1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/fs/ext2/file.c
4 *
5 * Copyright (C) 1992, 1993, 1994, 1995
6 * Remy Card (card@masi.ibp.fr)
7 * Laboratoire MASI - Institut Blaise Pascal
8 * Universite Pierre et Marie Curie (Paris VI)
9 *
10 * from
11 *
12 * linux/fs/minix/file.c
13 *
14 * Copyright (C) 1991, 1992 Linus Torvalds
15 *
16 * ext2 fs regular file handling primitives
17 *
18 * 64-bit file support on 64-bit platforms by Jakub Jelinek
19 * (jj@sunsite.ms.mff.cuni.cz)
20 */
21
22 #include <linux/time.h>
23 #include <linux/pagemap.h>
24 #include <linux/dax.h>
25 #include <linux/quotaops.h>
26 #include <linux/iomap.h>
27 #include <linux/uio.h>
28 #include "ext2.h"
29 #include "xattr.h"
30 #include "acl.h"
31
32 #ifdef CONFIG_FS_DAX
33 static ssize_t ext2_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
34 {
35 struct inode *inode = iocb->ki_filp->f_mapping->host;
36 ssize_t ret;
37
38 if (!iov_iter_count(to))
39 return 0; /* skip atime */
40
41 inode_lock_shared(inode);
42 ret = dax_iomap_rw(iocb, to, &ext2_iomap_ops);
43 inode_unlock_shared(inode);
44
45 file_accessed(iocb->ki_filp);
46 return ret;
47 }
48
49 static ssize_t ext2_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
50 {
51 struct file *file = iocb->ki_filp;
52 struct inode *inode = file->f_mapping->host;
53 ssize_t ret;
54
55 inode_lock(inode);
56 ret = generic_write_checks(iocb, from);
57 if (ret <= 0)
58 goto out_unlock;
59 ret = file_remove_privs(file);
60 if (ret)
61 goto out_unlock;
62 ret = file_update_time(file);
63 if (ret)
64 goto out_unlock;
65
66 ret = dax_iomap_rw(iocb, from, &ext2_iomap_ops);
67 if (ret > 0 && iocb->ki_pos > i_size_read(inode)) {
68 i_size_write(inode, iocb->ki_pos);
69 mark_inode_dirty(inode);
70 }
71
72 out_unlock:
73 inode_unlock(inode);
74 if (ret > 0)
75 ret = generic_write_sync(iocb, ret);
76 return ret;
77 }
78
79 /*
80 * The lock ordering for ext2 DAX fault paths is:
81 *
82 * mmap_sem (MM)
83 * sb_start_pagefault (vfs, freeze)
84 * ext2_inode_info->dax_sem
85 * address_space->i_mmap_rwsem or page_lock (mutually exclusive in DAX)
86 * ext2_inode_info->truncate_mutex
87 *
88 * The default page_lock and i_size verification done by non-DAX fault paths
89 * is sufficient because ext2 doesn't support hole punching.
90 */
91 static vm_fault_t ext2_dax_fault(struct vm_fault *vmf)
92 {
93 struct inode *inode = file_inode(vmf->vma->vm_file);
94 struct ext2_inode_info *ei = EXT2_I(inode);
95 vm_fault_t ret;
96
97 if (vmf->flags & FAULT_FLAG_WRITE) {
98 sb_start_pagefault(inode->i_sb);
99 file_update_time(vmf->vma->vm_file);
100 }
101 down_read(&ei->dax_sem);
102
103 ret = dax_iomap_fault(vmf, PE_SIZE_PTE, NULL, NULL, &ext2_iomap_ops);
104
105 up_read(&ei->dax_sem);
106 if (vmf->flags & FAULT_FLAG_WRITE)
107 sb_end_pagefault(inode->i_sb);
108 return ret;
109 }
110
111 static const struct vm_operations_struct ext2_dax_vm_ops = {
112 .fault = ext2_dax_fault,
113 /*
114 * .huge_fault is not supported for DAX because allocation in ext2
115 * cannot be reliably aligned to huge page sizes and so pmd faults
116 * will always fail and fail back to regular faults.
117 */
118 .page_mkwrite = ext2_dax_fault,
119 .pfn_mkwrite = ext2_dax_fault,
120 };
121
122 static int ext2_file_mmap(struct file *file, struct vm_area_struct *vma)
123 {
124 if (!IS_DAX(file_inode(file)))
125 return generic_file_mmap(file, vma);
126
127 file_accessed(file);
128 vma->vm_ops = &ext2_dax_vm_ops;
129 return 0;
130 }
131 #else
132 #define ext2_file_mmap generic_file_mmap
133 #endif
134
135 /*
136 * Called when filp is released. This happens when all file descriptors
137 * for a single struct file are closed. Note that different open() calls
138 * for the same file yield different struct file structures.
139 */
140 static int ext2_release_file (struct inode * inode, struct file * filp)
141 {
142 if (filp->f_mode & FMODE_WRITE) {
143 mutex_lock(&EXT2_I(inode)->truncate_mutex);
144 ext2_discard_reservation(inode);
145 mutex_unlock(&EXT2_I(inode)->truncate_mutex);
146 }
147 return 0;
148 }
149
150 int ext2_fsync(struct file *file, loff_t start, loff_t end, int datasync)
151 {
152 int ret;
153 struct super_block *sb = file->f_mapping->host->i_sb;
154
155 ret = generic_file_fsync(file, start, end, datasync);
156 if (ret == -EIO)
157 /* We don't really know where the IO error happened... */
158 ext2_error(sb, __func__,
159 "detected IO error when writing metadata buffers");
160 return ret;
161 }
162
163 static ssize_t ext2_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
164 {
165 #ifdef CONFIG_FS_DAX
166 if (IS_DAX(iocb->ki_filp->f_mapping->host))
167 return ext2_dax_read_iter(iocb, to);
168 #endif
169 return generic_file_read_iter(iocb, to);
170 }
171
172 static ssize_t ext2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
173 {
174 #ifdef CONFIG_FS_DAX
175 if (IS_DAX(iocb->ki_filp->f_mapping->host))
176 return ext2_dax_write_iter(iocb, from);
177 #endif
178 return generic_file_write_iter(iocb, from);
179 }
180
181 const struct file_operations ext2_file_operations = {
182 .llseek = generic_file_llseek,
183 .read_iter = ext2_file_read_iter,
184 .write_iter = ext2_file_write_iter,
185 .unlocked_ioctl = ext2_ioctl,
186 #ifdef CONFIG_COMPAT
187 .compat_ioctl = ext2_compat_ioctl,
188 #endif
189 .mmap = ext2_file_mmap,
190 .open = dquot_file_open,
191 .release = ext2_release_file,
192 .fsync = ext2_fsync,
193 .get_unmapped_area = thp_get_unmapped_area,
194 .splice_read = generic_file_splice_read,
195 .splice_write = iter_file_splice_write,
196 };
197
198 const struct inode_operations ext2_file_inode_operations = {
199 #ifdef CONFIG_EXT2_FS_XATTR
200 .listxattr = ext2_listxattr,
201 #endif
202 .getattr = ext2_getattr,
203 .setattr = ext2_setattr,
204 .get_acl = ext2_get_acl,
205 .set_acl = ext2_set_acl,
206 .fiemap = ext2_fiemap,
207 };
208
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