xref: /linux/fs/xfs/xfs_iunlink_item.c (revision d00c2359fc1852258d8ce218cf2f509086da720c)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2020-2022, Red Hat, Inc.
4  * All Rights Reserved.
5  */
6 #include "xfs.h"
7 #include "xfs_fs.h"
8 #include "xfs_shared.h"
9 #include "xfs_format.h"
10 #include "xfs_log_format.h"
11 #include "xfs_trans_resv.h"
12 #include "xfs_mount.h"
13 #include "xfs_inode.h"
14 #include "xfs_trans.h"
15 #include "xfs_trans_priv.h"
16 #include "xfs_ag.h"
17 #include "xfs_iunlink_item.h"
18 #include "xfs_trace.h"
19 #include "xfs_error.h"
20 
21 struct kmem_cache	*xfs_iunlink_cache;
22 
23 static inline struct xfs_iunlink_item *IUL_ITEM(struct xfs_log_item *lip)
24 {
25 	return container_of(lip, struct xfs_iunlink_item, item);
26 }
27 
28 static void
29 xfs_iunlink_item_release(
30 	struct xfs_log_item	*lip)
31 {
32 	struct xfs_iunlink_item	*iup = IUL_ITEM(lip);
33 
34 	xfs_perag_put(iup->pag);
35 	kmem_cache_free(xfs_iunlink_cache, IUL_ITEM(lip));
36 }
37 
38 
39 static uint64_t
40 xfs_iunlink_item_sort(
41 	struct xfs_log_item	*lip)
42 {
43 	return IUL_ITEM(lip)->ip->i_ino;
44 }
45 
46 /*
47  * Look up the inode cluster buffer and log the on-disk unlinked inode change
48  * we need to make.
49  */
50 static int
51 xfs_iunlink_log_dinode(
52 	struct xfs_trans	*tp,
53 	struct xfs_iunlink_item	*iup)
54 {
55 	struct xfs_inode	*ip = iup->ip;
56 	struct xfs_dinode	*dip;
57 	struct xfs_buf		*ibp;
58 	xfs_agino_t		old_ptr;
59 	int			offset;
60 	int			error;
61 
62 	error = xfs_imap_to_bp(tp->t_mountp, tp, &ip->i_imap, &ibp);
63 	if (error)
64 		return error;
65 	/*
66 	 * Don't log the unlinked field on stale buffers as this may be the
67 	 * transaction that frees the inode cluster and relogging the buffer
68 	 * here will incorrectly remove the stale state.
69 	 */
70 	if (ibp->b_flags & XBF_STALE)
71 		goto out;
72 
73 	dip = xfs_buf_offset(ibp, ip->i_imap.im_boffset);
74 
75 	/* Make sure the old pointer isn't garbage. */
76 	old_ptr = be32_to_cpu(dip->di_next_unlinked);
77 	if (old_ptr != iup->old_agino) {
78 		xfs_inode_verifier_error(ip, -EFSCORRUPTED, __func__, dip,
79 				sizeof(*dip), __this_address);
80 		error = -EFSCORRUPTED;
81 		goto out;
82 	}
83 
84 	trace_xfs_iunlink_update_dinode(iup, old_ptr);
85 
86 	dip->di_next_unlinked = cpu_to_be32(iup->next_agino);
87 	offset = ip->i_imap.im_boffset +
88 			offsetof(struct xfs_dinode, di_next_unlinked);
89 
90 	xfs_dinode_calc_crc(tp->t_mountp, dip);
91 	xfs_trans_inode_buf(tp, ibp);
92 	xfs_trans_log_buf(tp, ibp, offset, offset + sizeof(xfs_agino_t) - 1);
93 	return 0;
94 out:
95 	xfs_trans_brelse(tp, ibp);
96 	return error;
97 }
98 
99 /*
100  * On precommit, we grab the inode cluster buffer for the inode number we were
101  * passed, then update the next unlinked field for that inode in the buffer and
102  * log the buffer. This ensures that the inode cluster buffer was logged in the
103  * correct order w.r.t. other inode cluster buffers. We can then remove the
104  * iunlink item from the transaction and release it as it is has now served it's
105  * purpose.
106  */
107 static int
108 xfs_iunlink_item_precommit(
109 	struct xfs_trans	*tp,
110 	struct xfs_log_item	*lip)
111 {
112 	struct xfs_iunlink_item	*iup = IUL_ITEM(lip);
113 	int			error;
114 
115 	error = xfs_iunlink_log_dinode(tp, iup);
116 	list_del(&lip->li_trans);
117 	xfs_iunlink_item_release(lip);
118 	return error;
119 }
120 
121 static const struct xfs_item_ops xfs_iunlink_item_ops = {
122 	.iop_release	= xfs_iunlink_item_release,
123 	.iop_sort	= xfs_iunlink_item_sort,
124 	.iop_precommit	= xfs_iunlink_item_precommit,
125 };
126 
127 
128 /*
129  * Initialize the inode log item for a newly allocated (in-core) inode.
130  *
131  * Inode extents can only reside within an AG. Hence specify the starting
132  * block for the inode chunk by offset within an AG as well as the
133  * length of the allocated extent.
134  *
135  * This joins the item to the transaction and marks it dirty so
136  * that we don't need a separate call to do this, nor does the
137  * caller need to know anything about the iunlink item.
138  */
139 int
140 xfs_iunlink_log_inode(
141 	struct xfs_trans	*tp,
142 	struct xfs_inode	*ip,
143 	struct xfs_perag	*pag,
144 	xfs_agino_t		next_agino)
145 {
146 	struct xfs_mount	*mp = tp->t_mountp;
147 	struct xfs_iunlink_item	*iup;
148 
149 	ASSERT(xfs_verify_agino_or_null(pag, next_agino));
150 	ASSERT(xfs_verify_agino_or_null(pag, ip->i_next_unlinked));
151 
152 	/*
153 	 * Since we're updating a linked list, we should never find that the
154 	 * current pointer is the same as the new value, unless we're
155 	 * terminating the list.
156 	 */
157 	if (ip->i_next_unlinked == next_agino) {
158 		if (next_agino != NULLAGINO)
159 			return -EFSCORRUPTED;
160 		return 0;
161 	}
162 
163 	iup = kmem_cache_zalloc(xfs_iunlink_cache, GFP_KERNEL | __GFP_NOFAIL);
164 	xfs_log_item_init(mp, &iup->item, XFS_LI_IUNLINK,
165 			  &xfs_iunlink_item_ops);
166 
167 	iup->ip = ip;
168 	iup->next_agino = next_agino;
169 	iup->old_agino = ip->i_next_unlinked;
170 	iup->pag = xfs_perag_hold(pag);
171 
172 	xfs_trans_add_item(tp, &iup->item);
173 	tp->t_flags |= XFS_TRANS_DIRTY;
174 	set_bit(XFS_LI_DIRTY, &iup->item.li_flags);
175 	return 0;
176 }
177 
178