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 int ext2_fsync(struct file *file, loff_t start, loff_t end, int datasync) 51 { 52 int ret; 53 struct inode *inode = file->f_mapping->host; 54 struct super_block *sb = inode->i_sb; 55 56 ret = mmb_fsync(file, &EXT2_I(inode)->i_metadata_bhs, 57 start, end, datasync); 58 if (ret == -EIO) 59 /* We don't really know where the IO error happened... */ 60 ext2_error(sb, __func__, 61 "detected IO error when writing metadata buffers"); 62 return ret; 63 } 64 65 static ssize_t ext2_dio_read_iter(struct kiocb *iocb, struct iov_iter *to) 66 { 67 struct file *file = iocb->ki_filp; 68 struct inode *inode = file->f_mapping->host; 69 ssize_t ret; 70 71 trace_ext2_dio_read_begin(iocb, to, 0); 72 inode_lock_shared(inode); 73 ret = iomap_dio_rw(iocb, to, &ext2_iomap_ops, NULL, 0, NULL, 0); 74 inode_unlock_shared(inode); 75 trace_ext2_dio_read_end(iocb, to, ret); 76 77 return ret; 78 } 79 80 static int ext2_dio_write_end_io(struct kiocb *iocb, ssize_t size, 81 int error, unsigned int flags) 82 { 83 loff_t pos = iocb->ki_pos; 84 struct inode *inode = file_inode(iocb->ki_filp); 85 86 if (error) 87 goto out; 88 89 /* 90 * If we are extending the file, we have to update i_size here before 91 * page cache gets invalidated in iomap_dio_rw(). This prevents racing 92 * buffered reads from zeroing out too much from page cache pages. 93 * Note that all extending writes always happens synchronously with 94 * inode lock held by ext2_dio_write_iter(). So it is safe to update 95 * inode size here for extending file writes. 96 */ 97 pos += size; 98 if (pos > i_size_read(inode)) { 99 i_size_write(inode, pos); 100 mark_inode_dirty(inode); 101 } 102 out: 103 trace_ext2_dio_write_endio(iocb, size, error); 104 return error; 105 } 106 107 static const struct iomap_dio_ops ext2_dio_write_ops = { 108 .end_io = ext2_dio_write_end_io, 109 }; 110 111 static ssize_t ext2_dio_write_iter(struct kiocb *iocb, struct iov_iter *from) 112 { 113 struct file *file = iocb->ki_filp; 114 struct inode *inode = file->f_mapping->host; 115 ssize_t ret; 116 unsigned int flags = 0; 117 unsigned long blocksize = inode->i_sb->s_blocksize; 118 loff_t offset = iocb->ki_pos; 119 loff_t count = iov_iter_count(from); 120 ssize_t status = 0; 121 122 trace_ext2_dio_write_begin(iocb, from, 0); 123 inode_lock(inode); 124 ret = generic_write_checks(iocb, from); 125 if (ret <= 0) 126 goto out_unlock; 127 128 ret = kiocb_modified(iocb); 129 if (ret) 130 goto out_unlock; 131 132 /* use IOMAP_DIO_FORCE_WAIT for unaligned or extending writes */ 133 if (iocb->ki_pos + iov_iter_count(from) > i_size_read(inode) || 134 (!IS_ALIGNED(iocb->ki_pos | iov_iter_alignment(from), blocksize))) 135 flags |= IOMAP_DIO_FORCE_WAIT; 136 137 ret = iomap_dio_rw(iocb, from, &ext2_iomap_ops, &ext2_dio_write_ops, 138 flags, NULL, 0); 139 140 /* ENOTBLK is magic return value for fallback to buffered-io */ 141 if (ret == -ENOTBLK) 142 ret = 0; 143 144 if (ret < 0 && ret != -EIOCBQUEUED) 145 ext2_write_failed(inode->i_mapping, offset + count); 146 147 /* handle case for partial write and for fallback to buffered write */ 148 if (ret >= 0 && iov_iter_count(from)) { 149 loff_t pos, endbyte; 150 int ret2; 151 152 iocb->ki_flags &= ~IOCB_DIRECT; 153 pos = iocb->ki_pos; 154 status = generic_perform_write(iocb, from); 155 if (unlikely(status < 0)) { 156 ret = status; 157 goto out_unlock; 158 } 159 160 ret += status; 161 endbyte = pos + status - 1; 162 ret2 = filemap_write_and_wait_range(inode->i_mapping, pos, 163 endbyte); 164 if (!ret2) { 165 invalidate_mapping_pages(inode->i_mapping, 166 pos >> PAGE_SHIFT, 167 endbyte >> PAGE_SHIFT); 168 if (ret > 0) 169 ret = generic_write_sync(iocb, ret); 170 } else { 171 ret = ret2; 172 } 173 } 174 175 out_unlock: 176 inode_unlock(inode); 177 if (status) 178 trace_ext2_dio_write_buff_end(iocb, from, status); 179 trace_ext2_dio_write_end(iocb, from, ret); 180 return ret; 181 } 182 183 static ssize_t ext2_file_read_iter(struct kiocb *iocb, struct iov_iter *to) 184 { 185 if (iocb->ki_flags & IOCB_DIRECT) 186 return ext2_dio_read_iter(iocb, to); 187 188 return generic_file_read_iter(iocb, to); 189 } 190 191 static ssize_t ext2_file_write_iter(struct kiocb *iocb, struct iov_iter *from) 192 { 193 if (iocb->ki_flags & IOCB_DIRECT) 194 return ext2_dio_write_iter(iocb, from); 195 196 return generic_file_write_iter(iocb, from); 197 } 198 199 static int ext2_file_open(struct inode *inode, struct file *filp) 200 { 201 filp->f_mode |= FMODE_CAN_ODIRECT; 202 return dquot_file_open(inode, filp); 203 } 204 205 const struct file_operations ext2_file_operations = { 206 .llseek = generic_file_llseek, 207 .read_iter = ext2_file_read_iter, 208 .write_iter = ext2_file_write_iter, 209 .unlocked_ioctl = ext2_ioctl, 210 #ifdef CONFIG_COMPAT 211 .compat_ioctl = ext2_compat_ioctl, 212 #endif 213 .mmap_prepare = generic_file_mmap_prepare, 214 .open = ext2_file_open, 215 .release = ext2_release_file, 216 .fsync = ext2_fsync, 217 .get_unmapped_area = thp_get_unmapped_area, 218 .splice_read = filemap_splice_read, 219 .splice_write = iter_file_splice_write, 220 .setlease = generic_setlease, 221 }; 222 223 const struct inode_operations ext2_file_inode_operations = { 224 .listxattr = ext2_listxattr, 225 .getattr = ext2_getattr, 226 .setattr = ext2_setattr, 227 .get_inode_acl = ext2_get_acl, 228 .set_acl = ext2_set_acl, 229 .fiemap = ext2_fiemap, 230 .fileattr_get = ext2_fileattr_get, 231 .fileattr_set = ext2_fileattr_set, 232 }; 233