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/filelock.h> 25 #include <linux/quotaops.h> 26 #include <linux/iomap.h> 27 #include <linux/uio.h> 28 #include <linux/buffer_head.h> 29 #include "ext2.h" 30 #include "xattr.h" 31 #include "acl.h" 32 #include "trace.h" 33 34 35 /* 36 * Called when filp is released. This happens when all file descriptors 37 * for a single struct file are closed. Note that different open() calls 38 * for the same file yield different struct file structures. 39 */ 40 static int ext2_release_file (struct inode * inode, struct file * filp) 41 { 42 if (filp->f_mode & FMODE_WRITE) { 43 mutex_lock(&EXT2_I(inode)->truncate_mutex); 44 ext2_discard_reservation(inode); 45 mutex_unlock(&EXT2_I(inode)->truncate_mutex); 46 } 47 return 0; 48 } 49 50 static ssize_t ext2_dio_read_iter(struct kiocb *iocb, struct iov_iter *to) 51 { 52 struct file *file = iocb->ki_filp; 53 struct inode *inode = file->f_mapping->host; 54 ssize_t ret; 55 56 trace_ext2_dio_read_begin(iocb, to, 0); 57 inode_lock_shared(inode); 58 ret = iomap_dio_rw(iocb, to, &ext2_iomap_ops, NULL, 0, NULL, 0); 59 inode_unlock_shared(inode); 60 trace_ext2_dio_read_end(iocb, to, ret); 61 62 return ret; 63 } 64 65 static int ext2_dio_write_end_io(struct kiocb *iocb, ssize_t size, 66 int error, unsigned int flags) 67 { 68 loff_t pos = iocb->ki_pos; 69 struct inode *inode = file_inode(iocb->ki_filp); 70 71 if (error) 72 goto out; 73 74 /* 75 * If we are extending the file, we have to update i_size here before 76 * page cache gets invalidated in iomap_dio_rw(). This prevents racing 77 * buffered reads from zeroing out too much from page cache pages. 78 * Note that all extending writes always happens synchronously with 79 * inode lock held by ext2_dio_write_iter(). So it is safe to update 80 * inode size here for extending file writes. 81 */ 82 pos += size; 83 if (pos > i_size_read(inode)) { 84 i_size_write(inode, pos); 85 mark_inode_dirty(inode); 86 } 87 out: 88 trace_ext2_dio_write_endio(iocb, size, error); 89 return error; 90 } 91 92 static const struct iomap_dio_ops ext2_dio_write_ops = { 93 .end_io = ext2_dio_write_end_io, 94 }; 95 96 static ssize_t ext2_dio_write_iter(struct kiocb *iocb, struct iov_iter *from) 97 { 98 struct file *file = iocb->ki_filp; 99 struct inode *inode = file->f_mapping->host; 100 ssize_t ret; 101 unsigned int flags = 0; 102 unsigned long blocksize = inode->i_sb->s_blocksize; 103 loff_t offset = iocb->ki_pos; 104 loff_t count = iov_iter_count(from); 105 ssize_t status = 0; 106 107 trace_ext2_dio_write_begin(iocb, from, 0); 108 inode_lock(inode); 109 ret = generic_write_checks(iocb, from); 110 if (ret <= 0) 111 goto out_unlock; 112 113 ret = kiocb_modified(iocb); 114 if (ret) 115 goto out_unlock; 116 117 /* use IOMAP_DIO_FORCE_WAIT for unaligned or extending writes */ 118 if (iocb->ki_pos + iov_iter_count(from) > i_size_read(inode) || 119 (!IS_ALIGNED(iocb->ki_pos | iov_iter_alignment(from), blocksize))) 120 flags |= IOMAP_DIO_FORCE_WAIT; 121 122 ret = iomap_dio_rw(iocb, from, &ext2_iomap_ops, &ext2_dio_write_ops, 123 flags, NULL, 0); 124 125 /* ENOTBLK is magic return value for fallback to buffered-io */ 126 if (ret == -ENOTBLK) 127 ret = 0; 128 129 if (ret < 0 && ret != -EIOCBQUEUED) 130 ext2_write_failed(inode->i_mapping, offset + count); 131 132 /* handle case for partial write and for fallback to buffered write */ 133 if (ret >= 0 && iov_iter_count(from)) { 134 loff_t pos, endbyte; 135 int ret2; 136 137 iocb->ki_flags &= ~IOCB_DIRECT; 138 139 /* 140 * Prevent concurrent direct I/O and buffered I/O to the same file 141 * range. Wait for in-flight DIO to finish before dirtying pages. 142 */ 143 inode_dio_wait(inode); 144 145 pos = iocb->ki_pos; 146 status = generic_perform_write(iocb, from); 147 if (unlikely(status < 0)) { 148 ret = status; 149 goto out_unlock; 150 } 151 152 ret += status; 153 endbyte = pos + status - 1; 154 ret2 = filemap_write_and_wait_range(inode->i_mapping, pos, 155 endbyte); 156 if (!ret2) { 157 invalidate_mapping_pages(inode->i_mapping, 158 pos >> PAGE_SHIFT, 159 endbyte >> PAGE_SHIFT); 160 if (ret > 0) 161 ret = generic_write_sync(iocb, ret); 162 } else { 163 ret = ret2; 164 } 165 } 166 167 out_unlock: 168 inode_unlock(inode); 169 if (status) 170 trace_ext2_dio_write_buff_end(iocb, from, status); 171 trace_ext2_dio_write_end(iocb, from, ret); 172 return ret; 173 } 174 175 static ssize_t ext2_file_read_iter(struct kiocb *iocb, struct iov_iter *to) 176 { 177 if (iocb->ki_flags & IOCB_DIRECT) 178 return ext2_dio_read_iter(iocb, to); 179 180 return generic_file_read_iter(iocb, to); 181 } 182 183 static ssize_t ext2_file_write_iter(struct kiocb *iocb, struct iov_iter *from) 184 { 185 if (iocb->ki_flags & IOCB_DIRECT) 186 return ext2_dio_write_iter(iocb, from); 187 188 return generic_file_write_iter(iocb, from); 189 } 190 191 static int ext2_file_open(struct inode *inode, struct file *filp) 192 { 193 filp->f_mode |= FMODE_CAN_ODIRECT; 194 return dquot_file_open(inode, filp); 195 } 196 197 const struct file_operations ext2_file_operations = { 198 .llseek = generic_file_llseek, 199 .read_iter = ext2_file_read_iter, 200 .write_iter = ext2_file_write_iter, 201 .unlocked_ioctl = ext2_ioctl, 202 #ifdef CONFIG_COMPAT 203 .compat_ioctl = ext2_compat_ioctl, 204 #endif 205 .mmap_prepare = generic_file_mmap_prepare, 206 .open = ext2_file_open, 207 .release = ext2_release_file, 208 .fsync = simple_fsync, 209 .get_unmapped_area = thp_get_unmapped_area, 210 .splice_read = filemap_splice_read, 211 .splice_write = iter_file_splice_write, 212 .setlease = generic_setlease, 213 }; 214 215 const struct inode_operations ext2_file_inode_operations = { 216 .listxattr = ext2_listxattr, 217 .getattr = ext2_getattr, 218 .setattr = ext2_setattr, 219 .get_inode_acl = ext2_get_acl, 220 .set_acl = ext2_set_acl, 221 .fiemap = ext2_fiemap, 222 .fileattr_get = ext2_fileattr_get, 223 .fileattr_set = ext2_fileattr_set, 224 }; 225