Line data    Source code

       1             : /* SPDX-License-Identifier: GPL-2.0-only */
       2             : /*
       3             :  *
       4             :  * Copyright (C) 2011 Novell Inc.
       5             :  * Copyright (C) 2016 Red Hat, Inc.
       6             :  */
       7             : 
       8             : struct ovl_config {
       9             :         char *lowerdir;
      10             :         char *upperdir;
      11             :         char *workdir;
      12             :         bool default_permissions;
      13             :         bool redirect_dir;
      14             :         bool redirect_follow;
      15             :         const char *redirect_mode;
      16             :         bool index;
      17             :         bool uuid;
      18             :         bool nfs_export;
      19             :         int xino;
      20             :         bool metacopy;
      21             :         bool userxattr;
      22             :         bool ovl_volatile;
      23             : };
      24             : 
      25             : struct ovl_sb {
      26             :         struct super_block *sb;
      27             :         dev_t pseudo_dev;
      28             :         /* Unusable (conflicting) uuid */
      29             :         bool bad_uuid;
      30             :         /* Used as a lower layer (but maybe also as upper) */
      31             :         bool is_lower;
      32             : };
      33             : 
      34             : struct ovl_layer {
      35             :         struct vfsmount *mnt;
      36             :         /* Trap in ovl inode cache */
      37             :         struct inode *trap;
      38             :         struct ovl_sb *fs;
      39             :         /* Index of this layer in fs root (upper idx == 0) */
      40             :         int idx;
      41             :         /* One fsid per unique underlying sb (upper fsid == 0) */
      42             :         int fsid;
      43             : };
      44             : 
      45             : struct ovl_path {
      46             :         const struct ovl_layer *layer;
      47             :         struct dentry *dentry;
      48             : };
      49             : 
      50             : /* private information held for overlayfs's superblock */
      51             : struct ovl_fs {
      52             :         unsigned int numlayer;
      53             :         /* Number of unique fs among layers including upper fs */
      54             :         unsigned int numfs;
      55             :         const struct ovl_layer *layers;
      56             :         struct ovl_sb *fs;
      57             :         /* workbasedir is the path at workdir= mount option */
      58             :         struct dentry *workbasedir;
      59             :         /* workdir is the 'work' directory under workbasedir */
      60             :         struct dentry *workdir;
      61             :         /* index directory listing overlay inodes by origin file handle */
      62             :         struct dentry *indexdir;
      63             :         long namelen;
      64             :         /* pathnames of lower and upper dirs, for show_options */
      65             :         struct ovl_config config;
      66             :         /* creds of process who forced instantiation of super block */
      67             :         const struct cred *creator_cred;
      68             :         bool tmpfile;
      69             :         bool noxattr;
      70             :         /* Did we take the inuse lock? */
      71             :         bool upperdir_locked;
      72             :         bool workdir_locked;
      73             :         bool share_whiteout;
      74             :         /* Traps in ovl inode cache */
      75             :         struct inode *workbasedir_trap;
      76             :         struct inode *workdir_trap;
      77             :         struct inode *indexdir_trap;
      78             :         /* -1: disabled, 0: same fs, 1..32: number of unused ino bits */
      79             :         int xino_mode;
      80             :         /* For allocation of non-persistent inode numbers */
      81             :         atomic_long_t last_ino;
      82             :         /* Whiteout dentry cache */
      83             :         struct dentry *whiteout;
      84             :         /* r/o snapshot of upperdir sb's only taken on volatile mounts */
      85             :         errseq_t errseq;
      86             : };
      87             : 
      88          67 : static inline struct vfsmount *ovl_upper_mnt(struct ovl_fs *ofs)
      89             : {
      90          56 :         return ofs->layers[0].mnt;
      91             : }
      92             : 
      93          84 : static inline struct ovl_fs *OVL_FS(struct super_block *sb)
      94             : {
      95          84 :         return (struct ovl_fs *)sb->s_fs_info;
      96             : }
      97             : 
      98           6 : static inline bool ovl_should_sync(struct ovl_fs *ofs)
      99             : {
     100           6 :         return !ofs->config.ovl_volatile;
     101             : }
     102             : 
     103             : /* private information held for every overlayfs dentry */
     104             : struct ovl_entry {
     105             :         union {
     106             :                 struct {
     107             :                         unsigned long flags;
     108             :                 };
     109             :                 struct rcu_head rcu;
     110             :         };
     111             :         unsigned numlower;
     112             :         struct ovl_path lowerstack[];
     113             : };
     114             : 
     115             : struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
     116             : 
     117          86 : static inline struct ovl_entry *OVL_E(struct dentry *dentry)
     118             : {
     119          86 :         return (struct ovl_entry *) dentry->d_fsdata;
     120             : }
     121             : 
     122             : struct ovl_inode {
     123             :         union {
     124             :                 struct ovl_dir_cache *cache;    /* directory */
     125             :                 struct inode *lowerdata;        /* regular file */
     126             :         };
     127             :         const char *redirect;
     128             :         u64 version;
     129             :         unsigned long flags;
     130             :         struct inode vfs_inode;
     131             :         struct dentry *__upperdentry;
     132             :         struct inode *lower;
     133             : 
     134             :         /* synchronize copy up and more */
     135             :         struct mutex lock;
     136             : };
     137             : 
     138         700 : static inline struct ovl_inode *OVL_I(struct inode *inode)
     139             : {
     140         299 :         return container_of(inode, struct ovl_inode, vfs_inode);
     141             : }
     142             : 
     143         348 : static inline struct dentry *ovl_upperdentry_dereference(struct ovl_inode *oi)
     144             : {
     145         310 :         return READ_ONCE(oi->__upperdentry);
     146             : }