kernel/fork: always deny write access to current MM exe_file
[linux-2.6-microblaze.git] / fs / jfs / file.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *   Copyright (C) International Business Machines Corp., 2000-2002
4  *   Portions Copyright (C) Christoph Hellwig, 2001-2002
5  */
6
7 #include <linux/mm.h>
8 #include <linux/fs.h>
9 #include <linux/posix_acl.h>
10 #include <linux/quotaops.h>
11 #include "jfs_incore.h"
12 #include "jfs_inode.h"
13 #include "jfs_dmap.h"
14 #include "jfs_txnmgr.h"
15 #include "jfs_xattr.h"
16 #include "jfs_acl.h"
17 #include "jfs_debug.h"
18
19 int jfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
20 {
21         struct inode *inode = file->f_mapping->host;
22         int rc = 0;
23
24         rc = file_write_and_wait_range(file, start, end);
25         if (rc)
26                 return rc;
27
28         inode_lock(inode);
29         if (!(inode->i_state & I_DIRTY_ALL) ||
30             (datasync && !(inode->i_state & I_DIRTY_DATASYNC))) {
31                 /* Make sure committed changes hit the disk */
32                 jfs_flush_journal(JFS_SBI(inode->i_sb)->log, 1);
33                 inode_unlock(inode);
34                 return rc;
35         }
36
37         rc |= jfs_commit_inode(inode, 1);
38         inode_unlock(inode);
39
40         return rc ? -EIO : 0;
41 }
42
43 static int jfs_open(struct inode *inode, struct file *file)
44 {
45         int rc;
46
47         if ((rc = dquot_file_open(inode, file)))
48                 return rc;
49
50         /*
51          * We attempt to allow only one "active" file open per aggregate
52          * group.  Otherwise, appending to files in parallel can cause
53          * fragmentation within the files.
54          *
55          * If the file is empty, it was probably just created and going
56          * to be written to.  If it has a size, we'll hold off until the
57          * file is actually grown.
58          */
59         if (S_ISREG(inode->i_mode) && file->f_mode & FMODE_WRITE &&
60             (inode->i_size == 0)) {
61                 struct jfs_inode_info *ji = JFS_IP(inode);
62                 spin_lock_irq(&ji->ag_lock);
63                 if (ji->active_ag == -1) {
64                         struct jfs_sb_info *jfs_sb = JFS_SBI(inode->i_sb);
65                         ji->active_ag = BLKTOAG(addressPXD(&ji->ixpxd), jfs_sb);
66                         atomic_inc(&jfs_sb->bmap->db_active[ji->active_ag]);
67                 }
68                 spin_unlock_irq(&ji->ag_lock);
69         }
70
71         return 0;
72 }
73 static int jfs_release(struct inode *inode, struct file *file)
74 {
75         struct jfs_inode_info *ji = JFS_IP(inode);
76
77         spin_lock_irq(&ji->ag_lock);
78         if (ji->active_ag != -1) {
79                 struct bmap *bmap = JFS_SBI(inode->i_sb)->bmap;
80                 atomic_dec(&bmap->db_active[ji->active_ag]);
81                 ji->active_ag = -1;
82         }
83         spin_unlock_irq(&ji->ag_lock);
84
85         return 0;
86 }
87
88 int jfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
89                 struct iattr *iattr)
90 {
91         struct inode *inode = d_inode(dentry);
92         int rc;
93
94         rc = setattr_prepare(&init_user_ns, dentry, iattr);
95         if (rc)
96                 return rc;
97
98         if (is_quota_modification(inode, iattr)) {
99                 rc = dquot_initialize(inode);
100                 if (rc)
101                         return rc;
102         }
103         if ((iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)) ||
104             (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid))) {
105                 rc = dquot_transfer(inode, iattr);
106                 if (rc)
107                         return rc;
108         }
109
110         if ((iattr->ia_valid & ATTR_SIZE) &&
111             iattr->ia_size != i_size_read(inode)) {
112                 inode_dio_wait(inode);
113
114                 rc = inode_newsize_ok(inode, iattr->ia_size);
115                 if (rc)
116                         return rc;
117
118                 truncate_setsize(inode, iattr->ia_size);
119                 jfs_truncate(inode);
120         }
121
122         setattr_copy(&init_user_ns, inode, iattr);
123         mark_inode_dirty(inode);
124
125         if (iattr->ia_valid & ATTR_MODE)
126                 rc = posix_acl_chmod(&init_user_ns, inode, inode->i_mode);
127         return rc;
128 }
129
130 const struct inode_operations jfs_file_inode_operations = {
131         .listxattr      = jfs_listxattr,
132         .setattr        = jfs_setattr,
133         .fileattr_get   = jfs_fileattr_get,
134         .fileattr_set   = jfs_fileattr_set,
135 #ifdef CONFIG_JFS_POSIX_ACL
136         .get_acl        = jfs_get_acl,
137         .set_acl        = jfs_set_acl,
138 #endif
139 };
140
141 const struct file_operations jfs_file_operations = {
142         .open           = jfs_open,
143         .llseek         = generic_file_llseek,
144         .read_iter      = generic_file_read_iter,
145         .write_iter     = generic_file_write_iter,
146         .mmap           = generic_file_mmap,
147         .splice_read    = generic_file_splice_read,
148         .splice_write   = iter_file_splice_write,
149         .fsync          = jfs_fsync,
150         .release        = jfs_release,
151         .unlocked_ioctl = jfs_ioctl,
152         .compat_ioctl   = compat_ptr_ioctl,
153 };