xref: /openbmc/linux/fs/xfs/xfs_iunlink_item.c (revision 2a9eb57e)
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_mount	*mp = tp->t_mountp;
56 	struct xfs_inode	*ip = iup->ip;
57 	struct xfs_dinode	*dip;
58 	struct xfs_buf		*ibp;
59 	int			offset;
60 	int			error;
61 
62 	error = xfs_imap_to_bp(mp, 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 	if (be32_to_cpu(dip->di_next_unlinked) != iup->old_agino) {
77 		xfs_inode_verifier_error(ip, -EFSCORRUPTED, __func__, dip,
78 				sizeof(*dip), __this_address);
79 		error = -EFSCORRUPTED;
80 		goto out;
81 	}
82 
83 	trace_xfs_iunlink_update_dinode(mp, iup->pag->pag_agno,
84 			XFS_INO_TO_AGINO(mp, ip->i_ino),
85 			be32_to_cpu(dip->di_next_unlinked), iup->next_agino);
86 
87 	dip->di_next_unlinked = cpu_to_be32(iup->next_agino);
88 	offset = ip->i_imap.im_boffset +
89 			offsetof(struct xfs_dinode, di_next_unlinked);
90 
91 	xfs_dinode_calc_crc(mp, dip);
92 	xfs_trans_inode_buf(tp, ibp);
93 	xfs_trans_log_buf(tp, ibp, offset, offset + sizeof(xfs_agino_t) - 1);
94 	return 0;
95 out:
96 	xfs_trans_brelse(tp, ibp);
97 	return error;
98 }
99 
100 /*
101  * On precommit, we grab the inode cluster buffer for the inode number we were
102  * passed, then update the next unlinked field for that inode in the buffer and
103  * log the buffer. This ensures that the inode cluster buffer was logged in the
104  * correct order w.r.t. other inode cluster buffers. We can then remove the
105  * iunlink item from the transaction and release it as it is has now served it's
106  * purpose.
107  */
108 static int
109 xfs_iunlink_item_precommit(
110 	struct xfs_trans	*tp,
111 	struct xfs_log_item	*lip)
112 {
113 	struct xfs_iunlink_item	*iup = IUL_ITEM(lip);
114 	int			error;
115 
116 	error = xfs_iunlink_log_dinode(tp, iup);
117 	list_del(&lip->li_trans);
118 	xfs_iunlink_item_release(lip);
119 	return error;
120 }
121 
122 static const struct xfs_item_ops xfs_iunlink_item_ops = {
123 	.iop_release	= xfs_iunlink_item_release,
124 	.iop_sort	= xfs_iunlink_item_sort,
125 	.iop_precommit	= xfs_iunlink_item_precommit,
126 };
127 
128 
129 /*
130  * Initialize the inode log item for a newly allocated (in-core) inode.
131  *
132  * Inode extents can only reside within an AG. Hence specify the starting
133  * block for the inode chunk by offset within an AG as well as the
134  * length of the allocated extent.
135  *
136  * This joins the item to the transaction and marks it dirty so
137  * that we don't need a separate call to do this, nor does the
138  * caller need to know anything about the iunlink item.
139  */
140 int
141 xfs_iunlink_log_inode(
142 	struct xfs_trans	*tp,
143 	struct xfs_inode	*ip,
144 	struct xfs_perag	*pag,
145 	xfs_agino_t		next_agino)
146 {
147 	struct xfs_mount	*mp = tp->t_mountp;
148 	struct xfs_iunlink_item	*iup;
149 
150 	ASSERT(xfs_verify_agino_or_null(pag, next_agino));
151 	ASSERT(xfs_verify_agino_or_null(pag, ip->i_next_unlinked));
152 
153 	/*
154 	 * Since we're updating a linked list, we should never find that the
155 	 * current pointer is the same as the new value, unless we're
156 	 * terminating the list.
157 	 */
158 	if (ip->i_next_unlinked == next_agino) {
159 		if (next_agino != NULLAGINO)
160 			return -EFSCORRUPTED;
161 		return 0;
162 	}
163 
164 	iup = kmem_cache_zalloc(xfs_iunlink_cache, GFP_KERNEL | __GFP_NOFAIL);
165 	xfs_log_item_init(mp, &iup->item, XFS_LI_IUNLINK,
166 			  &xfs_iunlink_item_ops);
167 
168 	iup->ip = ip;
169 	iup->next_agino = next_agino;
170 	iup->old_agino = ip->i_next_unlinked;
171 
172 	atomic_inc(&pag->pag_ref);
173 	iup->pag = pag;
174 
175 	xfs_trans_add_item(tp, &iup->item);
176 	tp->t_flags |= XFS_TRANS_DIRTY;
177 	set_bit(XFS_LI_DIRTY, &iup->item.li_flags);
178 	return 0;
179 }
180 
181