fs/xfs/scrub/dirtree.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * Copyright (c) 2023-2024 Oracle.  All Rights Reserved.
   4  * Author: Darrick J. Wong <djwong@kernel.org>
   5  */
   6 #ifndef __XFS_SCRUB_DIRTREE_H__
   7 #define __XFS_SCRUB_DIRTREE_H__
   8
   9 /*
  10  * Each of these represents one parent pointer path step in a chain going
  11  * up towards the directory tree root.  These are stored inside an xfarray.
  12  */
  13 struct xchk_dirpath_step {
  14         /* Directory entry name associated with this parent link. */
  15         xfblob_cookie           name_cookie;
  16         unsigned int            name_len;
  17
  18         /* Handle of the parent directory. */
  19         struct xfs_parent_rec   pptr_rec;
  20 };
  21
  22 enum xchk_dirpath_outcome {
  23         XCHK_DIRPATH_SCANNING = 0,      /* still being put together */
  24         XCHK_DIRPATH_DELETE,            /* delete this path */
  25         XCHK_DIRPATH_CORRUPT,           /* corruption detected in path */
  26         XCHK_DIRPATH_LOOP,              /* cycle detected further up */
  27         XCHK_DIRPATH_STALE,             /* path is stale */
  28         XCHK_DIRPATH_OK,                /* path reaches the root */
  29
  30         XREP_DIRPATH_DELETING,          /* path is being deleted */
  31         XREP_DIRPATH_DELETED,           /* path has been deleted */
  32         XREP_DIRPATH_ADOPTING,          /* path is being adopted */
  33         XREP_DIRPATH_ADOPTED,           /* path has been adopted */
  34 };
  35
  36 /*
  37  * Each of these represents one parent pointer path out of the directory being
  38  * scanned.  These exist in-core, and hopefully there aren't more than a
  39  * handful of them.
  40  */
  41 struct xchk_dirpath {
  42         struct list_head        list;
  43
  44         /* Index of the first step in this path. */
  45         xfarray_idx_t           first_step;
  46
  47         /* Index of the second step in this path. */
  48         xfarray_idx_t           second_step;
  49
  50         /* Inodes seen while walking this path. */
  51         struct xino_bitmap      seen_inodes;
  52
  53         /* Number of steps in this path. */
  54         unsigned int            nr_steps;
  55
  56         /* Which path is this? */
  57         unsigned int            path_nr;
  58
  59         /* What did we conclude from following this path? */
  60         enum xchk_dirpath_outcome outcome;
  61 };
  62
  63 struct xchk_dirtree_outcomes {
  64         /* Number of XCHK_DIRPATH_DELETE */
  65         unsigned int            bad;
  66
  67         /* Number of XCHK_DIRPATH_CORRUPT or XCHK_DIRPATH_LOOP */
  68         unsigned int            suspect;
  69
  70         /* Number of XCHK_DIRPATH_OK */
  71         unsigned int            good;
  72
  73         /* Directory needs to be added to lost+found */
  74         bool                    needs_adoption;
  75 };
  76
  77 struct xchk_dirtree {
  78         struct xfs_scrub        *sc;
  79
  80         /* Root inode that we're looking for. */
  81         xfs_ino_t               root_ino;
  82
  83         /*
  84          * This is the inode that we're scanning.  The live update hook can
  85          * continue to be called after xchk_teardown drops sc->ip but before
  86          * it calls buf_cleanup, so we keep a copy.
  87          */
  88         xfs_ino_t               scan_ino;
  89
  90         /*
  91          * If we start deleting redundant paths to this subdirectory, this is
  92          * the inode number of the surviving parent and the dotdot entry will
  93          * be set to this value.  If the value is NULLFSINO, then use @root_ino
  94          * as a stand-in until the orphanage can adopt the subdirectory.
  95          */
  96         xfs_ino_t               parent_ino;
  97
  98         /* Scratch buffer for scanning pptr xattrs */
  99         struct xfs_parent_rec   pptr_rec;
 100         struct xfs_da_args      pptr_args;
 101
 102         /* Name buffer */
 103         struct xfs_name         xname;
 104         char                    namebuf[MAXNAMELEN];
 105
 106         /* Information for reparenting this directory. */
 107         struct xrep_adoption    adoption;
 108
 109         /*
 110          * Hook into directory updates so that we can receive live updates
 111          * from other writer threads.
 112          */
 113         struct xfs_dir_hook     dhook;
 114
 115         /* Parent pointer update arguments. */
 116         struct xfs_parent_args  ppargs;
 117
 118         /* lock for everything below here */
 119         struct mutex            lock;
 120
 121         /* buffer for the live update functions to use for dirent names */
 122         struct xfs_name         hook_xname;
 123         unsigned char           hook_namebuf[MAXNAMELEN];
 124
 125         /*
 126          * All path steps observed during this scan.  Each of the path
 127          * steps for a particular pathwalk are recorded in sequential
 128          * order in the xfarray.  A pathwalk ends either with a step
 129          * pointing to the root directory (success) or pointing to NULLFSINO
 130          * (loop detected, empty dir detected, etc).
 131          */
 132         struct xfarray          *path_steps;
 133
 134         /* All names observed during this scan. */
 135         struct xfblob           *path_names;
 136
 137         /* All paths being tracked by this scanner. */
 138         struct list_head        path_list;
 139
 140         /* Number of paths in path_list. */
 141         unsigned int            nr_paths;
 142
 143         /* Number of parents found by a pptr scan. */
 144         unsigned int            parents_found;
 145
 146         /* Have the path data been invalidated by a concurrent update? */
 147         bool                    stale:1;
 148
 149         /* Has the scan been aborted? */
 150         bool                    aborted:1;
 151 };
 152
 153 #define xchk_dirtree_for_each_path_safe(dl, path, n) \
 154         list_for_each_entry_safe((path), (n), &(dl)->path_list, list)
 155
 156 #define xchk_dirtree_for_each_path(dl, path) \
 157         list_for_each_entry((path), &(dl)->path_list, list)
 158
 159 bool xchk_dirtree_parentless(const struct xchk_dirtree *dl);
 160
 161 int xchk_dirtree_find_paths_to_root(struct xchk_dirtree *dl);
 162 int xchk_dirpath_append(struct xchk_dirtree *dl, struct xfs_inode *ip,
 163                 struct xchk_dirpath *path, const struct xfs_name *name,
 164                 const struct xfs_parent_rec *pptr);
 165 void xchk_dirtree_evaluate(struct xchk_dirtree *dl,
 166                 struct xchk_dirtree_outcomes *oc);
 167
 168 #endif /* __XFS_SCRUB_DIRTREE_H__ */