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_disk_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 error = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0,
57 &bp, &xfs_symlink_buf_ops);
60 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
61 if (pathlen < byte_cnt)
64 cur_chunk = bp->b_addr;
65 if (xfs_sb_version_hascrc(&mp->m_sb)) {
66 if (!xfs_symlink_hdr_ok(ip->i_ino, offset,
68 error = -EFSCORRUPTED;
70 "symlink header does not match required off/len/owner (0x%x/Ox%x,0x%llx)",
71 offset, byte_cnt, ip->i_ino);
77 cur_chunk += sizeof(struct xfs_dsymlink_hdr);
80 memcpy(link + offset, cur_chunk, byte_cnt);
89 link[ip->i_disk_size] = '\0';
101 struct xfs_mount *mp = ip->i_mount;
105 trace_xfs_readlink(ip);
107 ASSERT(ip->i_df.if_format != XFS_DINODE_FMT_LOCAL);
109 if (XFS_FORCED_SHUTDOWN(mp))
112 xfs_ilock(ip, XFS_ILOCK_SHARED);
114 pathlen = ip->i_disk_size;
118 if (pathlen < 0 || pathlen > XFS_SYMLINK_MAXLEN) {
119 xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",
120 __func__, (unsigned long long) ip->i_ino,
121 (long long) pathlen);
123 error = -EFSCORRUPTED;
128 error = xfs_readlink_bmap_ilocked(ip, link);
131 xfs_iunlock(ip, XFS_ILOCK_SHARED);
137 struct user_namespace *mnt_userns,
138 struct xfs_inode *dp,
139 struct xfs_name *link_name,
140 const char *target_path,
142 struct xfs_inode **ipp)
144 struct xfs_mount *mp = dp->i_mount;
145 struct xfs_trans *tp = NULL;
146 struct xfs_inode *ip = NULL;
149 bool unlock_dp_on_error = false;
150 xfs_fileoff_t first_fsb;
151 xfs_filblks_t fs_blocks;
153 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
155 const char *cur_chunk;
160 struct xfs_dquot *udqp = NULL;
161 struct xfs_dquot *gdqp = NULL;
162 struct xfs_dquot *pdqp = NULL;
167 trace_xfs_symlink(dp, link_name);
169 if (XFS_FORCED_SHUTDOWN(mp))
173 * Check component lengths of the target path name.
175 pathlen = strlen(target_path);
176 if (pathlen >= XFS_SYMLINK_MAXLEN) /* total string too long */
177 return -ENAMETOOLONG;
180 prid = xfs_get_initial_prid(dp);
183 * Make sure that we have allocated dquot(s) on disk.
185 error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns),
186 mapped_fsgid(mnt_userns), prid,
187 XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT,
188 &udqp, &gdqp, &pdqp);
193 * The symlink will fit into the inode data fork?
194 * There can't be any attributes so we get the whole variable part.
196 if (pathlen <= XFS_LITINO(mp))
199 fs_blocks = xfs_symlink_blocks(mp, pathlen);
200 resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks);
202 error = xfs_trans_alloc_icreate(mp, &M_RES(mp)->tr_symlink, udqp, gdqp,
205 goto out_release_dquots;
207 xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
208 unlock_dp_on_error = true;
211 * Check whether the directory allows new symlinks or not.
213 if (dp->i_diflags & XFS_DIFLAG_NOSYMLINKS) {
215 goto out_trans_cancel;
218 error = xfs_iext_count_may_overflow(dp, XFS_DATA_FORK,
219 XFS_IEXT_DIR_MANIP_CNT(mp));
221 goto out_trans_cancel;
224 * Allocate an inode for the symlink.
226 error = xfs_dir_ialloc(mnt_userns, &tp, dp, S_IFLNK | (mode & ~S_IFMT),
227 1, 0, prid, false, &ip);
229 goto out_trans_cancel;
232 * Now we join the directory inode to the transaction. We do not do it
233 * earlier because xfs_dir_ialloc might commit the previous transaction
234 * (and release all the locks). An error from here on will result in
235 * the transaction cancel unlocking dp so don't do it explicitly in the
238 xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
239 unlock_dp_on_error = false;
242 * Also attach the dquot(s) to it, if applicable.
244 xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);
246 resblks -= XFS_IALLOC_SPACE_RES(mp);
248 * If the symlink will fit into the inode, write it inline.
250 if (pathlen <= XFS_IFORK_DSIZE(ip)) {
251 xfs_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen);
253 ip->i_disk_size = pathlen;
254 ip->i_df.if_format = XFS_DINODE_FMT_LOCAL;
255 xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE);
260 nmaps = XFS_SYMLINK_MAPS;
262 error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks,
263 XFS_BMAPI_METADATA, resblks, mval, &nmaps);
265 goto out_trans_cancel;
267 resblks -= fs_blocks;
268 ip->i_disk_size = pathlen;
269 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
271 cur_chunk = target_path;
273 for (n = 0; n < nmaps; n++) {
276 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
277 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
278 error = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
279 BTOBB(byte_cnt), 0, &bp);
281 goto out_trans_cancel;
282 bp->b_ops = &xfs_symlink_buf_ops;
284 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
285 byte_cnt = min(byte_cnt, pathlen);
288 buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset,
291 memcpy(buf, cur_chunk, byte_cnt);
293 cur_chunk += byte_cnt;
297 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF);
298 xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) -
301 ASSERT(pathlen == 0);
303 i_size_write(VFS_I(ip), ip->i_disk_size);
306 * Create the directory entry for the symlink.
308 error = xfs_dir_createname(tp, dp, link_name, ip->i_ino, resblks);
310 goto out_trans_cancel;
311 xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
312 xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
315 * If this is a synchronous mount, make sure that the
316 * symlink transaction goes to disk before returning to
319 if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) {
320 xfs_trans_set_sync(tp);
323 error = xfs_trans_commit(tp);
325 goto out_release_inode;
335 xfs_trans_cancel(tp);
338 * Wait until after the current transaction is aborted to finish the
339 * setup of the inode and release the inode. This prevents recursive
340 * transactions and deadlocks from xfs_inactive.
343 xfs_finish_inode_setup(ip);
351 if (unlock_dp_on_error)
352 xfs_iunlock(dp, XFS_ILOCK_EXCL);
357 * Free a symlink that has blocks associated with it.
359 * Note: zero length symlinks are not allowed to exist. When we set the size to
360 * zero, also change it to a regular file so that it does not get written to
361 * disk as a zero length symlink. The inode is on the unlinked list already, so
362 * userspace cannot find this inode anymore, so this change is not user visible
363 * but allows us to catch corrupt zero-length symlinks in the verifiers.
366 xfs_inactive_symlink_rmt(
367 struct xfs_inode *ip)
374 xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS];
380 ASSERT(!xfs_need_iread_extents(&ip->i_df));
382 * We're freeing a symlink that has some
383 * blocks allocated to it. Free the
384 * blocks here. We know that we've got
385 * either 1 or 2 extents and that we can
386 * free them all in one bunmapi call.
388 ASSERT(ip->i_df.if_nextents > 0 && ip->i_df.if_nextents <= 2);
390 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
394 xfs_ilock(ip, XFS_ILOCK_EXCL);
395 xfs_trans_ijoin(tp, ip, 0);
398 * Lock the inode, fix the size, turn it into a regular file and join it
399 * to the transaction. Hold it so in the normal path, we still have it
400 * locked for the second transaction. In the error paths we need it
401 * held so the cancel won't rele it, see below.
403 size = (int)ip->i_disk_size;
405 VFS_I(ip)->i_mode = (VFS_I(ip)->i_mode & ~S_IFMT) | S_IFREG;
406 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
408 * Find the block(s) so we can inval and unmap them.
411 nmaps = ARRAY_SIZE(mval);
412 error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size),
415 goto error_trans_cancel;
417 * Invalidate the block(s). No validation is done.
419 for (i = 0; i < nmaps; i++) {
420 error = xfs_trans_get_buf(tp, mp->m_ddev_targp,
421 XFS_FSB_TO_DADDR(mp, mval[i].br_startblock),
422 XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0,
425 goto error_trans_cancel;
426 xfs_trans_binval(tp, bp);
429 * Unmap the dead block(s) to the dfops.
431 error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps, &done);
433 goto error_trans_cancel;
437 * Commit the transaction. This first logs the EFI and the inode, then
438 * rolls and commits the transaction that frees the extents.
440 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
441 error = xfs_trans_commit(tp);
443 ASSERT(XFS_FORCED_SHUTDOWN(mp));
448 * Remove the memory for extent descriptions (just bookkeeping).
450 if (ip->i_df.if_bytes)
451 xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK);
452 ASSERT(ip->i_df.if_bytes == 0);
454 xfs_iunlock(ip, XFS_ILOCK_EXCL);
458 xfs_trans_cancel(tp);
460 xfs_iunlock(ip, XFS_ILOCK_EXCL);
465 * xfs_inactive_symlink - free a symlink
468 xfs_inactive_symlink(
469 struct xfs_inode *ip)
471 struct xfs_mount *mp = ip->i_mount;
474 trace_xfs_inactive_symlink(ip);
476 if (XFS_FORCED_SHUTDOWN(mp))
479 xfs_ilock(ip, XFS_ILOCK_EXCL);
480 pathlen = (int)ip->i_disk_size;
483 if (pathlen <= 0 || pathlen > XFS_SYMLINK_MAXLEN) {
484 xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)",
485 __func__, (unsigned long long)ip->i_ino, pathlen);
486 xfs_iunlock(ip, XFS_ILOCK_EXCL);
488 return -EFSCORRUPTED;
492 * Inline fork state gets removed by xfs_difree() so we have nothing to
493 * do here in that case.
495 if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL) {
496 xfs_iunlock(ip, XFS_ILOCK_EXCL);
500 xfs_iunlock(ip, XFS_ILOCK_EXCL);
502 /* remove the remote symlink */
503 return xfs_inactive_symlink_rmt(ip);