->bin_buffer, len); + down_read(&frag->frag_sem); + if (!frag->frag_dead) + len = buffer->bin_attr->read(buffer->item, + buffer->bin_buffer, len); + else + len = -ENOENT; + up_read(&frag->frag_sem); if (len < 0) { retval = len; vfree(buffer->bin_buffer); @@ -240,25 +254,17 @@ fill_write_buffer(struct configfs_buffer * buffer, const char __user * buf, size return error ? -EFAULT : count; } - -/** - * flush_write_buffer - push buffer to config_item. - * @dentry: dentry to the attribute - * @buffer: data buffer for file. - * @count: number of bytes - * - * Get the correct pointers for the config_item and the attribute we're - * dealing with, then call the store() method for the attribute, - * passing the buffer that we acquired in fill_write_buffer(). - */ - static int -flush_write_buffer(struct dentry * dentry, struct configfs_buffer * buffer, size_t count) +flush_write_buffer(struct file *file, struct configfs_buffer *buffer, size_t count) { - struct configfs_attribute * attr = to_attr(dentry); - struct config_item * item = to_item(dentry->d_parent); - - return attr->store(item, buffer->page, count); + struct configfs_fragment *frag = to_frag(file); + int res = -ENOENT; + + down_read(&frag->frag_sem); + if (!frag->frag_dead) + res = buffer->attr->store(buffer->item, buffer->page, count); + up_read(&frag->frag_sem); + return res; } @@ -282,13 +288,13 @@ flush_write_buffer(struct dentry * dentry, struct configfs_buffer * buffer, size static ssize_t configfs_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { - struct configfs_buffer * buffer = file->private_data; + struct configfs_buffer *buffer = file->private_data; ssize_t len; mutex_lock(&buffer->mutex); len = fill_write_buffer(buffer, buf, count); if (len > 0) - len = flush_write_buffer(file->f_path.dentry, buffer, len); + len = flush_write_buffer(file, buffer, len); if (len > 0) *ppos += len; mutex_unlock(&buffer->mutex); @@ -313,8 +319,6 @@ configfs_write_bin_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { struct configfs_buffer *buffer = file->private_data; - struct dentry *dentry = file->f_path.dentry; - struct configfs_bin_attribute *bin_attr = to_bin_attr(dentry); void *tbuf = NULL; ssize_t len; @@ -325,13 +329,13 @@ configfs_write_bin_file(struct file *file, const char __user *buf, len = -ETXTBSY; goto out; } - buffer->write_in_progress = 1; + buffer->write_in_progress = true; /* buffer grows? */ if (*ppos + count > buffer->bin_buffer_size) { - if (bin_attr->cb_max_size && - *ppos + count > bin_attr->cb_max_size) { + if (buffer->cb_max_size && + *ppos + count > buffer->cb_max_size) { len = -EFBIG; goto out; } @@ -363,31 +367,51 @@ out: return len; } -static int check_perm(struct inode * inode, struct file * file, int type) +static int __configfs_open_file(struct inode *inode, struct file *file, int type) { - struct config_item *item = configfs_get_config_item(file->f_path.dentry->d_parent); - struct configfs_attribute * attr = to_attr(file->f_path.dentry); - struct configfs_bin_attribute *bin_attr = NULL; - struct configfs_buffer * buffer; - struct configfs_item_operations * ops = NULL; - int error = 0; + struct dentry *dentry = file->f_path.dentry; + struct configfs_fragment *frag = to_frag(file); + struct configfs_attribute *attr; + struct configfs_buffer *buffer; + int error; - if (!item || !attr) - goto Einval; + error = -ENOMEM; + buffer = kzalloc(sizeof(struct configfs_buffer), GFP_KERNEL); + if (!buffer) + goto out; - if (type & CONFIGFS_ITEM_BIN_ATTR) - bin_attr = to_bin_attr(file->f_path.dentry); + error = -ENOENT; + down_read(&frag->frag_sem); + if (unlikely(frag->frag_dead)) + goto out_free_buffer; - /* Grab the module reference for this attribute if we have one */ - if (!try_module_get(attr->ca_owner)) { - error = -ENODEV; - goto Done; + error = -EINVAL; + buffer->item = to_item(dentry->d_parent); + if (!buffer->item) + goto out_free_buffer; + + attr = to_attr(dentry); + if (!attr) + goto out_put_item; + + if (type & CONFIGFS_ITEM_BIN_ATTR) { + buffer->bin_attr = to_bin_attr(dentry); + buffer->cb_max_size = buffer->bin_attr->cb_max_size; + } else { + buffer->attr = attr; } - if (item->ci_type) - ops = item->ci_type->ct_item_ops; - else - goto Eaccess; + buffer->owner = attr->ca_owner; + /* Grab the module reference for this attribute if we have one */ + error = -ENODEV; + if (!try_module_get(buffer->owner)) + goto out_put_item; + + error = -EACCES; + if (!buffer->item->ci_type) + goto out_put_module; + + buffer->ops = buffer->item->ci_type->ct_item_ops; /* File needs write support. * The inode's perms must say it's ok, @@ -395,13 +419,11 @@ static int check_perm(struct inode * inode, struct file * file, int type) */ if (file->f_mode & FMODE_WRITE) { if (!(inode->i_mode & S_IWUGO)) - goto Eaccess; - + goto out_put_module; if ((type & CONFIGFS_ITEM_ATTR) && !attr->store) - goto Eaccess; - - if ((type & CONFIGFS_ITEM_BIN_ATTR) && !bin_attr->write) - goto Eaccess; + goto out_put_module; + if ((type & CONFIGFS_ITEM_BIN_ATTR) && !buffer->bin_attr->write) + goto out_put_module; } /* File needs read support. @@ -410,92 +432,72 @@ static int check_perm(struct inode * inode, struct file * file, int type) */ if (file->f_mode & FMODE_READ) { if (!(inode->i_mode & S_IRUGO)) - goto Eaccess; - + goto out_put_module; if ((type & CONFIGFS_ITEM_ATTR) && !attr->show) - goto Eaccess; - - if ((type & CONFIGFS_ITEM_BIN_ATTR) && !bin_attr->read) - goto Eaccess; + goto out_put_module; + if ((type & CONFIGFS_ITEM_BIN_ATTR) && !buffer->bin_attr->read) + goto out_put_module; } - /* No error? Great, allocate a buffer for the file, and store it - * it in file->private_data for easy access. - */ - buffer = kzalloc(sizeof(struct configfs_buffer),GFP_KERNEL); - if (!buffer) { - error = -ENOMEM; - goto Enomem; - } mutex_init(&buffer->mutex); buffer->needs_read_fill = 1; - buffer->read_in_progress = 0; - buffer->write_in_progress = 0; - buffer->ops = ops; + buffer->read_in_progress = false; + buffer->write_in_progress = false; file->private_data = buffer; - goto Done; + up_read(&frag->frag_sem); + return 0; - Einval: - error = -EINVAL; - goto Done; - Eaccess: - error = -EACCES; - Enomem: - module_put(attr->ca_owner); - Done: - if (error && item) - config_item_put(item); +out_put_module: + module_put(buffer->owner); +out_put_item: + config_item_put(buffer->item); +out_free_buffer: + up_read(&frag->frag_sem); + kfree(buffer); +out: return error; } static int configfs_release(struct inode *inode, struct file *filp) { - struct config_item * item = to_item(filp->f_path.dentry->d_parent); - struct configfs_attribute * attr = to_attr(filp->f_path.dentry); - struct module * owner = attr->ca_owner; - struct configfs_buffer * buffer = filp->private_data; - - if (item) - config_item_put(item); - /* After this point, attr should not be accessed. */ - module_put(owner); - - if (buffer) { - if (buffer->page) - free_page((unsigned long)buffer->page); - mutex_destroy(&buffer->mutex); - kfree(buffer); - } + struct configfs_buffer *buffer = filp->private_data; + + module_put(buffer->owner); + if (buffer->page) + free_page((unsigned long)buffer->page); + mutex_destroy(&buffer->mutex); + kfree(buffer); return 0; } static int configfs_open_file(struct inode *inode, struct file *filp) { - return check_perm(inode, filp, CONFIGFS_ITEM_ATTR); + return __configfs_open_file(inode, filp, CONFIGFS_ITEM_ATTR); } static int configfs_open_bin_file(struct inode *inode, struct file *filp) { - return check_perm(inode, filp, CONFIGFS_ITEM_BIN_ATTR); + return __configfs_open_file(inode, filp, CONFIGFS_ITEM_BIN_ATTR); } -static int configfs_release_bin_file(struct inode *inode, struct file *filp) +static int configfs_release_bin_file(struct inode *inode, struct file *file) { - struct configfs_buffer *buffer = filp->private_data; - struct dentry *dentry = filp->f_path.dentry; - struct config_item *item = to_item(dentry->d_parent); - struct configfs_bin_attribute *bin_attr = to_bin_attr(dentry); - ssize_t len = 0; - int ret; + struct configfs_buffer *buffer = file->private_data; - buffer->read_in_progress = 0; + buffer->read_in_progress = false; if (buffer->write_in_progress) { - buffer->write_in_progress = 0; - - len = bin_attr->write(item, buffer->bin_buffer, - buffer->bin_buffer_size); - + struct configfs_fragment *frag = to_frag(file); + buffer->write_in_progress = false; + + down_read(&frag->frag_sem); + if (!frag->frag_dead) { + /* result of ->release() is ignored */ + buffer->bin_attr->write(buffer->item, + buffer->bin_buffer, + buffer->bin_buffer_size); + } + up_read(&frag->frag_sem); /* vfree on NULL is safe */ vfree(buffer->bin_buffer); buffer->bin_buffer = NULL; @@ -503,10 +505,8 @@ static int configfs_release_bin_file(struct inode *inode, struct file *filp) buffer->needs_read_fill = 1; } - ret = configfs_release(inode, filp); - if (len < 0) - return len; - return ret; + configfs_release(inode, file); + return 0; } @@ -541,7 +541,7 @@ int configfs_create_file(struct config_item * item, const struct configfs_attrib inode_lock_nested(d_inode(dir), I_MUTEX_NORMAL); error = configfs_make_dirent(parent_sd, NULL, (void *) attr, mode, - CONFIGFS_ITEM_ATTR); + CONFIGFS_ITEM_ATTR, parent_sd->s_frag); inode_unlock(d_inode(dir)); return error; @@ -563,7 +563,7 @@ int configfs_create_bin_file(struct config_item *item, inode_lock_nested(dir->d_inode, I_MUTEX_NORMAL); error = configfs_make_dirent(parent_sd, NULL, (void *) bin_attr, mode, - CONFIGFS_ITEM_BIN_ATTR); + CONFIGFS_ITEM_BIN_ATTR, parent_sd->s_frag); inode_unlock(dir->d_inode); return error; diff --git a/fs/configfs/symlink.c b/fs/configfs/symlink.c index fea6db1ee065..afd79a1a34b3 100644 --- a/fs/configfs/symlink.c +++ b/fs/configfs/symlink.c @@ -157,11 +157,42 @@ 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); |