1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2000-2001 Christoph Hellwig.
4  */
5 
6 /*
7  * Veritas filesystem driver - shared subroutines.
8  */
9 #include <linux/fs.h>
10 #include <linux/buffer_head.h>
11 #include <linux/kernel.h>
12 #include <linux/pagemap.h>
13 
14 #include "vxfs_extern.h"
15 
16 
17 static int		vxfs_read_folio(struct file *, struct folio *);
18 static sector_t		vxfs_bmap(struct address_space *, sector_t);
19 
20 const struct address_space_operations vxfs_aops = {
21 	.read_folio =		vxfs_read_folio,
22 	.bmap =			vxfs_bmap,
23 };
24 
25 inline void
vxfs_put_page(struct page * pp)26 vxfs_put_page(struct page *pp)
27 {
28 	kunmap(pp);
29 	put_page(pp);
30 }
31 
32 /**
33  * vxfs_get_page - read a page into memory.
34  * @mapping:	mapping to read from
35  * @n:		page number
36  *
37  * Description:
38  *   vxfs_get_page reads the @n th page of @ip into the pagecache.
39  *
40  * Returns:
41  *   The wanted page on success, else a NULL pointer.
42  */
43 struct page *
vxfs_get_page(struct address_space * mapping,u_long n)44 vxfs_get_page(struct address_space *mapping, u_long n)
45 {
46 	struct page *			pp;
47 
48 	pp = read_mapping_page(mapping, n, NULL);
49 
50 	if (!IS_ERR(pp)) {
51 		kmap(pp);
52 		/** if (!PageChecked(pp)) **/
53 			/** vxfs_check_page(pp); **/
54 	}
55 
56 	return (pp);
57 }
58 
59 /**
60  * vxfs_bread - read buffer for a give inode,block tuple
61  * @ip:		inode
62  * @block:	logical block
63  *
64  * Description:
65  *   The vxfs_bread function reads block no @block  of
66  *   @ip into the buffercache.
67  *
68  * Returns:
69  *   The resulting &struct buffer_head.
70  */
71 struct buffer_head *
vxfs_bread(struct inode * ip,int block)72 vxfs_bread(struct inode *ip, int block)
73 {
74 	struct buffer_head	*bp;
75 	daddr_t			pblock;
76 
77 	pblock = vxfs_bmap1(ip, block);
78 	bp = sb_bread(ip->i_sb, pblock);
79 
80 	return (bp);
81 }
82 
83 /**
84  * vxfs_getblk - locate buffer for given inode,block tuple
85  * @ip:		inode
86  * @iblock:	logical block
87  * @bp:		buffer skeleton
88  * @create:	%TRUE if blocks may be newly allocated.
89  *
90  * Description:
91  *   The vxfs_getblk function fills @bp with the right physical
92  *   block and device number to perform a lowlevel read/write on
93  *   it.
94  *
95  * Returns:
96  *   Zero on success, else a negativ error code (-EIO).
97  */
98 static int
vxfs_getblk(struct inode * ip,sector_t iblock,struct buffer_head * bp,int create)99 vxfs_getblk(struct inode *ip, sector_t iblock,
100 	    struct buffer_head *bp, int create)
101 {
102 	daddr_t			pblock;
103 
104 	pblock = vxfs_bmap1(ip, iblock);
105 	if (pblock != 0) {
106 		map_bh(bp, ip->i_sb, pblock);
107 		return 0;
108 	}
109 
110 	return -EIO;
111 }
112 
113 /**
114  * vxfs_read_folio - read one page synchronously into the pagecache
115  * @file:	file context (unused)
116  * @folio:	folio to fill in.
117  *
118  * Description:
119  *   The vxfs_read_folio routine reads @folio synchronously into the
120  *   pagecache.
121  *
122  * Returns:
123  *   Zero on success, else a negative error code.
124  *
125  * Locking status:
126  *   @folio is locked and will be unlocked.
127  */
vxfs_read_folio(struct file * file,struct folio * folio)128 static int vxfs_read_folio(struct file *file, struct folio *folio)
129 {
130 	return block_read_full_folio(folio, vxfs_getblk);
131 }
132 
133 /**
134  * vxfs_bmap - perform logical to physical block mapping
135  * @mapping:	logical to physical mapping to use
136  * @block:	logical block (relative to @mapping).
137  *
138  * Description:
139  *   Vxfs_bmap find out the corresponding phsical block to the
140  *   @mapping, @block pair.
141  *
142  * Returns:
143  *   Physical block number on success, else Zero.
144  *
145  * Locking status:
146  *   We are under the bkl.
147  */
148 static sector_t
vxfs_bmap(struct address_space * mapping,sector_t block)149 vxfs_bmap(struct address_space *mapping, sector_t block)
150 {
151 	return generic_block_bmap(mapping, block, vxfs_getblk);
152 }
153