| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Copyright (c) 2000-2006 Silicon Graphics, Inc. |
| * Copyright (c) 2012-2013 Red Hat, Inc. |
| * All rights reserved. |
| */ |
| #include "xfs.h" |
| #include "xfs_shared.h" |
| #include "xfs_fs.h" |
| #include "xfs_format.h" |
| #include "xfs_log_format.h" |
| #include "xfs_trans_resv.h" |
| #include "xfs_bit.h" |
| #include "xfs_mount.h" |
| #include "xfs_dir2.h" |
| #include "xfs_inode.h" |
| #include "xfs_bmap.h" |
| #include "xfs_bmap_btree.h" |
| #include "xfs_quota.h" |
| #include "xfs_symlink.h" |
| #include "xfs_trans_space.h" |
| #include "xfs_trace.h" |
| #include "xfs_trans.h" |
| #include "xfs_ialloc.h" |
| #include "xfs_error.h" |
| #include "xfs_health.h" |
| #include "xfs_symlink_remote.h" |
| |
| int |
| xfs_readlink( |
| struct xfs_inode *ip, |
| char *link) |
| { |
| struct xfs_mount *mp = ip->i_mount; |
| xfs_fsize_t pathlen; |
| int error; |
| |
| trace_xfs_readlink(ip); |
| |
| if (xfs_is_shutdown(mp)) |
| return -EIO; |
| if (xfs_ifork_zapped(ip, XFS_DATA_FORK)) |
| return -EIO; |
| |
| xfs_ilock(ip, XFS_ILOCK_SHARED); |
| |
| pathlen = ip->i_disk_size; |
| if (!pathlen) |
| goto out_corrupt; |
| |
| if (pathlen < 0 || pathlen > XFS_SYMLINK_MAXLEN) { |
| xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)", |
| __func__, (unsigned long long) ip->i_ino, |
| (long long) pathlen); |
| ASSERT(0); |
| goto out_corrupt; |
| } |
| |
| if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL) { |
| /* |
| * The VFS crashes on a NULL pointer, so return -EFSCORRUPTED |
| * if if_data is junk. |
| */ |
| if (XFS_IS_CORRUPT(ip->i_mount, !ip->i_df.if_data)) |
| goto out_corrupt; |
| |
| memcpy(link, ip->i_df.if_data, pathlen + 1); |
| error = 0; |
| } else { |
| error = xfs_symlink_remote_read(ip, link); |
| } |
| |
| xfs_iunlock(ip, XFS_ILOCK_SHARED); |
| return error; |
| out_corrupt: |
| xfs_iunlock(ip, XFS_ILOCK_SHARED); |
| xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK); |
| return -EFSCORRUPTED; |
| } |
| |
| int |
| xfs_symlink( |
| struct mnt_idmap *idmap, |
| struct xfs_inode *dp, |
| struct xfs_name *link_name, |
| const char *target_path, |
| umode_t mode, |
| struct xfs_inode **ipp) |
| { |
| struct xfs_mount *mp = dp->i_mount; |
| struct xfs_trans *tp = NULL; |
| struct xfs_inode *ip = NULL; |
| int error = 0; |
| int pathlen; |
| bool unlock_dp_on_error = false; |
| xfs_filblks_t fs_blocks; |
| prid_t prid; |
| struct xfs_dquot *udqp = NULL; |
| struct xfs_dquot *gdqp = NULL; |
| struct xfs_dquot *pdqp = NULL; |
| uint resblks; |
| xfs_ino_t ino; |
| |
| *ipp = NULL; |
| |
| trace_xfs_symlink(dp, link_name); |
| |
| if (xfs_is_shutdown(mp)) |
| return -EIO; |
| |
| /* |
| * Check component lengths of the target path name. |
| */ |
| pathlen = strlen(target_path); |
| if (pathlen >= XFS_SYMLINK_MAXLEN) /* total string too long */ |
| return -ENAMETOOLONG; |
| ASSERT(pathlen > 0); |
| |
| prid = xfs_get_initial_prid(dp); |
| |
| /* |
| * Make sure that we have allocated dquot(s) on disk. |
| */ |
| error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(idmap, &init_user_ns), |
| mapped_fsgid(idmap, &init_user_ns), prid, |
| XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT, |
| &udqp, &gdqp, &pdqp); |
| if (error) |
| return error; |
| |
| /* |
| * The symlink will fit into the inode data fork? |
| * There can't be any attributes so we get the whole variable part. |
| */ |
| if (pathlen <= XFS_LITINO(mp)) |
| fs_blocks = 0; |
| else |
| fs_blocks = xfs_symlink_blocks(mp, pathlen); |
| resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks); |
| |
| error = xfs_trans_alloc_icreate(mp, &M_RES(mp)->tr_symlink, udqp, gdqp, |
| pdqp, resblks, &tp); |
| if (error) |
| goto out_release_dquots; |
| |
| xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT); |
| unlock_dp_on_error = true; |
| |
| /* |
| * Check whether the directory allows new symlinks or not. |
| */ |
| if (dp->i_diflags & XFS_DIFLAG_NOSYMLINKS) { |
| error = -EPERM; |
| goto out_trans_cancel; |
| } |
| |
| /* |
| * Allocate an inode for the symlink. |
| */ |
| error = xfs_dialloc(&tp, dp->i_ino, S_IFLNK, &ino); |
| if (!error) |
| error = xfs_init_new_inode(idmap, tp, dp, ino, |
| S_IFLNK | (mode & ~S_IFMT), 1, 0, prid, |
| false, &ip); |
| if (error) |
| goto out_trans_cancel; |
| |
| /* |
| * Now we join the directory inode to the transaction. We do not do it |
| * earlier because xfs_dir_ialloc might commit the previous transaction |
| * (and release all the locks). An error from here on will result in |
| * the transaction cancel unlocking dp so don't do it explicitly in the |
| * error path. |
| */ |
| xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL); |
| unlock_dp_on_error = false; |
| |
| /* |
| * Also attach the dquot(s) to it, if applicable. |
| */ |
| xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp); |
| |
| resblks -= XFS_IALLOC_SPACE_RES(mp); |
| error = xfs_symlink_write_target(tp, ip, target_path, pathlen, |
| fs_blocks, resblks); |
| if (error) |
| goto out_trans_cancel; |
| resblks -= fs_blocks; |
| i_size_write(VFS_I(ip), ip->i_disk_size); |
| |
| /* |
| * Create the directory entry for the symlink. |
| */ |
| error = xfs_dir_createname(tp, dp, link_name, ip->i_ino, resblks); |
| if (error) |
| goto out_trans_cancel; |
| xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG); |
| xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE); |
| xfs_dir_update_hook(dp, ip, 1, link_name); |
| |
| /* |
| * If this is a synchronous mount, make sure that the |
| * symlink transaction goes to disk before returning to |
| * the user. |
| */ |
| if (xfs_has_wsync(mp) || xfs_has_dirsync(mp)) |
| xfs_trans_set_sync(tp); |
| |
| error = xfs_trans_commit(tp); |
| if (error) |
| goto out_release_inode; |
| |
| xfs_qm_dqrele(udqp); |
| xfs_qm_dqrele(gdqp); |
| xfs_qm_dqrele(pdqp); |
| |
| *ipp = ip; |
| return 0; |
| |
| out_trans_cancel: |
| xfs_trans_cancel(tp); |
| out_release_inode: |
| /* |
| * Wait until after the current transaction is aborted to finish the |
| * setup of the inode and release the inode. This prevents recursive |
| * transactions and deadlocks from xfs_inactive. |
| */ |
| if (ip) { |
| xfs_finish_inode_setup(ip); |
| xfs_irele(ip); |
| } |
| out_release_dquots: |
| xfs_qm_dqrele(udqp); |
| xfs_qm_dqrele(gdqp); |
| xfs_qm_dqrele(pdqp); |
| |
| if (unlock_dp_on_error) |
| xfs_iunlock(dp, XFS_ILOCK_EXCL); |
| return error; |
| } |
| |
| /* |
| * Free a symlink that has blocks associated with it. |
| * |
| * Note: zero length symlinks are not allowed to exist. When we set the size to |
| * zero, also change it to a regular file so that it does not get written to |
| * disk as a zero length symlink. The inode is on the unlinked list already, so |
| * userspace cannot find this inode anymore, so this change is not user visible |
| * but allows us to catch corrupt zero-length symlinks in the verifiers. |
| */ |
| STATIC int |
| xfs_inactive_symlink_rmt( |
| struct xfs_inode *ip) |
| { |
| struct xfs_buf *bp; |
| int done; |
| int error; |
| int i; |
| xfs_mount_t *mp; |
| xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS]; |
| int nmaps; |
| int size; |
| xfs_trans_t *tp; |
| |
| mp = ip->i_mount; |
| ASSERT(!xfs_need_iread_extents(&ip->i_df)); |
| /* |
| * We're freeing a symlink that has some |
| * blocks allocated to it. Free the |
| * blocks here. We know that we've got |
| * either 1 or 2 extents and that we can |
| * free them all in one bunmapi call. |
| */ |
| ASSERT(ip->i_df.if_nextents > 0 && ip->i_df.if_nextents <= 2); |
| |
| error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp); |
| if (error) |
| return error; |
| |
| xfs_ilock(ip, XFS_ILOCK_EXCL); |
| xfs_trans_ijoin(tp, ip, 0); |
| |
| /* |
| * Lock the inode, fix the size, turn it into a regular file and join it |
| * to the transaction. Hold it so in the normal path, we still have it |
| * locked for the second transaction. In the error paths we need it |
| * held so the cancel won't rele it, see below. |
| */ |
| size = (int)ip->i_disk_size; |
| ip->i_disk_size = 0; |
| VFS_I(ip)->i_mode = (VFS_I(ip)->i_mode & ~S_IFMT) | S_IFREG; |
| xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); |
| /* |
| * Find the block(s) so we can inval and unmap them. |
| */ |
| done = 0; |
| nmaps = ARRAY_SIZE(mval); |
| error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size), |
| mval, &nmaps, 0); |
| if (error) |
| goto error_trans_cancel; |
| /* |
| * Invalidate the block(s). No validation is done. |
| */ |
| for (i = 0; i < nmaps; i++) { |
| error = xfs_trans_get_buf(tp, mp->m_ddev_targp, |
| XFS_FSB_TO_DADDR(mp, mval[i].br_startblock), |
| XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0, |
| &bp); |
| if (error) |
| goto error_trans_cancel; |
| xfs_trans_binval(tp, bp); |
| } |
| /* |
| * Unmap the dead block(s) to the dfops. |
| */ |
| error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps, &done); |
| if (error) |
| goto error_trans_cancel; |
| ASSERT(done); |
| |
| /* |
| * Commit the transaction. This first logs the EFI and the inode, then |
| * rolls and commits the transaction that frees the extents. |
| */ |
| xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); |
| error = xfs_trans_commit(tp); |
| if (error) { |
| ASSERT(xfs_is_shutdown(mp)); |
| goto error_unlock; |
| } |
| |
| /* |
| * Remove the memory for extent descriptions (just bookkeeping). |
| */ |
| if (ip->i_df.if_bytes) |
| xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK); |
| ASSERT(ip->i_df.if_bytes == 0); |
| |
| xfs_iunlock(ip, XFS_ILOCK_EXCL); |
| return 0; |
| |
| error_trans_cancel: |
| xfs_trans_cancel(tp); |
| error_unlock: |
| xfs_iunlock(ip, XFS_ILOCK_EXCL); |
| return error; |
| } |
| |
| /* |
| * xfs_inactive_symlink - free a symlink |
| */ |
| int |
| xfs_inactive_symlink( |
| struct xfs_inode *ip) |
| { |
| struct xfs_mount *mp = ip->i_mount; |
| int pathlen; |
| |
| trace_xfs_inactive_symlink(ip); |
| |
| if (xfs_is_shutdown(mp)) |
| return -EIO; |
| |
| xfs_ilock(ip, XFS_ILOCK_EXCL); |
| pathlen = (int)ip->i_disk_size; |
| ASSERT(pathlen); |
| |
| if (pathlen <= 0 || pathlen > XFS_SYMLINK_MAXLEN) { |
| xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)", |
| __func__, (unsigned long long)ip->i_ino, pathlen); |
| xfs_iunlock(ip, XFS_ILOCK_EXCL); |
| ASSERT(0); |
| xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK); |
| return -EFSCORRUPTED; |
| } |
| |
| /* |
| * Inline fork state gets removed by xfs_difree() so we have nothing to |
| * do here in that case. |
| */ |
| if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL) { |
| xfs_iunlock(ip, XFS_ILOCK_EXCL); |
| return 0; |
| } |
| |
| xfs_iunlock(ip, XFS_ILOCK_EXCL); |
| |
| /* remove the remote symlink */ |
| return xfs_inactive_symlink_rmt(ip); |
| } |