Dave Chinner | 1fb7e48d | 2013-08-12 20:49:40 +1000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2000-2006 Silicon Graphics, Inc. |
| 3 | * Copyright (c) 2012-2013 Red Hat, Inc. |
| 4 | * All rights reserved. |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License as |
| 8 | * published by the Free Software Foundation. |
| 9 | * |
| 10 | * This program is distributed in the hope that it would be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License |
| 16 | * along with this program; if not, write the Free Software Foundation, |
| 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 18 | */ |
| 19 | #include "xfs.h" |
| 20 | #include "xfs_fs.h" |
| 21 | #include "xfs_format.h" |
| 22 | #include "xfs_log.h" |
| 23 | #include "xfs_trans.h" |
Dave Chinner | 9356fe2 | 2013-08-12 20:49:55 +1000 | [diff] [blame^] | 24 | #include "xfs_ag.h" |
Dave Chinner | 1fb7e48d | 2013-08-12 20:49:40 +1000 | [diff] [blame] | 25 | #include "xfs_sb.h" |
| 26 | #include "xfs_mount.h" |
| 27 | #include "xfs_bmap_btree.h" |
| 28 | #include "xfs_inode.h" |
| 29 | #include "xfs_error.h" |
| 30 | #include "xfs_trace.h" |
| 31 | #include "xfs_symlink.h" |
| 32 | #include "xfs_cksum.h" |
| 33 | #include "xfs_buf_item.h" |
| 34 | |
| 35 | |
| 36 | /* |
| 37 | * Each contiguous block has a header, so it is not just a simple pathlen |
| 38 | * to FSB conversion. |
| 39 | */ |
| 40 | int |
| 41 | xfs_symlink_blocks( |
| 42 | struct xfs_mount *mp, |
| 43 | int pathlen) |
| 44 | { |
| 45 | int buflen = XFS_SYMLINK_BUF_SPACE(mp, mp->m_sb.sb_blocksize); |
| 46 | |
| 47 | return (pathlen + buflen - 1) / buflen; |
| 48 | } |
| 49 | |
| 50 | int |
| 51 | xfs_symlink_hdr_set( |
| 52 | struct xfs_mount *mp, |
| 53 | xfs_ino_t ino, |
| 54 | uint32_t offset, |
| 55 | uint32_t size, |
| 56 | struct xfs_buf *bp) |
| 57 | { |
| 58 | struct xfs_dsymlink_hdr *dsl = bp->b_addr; |
| 59 | |
| 60 | if (!xfs_sb_version_hascrc(&mp->m_sb)) |
| 61 | return 0; |
| 62 | |
| 63 | dsl->sl_magic = cpu_to_be32(XFS_SYMLINK_MAGIC); |
| 64 | dsl->sl_offset = cpu_to_be32(offset); |
| 65 | dsl->sl_bytes = cpu_to_be32(size); |
| 66 | uuid_copy(&dsl->sl_uuid, &mp->m_sb.sb_uuid); |
| 67 | dsl->sl_owner = cpu_to_be64(ino); |
| 68 | dsl->sl_blkno = cpu_to_be64(bp->b_bn); |
| 69 | bp->b_ops = &xfs_symlink_buf_ops; |
| 70 | |
| 71 | return sizeof(struct xfs_dsymlink_hdr); |
| 72 | } |
| 73 | |
| 74 | /* |
| 75 | * Checking of the symlink header is split into two parts. the verifier does |
| 76 | * CRC, location and bounds checking, the unpacking function checks the path |
| 77 | * parameters and owner. |
| 78 | */ |
| 79 | bool |
| 80 | xfs_symlink_hdr_ok( |
| 81 | struct xfs_mount *mp, |
| 82 | xfs_ino_t ino, |
| 83 | uint32_t offset, |
| 84 | uint32_t size, |
| 85 | struct xfs_buf *bp) |
| 86 | { |
| 87 | struct xfs_dsymlink_hdr *dsl = bp->b_addr; |
| 88 | |
| 89 | if (offset != be32_to_cpu(dsl->sl_offset)) |
| 90 | return false; |
| 91 | if (size != be32_to_cpu(dsl->sl_bytes)) |
| 92 | return false; |
| 93 | if (ino != be64_to_cpu(dsl->sl_owner)) |
| 94 | return false; |
| 95 | |
| 96 | /* ok */ |
| 97 | return true; |
| 98 | } |
| 99 | |
| 100 | static bool |
| 101 | xfs_symlink_verify( |
| 102 | struct xfs_buf *bp) |
| 103 | { |
| 104 | struct xfs_mount *mp = bp->b_target->bt_mount; |
| 105 | struct xfs_dsymlink_hdr *dsl = bp->b_addr; |
| 106 | |
| 107 | if (!xfs_sb_version_hascrc(&mp->m_sb)) |
| 108 | return false; |
| 109 | if (dsl->sl_magic != cpu_to_be32(XFS_SYMLINK_MAGIC)) |
| 110 | return false; |
| 111 | if (!uuid_equal(&dsl->sl_uuid, &mp->m_sb.sb_uuid)) |
| 112 | return false; |
| 113 | if (bp->b_bn != be64_to_cpu(dsl->sl_blkno)) |
| 114 | return false; |
| 115 | if (be32_to_cpu(dsl->sl_offset) + |
| 116 | be32_to_cpu(dsl->sl_bytes) >= MAXPATHLEN) |
| 117 | return false; |
| 118 | if (dsl->sl_owner == 0) |
| 119 | return false; |
| 120 | |
| 121 | return true; |
| 122 | } |
| 123 | |
| 124 | static void |
| 125 | xfs_symlink_read_verify( |
| 126 | struct xfs_buf *bp) |
| 127 | { |
| 128 | struct xfs_mount *mp = bp->b_target->bt_mount; |
| 129 | |
| 130 | /* no verification of non-crc buffers */ |
| 131 | if (!xfs_sb_version_hascrc(&mp->m_sb)) |
| 132 | return; |
| 133 | |
| 134 | if (!xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length), |
| 135 | offsetof(struct xfs_dsymlink_hdr, sl_crc)) || |
| 136 | !xfs_symlink_verify(bp)) { |
| 137 | XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr); |
| 138 | xfs_buf_ioerror(bp, EFSCORRUPTED); |
| 139 | } |
| 140 | } |
| 141 | |
| 142 | static void |
| 143 | xfs_symlink_write_verify( |
| 144 | struct xfs_buf *bp) |
| 145 | { |
| 146 | struct xfs_mount *mp = bp->b_target->bt_mount; |
| 147 | struct xfs_buf_log_item *bip = bp->b_fspriv; |
| 148 | |
| 149 | /* no verification of non-crc buffers */ |
| 150 | if (!xfs_sb_version_hascrc(&mp->m_sb)) |
| 151 | return; |
| 152 | |
| 153 | if (!xfs_symlink_verify(bp)) { |
| 154 | XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr); |
| 155 | xfs_buf_ioerror(bp, EFSCORRUPTED); |
| 156 | return; |
| 157 | } |
| 158 | |
| 159 | if (bip) { |
| 160 | struct xfs_dsymlink_hdr *dsl = bp->b_addr; |
| 161 | dsl->sl_lsn = cpu_to_be64(bip->bli_item.li_lsn); |
| 162 | } |
| 163 | xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length), |
| 164 | offsetof(struct xfs_dsymlink_hdr, sl_crc)); |
| 165 | } |
| 166 | |
| 167 | const struct xfs_buf_ops xfs_symlink_buf_ops = { |
| 168 | .verify_read = xfs_symlink_read_verify, |
| 169 | .verify_write = xfs_symlink_write_verify, |
| 170 | }; |
| 171 | |
| 172 | void |
| 173 | xfs_symlink_local_to_remote( |
| 174 | struct xfs_trans *tp, |
| 175 | struct xfs_buf *bp, |
| 176 | struct xfs_inode *ip, |
| 177 | struct xfs_ifork *ifp) |
| 178 | { |
| 179 | struct xfs_mount *mp = ip->i_mount; |
| 180 | char *buf; |
| 181 | |
| 182 | if (!xfs_sb_version_hascrc(&mp->m_sb)) { |
| 183 | bp->b_ops = NULL; |
| 184 | memcpy(bp->b_addr, ifp->if_u1.if_data, ifp->if_bytes); |
| 185 | return; |
| 186 | } |
| 187 | |
| 188 | /* |
| 189 | * As this symlink fits in an inode literal area, it must also fit in |
| 190 | * the smallest buffer the filesystem supports. |
| 191 | */ |
| 192 | ASSERT(BBTOB(bp->b_length) >= |
| 193 | ifp->if_bytes + sizeof(struct xfs_dsymlink_hdr)); |
| 194 | |
| 195 | bp->b_ops = &xfs_symlink_buf_ops; |
| 196 | |
| 197 | buf = bp->b_addr; |
| 198 | buf += xfs_symlink_hdr_set(mp, ip->i_ino, 0, ifp->if_bytes, bp); |
| 199 | memcpy(buf, ifp->if_u1.if_data, ifp->if_bytes); |
| 200 | } |