fs/xfs/libxfs/xfs_attr.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright (c) 2000,2002-2003,2005 Silicon Graphics, Inc.
   4  * All Rights Reserved.
   5  */
   6 #ifndef __XFS_ATTR_H__
   7 #define __XFS_ATTR_H__
   8
   9 struct xfs_inode;
  10 struct xfs_da_args;
  11 struct xfs_attr_list_context;
  12
  13 /*
  14  * Large attribute lists are structured around Btrees where all the data
  15  * elements are in the leaf nodes.  Attribute names are hashed into an int,
  16  * then that int is used as the index into the Btree.  Since the hashval
  17  * of an attribute name may not be unique, we may have duplicate keys.
  18  * The internal links in the Btree are logical block offsets into the file.
  19  *
  20  * Small attribute lists use a different format and are packed as tightly
  21  * as possible so as to fit into the literal area of the inode.
  22  */
  23
  24 /*
  25  * The maximum size (into the kernel or returned from the kernel) of an
  26  * attribute value or the buffer used for an attr_list() call.  Larger
  27  * sizes will result in an ERANGE return code.
  28  */
  29 #define ATTR_MAX_VALUELEN       (64*1024)       /* max length of a value */
  30
  31 /*
  32  * Kernel-internal version of the attrlist cursor.
  33  */
  34 struct xfs_attrlist_cursor_kern {
  35         __u32   hashval;        /* hash value of next entry to add */
  36         __u32   blkno;          /* block containing entry (suggestion) */
  37         __u32   offset;         /* offset in list of equal-hashvals */
  38         __u16   pad1;           /* padding to match user-level */
  39         __u8    pad2;           /* padding to match user-level */
  40         __u8    initted;        /* T/F: cursor has been initialized */
  41 };
  42
  43
  44 /*========================================================================
  45  * Structure used to pass context around among the routines.
  46  *========================================================================*/
  47
  48
  49 /* void; state communicated via *context */
  50 typedef void (*put_listent_func_t)(struct xfs_attr_list_context *, int,
  51                               unsigned char *, int, int);
  52
  53 struct xfs_attr_list_context {
  54         struct xfs_trans        *tp;
  55         struct xfs_inode        *dp;            /* inode */
  56         struct xfs_attrlist_cursor_kern cursor; /* position in list */
  57         void                    *buffer;        /* output buffer */
  58
  59         /*
  60          * Abort attribute list iteration if non-zero.  Can be used to pass
  61          * error values to the xfs_attr_list caller.
  62          */
  63         int                     seen_enough;
  64         bool                    allow_incomplete;
  65
  66         ssize_t                 count;          /* num used entries */
  67         int                     dupcnt;         /* count dup hashvals seen */
  68         int                     bufsize;        /* total buffer size */
  69         int                     firstu;         /* first used byte in buffer */
  70         unsigned int            attr_filter;    /* XFS_ATTR_{ROOT,SECURE} */
  71         int                     resynch;        /* T/F: resynch with cursor */
  72         put_listent_func_t      put_listent;    /* list output fmt function */
  73         int                     index;          /* index into output buffer */
  74 };
  75
  76
  77 /*========================================================================
  78  * Function prototypes for the kernel.
  79  *========================================================================*/
  80
  81 /*
  82  * Overall external interface routines.
  83  */
  84 int xfs_attr_inactive(struct xfs_inode *dp);
  85 int xfs_attr_list_ilocked(struct xfs_attr_list_context *);
  86 int xfs_attr_list(struct xfs_attr_list_context *);
  87 int xfs_inode_hasattr(struct xfs_inode *ip);
  88 int xfs_attr_get_ilocked(struct xfs_da_args *args);
  89 int xfs_attr_get(struct xfs_da_args *args);
  90 int xfs_attr_set(struct xfs_da_args *args);
  91 int xfs_attr_set_args(struct xfs_da_args *args);
  92 int xfs_has_attr(struct xfs_da_args *args);
  93 int xfs_attr_remove_args(struct xfs_da_args *args);
  94 bool xfs_attr_namecheck(const void *name, size_t length);
  95
  96 #endif  /* __XFS_ATTR_H__ */