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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 | /* * linux/fs/nfs/file.c * * Copyright (C) 1992 Rick Sladkey * * Changes Copyright (C) 1994 by Florian La Roche * - Do not copy data too often around in the kernel. * - In nfs_file_read the return value of kmalloc wasn't checked. * - Put in a better version of read look-ahead buffering. Original idea * and implementation by Wai S Kok elekokws@ee.nus.sg. * * Expire cache on write to a file by Wai S Kok (Oct 1994). * * Total rewrite of read side for new NFS buffer cache.. Linus. * * nfs regular file handling functions */ #include <linux/sched.h> #include <linux/kernel.h> #include <linux/errno.h> #include <linux/fcntl.h> #include <linux/stat.h> #include <linux/mm.h> #include <linux/nfs_fs.h> #include <linux/malloc.h> #include <linux/pagemap.h> #include <asm/segment.h> #include <asm/system.h> static int nfs_file_mmap(struct inode *, struct file *, struct vm_area_struct *); static int nfs_file_read(struct inode *, struct file *, char *, int); static int nfs_file_write(struct inode *, struct file *, const char *, int); static int nfs_fsync(struct inode *, struct file *); static int nfs_readpage(struct inode * inode, struct page * page); static struct file_operations nfs_file_operations = { NULL, /* lseek - default */ nfs_file_read, /* read */ nfs_file_write, /* write */ NULL, /* readdir - bad */ NULL, /* select - default */ NULL, /* ioctl - default */ nfs_file_mmap, /* mmap */ NULL, /* no special open is needed */ NULL, /* release */ nfs_fsync, /* fsync */ }; struct inode_operations nfs_file_inode_operations = { &nfs_file_operations, /* default file operations */ NULL, /* create */ NULL, /* lookup */ NULL, /* link */ NULL, /* unlink */ NULL, /* symlink */ NULL, /* mkdir */ NULL, /* rmdir */ NULL, /* mknod */ NULL, /* rename */ NULL, /* readlink */ NULL, /* follow_link */ nfs_readpage, /* readpage */ NULL, /* writepage */ NULL, /* bmap */ NULL /* truncate */ }; static inline void revalidate_inode(struct nfs_server * server, struct inode * inode) { struct nfs_fattr fattr; if (jiffies - NFS_READTIME(inode) < server->acregmax) return; NFS_READTIME(inode) = jiffies; if (nfs_proc_getattr(server, NFS_FH(inode), &fattr) == 0) { nfs_refresh_inode(inode, &fattr); if (fattr.mtime.seconds == NFS_OLDMTIME(inode)) return; NFS_OLDMTIME(inode) = fattr.mtime.seconds; } invalidate_inode_pages(inode); } static int nfs_file_read(struct inode * inode, struct file * file, char * buf, int count) { revalidate_inode(NFS_SERVER(inode), inode); return generic_file_read(inode, file, buf, count); } static int nfs_file_mmap(struct inode * inode, struct file * file, struct vm_area_struct * vma) { revalidate_inode(NFS_SERVER(inode), inode); return generic_file_mmap(inode, file, vma); } static int nfs_fsync(struct inode *inode, struct file *file) { return 0; } static inline void do_read_nfs(struct inode * inode, char * buf, unsigned long pos) { int refresh = 0; int count = PAGE_SIZE; int rsize = NFS_SERVER(inode)->rsize; struct nfs_fattr fattr; do { int result; if (count < rsize) rsize = count; result = nfs_proc_read(NFS_SERVER(inode), NFS_FH(inode), pos, rsize, buf, &fattr); if (result < 0) break; refresh = 1; count -= result; pos += result; buf += result; if (result < rsize) break; } while (count); memset(buf, 0, count); if (refresh) nfs_refresh_inode(inode, &fattr); } static int nfs_readpage(struct inode * inode, struct page * page) { unsigned long address; address = page_address(page); page->count++; wait_on_page(page); if (page->uptodate) { free_page(address); return 0; } page->locked = 1; do_read_nfs(inode, (char *) address, page->offset); page->locked = 0; page->uptodate = 1; wake_up(&page->wait); free_page(address); return 0; } static int nfs_file_write(struct inode *inode, struct file *file, const char *buf, int count) { int result, hunk, i, n, pos; struct nfs_fattr fattr; if (!inode) { printk("nfs_file_write: inode = NULL\n"); return -EINVAL; } if (!S_ISREG(inode->i_mode)) { printk("nfs_file_write: write to non-file, mode %07o\n", inode->i_mode); return -EINVAL; } if (count <= 0) return 0; pos = file->f_pos; if (file->f_flags & O_APPEND) pos = inode->i_size; n = NFS_SERVER(inode)->wsize; for (i = 0; i < count; i += n) { hunk = count - i; if (hunk >= n) hunk = n; result = nfs_proc_write(inode, pos, hunk, buf, &fattr); if (result < 0) return result; pos += hunk; buf += hunk; if (hunk < n) { i += hunk; break; } } file->f_pos = pos; nfs_refresh_inode(inode, &fattr); return i; } |