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"
24 #include "xfs_ialloc.h"
26 /* ----- Kernel only functions below ----- */
28 xfs_readlink_bmap_ilocked(
32 struct xfs_mount *mp = ip->i_mount;
33 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
37 int pathlen = ip->i_disk_size;
38 int nmaps = XFS_SYMLINK_MAPS;
45 ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
47 fsblocks = xfs_symlink_blocks(mp, pathlen);
48 error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0);
53 for (n = 0; n < nmaps; n++) {
54 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
55 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
57 error = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0,
58 &bp, &xfs_symlink_buf_ops);
61 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
62 if (pathlen < byte_cnt)
65 cur_chunk = bp->b_addr;
66 if (xfs_sb_version_hascrc(&mp->m_sb)) {
67 if (!xfs_symlink_hdr_ok(ip->i_ino, offset,
69 error = -EFSCORRUPTED;
71 "symlink header does not match required off/len/owner (0x%x/Ox%x,0x%llx)",
72 offset, byte_cnt, ip->i_ino);
78 cur_chunk += sizeof(struct xfs_dsymlink_hdr);
81 memcpy(link + offset, cur_chunk, byte_cnt);
90 link[ip->i_disk_size] = '\0';
102 struct xfs_mount *mp = ip->i_mount;
106 trace_xfs_readlink(ip);
108 ASSERT(ip->i_df.if_format != XFS_DINODE_FMT_LOCAL);
110 if (XFS_FORCED_SHUTDOWN(mp))
113 xfs_ilock(ip, XFS_ILOCK_SHARED);
115 pathlen = ip->i_disk_size;
119 if (pathlen < 0 || pathlen > XFS_SYMLINK_MAXLEN) {
120 xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",
121 __func__, (unsigned long long) ip->i_ino,
122 (long long) pathlen);
124 error = -EFSCORRUPTED;
129 error = xfs_readlink_bmap_ilocked(ip, link);
132 xfs_iunlock(ip, XFS_ILOCK_SHARED);
138 struct user_namespace *mnt_userns,
139 struct xfs_inode *dp,
140 struct xfs_name *link_name,
141 const char *target_path,
143 struct xfs_inode **ipp)
145 struct xfs_mount *mp = dp->i_mount;
146 struct xfs_trans *tp = NULL;
147 struct xfs_inode *ip = NULL;
150 bool unlock_dp_on_error = false;
151 xfs_fileoff_t first_fsb;
152 xfs_filblks_t fs_blocks;
154 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
156 const char *cur_chunk;
161 struct xfs_dquot *udqp = NULL;
162 struct xfs_dquot *gdqp = NULL;
163 struct xfs_dquot *pdqp = NULL;
169 trace_xfs_symlink(dp, link_name);
171 if (XFS_FORCED_SHUTDOWN(mp))
175 * Check component lengths of the target path name.
177 pathlen = strlen(target_path);
178 if (pathlen >= XFS_SYMLINK_MAXLEN) /* total string too long */
179 return -ENAMETOOLONG;
182 prid = xfs_get_initial_prid(dp);
185 * Make sure that we have allocated dquot(s) on disk.
187 error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns),
188 mapped_fsgid(mnt_userns), prid,
189 XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT,
190 &udqp, &gdqp, &pdqp);
195 * The symlink will fit into the inode data fork?
196 * There can't be any attributes so we get the whole variable part.
198 if (pathlen <= XFS_LITINO(mp))
201 fs_blocks = xfs_symlink_blocks(mp, pathlen);
202 resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks);
204 error = xfs_trans_alloc_icreate(mp, &M_RES(mp)->tr_symlink, udqp, gdqp,
207 goto out_release_dquots;
209 xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
210 unlock_dp_on_error = true;
213 * Check whether the directory allows new symlinks or not.
215 if (dp->i_diflags & XFS_DIFLAG_NOSYMLINKS) {
217 goto out_trans_cancel;
220 error = xfs_iext_count_may_overflow(dp, XFS_DATA_FORK,
221 XFS_IEXT_DIR_MANIP_CNT(mp));
223 goto out_trans_cancel;
226 * Allocate an inode for the symlink.
228 error = xfs_dialloc(&tp, dp->i_ino, S_IFLNK, &ino);
230 error = xfs_init_new_inode(mnt_userns, tp, dp, ino,
231 S_IFLNK | (mode & ~S_IFMT), 1, 0, prid,
234 goto out_trans_cancel;
237 * Now we join the directory inode to the transaction. We do not do it
238 * earlier because xfs_dir_ialloc might commit the previous transaction
239 * (and release all the locks). An error from here on will result in
240 * the transaction cancel unlocking dp so don't do it explicitly in the
243 xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
244 unlock_dp_on_error = false;
247 * Also attach the dquot(s) to it, if applicable.
249 xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);
251 resblks -= XFS_IALLOC_SPACE_RES(mp);
253 * If the symlink will fit into the inode, write it inline.
255 if (pathlen <= XFS_IFORK_DSIZE(ip)) {
256 xfs_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen);
258 ip->i_disk_size = pathlen;
259 ip->i_df.if_format = XFS_DINODE_FMT_LOCAL;
260 xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE);
265 nmaps = XFS_SYMLINK_MAPS;
267 error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks,
268 XFS_BMAPI_METADATA, resblks, mval, &nmaps);
270 goto out_trans_cancel;
272 resblks -= fs_blocks;
273 ip->i_disk_size = pathlen;
274 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
276 cur_chunk = target_path;
278 for (n = 0; n < nmaps; n++) {
281 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
282 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
283 error = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
284 BTOBB(byte_cnt), 0, &bp);
286 goto out_trans_cancel;
287 bp->b_ops = &xfs_symlink_buf_ops;
289 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
290 byte_cnt = min(byte_cnt, pathlen);
293 buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset,
296 memcpy(buf, cur_chunk, byte_cnt);
298 cur_chunk += byte_cnt;
302 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF);
303 xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) -
306 ASSERT(pathlen == 0);
308 i_size_write(VFS_I(ip), ip->i_disk_size);
311 * Create the directory entry for the symlink.
313 error = xfs_dir_createname(tp, dp, link_name, ip->i_ino, resblks);
315 goto out_trans_cancel;
316 xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
317 xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
320 * If this is a synchronous mount, make sure that the
321 * symlink transaction goes to disk before returning to
324 if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) {
325 xfs_trans_set_sync(tp);
328 error = xfs_trans_commit(tp);
330 goto out_release_inode;
340 xfs_trans_cancel(tp);
343 * Wait until after the current transaction is aborted to finish the
344 * setup of the inode and release the inode. This prevents recursive
345 * transactions and deadlocks from xfs_inactive.
348 xfs_finish_inode_setup(ip);
356 if (unlock_dp_on_error)
357 xfs_iunlock(dp, XFS_ILOCK_EXCL);
362 * Free a symlink that has blocks associated with it.
364 * Note: zero length symlinks are not allowed to exist. When we set the size to
365 * zero, also change it to a regular file so that it does not get written to
366 * disk as a zero length symlink. The inode is on the unlinked list already, so
367 * userspace cannot find this inode anymore, so this change is not user visible
368 * but allows us to catch corrupt zero-length symlinks in the verifiers.
371 xfs_inactive_symlink_rmt(
372 struct xfs_inode *ip)
379 xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS];
385 ASSERT(!xfs_need_iread_extents(&ip->i_df));
387 * We're freeing a symlink that has some
388 * blocks allocated to it. Free the
389 * blocks here. We know that we've got
390 * either 1 or 2 extents and that we can
391 * free them all in one bunmapi call.
393 ASSERT(ip->i_df.if_nextents > 0 && ip->i_df.if_nextents <= 2);
395 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
399 xfs_ilock(ip, XFS_ILOCK_EXCL);
400 xfs_trans_ijoin(tp, ip, 0);
403 * Lock the inode, fix the size, turn it into a regular file and join it
404 * to the transaction. Hold it so in the normal path, we still have it
405 * locked for the second transaction. In the error paths we need it
406 * held so the cancel won't rele it, see below.
408 size = (int)ip->i_disk_size;
410 VFS_I(ip)->i_mode = (VFS_I(ip)->i_mode & ~S_IFMT) | S_IFREG;
411 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
413 * Find the block(s) so we can inval and unmap them.
416 nmaps = ARRAY_SIZE(mval);
417 error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size),
420 goto error_trans_cancel;
422 * Invalidate the block(s). No validation is done.
424 for (i = 0; i < nmaps; i++) {
425 error = xfs_trans_get_buf(tp, mp->m_ddev_targp,
426 XFS_FSB_TO_DADDR(mp, mval[i].br_startblock),
427 XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0,
430 goto error_trans_cancel;
431 xfs_trans_binval(tp, bp);
434 * Unmap the dead block(s) to the dfops.
436 error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps, &done);
438 goto error_trans_cancel;
442 * Commit the transaction. This first logs the EFI and the inode, then
443 * rolls and commits the transaction that frees the extents.
445 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
446 error = xfs_trans_commit(tp);
448 ASSERT(XFS_FORCED_SHUTDOWN(mp));
453 * Remove the memory for extent descriptions (just bookkeeping).
455 if (ip->i_df.if_bytes)
456 xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK);
457 ASSERT(ip->i_df.if_bytes == 0);
459 xfs_iunlock(ip, XFS_ILOCK_EXCL);
463 xfs_trans_cancel(tp);
465 xfs_iunlock(ip, XFS_ILOCK_EXCL);
470 * xfs_inactive_symlink - free a symlink
473 xfs_inactive_symlink(
474 struct xfs_inode *ip)
476 struct xfs_mount *mp = ip->i_mount;
479 trace_xfs_inactive_symlink(ip);
481 if (XFS_FORCED_SHUTDOWN(mp))
484 xfs_ilock(ip, XFS_ILOCK_EXCL);
485 pathlen = (int)ip->i_disk_size;
488 if (pathlen <= 0 || pathlen > XFS_SYMLINK_MAXLEN) {
489 xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)",
490 __func__, (unsigned long long)ip->i_ino, pathlen);
491 xfs_iunlock(ip, XFS_ILOCK_EXCL);
493 return -EFSCORRUPTED;
497 * Inline fork state gets removed by xfs_difree() so we have nothing to
498 * do here in that case.
500 if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL) {
501 xfs_iunlock(ip, XFS_ILOCK_EXCL);
505 xfs_iunlock(ip, XFS_ILOCK_EXCL);
507 /* remove the remote symlink */
508 return xfs_inactive_symlink_rmt(ip);