1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (c) 2014 Christoph Hellwig. 4 */ 5 #include "xfs.h" 6 #include "xfs_shared.h" 7 #include "xfs_format.h" 8 #include "xfs_log_format.h" 9 #include "xfs_trans_resv.h" 10 #include "xfs_mount.h" 11 #include "xfs_inode.h" 12 #include "xfs_trans.h" 13 #include "xfs_bmap.h" 14 #include "xfs_iomap.h" 15 16 /* 17 * Ensure that we do not have any outstanding pNFS layouts that can be used by 18 * clients to directly read from or write to this inode. This must be called 19 * before every operation that can remove blocks from the extent map. 20 * Additionally we call it during the write operation, where aren't concerned 21 * about exposing unallocated blocks but just want to provide basic 22 * synchronization between a local writer and pNFS clients. mmap writes would 23 * also benefit from this sort of synchronization, but due to the tricky locking 24 * rules in the page fault path we don't bother. 25 */ 26 int 27 xfs_break_leased_layouts( 28 struct inode *inode, 29 uint *iolock, 30 bool *did_unlock) 31 { 32 struct xfs_inode *ip = XFS_I(inode); 33 int error; 34 35 while ((error = break_layout(inode, false) == -EWOULDBLOCK)) { 36 xfs_iunlock(ip, *iolock); 37 *did_unlock = true; 38 error = break_layout(inode, true); 39 *iolock &= ~XFS_IOLOCK_SHARED; 40 *iolock |= XFS_IOLOCK_EXCL; 41 xfs_ilock(ip, *iolock); 42 } 43 44 return error; 45 } 46 47 /* 48 * Get a unique ID including its location so that the client can identify 49 * the exported device. 50 */ 51 int 52 xfs_fs_get_uuid( 53 struct super_block *sb, 54 u8 *buf, 55 u32 *len, 56 u64 *offset) 57 { 58 struct xfs_mount *mp = XFS_M(sb); 59 60 printk_once(KERN_NOTICE 61 "XFS (%s): using experimental pNFS feature, use at your own risk!\n", 62 mp->m_fsname); 63 64 if (*len < sizeof(uuid_t)) 65 return -EINVAL; 66 67 memcpy(buf, &mp->m_sb.sb_uuid, sizeof(uuid_t)); 68 *len = sizeof(uuid_t); 69 *offset = offsetof(struct xfs_dsb, sb_uuid); 70 return 0; 71 } 72 73 /* 74 * Get a layout for the pNFS client. 75 */ 76 int 77 xfs_fs_map_blocks( 78 struct inode *inode, 79 loff_t offset, 80 u64 length, 81 struct iomap *iomap, 82 bool write, 83 u32 *device_generation) 84 { 85 struct xfs_inode *ip = XFS_I(inode); 86 struct xfs_mount *mp = ip->i_mount; 87 struct xfs_bmbt_irec imap; 88 xfs_fileoff_t offset_fsb, end_fsb; 89 loff_t limit; 90 int bmapi_flags = XFS_BMAPI_ENTIRE; 91 int nimaps = 1; 92 uint lock_flags; 93 int error = 0; 94 95 if (XFS_FORCED_SHUTDOWN(mp)) 96 return -EIO; 97 98 /* 99 * We can't export inodes residing on the realtime device. The realtime 100 * device doesn't have a UUID to identify it, so the client has no way 101 * to find it. 102 */ 103 if (XFS_IS_REALTIME_INODE(ip)) 104 return -ENXIO; 105 106 /* 107 * The pNFS block layout spec actually supports reflink like 108 * functionality, but the Linux pNFS server doesn't implement it yet. 109 */ 110 if (xfs_is_reflink_inode(ip)) 111 return -ENXIO; 112 113 /* 114 * Lock out any other I/O before we flush and invalidate the pagecache, 115 * and then hand out a layout to the remote system. This is very 116 * similar to direct I/O, except that the synchronization is much more 117 * complicated. See the comment near xfs_break_leased_layouts 118 * for a detailed explanation. 119 */ 120 xfs_ilock(ip, XFS_IOLOCK_EXCL); 121 122 error = -EINVAL; 123 limit = mp->m_super->s_maxbytes; 124 if (!write) 125 limit = max(limit, round_up(i_size_read(inode), 126 inode->i_sb->s_blocksize)); 127 if (offset > limit) 128 goto out_unlock; 129 if (offset > limit - length) 130 length = limit - offset; 131 132 error = filemap_write_and_wait(inode->i_mapping); 133 if (error) 134 goto out_unlock; 135 error = invalidate_inode_pages2(inode->i_mapping); 136 if (WARN_ON_ONCE(error)) 137 return error; 138 139 end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + length); 140 offset_fsb = XFS_B_TO_FSBT(mp, offset); 141 142 lock_flags = xfs_ilock_data_map_shared(ip); 143 error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, 144 &imap, &nimaps, bmapi_flags); 145 xfs_iunlock(ip, lock_flags); 146 147 if (error) 148 goto out_unlock; 149 150 if (write) { 151 enum xfs_prealloc_flags flags = 0; 152 153 ASSERT(imap.br_startblock != DELAYSTARTBLOCK); 154 155 if (!nimaps || imap.br_startblock == HOLESTARTBLOCK) { 156 /* 157 * xfs_iomap_write_direct() expects to take ownership of 158 * the shared ilock. 159 */ 160 xfs_ilock(ip, XFS_ILOCK_SHARED); 161 error = xfs_iomap_write_direct(ip, offset, length, 162 &imap, nimaps); 163 if (error) 164 goto out_unlock; 165 166 /* 167 * Ensure the next transaction is committed 168 * synchronously so that the blocks allocated and 169 * handed out to the client are guaranteed to be 170 * present even after a server crash. 171 */ 172 flags |= XFS_PREALLOC_SET | XFS_PREALLOC_SYNC; 173 } 174 175 error = xfs_update_prealloc_flags(ip, flags); 176 if (error) 177 goto out_unlock; 178 } 179 xfs_iunlock(ip, XFS_IOLOCK_EXCL); 180 181 error = xfs_bmbt_to_iomap(ip, iomap, &imap, false); 182 *device_generation = mp->m_generation; 183 return error; 184 out_unlock: 185 xfs_iunlock(ip, XFS_IOLOCK_EXCL); 186 return error; 187 } 188 189 /* 190 * Ensure the size update falls into a valid allocated block. 191 */ 192 static int 193 xfs_pnfs_validate_isize( 194 struct xfs_inode *ip, 195 xfs_off_t isize) 196 { 197 struct xfs_bmbt_irec imap; 198 int nimaps = 1; 199 int error = 0; 200 201 xfs_ilock(ip, XFS_ILOCK_SHARED); 202 error = xfs_bmapi_read(ip, XFS_B_TO_FSBT(ip->i_mount, isize - 1), 1, 203 &imap, &nimaps, 0); 204 xfs_iunlock(ip, XFS_ILOCK_SHARED); 205 if (error) 206 return error; 207 208 if (imap.br_startblock == HOLESTARTBLOCK || 209 imap.br_startblock == DELAYSTARTBLOCK || 210 imap.br_state == XFS_EXT_UNWRITTEN) 211 return -EIO; 212 return 0; 213 } 214 215 /* 216 * Make sure the blocks described by maps are stable on disk. This includes 217 * converting any unwritten extents, flushing the disk cache and updating the 218 * time stamps. 219 * 220 * Note that we rely on the caller to always send us a timestamp update so that 221 * we always commit a transaction here. If that stops being true we will have 222 * to manually flush the cache here similar to what the fsync code path does 223 * for datasyncs on files that have no dirty metadata. 224 */ 225 int 226 xfs_fs_commit_blocks( 227 struct inode *inode, 228 struct iomap *maps, 229 int nr_maps, 230 struct iattr *iattr) 231 { 232 struct xfs_inode *ip = XFS_I(inode); 233 struct xfs_mount *mp = ip->i_mount; 234 struct xfs_trans *tp; 235 bool update_isize = false; 236 int error, i; 237 loff_t size; 238 239 ASSERT(iattr->ia_valid & (ATTR_ATIME|ATTR_CTIME|ATTR_MTIME)); 240 241 xfs_ilock(ip, XFS_IOLOCK_EXCL); 242 243 size = i_size_read(inode); 244 if ((iattr->ia_valid & ATTR_SIZE) && iattr->ia_size > size) { 245 update_isize = true; 246 size = iattr->ia_size; 247 } 248 249 for (i = 0; i < nr_maps; i++) { 250 u64 start, length, end; 251 252 start = maps[i].offset; 253 if (start > size) 254 continue; 255 256 end = start + maps[i].length; 257 if (end > size) 258 end = size; 259 260 length = end - start; 261 if (!length) 262 continue; 263 264 /* 265 * Make sure reads through the pagecache see the new data. 266 */ 267 error = invalidate_inode_pages2_range(inode->i_mapping, 268 start >> PAGE_SHIFT, 269 (end - 1) >> PAGE_SHIFT); 270 WARN_ON_ONCE(error); 271 272 error = xfs_iomap_write_unwritten(ip, start, length, false); 273 if (error) 274 goto out_drop_iolock; 275 } 276 277 if (update_isize) { 278 error = xfs_pnfs_validate_isize(ip, size); 279 if (error) 280 goto out_drop_iolock; 281 } 282 283 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp); 284 if (error) 285 goto out_drop_iolock; 286 287 xfs_ilock(ip, XFS_ILOCK_EXCL); 288 xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL); 289 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 290 291 xfs_setattr_time(ip, iattr); 292 if (update_isize) { 293 i_size_write(inode, iattr->ia_size); 294 ip->i_d.di_size = iattr->ia_size; 295 } 296 297 xfs_trans_set_sync(tp); 298 error = xfs_trans_commit(tp); 299 300 out_drop_iolock: 301 xfs_iunlock(ip, XFS_IOLOCK_EXCL); 302 return error; 303 } 304