From 1afaba1ecb5299cdd0f69b5bad98b0185fe71e79 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Sat, 13 Dec 2014 00:59:42 +0100 Subject: [PATCH] ovl: make path-type a bitmap OVL_PATH_PURE_UPPER -> __OVL_PATH_UPPER | __OVL_PATH_PURE OVL_PATH_UPPER -> __OVL_PATH_UPPER OVL_PATH_MERGE -> __OVL_PATH_UPPER | __OVL_PATH_MERGE OVL_PATH_LOWER -> 0 Multiple R/O layers will allow __OVL_PATH_MERGE without __OVL_PATH_UPPER. Signed-off-by: Miklos Szeredi --- fs/overlayfs/copy_up.c | 4 ++-- fs/overlayfs/dir.c | 22 +++++++++++----------- fs/overlayfs/inode.c | 9 ++++++--- fs/overlayfs/overlayfs.h | 13 +++++++++---- fs/overlayfs/readdir.c | 10 +++++----- fs/overlayfs/super.c | 19 ++++++++----------- 6 files changed, 41 insertions(+), 36 deletions(-) diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index ea10a8719107..a5bfd60f4f6f 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -385,7 +385,7 @@ int ovl_copy_up(struct dentry *dentry) struct kstat stat; enum ovl_path_type type = ovl_path_type(dentry); - if (type != OVL_PATH_LOWER) + if (OVL_TYPE_UPPER(type)) break; next = dget(dentry); @@ -394,7 +394,7 @@ int ovl_copy_up(struct dentry *dentry) parent = dget_parent(next); type = ovl_path_type(parent); - if (type != OVL_PATH_LOWER) + if (OVL_TYPE_UPPER(type)) break; dput(next); diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c index 8ffc4b980f1b..ab50bd111feb 100644 --- a/fs/overlayfs/dir.c +++ b/fs/overlayfs/dir.c @@ -152,7 +152,7 @@ static int ovl_dir_getattr(struct vfsmount *mnt, struct dentry *dentry, * correct link count. nlink=1 seems to pacify 'find' and * other utilities. */ - if (type == OVL_PATH_MERGE) + if (OVL_TYPE_MERGE(type)) stat->nlink = 1; return 0; @@ -630,7 +630,7 @@ static int ovl_do_remove(struct dentry *dentry, bool is_dir) goto out_drop_write; type = ovl_path_type(dentry); - if (type == OVL_PATH_PURE_UPPER) { + if (OVL_TYPE_PURE_UPPER(type)) { err = ovl_remove_upper(dentry, is_dir); } else { const struct cred *old_cred; @@ -712,7 +712,7 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old, /* Don't copy up directory trees */ old_type = ovl_path_type(old); err = -EXDEV; - if ((old_type == OVL_PATH_LOWER || old_type == OVL_PATH_MERGE) && is_dir) + if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir) goto out; if (new->d_inode) { @@ -725,25 +725,25 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old, new_type = ovl_path_type(new); err = -EXDEV; - if (!overwrite && (new_type == OVL_PATH_LOWER || new_type == OVL_PATH_MERGE) && new_is_dir) + if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) goto out; err = 0; - if (new_type == OVL_PATH_LOWER && old_type == OVL_PATH_LOWER) { + if (!OVL_TYPE_UPPER(new_type) && !OVL_TYPE_UPPER(old_type)) { if (ovl_dentry_lower(old)->d_inode == ovl_dentry_lower(new)->d_inode) goto out; } - if (new_type != OVL_PATH_LOWER && old_type != OVL_PATH_LOWER) { + if (OVL_TYPE_UPPER(new_type) && OVL_TYPE_UPPER(old_type)) { if (ovl_dentry_upper(old)->d_inode == ovl_dentry_upper(new)->d_inode) goto out; } } else { if (ovl_dentry_is_opaque(new)) - new_type = OVL_PATH_UPPER; + new_type = __OVL_PATH_UPPER; else - new_type = OVL_PATH_PURE_UPPER; + new_type = __OVL_PATH_UPPER | __OVL_PATH_PURE; } err = ovl_want_write(old); @@ -763,8 +763,8 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old, goto out_drop_write; } - old_opaque = old_type != OVL_PATH_PURE_UPPER; - new_opaque = new_type != OVL_PATH_PURE_UPPER; + old_opaque = !OVL_TYPE_PURE_UPPER(old_type); + new_opaque = !OVL_TYPE_PURE_UPPER(new_type); if (old_opaque || new_opaque) { err = -ENOMEM; @@ -787,7 +787,7 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old, old_cred = override_creds(override_cred); } - if (overwrite && (new_type == OVL_PATH_LOWER || new_type == OVL_PATH_MERGE) && new_is_dir) { + if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) { opaquedir = ovl_check_empty_and_clear(new); err = PTR_ERR(opaquedir); if (IS_ERR(opaquedir)) { diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 07d74b24913b..48492f1240ad 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -238,7 +238,10 @@ out: static bool ovl_need_xattr_filter(struct dentry *dentry, enum ovl_path_type type) { - return type == OVL_PATH_UPPER && S_ISDIR(dentry->d_inode->i_mode); + if ((type & (__OVL_PATH_PURE | __OVL_PATH_UPPER)) == __OVL_PATH_UPPER) + return S_ISDIR(dentry->d_inode->i_mode); + else + return false; } ssize_t ovl_getxattr(struct dentry *dentry, const char *name, @@ -299,7 +302,7 @@ int ovl_removexattr(struct dentry *dentry, const char *name) if (ovl_need_xattr_filter(dentry, type) && ovl_is_private_xattr(name)) goto out_drop_write; - if (type == OVL_PATH_LOWER) { + if (!OVL_TYPE_UPPER(type)) { err = vfs_getxattr(realpath.dentry, name, NULL, 0); if (err < 0) goto out_drop_write; @@ -321,7 +324,7 @@ out: static bool ovl_open_need_copy_up(int flags, enum ovl_path_type type, struct dentry *realdentry) { - if (type != OVL_PATH_LOWER) + if (OVL_TYPE_UPPER(type)) return false; if (special_file(realdentry->d_inode->i_mode)) diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 814bed33dd07..d39eaa8f5e47 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -12,12 +12,17 @@ struct ovl_entry; enum ovl_path_type { - OVL_PATH_PURE_UPPER, - OVL_PATH_UPPER, - OVL_PATH_MERGE, - OVL_PATH_LOWER, + __OVL_PATH_PURE = (1 << 0), + __OVL_PATH_UPPER = (1 << 1), + __OVL_PATH_MERGE = (1 << 2), }; +#define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER) +#define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE) +#define OVL_TYPE_PURE_UPPER(type) ((type) & __OVL_PATH_PURE) +#define OVL_TYPE_MERGE_OR_LOWER(type) \ + (OVL_TYPE_MERGE(type) || !OVL_TYPE_UPPER(type)) + extern const char *ovl_opaque_xattr; static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry) diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c index 3efa44acf98b..481e44873b65 100644 --- a/fs/overlayfs/readdir.c +++ b/fs/overlayfs/readdir.c @@ -253,8 +253,8 @@ static void ovl_dir_reset(struct file *file) ovl_cache_put(od, dentry); od->cache = NULL; } - WARN_ON(!od->is_real && type != OVL_PATH_MERGE); - if (od->is_real && type == OVL_PATH_MERGE) + WARN_ON(!od->is_real && !OVL_TYPE_MERGE(type)); + if (od->is_real && OVL_TYPE_MERGE(type)) od->is_real = false; } @@ -429,7 +429,7 @@ static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end, /* * Need to check if we started out being a lower dir, but got copied up */ - if (!od->is_upper && ovl_path_type(dentry) != OVL_PATH_LOWER) { + if (!od->is_upper && OVL_TYPE_UPPER(ovl_path_type(dentry))) { struct inode *inode = file_inode(file); realfile = lockless_dereference(od->upperfile); @@ -495,8 +495,8 @@ static int ovl_dir_open(struct inode *inode, struct file *file) } INIT_LIST_HEAD(&od->cursor.l_node); od->realfile = realfile; - od->is_real = (type != OVL_PATH_MERGE); - od->is_upper = (type != OVL_PATH_LOWER); + od->is_real = !OVL_TYPE_MERGE(type); + od->is_upper = OVL_TYPE_UPPER(type); od->cursor.is_cursor = true; file->private_data = od; diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index f16d318b71f8..821719cc8537 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -64,22 +64,19 @@ const char *ovl_opaque_xattr = "trusted.overlay.opaque"; enum ovl_path_type ovl_path_type(struct dentry *dentry) { struct ovl_entry *oe = dentry->d_fsdata; + enum ovl_path_type type = 0; if (oe->__upperdentry) { + type = __OVL_PATH_UPPER; + if (oe->lowerdentry) { if (S_ISDIR(dentry->d_inode->i_mode)) - return OVL_PATH_MERGE; - else - return OVL_PATH_UPPER; - } else { - if (oe->opaque) - return OVL_PATH_UPPER; - else - return OVL_PATH_PURE_UPPER; + type |= __OVL_PATH_MERGE; + } else if (!oe->opaque) { + type |= __OVL_PATH_PURE; } - } else { - return OVL_PATH_LOWER; } + return type; } static struct dentry *ovl_upperdentry_dereference(struct ovl_entry *oe) @@ -101,7 +98,7 @@ enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path) enum ovl_path_type type = ovl_path_type(dentry); - if (type == OVL_PATH_LOWER) + if (!OVL_TYPE_UPPER(type)) ovl_path_lower(dentry, path); else ovl_path_upper(dentry, path); -- 2.34.1