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-rw-r--r--fs/overlayfs/ovl_entry.h197
1 files changed, 197 insertions, 0 deletions
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
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index 0000000000..d82d2a043d
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+++ b/fs/overlayfs/ovl_entry.h
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+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ *
+ * Copyright (C) 2011 Novell Inc.
+ * Copyright (C) 2016 Red Hat, Inc.
+ */
+
+struct ovl_config {
+ char *upperdir;
+ char *workdir;
+ char **lowerdirs;
+ bool default_permissions;
+ int redirect_mode;
+ int verity_mode;
+ bool index;
+ int uuid;
+ bool nfs_export;
+ int xino;
+ bool metacopy;
+ bool userxattr;
+ bool ovl_volatile;
+};
+
+struct ovl_sb {
+ struct super_block *sb;
+ dev_t pseudo_dev;
+ /* Unusable (conflicting) uuid */
+ bool bad_uuid;
+ /* Used as a lower layer (but maybe also as upper) */
+ bool is_lower;
+};
+
+struct ovl_layer {
+ /* ovl_free_fs() relies on @mnt being the first member! */
+ struct vfsmount *mnt;
+ /* Trap in ovl inode cache */
+ struct inode *trap;
+ struct ovl_sb *fs;
+ /* Index of this layer in fs root (upper idx == 0) */
+ int idx;
+ /* One fsid per unique underlying sb (upper fsid == 0) */
+ int fsid;
+};
+
+struct ovl_path {
+ const struct ovl_layer *layer;
+ struct dentry *dentry;
+};
+
+struct ovl_entry {
+ unsigned int __numlower;
+ struct ovl_path __lowerstack[];
+};
+
+/* private information held for overlayfs's superblock */
+struct ovl_fs {
+ unsigned int numlayer;
+ /* Number of unique fs among layers including upper fs */
+ unsigned int numfs;
+ /* Number of data-only lower layers */
+ unsigned int numdatalayer;
+ const struct ovl_layer *layers;
+ struct ovl_sb *fs;
+ /* workbasedir is the path at workdir= mount option */
+ struct dentry *workbasedir;
+ /* workdir is the 'work' directory under workbasedir */
+ struct dentry *workdir;
+ /* index directory listing overlay inodes by origin file handle */
+ struct dentry *indexdir;
+ long namelen;
+ /* pathnames of lower and upper dirs, for show_options */
+ struct ovl_config config;
+ /* creds of process who forced instantiation of super block */
+ const struct cred *creator_cred;
+ bool tmpfile;
+ bool noxattr;
+ bool nofh;
+ /* Did we take the inuse lock? */
+ bool upperdir_locked;
+ bool workdir_locked;
+ /* Traps in ovl inode cache */
+ struct inode *workbasedir_trap;
+ struct inode *workdir_trap;
+ struct inode *indexdir_trap;
+ /* -1: disabled, 0: same fs, 1..32: number of unused ino bits */
+ int xino_mode;
+ /* For allocation of non-persistent inode numbers */
+ atomic_long_t last_ino;
+ /* Shared whiteout cache */
+ struct dentry *whiteout;
+ bool no_shared_whiteout;
+ /* r/o snapshot of upperdir sb's only taken on volatile mounts */
+ errseq_t errseq;
+};
+
+/* Number of lower layers, not including data-only layers */
+static inline unsigned int ovl_numlowerlayer(struct ovl_fs *ofs)
+{
+ return ofs->numlayer - ofs->numdatalayer - 1;
+}
+
+static inline struct vfsmount *ovl_upper_mnt(struct ovl_fs *ofs)
+{
+ return ofs->layers[0].mnt;
+}
+
+static inline struct mnt_idmap *ovl_upper_mnt_idmap(struct ovl_fs *ofs)
+{
+ return mnt_idmap(ovl_upper_mnt(ofs));
+}
+
+extern struct file_system_type ovl_fs_type;
+
+static inline struct ovl_fs *OVL_FS(struct super_block *sb)
+{
+ if (IS_ENABLED(CONFIG_OVERLAY_FS_DEBUG))
+ WARN_ON_ONCE(sb->s_type != &ovl_fs_type);
+
+ return (struct ovl_fs *)sb->s_fs_info;
+}
+
+static inline bool ovl_should_sync(struct ovl_fs *ofs)
+{
+ return !ofs->config.ovl_volatile;
+}
+
+static inline unsigned int ovl_numlower(struct ovl_entry *oe)
+{
+ return oe ? oe->__numlower : 0;
+}
+
+static inline struct ovl_path *ovl_lowerstack(struct ovl_entry *oe)
+{
+ return ovl_numlower(oe) ? oe->__lowerstack : NULL;
+}
+
+static inline struct ovl_path *ovl_lowerpath(struct ovl_entry *oe)
+{
+ return ovl_lowerstack(oe);
+}
+
+static inline struct ovl_path *ovl_lowerdata(struct ovl_entry *oe)
+{
+ struct ovl_path *lowerstack = ovl_lowerstack(oe);
+
+ return lowerstack ? &lowerstack[oe->__numlower - 1] : NULL;
+}
+
+/* May return NULL if lazy lookup of lowerdata is needed */
+static inline struct dentry *ovl_lowerdata_dentry(struct ovl_entry *oe)
+{
+ struct ovl_path *lowerdata = ovl_lowerdata(oe);
+
+ return lowerdata ? READ_ONCE(lowerdata->dentry) : NULL;
+}
+
+/* private information held for every overlayfs dentry */
+static inline unsigned long *OVL_E_FLAGS(struct dentry *dentry)
+{
+ return (unsigned long *) &dentry->d_fsdata;
+}
+
+struct ovl_inode {
+ union {
+ struct ovl_dir_cache *cache; /* directory */
+ const char *lowerdata_redirect; /* regular file */
+ };
+ const char *redirect;
+ u64 version;
+ unsigned long flags;
+ struct inode vfs_inode;
+ struct dentry *__upperdentry;
+ struct ovl_entry *oe;
+
+ /* synchronize copy up and more */
+ struct mutex lock;
+};
+
+static inline struct ovl_inode *OVL_I(struct inode *inode)
+{
+ return container_of(inode, struct ovl_inode, vfs_inode);
+}
+
+static inline struct ovl_entry *OVL_I_E(struct inode *inode)
+{
+ return inode ? OVL_I(inode)->oe : NULL;
+}
+
+static inline struct ovl_entry *OVL_E(struct dentry *dentry)
+{
+ return OVL_I_E(d_inode(dentry));
+}
+
+static inline struct dentry *ovl_upperdentry_dereference(struct ovl_inode *oi)
+{
+ return READ_ONCE(oi->__upperdentry);
+}