1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (c) 2000-2006 Silicon Graphics, Inc.
4 * Copyright (c) 2012-2013 Red Hat, Inc.
8 #include "xfs_shared.h"
10 #include "xfs_format.h"
11 #include "xfs_log_format.h"
12 #include "xfs_trans_resv.h"
14 #include "xfs_mount.h"
16 #include "xfs_inode.h"
18 #include "xfs_bmap_btree.h"
19 #include "xfs_quota.h"
20 #include "xfs_symlink.h"
21 #include "xfs_trans_space.h"
22 #include "xfs_trace.h"
23 #include "xfs_trans.h"
25 /* ----- Kernel only functions below ----- */
27 xfs_readlink_bmap_ilocked(
31 struct xfs_mount *mp = ip->i_mount;
32 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
36 int pathlen = ip->i_d.di_size;
37 int nmaps = XFS_SYMLINK_MAPS;
44 ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
46 fsblocks = xfs_symlink_blocks(mp, pathlen);
47 error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0);
52 for (n = 0; n < nmaps; n++) {
53 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
54 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
56 bp = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0,
57 &xfs_symlink_buf_ops);
62 xfs_buf_ioerror_alert(bp, __func__);
65 /* bad CRC means corrupted metadata */
66 if (error == -EFSBADCRC)
67 error = -EFSCORRUPTED;
70 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
71 if (pathlen < byte_cnt)
74 cur_chunk = bp->b_addr;
75 if (xfs_sb_version_hascrc(&mp->m_sb)) {
76 if (!xfs_symlink_hdr_ok(ip->i_ino, offset,
78 error = -EFSCORRUPTED;
80 "symlink header does not match required off/len/owner (0x%x/Ox%x,0x%llx)",
81 offset, byte_cnt, ip->i_ino);
87 cur_chunk += sizeof(struct xfs_dsymlink_hdr);
90 memcpy(link + offset, cur_chunk, byte_cnt);
99 link[ip->i_d.di_size] = '\0';
108 struct xfs_inode *ip,
111 struct xfs_mount *mp = ip->i_mount;
115 trace_xfs_readlink(ip);
117 ASSERT(!(ip->i_df.if_flags & XFS_IFINLINE));
119 if (XFS_FORCED_SHUTDOWN(mp))
122 xfs_ilock(ip, XFS_ILOCK_SHARED);
124 pathlen = ip->i_d.di_size;
128 if (pathlen < 0 || pathlen > XFS_SYMLINK_MAXLEN) {
129 xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",
130 __func__, (unsigned long long) ip->i_ino,
131 (long long) pathlen);
133 error = -EFSCORRUPTED;
138 error = xfs_readlink_bmap_ilocked(ip, link);
141 xfs_iunlock(ip, XFS_ILOCK_SHARED);
147 struct xfs_inode *dp,
148 struct xfs_name *link_name,
149 const char *target_path,
151 struct xfs_inode **ipp)
153 struct xfs_mount *mp = dp->i_mount;
154 struct xfs_trans *tp = NULL;
155 struct xfs_inode *ip = NULL;
158 bool unlock_dp_on_error = false;
159 xfs_fileoff_t first_fsb;
160 xfs_filblks_t fs_blocks;
162 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
164 const char *cur_chunk;
169 struct xfs_dquot *udqp = NULL;
170 struct xfs_dquot *gdqp = NULL;
171 struct xfs_dquot *pdqp = NULL;
176 trace_xfs_symlink(dp, link_name);
178 if (XFS_FORCED_SHUTDOWN(mp))
182 * Check component lengths of the target path name.
184 pathlen = strlen(target_path);
185 if (pathlen >= XFS_SYMLINK_MAXLEN) /* total string too long */
186 return -ENAMETOOLONG;
190 prid = xfs_get_initial_prid(dp);
193 * Make sure that we have allocated dquot(s) on disk.
195 error = xfs_qm_vop_dqalloc(dp,
196 xfs_kuid_to_uid(current_fsuid()),
197 xfs_kgid_to_gid(current_fsgid()), prid,
198 XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT,
199 &udqp, &gdqp, &pdqp);
204 * The symlink will fit into the inode data fork?
205 * There can't be any attributes so we get the whole variable part.
207 if (pathlen <= XFS_LITINO(mp, dp->i_d.di_version))
210 fs_blocks = xfs_symlink_blocks(mp, pathlen);
211 resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks);
213 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_symlink, resblks, 0, 0, &tp);
215 goto out_release_inode;
217 xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
218 unlock_dp_on_error = true;
221 * Check whether the directory allows new symlinks or not.
223 if (dp->i_d.di_flags & XFS_DIFLAG_NOSYMLINKS) {
225 goto out_trans_cancel;
229 * Reserve disk quota : blocks and inode.
231 error = xfs_trans_reserve_quota(tp, mp, udqp, gdqp,
232 pdqp, resblks, 1, 0);
234 goto out_trans_cancel;
237 * Allocate an inode for the symlink.
239 error = xfs_dir_ialloc(&tp, dp, S_IFLNK | (mode & ~S_IFMT), 1, 0,
242 goto out_trans_cancel;
245 * Now we join the directory inode to the transaction. We do not do it
246 * earlier because xfs_dir_ialloc might commit the previous transaction
247 * (and release all the locks). An error from here on will result in
248 * the transaction cancel unlocking dp so don't do it explicitly in the
251 xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
252 unlock_dp_on_error = false;
255 * Also attach the dquot(s) to it, if applicable.
257 xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);
260 resblks -= XFS_IALLOC_SPACE_RES(mp);
262 * If the symlink will fit into the inode, write it inline.
264 if (pathlen <= XFS_IFORK_DSIZE(ip)) {
265 xfs_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen);
267 ip->i_d.di_size = pathlen;
268 ip->i_d.di_format = XFS_DINODE_FMT_LOCAL;
269 xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE);
274 nmaps = XFS_SYMLINK_MAPS;
276 error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks,
277 XFS_BMAPI_METADATA, resblks, mval, &nmaps);
279 goto out_trans_cancel;
282 resblks -= fs_blocks;
283 ip->i_d.di_size = pathlen;
284 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
286 cur_chunk = target_path;
288 for (n = 0; n < nmaps; n++) {
291 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
292 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
293 bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
297 goto out_trans_cancel;
299 bp->b_ops = &xfs_symlink_buf_ops;
301 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
302 byte_cnt = min(byte_cnt, pathlen);
305 buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset,
308 memcpy(buf, cur_chunk, byte_cnt);
310 cur_chunk += byte_cnt;
314 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF);
315 xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) -
318 ASSERT(pathlen == 0);
322 * Create the directory entry for the symlink.
324 error = xfs_dir_createname(tp, dp, link_name, ip->i_ino, resblks);
326 goto out_trans_cancel;
327 xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
328 xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
331 * If this is a synchronous mount, make sure that the
332 * symlink transaction goes to disk before returning to
335 if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) {
336 xfs_trans_set_sync(tp);
339 error = xfs_trans_commit(tp);
341 goto out_release_inode;
351 xfs_trans_cancel(tp);
354 * Wait until after the current transaction is aborted to finish the
355 * setup of the inode and release the inode. This prevents recursive
356 * transactions and deadlocks from xfs_inactive.
359 xfs_finish_inode_setup(ip);
367 if (unlock_dp_on_error)
368 xfs_iunlock(dp, XFS_ILOCK_EXCL);
373 * Free a symlink that has blocks associated with it.
375 * Note: zero length symlinks are not allowed to exist. When we set the size to
376 * zero, also change it to a regular file so that it does not get written to
377 * disk as a zero length symlink. The inode is on the unlinked list already, so
378 * userspace cannot find this inode anymore, so this change is not user visible
379 * but allows us to catch corrupt zero-length symlinks in the verifiers.
382 xfs_inactive_symlink_rmt(
383 struct xfs_inode *ip)
390 xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS];
396 ASSERT(ip->i_df.if_flags & XFS_IFEXTENTS);
398 * We're freeing a symlink that has some
399 * blocks allocated to it. Free the
400 * blocks here. We know that we've got
401 * either 1 or 2 extents and that we can
402 * free them all in one bunmapi call.
404 ASSERT(ip->i_d.di_nextents > 0 && ip->i_d.di_nextents <= 2);
406 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
410 xfs_ilock(ip, XFS_ILOCK_EXCL);
411 xfs_trans_ijoin(tp, ip, 0);
414 * Lock the inode, fix the size, turn it into a regular file and join it
415 * to the transaction. Hold it so in the normal path, we still have it
416 * locked for the second transaction. In the error paths we need it
417 * held so the cancel won't rele it, see below.
419 size = (int)ip->i_d.di_size;
421 VFS_I(ip)->i_mode = (VFS_I(ip)->i_mode & ~S_IFMT) | S_IFREG;
422 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
424 * Find the block(s) so we can inval and unmap them.
427 nmaps = ARRAY_SIZE(mval);
428 error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size),
431 goto error_trans_cancel;
433 * Invalidate the block(s). No validation is done.
435 for (i = 0; i < nmaps; i++) {
436 bp = xfs_trans_get_buf(tp, mp->m_ddev_targp,
437 XFS_FSB_TO_DADDR(mp, mval[i].br_startblock),
438 XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0);
441 goto error_trans_cancel;
443 xfs_trans_binval(tp, bp);
446 * Unmap the dead block(s) to the dfops.
448 error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps, &done);
450 goto error_trans_cancel;
454 * Commit the transaction. This first logs the EFI and the inode, then
455 * rolls and commits the transaction that frees the extents.
457 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
458 error = xfs_trans_commit(tp);
460 ASSERT(XFS_FORCED_SHUTDOWN(mp));
465 * Remove the memory for extent descriptions (just bookkeeping).
467 if (ip->i_df.if_bytes)
468 xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK);
469 ASSERT(ip->i_df.if_bytes == 0);
471 xfs_iunlock(ip, XFS_ILOCK_EXCL);
475 xfs_trans_cancel(tp);
477 xfs_iunlock(ip, XFS_ILOCK_EXCL);
482 * xfs_inactive_symlink - free a symlink
485 xfs_inactive_symlink(
486 struct xfs_inode *ip)
488 struct xfs_mount *mp = ip->i_mount;
491 trace_xfs_inactive_symlink(ip);
493 if (XFS_FORCED_SHUTDOWN(mp))
496 xfs_ilock(ip, XFS_ILOCK_EXCL);
497 pathlen = (int)ip->i_d.di_size;
500 if (pathlen <= 0 || pathlen > XFS_SYMLINK_MAXLEN) {
501 xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)",
502 __func__, (unsigned long long)ip->i_ino, pathlen);
503 xfs_iunlock(ip, XFS_ILOCK_EXCL);
505 return -EFSCORRUPTED;
509 * Inline fork state gets removed by xfs_difree() so we have nothing to
510 * do here in that case.
512 if (ip->i_df.if_flags & XFS_IFINLINE) {
513 xfs_iunlock(ip, XFS_ILOCK_EXCL);
517 xfs_iunlock(ip, XFS_ILOCK_EXCL);
519 /* remove the remote symlink */
520 return xfs_inactive_symlink_rmt(ip);