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#include "xfs_pnfs.h" 16 17/* 18 * Ensure that we do not have any outstanding pNFS layouts that can be used by 19 * clients to directly read from or write to this inode. This must be called 20 * before every operation that can remove blocks from the extent map. 21 * Additionally we call it during the write operation, where aren't concerned 22 * about exposing unallocated blocks but just want to provide basic 23 * synchronization between a local writer and pNFS clients. mmap writes would 24 * also benefit from this sort of synchronization, but due to the tricky locking 25 * rules in the page fault path we don't bother. 26 */ 27int 28xfs_break_leased_layouts( 29 struct inode *inode, 30 uint *iolock, 31 bool *did_unlock) 32{ 33 struct xfs_inode *ip = XFS_I(inode); 34 int error; 35 36 while ((error = break_layout(inode, false)) == -EWOULDBLOCK) { 37 xfs_iunlock(ip, *iolock); 38 *did_unlock = true; 39 error = break_layout(inode, true); 40 *iolock &= ~XFS_IOLOCK_SHARED; 41 *iolock |= XFS_IOLOCK_EXCL; 42 xfs_ilock(ip, *iolock); 43 } 44 45 return error; 46} 47 48/* 49 * Get a unique ID including its location so that the client can identify 50 * the exported device. 51 */ 52int 53xfs_fs_get_uuid( 54 struct super_block *sb, 55 u8 *buf, 56 u32 *len, 57 u64 *offset) 58{ 59 struct xfs_mount *mp = XFS_M(sb); 60 61 xfs_notice_once(mp, 62"Using experimental pNFS feature, use at your own risk!"); 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 */ 76int 77xfs_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 goto out_unlock; 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); 145 146 ASSERT(!nimaps || imap.br_startblock != DELAYSTARTBLOCK); 147 148 if (!error && write && 149 (!nimaps || imap.br_startblock == HOLESTARTBLOCK)) { 150 if (offset + length > XFS_ISIZE(ip)) 151 end_fsb = xfs_iomap_eof_align_last_fsb(ip, end_fsb); 152 else if (nimaps && imap.br_startblock == HOLESTARTBLOCK) 153 end_fsb = min(end_fsb, imap.br_startoff + 154 imap.br_blockcount); 155 xfs_iunlock(ip, lock_flags); 156 157 error = xfs_iomap_write_direct(ip, offset_fsb, 158 end_fsb - offset_fsb, &imap); 159 if (error) 160 goto out_unlock; 161 162 /* 163 * Ensure the next transaction is committed synchronously so 164 * that the blocks allocated and handed out to the client are 165 * guaranteed to be present even after a server crash. 166 */ 167 error = xfs_update_prealloc_flags(ip, XFS_PREALLOC_SET); 168 if (!error) 169 error = xfs_log_force_inode(ip); 170 if (error) 171 goto out_unlock; 172 173 } else { 174 xfs_iunlock(ip, lock_flags); 175 } 176 xfs_iunlock(ip, XFS_IOLOCK_EXCL); 177 178 error = xfs_bmbt_to_iomap(ip, iomap, &imap, 0); 179 *device_generation = mp->m_generation; 180 return error; 181out_unlock: 182 xfs_iunlock(ip, XFS_IOLOCK_EXCL); 183 return error; 184} 185 186/* 187 * Ensure the size update falls into a valid allocated block. 188 */ 189static int 190xfs_pnfs_validate_isize( 191 struct xfs_inode *ip, 192 xfs_off_t isize) 193{ 194 struct xfs_bmbt_irec imap; 195 int nimaps = 1; 196 int error = 0; 197 198 xfs_ilock(ip, XFS_ILOCK_SHARED); 199 error = xfs_bmapi_read(ip, XFS_B_TO_FSBT(ip->i_mount, isize - 1), 1, 200 &imap, &nimaps, 0); 201 xfs_iunlock(ip, XFS_ILOCK_SHARED); 202 if (error) 203 return error; 204 205 if (imap.br_startblock == HOLESTARTBLOCK || 206 imap.br_startblock == DELAYSTARTBLOCK || 207 imap.br_state == XFS_EXT_UNWRITTEN) 208 return -EIO; 209 return 0; 210} 211 212/* 213 * Make sure the blocks described by maps are stable on disk. This includes 214 * converting any unwritten extents, flushing the disk cache and updating the 215 * time stamps. 216 * 217 * Note that we rely on the caller to always send us a timestamp update so that 218 * we always commit a transaction here. If that stops being true we will have 219 * to manually flush the cache here similar to what the fsync code path does 220 * for datasyncs on files that have no dirty metadata. 221 */ 222int 223xfs_fs_commit_blocks( 224 struct inode *inode, 225 struct iomap *maps, 226 int nr_maps, 227 struct iattr *iattr) 228{ 229 struct xfs_inode *ip = XFS_I(inode); 230 struct xfs_mount *mp = ip->i_mount; 231 struct xfs_trans *tp; 232 bool update_isize = false; 233 int error, i; 234 loff_t size; 235 236 ASSERT(iattr->ia_valid & (ATTR_ATIME|ATTR_CTIME|ATTR_MTIME)); 237 238 xfs_ilock(ip, XFS_IOLOCK_EXCL); 239 240 size = i_size_read(inode); 241 if ((iattr->ia_valid & ATTR_SIZE) && iattr->ia_size > size) { 242 update_isize = true; 243 size = iattr->ia_size; 244 } 245 246 for (i = 0; i < nr_maps; i++) { 247 u64 start, length, end; 248 249 start = maps[i].offset; 250 if (start > size) 251 continue; 252 253 end = start + maps[i].length; 254 if (end > size) 255 end = size; 256 257 length = end - start; 258 if (!length) 259 continue; 260 261 /* 262 * Make sure reads through the pagecache see the new data. 263 */ 264 error = invalidate_inode_pages2_range(inode->i_mapping, 265 start >> PAGE_SHIFT, 266 (end - 1) >> PAGE_SHIFT); 267 WARN_ON_ONCE(error); 268 269 error = xfs_iomap_write_unwritten(ip, start, length, false); 270 if (error) 271 goto out_drop_iolock; 272 } 273 274 if (update_isize) { 275 error = xfs_pnfs_validate_isize(ip, size); 276 if (error) 277 goto out_drop_iolock; 278 } 279 280 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp); 281 if (error) 282 goto out_drop_iolock; 283 284 xfs_ilock(ip, XFS_ILOCK_EXCL); 285 xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL); 286 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 287 288 ASSERT(!(iattr->ia_valid & (ATTR_UID | ATTR_GID))); 289 setattr_copy(inode, iattr); 290 if (update_isize) { 291 i_size_write(inode, iattr->ia_size); 292 ip->i_d.di_size = iattr->ia_size; 293 } 294 295 xfs_trans_set_sync(tp); 296 error = xfs_trans_commit(tp); 297 298out_drop_iolock: 299 xfs_iunlock(ip, XFS_IOLOCK_EXCL); 300 return error; 301} 302