1 /* SPDX-License-Identifier: GPL-2.0 */
3 * Copyright (c) 2000,2002-2003,2005 Silicon Graphics, Inc.
11 struct xfs_attr_list_context;
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.
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.
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.
29 #define ATTR_MAX_VALUELEN (64*1024) /* max length of a value */
32 * Kernel-internal version of the attrlist cursor.
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 */
44 /*========================================================================
45 * Structure used to pass context around among the routines.
46 *========================================================================*/
49 /* void; state communicated via *context */
50 typedef void (*put_listent_func_t)(struct xfs_attr_list_context *, int,
51 unsigned char *, int, int);
53 struct xfs_attr_list_context {
55 struct xfs_inode *dp; /* inode */
56 struct xfs_attrlist_cursor_kern cursor; /* position in list */
57 void *buffer; /* output buffer */
60 * Abort attribute list iteration if non-zero. Can be used to pass
61 * error values to the xfs_attr_list caller.
64 bool allow_incomplete;
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 */
78 * ========================================================================
79 * Structure used to pass context around among the delayed routines.
80 * ========================================================================
84 * Below is a state machine diagram for attr remove operations. The XFS_DAS_*
85 * states indicate places where the function would return -EAGAIN, and then
86 * immediately resume from after being called by the calling function. States
87 * marked as a "subroutine state" indicate that they belong to a subroutine, and
88 * so the calling function needs to pass them back to that subroutine to allow
89 * it to finish where it left off. But they otherwise do not have a role in the
90 * calling function other than just passing through.
92 * xfs_attr_remove_iter()
95 * have attr to remove? ──n──> done
100 * are we short form? ──y──> xfs_attr_shortform_remove ──> done
105 * are we leaf form? ──y──> xfs_attr_leaf_removename ──> done
110 * ┌── need to setup state?
115 * │ find attr and get state
116 * │ attr has remote blks? ──n─┐
118 * │ │ find and invalidate
119 * │ y the remote blocks.
120 * │ │ mark attr incomplete
121 * │ ├────────────────┘
125 * Have remote blks to remove? ───y─────┐
126 * │ ^ remove the blks
129 * │ XFS_DAS_RMTBLK <─n── done?
131 * │ one less blk to y
139 * ├─────────────────────────┘
144 * xfs_attr_node_remove_cleanup
156 * XFS_DAS_RM_SHRINK │
170 * Enum values for xfs_delattr_context.da_state
172 * These values are used by delayed attribute operations to keep track of where
173 * they were before they returned -EAGAIN. A return code of -EAGAIN signals the
174 * calling function to roll the transaction, and then call the subroutine to
175 * finish the operation. The enum is then used by the subroutine to jump back
176 * to where it was and resume executing where it left off.
178 enum xfs_delattr_state {
179 XFS_DAS_UNINIT = 0, /* No state has been set yet */
180 XFS_DAS_RMTBLK, /* Removing remote blks */
181 XFS_DAS_RM_NAME, /* Remove attr name */
182 XFS_DAS_RM_SHRINK, /* We are shrinking the tree */
186 * Defines for xfs_delattr_context.flags
188 #define XFS_DAC_DEFER_FINISH 0x01 /* finish the transaction */
191 * Context used for keeping track of delayed attribute operations
193 struct xfs_delattr_context {
194 struct xfs_da_args *da_args;
196 /* Used in xfs_attr_node_removename to roll through removing blocks */
197 struct xfs_da_state *da_state;
199 /* Used to keep track of current state of delayed operation */
201 enum xfs_delattr_state dela_state;
204 /*========================================================================
205 * Function prototypes for the kernel.
206 *========================================================================*/
209 * Overall external interface routines.
211 int xfs_attr_inactive(struct xfs_inode *dp);
212 int xfs_attr_list_ilocked(struct xfs_attr_list_context *);
213 int xfs_attr_list(struct xfs_attr_list_context *);
214 int xfs_inode_hasattr(struct xfs_inode *ip);
215 bool xfs_attr_is_leaf(struct xfs_inode *ip);
216 int xfs_attr_get_ilocked(struct xfs_da_args *args);
217 int xfs_attr_get(struct xfs_da_args *args);
218 int xfs_attr_set(struct xfs_da_args *args);
219 int xfs_attr_set_args(struct xfs_da_args *args);
220 int xfs_has_attr(struct xfs_da_args *args);
221 int xfs_attr_remove_args(struct xfs_da_args *args);
222 int xfs_attr_remove_iter(struct xfs_delattr_context *dac);
223 int xfs_attr_trans_roll(struct xfs_delattr_context *dac);
224 bool xfs_attr_namecheck(const void *name, size_t length);
225 void xfs_delattr_context_init(struct xfs_delattr_context *dac,
226 struct xfs_da_args *args);
228 #endif /* __XFS_ATTR_H__ */