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1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright (c) 2000-2006 Silicon Graphics, Inc.4 * Copyright (c) 2012-2013 Red Hat, Inc.5 * All rights reserved.6 */7#include "xfs.h"8#include "xfs_shared.h"9#include "xfs_fs.h"10#include "xfs_format.h"11#include "xfs_log_format.h"12#include "xfs_trans_resv.h"13#include "xfs_bit.h"14#include "xfs_mount.h"15#include "xfs_dir2.h"16#include "xfs_inode.h"17#include "xfs_bmap.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"25#include "xfs_error.h"26#include "xfs_health.h"27#include "xfs_symlink_remote.h"28#include "xfs_parent.h"29#include "xfs_defer.h"30 31int32xfs_readlink(33 struct xfs_inode *ip,34 char *link)35{36 struct xfs_mount *mp = ip->i_mount;37 xfs_fsize_t pathlen;38 int error;39 40 trace_xfs_readlink(ip);41 42 if (xfs_is_shutdown(mp))43 return -EIO;44 if (xfs_ifork_zapped(ip, XFS_DATA_FORK))45 return -EIO;46 47 xfs_ilock(ip, XFS_ILOCK_SHARED);48 49 pathlen = ip->i_disk_size;50 if (!pathlen)51 goto out_corrupt;52 53 if (pathlen < 0 || pathlen > XFS_SYMLINK_MAXLEN) {54 xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",55 __func__, (unsigned long long) ip->i_ino,56 (long long) pathlen);57 ASSERT(0);58 goto out_corrupt;59 }60 61 if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL) {62 /*63 * The VFS crashes on a NULL pointer, so return -EFSCORRUPTED64 * if if_data is junk.65 */66 if (XFS_IS_CORRUPT(ip->i_mount, !ip->i_df.if_data))67 goto out_corrupt;68 69 memcpy(link, ip->i_df.if_data, pathlen + 1);70 error = 0;71 } else {72 error = xfs_symlink_remote_read(ip, link);73 }74 75 xfs_iunlock(ip, XFS_ILOCK_SHARED);76 return error;77 out_corrupt:78 xfs_iunlock(ip, XFS_ILOCK_SHARED);79 xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK);80 return -EFSCORRUPTED;81}82 83int84xfs_symlink(85 struct mnt_idmap *idmap,86 struct xfs_inode *dp,87 struct xfs_name *link_name,88 const char *target_path,89 umode_t mode,90 struct xfs_inode **ipp)91{92 struct xfs_mount *mp = dp->i_mount;93 struct xfs_icreate_args args = {94 .idmap = idmap,95 .pip = dp,96 .mode = S_IFLNK | (mode & ~S_IFMT),97 };98 struct xfs_dir_update du = {99 .dp = dp,100 .name = link_name,101 };102 struct xfs_trans *tp = NULL;103 int error = 0;104 int pathlen;105 bool unlock_dp_on_error = false;106 xfs_filblks_t fs_blocks;107 struct xfs_dquot *udqp;108 struct xfs_dquot *gdqp;109 struct xfs_dquot *pdqp;110 uint resblks;111 xfs_ino_t ino;112 113 *ipp = NULL;114 115 trace_xfs_symlink(dp, link_name);116 117 if (xfs_is_shutdown(mp))118 return -EIO;119 120 /*121 * Check component lengths of the target path name.122 */123 pathlen = strlen(target_path);124 if (pathlen >= XFS_SYMLINK_MAXLEN) /* total string too long */125 return -ENAMETOOLONG;126 ASSERT(pathlen > 0);127 128 /* Make sure that we have allocated dquot(s) on disk. */129 error = xfs_icreate_dqalloc(&args, &udqp, &gdqp, &pdqp);130 if (error)131 return error;132 133 /*134 * The symlink will fit into the inode data fork?135 * If there are no parent pointers, then there wont't be any attributes.136 * So we get the whole variable part, and do not need to reserve extra137 * blocks. Otherwise, we need to reserve the blocks.138 */139 if (pathlen <= XFS_LITINO(mp) && !xfs_has_parent(mp))140 fs_blocks = 0;141 else142 fs_blocks = xfs_symlink_blocks(mp, pathlen);143 resblks = xfs_symlink_space_res(mp, link_name->len, fs_blocks);144 145 error = xfs_parent_start(mp, &du.ppargs);146 if (error)147 goto out_release_dquots;148 149 error = xfs_trans_alloc_icreate(mp, &M_RES(mp)->tr_symlink, udqp, gdqp,150 pdqp, resblks, &tp);151 if (error)152 goto out_parent;153 154 xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);155 unlock_dp_on_error = true;156 157 /*158 * Check whether the directory allows new symlinks or not.159 */160 if (dp->i_diflags & XFS_DIFLAG_NOSYMLINKS) {161 error = -EPERM;162 goto out_trans_cancel;163 }164 165 /*166 * Allocate an inode for the symlink.167 */168 error = xfs_dialloc(&tp, &args, &ino);169 if (!error)170 error = xfs_icreate(tp, ino, &args, &du.ip);171 if (error)172 goto out_trans_cancel;173 174 /*175 * Now we join the directory inode to the transaction. We do not do it176 * earlier because xfs_dir_ialloc might commit the previous transaction177 * (and release all the locks). An error from here on will result in178 * the transaction cancel unlocking dp so don't do it explicitly in the179 * error path.180 */181 xfs_trans_ijoin(tp, dp, 0);182 183 /*184 * Also attach the dquot(s) to it, if applicable.185 */186 xfs_qm_vop_create_dqattach(tp, du.ip, udqp, gdqp, pdqp);187 188 resblks -= XFS_IALLOC_SPACE_RES(mp);189 error = xfs_symlink_write_target(tp, du.ip, du.ip->i_ino, target_path,190 pathlen, fs_blocks, resblks);191 if (error)192 goto out_trans_cancel;193 resblks -= fs_blocks;194 i_size_write(VFS_I(du.ip), du.ip->i_disk_size);195 196 /*197 * Create the directory entry for the symlink.198 */199 error = xfs_dir_create_child(tp, resblks, &du);200 if (error)201 goto out_trans_cancel;202 203 /*204 * If this is a synchronous mount, make sure that the205 * symlink transaction goes to disk before returning to206 * the user.207 */208 if (xfs_has_wsync(mp) || xfs_has_dirsync(mp))209 xfs_trans_set_sync(tp);210 211 error = xfs_trans_commit(tp);212 if (error)213 goto out_release_inode;214 215 xfs_qm_dqrele(udqp);216 xfs_qm_dqrele(gdqp);217 xfs_qm_dqrele(pdqp);218 219 *ipp = du.ip;220 xfs_iunlock(du.ip, XFS_ILOCK_EXCL);221 xfs_iunlock(dp, XFS_ILOCK_EXCL);222 xfs_parent_finish(mp, du.ppargs);223 return 0;224 225out_trans_cancel:226 xfs_trans_cancel(tp);227out_release_inode:228 /*229 * Wait until after the current transaction is aborted to finish the230 * setup of the inode and release the inode. This prevents recursive231 * transactions and deadlocks from xfs_inactive.232 */233 if (du.ip) {234 xfs_iunlock(du.ip, XFS_ILOCK_EXCL);235 xfs_finish_inode_setup(du.ip);236 xfs_irele(du.ip);237 }238out_parent:239 xfs_parent_finish(mp, du.ppargs);240out_release_dquots:241 xfs_qm_dqrele(udqp);242 xfs_qm_dqrele(gdqp);243 xfs_qm_dqrele(pdqp);244 245 if (unlock_dp_on_error)246 xfs_iunlock(dp, XFS_ILOCK_EXCL);247 return error;248}249 250/*251 * Free a symlink that has blocks associated with it.252 *253 * Note: zero length symlinks are not allowed to exist. When we set the size to254 * zero, also change it to a regular file so that it does not get written to255 * disk as a zero length symlink. The inode is on the unlinked list already, so256 * userspace cannot find this inode anymore, so this change is not user visible257 * but allows us to catch corrupt zero-length symlinks in the verifiers.258 */259STATIC int260xfs_inactive_symlink_rmt(261 struct xfs_inode *ip)262{263 struct xfs_mount *mp = ip->i_mount;264 struct xfs_trans *tp;265 int error;266 267 ASSERT(!xfs_need_iread_extents(&ip->i_df));268 /*269 * We're freeing a symlink that has some270 * blocks allocated to it. Free the271 * blocks here. We know that we've got272 * either 1 or 2 extents and that we can273 * free them all in one bunmapi call.274 */275 ASSERT(ip->i_df.if_nextents > 0 && ip->i_df.if_nextents <= 2);276 277 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);278 if (error)279 return error;280 281 xfs_ilock(ip, XFS_ILOCK_EXCL);282 xfs_trans_ijoin(tp, ip, 0);283 284 /*285 * Lock the inode, fix the size, turn it into a regular file and join it286 * to the transaction. Hold it so in the normal path, we still have it287 * locked for the second transaction. In the error paths we need it288 * held so the cancel won't rele it, see below.289 */290 ip->i_disk_size = 0;291 VFS_I(ip)->i_mode = (VFS_I(ip)->i_mode & ~S_IFMT) | S_IFREG;292 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);293 294 error = xfs_symlink_remote_truncate(tp, ip);295 if (error)296 goto error_trans_cancel;297 298 error = xfs_trans_commit(tp);299 if (error) {300 ASSERT(xfs_is_shutdown(mp));301 goto error_unlock;302 }303 304 /*305 * Remove the memory for extent descriptions (just bookkeeping).306 */307 if (ip->i_df.if_bytes)308 xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK);309 ASSERT(ip->i_df.if_bytes == 0);310 311 xfs_iunlock(ip, XFS_ILOCK_EXCL);312 return 0;313 314error_trans_cancel:315 xfs_trans_cancel(tp);316error_unlock:317 xfs_iunlock(ip, XFS_ILOCK_EXCL);318 return error;319}320 321/*322 * xfs_inactive_symlink - free a symlink323 */324int325xfs_inactive_symlink(326 struct xfs_inode *ip)327{328 struct xfs_mount *mp = ip->i_mount;329 int pathlen;330 331 trace_xfs_inactive_symlink(ip);332 333 if (xfs_is_shutdown(mp))334 return -EIO;335 336 xfs_ilock(ip, XFS_ILOCK_EXCL);337 pathlen = (int)ip->i_disk_size;338 ASSERT(pathlen);339 340 if (pathlen <= 0 || pathlen > XFS_SYMLINK_MAXLEN) {341 xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)",342 __func__, (unsigned long long)ip->i_ino, pathlen);343 xfs_iunlock(ip, XFS_ILOCK_EXCL);344 ASSERT(0);345 xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK);346 return -EFSCORRUPTED;347 }348 349 /*350 * Inline fork state gets removed by xfs_difree() so we have nothing to351 * do here in that case.352 */353 if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL) {354 xfs_iunlock(ip, XFS_ILOCK_EXCL);355 return 0;356 }357 358 xfs_iunlock(ip, XFS_ILOCK_EXCL);359 360 /* remove the remote symlink */361 return xfs_inactive_symlink_rmt(ip);362}363