diff options
| -rw-r--r-- | fs/kernfs/inode.c | 89 | ||||
| -rw-r--r-- | fs/kernfs/kernfs-internal.h | 2 | ||||
| -rw-r--r-- | include/linux/kernfs.h | 11 |
3 files changed, 100 insertions, 2 deletions
diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c index 5f10ae95fbfa..fc2469a20fed 100644 --- a/fs/kernfs/inode.c +++ b/fs/kernfs/inode.c @@ -53,6 +53,8 @@ static struct kernfs_iattrs *__kernfs_iattrs(struct kernfs_node *kn, int alloc) kn->iattr->ia_ctime = kn->iattr->ia_atime; simple_xattrs_init(&kn->iattr->xattrs); + atomic_set(&kn->iattr->nr_user_xattrs, 0); + atomic_set(&kn->iattr->user_xattr_size, 0); out_unlock: ret = kn->iattr; mutex_unlock(&iattr_mutex); @@ -327,6 +329,86 @@ static int kernfs_vfs_xattr_set(const struct xattr_handler *handler, return kernfs_xattr_set(kn, name, value, size, flags); } +static int kernfs_vfs_user_xattr_add(struct kernfs_node *kn, + const char *full_name, + struct simple_xattrs *xattrs, + const void *value, size_t size, int flags) +{ + atomic_t *sz = &kn->iattr->user_xattr_size; + atomic_t *nr = &kn->iattr->nr_user_xattrs; + ssize_t removed_size; + int ret; + + if (atomic_inc_return(nr) > KERNFS_MAX_USER_XATTRS) { + ret = -ENOSPC; + goto dec_count_out; + } + + if (atomic_add_return(size, sz) > KERNFS_USER_XATTR_SIZE_LIMIT) { + ret = -ENOSPC; + goto dec_size_out; + } + + ret = simple_xattr_set(xattrs, full_name, value, size, flags, + &removed_size); + + if (!ret && removed_size >= 0) + size = removed_size; + else if (!ret) + return 0; +dec_size_out: + atomic_sub(size, sz); +dec_count_out: + atomic_dec(nr); + return ret; +} + +static int kernfs_vfs_user_xattr_rm(struct kernfs_node *kn, + const char *full_name, + struct simple_xattrs *xattrs, + const void *value, size_t size, int flags) +{ + atomic_t *sz = &kn->iattr->user_xattr_size; + atomic_t *nr = &kn->iattr->nr_user_xattrs; + ssize_t removed_size; + int ret; + + ret = simple_xattr_set(xattrs, full_name, value, size, flags, + &removed_size); + + if (removed_size >= 0) { + atomic_sub(removed_size, sz); + atomic_dec(nr); + } + + return ret; +} + +static int kernfs_vfs_user_xattr_set(const struct xattr_handler *handler, + struct dentry *unused, struct inode *inode, + const char *suffix, const void *value, + size_t size, int flags) +{ + const char *full_name = xattr_full_name(handler, suffix); + struct kernfs_node *kn = inode->i_private; + struct kernfs_iattrs *attrs; + + if (!(kernfs_root(kn)->flags & KERNFS_ROOT_SUPPORT_USER_XATTR)) + return -EOPNOTSUPP; + + attrs = kernfs_iattrs(kn); + if (!attrs) + return -ENOMEM; + + if (value) + return kernfs_vfs_user_xattr_add(kn, full_name, &attrs->xattrs, + value, size, flags); + else + return kernfs_vfs_user_xattr_rm(kn, full_name, &attrs->xattrs, + value, size, flags); + +} + static const struct xattr_handler kernfs_trusted_xattr_handler = { .prefix = XATTR_TRUSTED_PREFIX, .get = kernfs_vfs_xattr_get, @@ -339,8 +421,15 @@ static const struct xattr_handler kernfs_security_xattr_handler = { .set = kernfs_vfs_xattr_set, }; +static const struct xattr_handler kernfs_user_xattr_handler = { + .prefix = XATTR_USER_PREFIX, + .get = kernfs_vfs_xattr_get, + .set = kernfs_vfs_user_xattr_set, +}; + const struct xattr_handler *kernfs_xattr_handlers[] = { &kernfs_trusted_xattr_handler, &kernfs_security_xattr_handler, + &kernfs_user_xattr_handler, NULL }; diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h index 2f3c51d55261..7ee97ef59184 100644 --- a/fs/kernfs/kernfs-internal.h +++ b/fs/kernfs/kernfs-internal.h @@ -26,6 +26,8 @@ struct kernfs_iattrs { struct timespec64 ia_ctime; struct simple_xattrs xattrs; + atomic_t nr_user_xattrs; + atomic_t user_xattr_size; }; /* +1 to avoid triggering overflow warning when negating it */ diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h index dded2e5a9f42..89f6a4214a70 100644 --- a/include/linux/kernfs.h +++ b/include/linux/kernfs.h @@ -37,8 +37,10 @@ enum kernfs_node_type { KERNFS_LINK = 0x0004, }; -#define KERNFS_TYPE_MASK 0x000f -#define KERNFS_FLAG_MASK ~KERNFS_TYPE_MASK +#define KERNFS_TYPE_MASK 0x000f +#define KERNFS_FLAG_MASK ~KERNFS_TYPE_MASK +#define KERNFS_MAX_USER_XATTRS 128 +#define KERNFS_USER_XATTR_SIZE_LIMIT (128 << 10) enum kernfs_node_flag { KERNFS_ACTIVATED = 0x0010, @@ -78,6 +80,11 @@ enum kernfs_root_flag { * fhandle to access nodes of the fs. */ KERNFS_ROOT_SUPPORT_EXPORTOP = 0x0004, + + /* + * Support user xattrs to be written to nodes rooted at this root. + */ + KERNFS_ROOT_SUPPORT_USER_XATTR = 0x0008, }; /* type-specific structures for kernfs_node union members */ |