156 lines
3.7 KiB
C
156 lines
3.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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*
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* Copyright (C) 2011 Novell Inc.
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* Copyright (C) 2016 Red Hat, Inc.
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*/
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struct ovl_config {
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char *lowerdir;
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char *upperdir;
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char *workdir;
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bool default_permissions;
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bool redirect_dir;
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bool redirect_follow;
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const char *redirect_mode;
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bool index;
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bool uuid;
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bool nfs_export;
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int xino;
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bool metacopy;
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bool userxattr;
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bool ovl_volatile;
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};
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struct ovl_sb {
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struct super_block *sb;
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dev_t pseudo_dev;
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/* Unusable (conflicting) uuid */
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bool bad_uuid;
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/* Used as a lower layer (but maybe also as upper) */
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bool is_lower;
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};
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struct ovl_layer {
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/* ovl_free_fs() relies on @mnt being the first member! */
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struct vfsmount *mnt;
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/* Trap in ovl inode cache */
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struct inode *trap;
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struct ovl_sb *fs;
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/* Index of this layer in fs root (upper idx == 0) */
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int idx;
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/* One fsid per unique underlying sb (upper fsid == 0) */
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int fsid;
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};
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/*
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* ovl_free_fs() relies on @mnt being the first member when unmounting
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* the private mounts created for each layer. Let's check both the
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* offset and type.
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*/
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static_assert(offsetof(struct ovl_layer, mnt) == 0);
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static_assert(__same_type(typeof_member(struct ovl_layer, mnt), struct vfsmount *));
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struct ovl_path {
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const struct ovl_layer *layer;
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struct dentry *dentry;
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};
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/* private information held for overlayfs's superblock */
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struct ovl_fs {
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unsigned int numlayer;
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/* Number of unique fs among layers including upper fs */
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unsigned int numfs;
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const struct ovl_layer *layers;
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struct ovl_sb *fs;
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/* workbasedir is the path at workdir= mount option */
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struct dentry *workbasedir;
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/* workdir is the 'work' directory under workbasedir */
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struct dentry *workdir;
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/* index directory listing overlay inodes by origin file handle */
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struct dentry *indexdir;
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long namelen;
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/* pathnames of lower and upper dirs, for show_options */
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struct ovl_config config;
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/* creds of process who forced instantiation of super block */
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const struct cred *creator_cred;
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bool tmpfile;
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bool noxattr;
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/* Did we take the inuse lock? */
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bool upperdir_locked;
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bool workdir_locked;
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bool share_whiteout;
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/* Traps in ovl inode cache */
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struct inode *workbasedir_trap;
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struct inode *workdir_trap;
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struct inode *indexdir_trap;
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/* -1: disabled, 0: same fs, 1..32: number of unused ino bits */
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int xino_mode;
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/* For allocation of non-persistent inode numbers */
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atomic_long_t last_ino;
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/* Whiteout dentry cache */
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struct dentry *whiteout;
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/* r/o snapshot of upperdir sb's only taken on volatile mounts */
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errseq_t errseq;
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};
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static inline struct vfsmount *ovl_upper_mnt(struct ovl_fs *ofs)
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{
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return ofs->layers[0].mnt;
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}
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static inline struct ovl_fs *OVL_FS(struct super_block *sb)
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{
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return (struct ovl_fs *)sb->s_fs_info;
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}
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static inline bool ovl_should_sync(struct ovl_fs *ofs)
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{
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return !ofs->config.ovl_volatile;
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}
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/* private information held for every overlayfs dentry */
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struct ovl_entry {
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union {
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struct {
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unsigned long flags;
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};
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struct rcu_head rcu;
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};
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unsigned numlower;
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struct ovl_path lowerstack[];
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};
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struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
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static inline struct ovl_entry *OVL_E(struct dentry *dentry)
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{
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return (struct ovl_entry *) dentry->d_fsdata;
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}
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struct ovl_inode {
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union {
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struct ovl_dir_cache *cache; /* directory */
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struct inode *lowerdata; /* regular file */
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};
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const char *redirect;
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u64 version;
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unsigned long flags;
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struct inode vfs_inode;
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struct dentry *__upperdentry;
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struct ovl_path lowerpath;
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/* synchronize copy up and more */
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struct mutex lock;
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};
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static inline struct ovl_inode *OVL_I(struct inode *inode)
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{
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return container_of(inode, struct ovl_inode, vfs_inode);
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}
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static inline struct dentry *ovl_upperdentry_dereference(struct ovl_inode *oi)
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{
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return READ_ONCE(oi->__upperdentry);
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}
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