diff options
Diffstat (limited to 'fs/xfs/scrub/attr.c')
| -rw-r--r-- | fs/xfs/scrub/attr.c | 471 |
1 files changed, 471 insertions, 0 deletions
diff --git a/fs/xfs/scrub/attr.c b/fs/xfs/scrub/attr.c new file mode 100644 index 000000000000..4ed80474f545 --- /dev/null +++ b/fs/xfs/scrub/attr.c @@ -0,0 +1,471 @@ +/* + * Copyright (C) 2017 Oracle. All Rights Reserved. + * + * Author: Darrick J. Wong <darrick.wong@oracle.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it would be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. + */ +#include "xfs.h" +#include "xfs_fs.h" +#include "xfs_shared.h" +#include "xfs_format.h" +#include "xfs_trans_resv.h" +#include "xfs_mount.h" +#include "xfs_defer.h" +#include "xfs_btree.h" +#include "xfs_bit.h" +#include "xfs_log_format.h" +#include "xfs_trans.h" +#include "xfs_sb.h" +#include "xfs_inode.h" +#include "xfs_da_format.h" +#include "xfs_da_btree.h" +#include "xfs_dir2.h" +#include "xfs_attr.h" +#include "xfs_attr_leaf.h" +#include "scrub/xfs_scrub.h" +#include "scrub/scrub.h" +#include "scrub/common.h" +#include "scrub/dabtree.h" +#include "scrub/trace.h" + +#include <linux/posix_acl_xattr.h> +#include <linux/xattr.h> + +/* Set us up to scrub an inode's extended attributes. */ +int +xfs_scrub_setup_xattr( + struct xfs_scrub_context *sc, + struct xfs_inode *ip) +{ + size_t sz; + + /* + * Allocate the buffer without the inode lock held. We need enough + * space to read every xattr value in the file or enough space to + * hold three copies of the xattr free space bitmap. (Not both at + * the same time.) + */ + sz = max_t(size_t, XATTR_SIZE_MAX, 3 * sizeof(long) * + BITS_TO_LONGS(sc->mp->m_attr_geo->blksize)); + sc->buf = kmem_zalloc_large(sz, KM_SLEEP); + if (!sc->buf) + return -ENOMEM; + + return xfs_scrub_setup_inode_contents(sc, ip, 0); +} + +/* Extended Attributes */ + +struct xfs_scrub_xattr { + struct xfs_attr_list_context context; + struct xfs_scrub_context *sc; +}; + +/* + * Check that an extended attribute key can be looked up by hash. + * + * We use the XFS attribute list iterator (i.e. xfs_attr_list_int_ilocked) + * to call this function for every attribute key in an inode. Once + * we're here, we load the attribute value to see if any errors happen, + * or if we get more or less data than we expected. + */ +static void +xfs_scrub_xattr_listent( + struct xfs_attr_list_context *context, + int flags, + unsigned char *name, + int namelen, + int valuelen) +{ + struct xfs_scrub_xattr *sx; + struct xfs_da_args args = { NULL }; + int error = 0; + + sx = container_of(context, struct xfs_scrub_xattr, context); + + if (flags & XFS_ATTR_INCOMPLETE) { + /* Incomplete attr key, just mark the inode for preening. */ + xfs_scrub_ino_set_preen(sx->sc, context->dp->i_ino, NULL); + return; + } + + args.flags = ATTR_KERNOTIME; + if (flags & XFS_ATTR_ROOT) + args.flags |= ATTR_ROOT; + else if (flags & XFS_ATTR_SECURE) + args.flags |= ATTR_SECURE; + args.geo = context->dp->i_mount->m_attr_geo; + args.whichfork = XFS_ATTR_FORK; + args.dp = context->dp; + args.name = name; + args.namelen = namelen; + args.hashval = xfs_da_hashname(args.name, args.namelen); + args.trans = context->tp; + args.value = sx->sc->buf; + args.valuelen = XATTR_SIZE_MAX; + + error = xfs_attr_get_ilocked(context->dp, &args); + if (error == -EEXIST) + error = 0; + if (!xfs_scrub_fblock_process_error(sx->sc, XFS_ATTR_FORK, args.blkno, + &error)) + goto fail_xref; + if (args.valuelen != valuelen) + xfs_scrub_fblock_set_corrupt(sx->sc, XFS_ATTR_FORK, + args.blkno); + +fail_xref: + return; +} + +/* + * Mark a range [start, start+len) in this map. Returns true if the + * region was free, and false if there's a conflict or a problem. + * + * Within a char, the lowest bit of the char represents the byte with + * the smallest address + */ +STATIC bool +xfs_scrub_xattr_set_map( + struct xfs_scrub_context *sc, + unsigned long *map, + unsigned int start, + unsigned int len) +{ + unsigned int mapsize = sc->mp->m_attr_geo->blksize; + bool ret = true; + + if (start >= mapsize) + return false; + if (start + len > mapsize) { + len = mapsize - start; + ret = false; + } + + if (find_next_bit(map, mapsize, start) < start + len) + ret = false; + bitmap_set(map, start, len); + + return ret; +} + +/* + * Check the leaf freemap from the usage bitmap. Returns false if the + * attr freemap has problems or points to used space. + */ +STATIC bool +xfs_scrub_xattr_check_freemap( + struct xfs_scrub_context *sc, + unsigned long *map, + struct xfs_attr3_icleaf_hdr *leafhdr) +{ + unsigned long *freemap; + unsigned long *dstmap; + unsigned int mapsize = sc->mp->m_attr_geo->blksize; + int i; + + /* Construct bitmap of freemap contents. */ + freemap = (unsigned long *)sc->buf + BITS_TO_LONGS(mapsize); + bitmap_zero(freemap, mapsize); + for (i = 0; i < XFS_ATTR_LEAF_MAPSIZE; i++) { + if (!xfs_scrub_xattr_set_map(sc, freemap, + leafhdr->freemap[i].base, + leafhdr->freemap[i].size)) + return false; + } + + /* Look for bits that are set in freemap and are marked in use. */ + dstmap = freemap + BITS_TO_LONGS(mapsize); + return bitmap_and(dstmap, freemap, map, mapsize) == 0; +} + +/* + * Check this leaf entry's relations to everything else. + * Returns the number of bytes used for the name/value data. + */ +STATIC void +xfs_scrub_xattr_entry( + struct xfs_scrub_da_btree *ds, + int level, + char *buf_end, + struct xfs_attr_leafblock *leaf, + struct xfs_attr3_icleaf_hdr *leafhdr, + unsigned long *usedmap, + struct xfs_attr_leaf_entry *ent, + int idx, + unsigned int *usedbytes, + __u32 *last_hashval) +{ + struct xfs_mount *mp = ds->state->mp; + char *name_end; + struct xfs_attr_leaf_name_local *lentry; + struct xfs_attr_leaf_name_remote *rentry; + unsigned int nameidx; + unsigned int namesize; + + if (ent->pad2 != 0) + xfs_scrub_da_set_corrupt(ds, level); + + /* Hash values in order? */ + if (be32_to_cpu(ent->hashval) < *last_hashval) + xfs_scrub_da_set_corrupt(ds, level); + *last_hashval = be32_to_cpu(ent->hashval); + + nameidx = be16_to_cpu(ent->nameidx); + if (nameidx < leafhdr->firstused || + nameidx >= mp->m_attr_geo->blksize) { + xfs_scrub_da_set_corrupt(ds, level); + return; + } + + /* Check the name information. */ + if (ent->flags & XFS_ATTR_LOCAL) { + lentry = xfs_attr3_leaf_name_local(leaf, idx); + namesize = xfs_attr_leaf_entsize_local(lentry->namelen, + be16_to_cpu(lentry->valuelen)); + name_end = (char *)lentry + namesize; + if (lentry->namelen == 0) + xfs_scrub_da_set_corrupt(ds, level); + } else { + rentry = xfs_attr3_leaf_name_remote(leaf, idx); + namesize = xfs_attr_leaf_entsize_remote(rentry->namelen); + name_end = (char *)rentry + namesize; + if (rentry->namelen == 0 || rentry->valueblk == 0) + xfs_scrub_da_set_corrupt(ds, level); + } + if (name_end > buf_end) + xfs_scrub_da_set_corrupt(ds, level); + + if (!xfs_scrub_xattr_set_map(ds->sc, usedmap, nameidx, namesize)) + xfs_scrub_da_set_corrupt(ds, level); + if (!(ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)) + *usedbytes += namesize; +} + +/* Scrub an attribute leaf. */ +STATIC int +xfs_scrub_xattr_block( + struct xfs_scrub_da_btree *ds, + int level) +{ + struct xfs_attr3_icleaf_hdr leafhdr; + struct xfs_mount *mp = ds->state->mp; + struct xfs_da_state_blk *blk = &ds->state->path.blk[level]; + struct xfs_buf *bp = blk->bp; + xfs_dablk_t *last_checked = ds->private; + struct xfs_attr_leafblock *leaf = bp->b_addr; + struct xfs_attr_leaf_entry *ent; + struct xfs_attr_leaf_entry *entries; + unsigned long *usedmap = ds->sc->buf; + char *buf_end; + size_t off; + __u32 last_hashval = 0; + unsigned int usedbytes = 0; + unsigned int hdrsize; + int i; + + if (*last_checked == blk->blkno) + return 0; + *last_checked = blk->blkno; + bitmap_zero(usedmap, mp->m_attr_geo->blksize); + + /* Check all the padding. */ + if (xfs_sb_version_hascrc(&ds->sc->mp->m_sb)) { + struct xfs_attr3_leafblock *leaf = bp->b_addr; + + if (leaf->hdr.pad1 != 0 || leaf->hdr.pad2 != 0 || + leaf->hdr.info.hdr.pad != 0) + xfs_scrub_da_set_corrupt(ds, level); + } else { + if (leaf->hdr.pad1 != 0 || leaf->hdr.info.pad != 0) + xfs_scrub_da_set_corrupt(ds, level); + } + + /* Check the leaf header */ + xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &leafhdr, leaf); + hdrsize = xfs_attr3_leaf_hdr_size(leaf); + + if (leafhdr.usedbytes > mp->m_attr_geo->blksize) + xfs_scrub_da_set_corrupt(ds, level); + if (leafhdr.firstused > mp->m_attr_geo->blksize) + xfs_scrub_da_set_corrupt(ds, level); + if (leafhdr.firstused < hdrsize) + xfs_scrub_da_set_corrupt(ds, level); + if (!xfs_scrub_xattr_set_map(ds->sc, usedmap, 0, hdrsize)) + xfs_scrub_da_set_corrupt(ds, level); + + if (ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT) + goto out; + + entries = xfs_attr3_leaf_entryp(leaf); + if ((char *)&entries[leafhdr.count] > (char *)leaf + leafhdr.firstused) + xfs_scrub_da_set_corrupt(ds, level); + + buf_end = (char *)bp->b_addr + mp->m_attr_geo->blksize; + for (i = 0, ent = entries; i < leafhdr.count; ent++, i++) { + /* Mark the leaf entry itself. */ + off = (char *)ent - (char *)leaf; + if (!xfs_scrub_xattr_set_map(ds->sc, usedmap, off, + sizeof(xfs_attr_leaf_entry_t))) { + xfs_scrub_da_set_corrupt(ds, level); + goto out; + } + + /* Check the entry and nameval. */ + xfs_scrub_xattr_entry(ds, level, buf_end, leaf, &leafhdr, + usedmap, ent, i, &usedbytes, &last_hashval); + + if (ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT) + goto out; + } + + if (!xfs_scrub_xattr_check_freemap(ds->sc, usedmap, &leafhdr)) + xfs_scrub_da_set_corrupt(ds, level); + + if (leafhdr.usedbytes != usedbytes) + xfs_scrub_da_set_corrupt(ds, level); + +out: + return 0; +} + +/* Scrub a attribute btree record. */ +STATIC int +xfs_scrub_xattr_rec( + struct xfs_scrub_da_btree *ds, + int level, + void *rec) +{ + struct xfs_mount *mp = ds->state->mp; + struct xfs_attr_leaf_entry *ent = rec; + struct xfs_da_state_blk *blk; + struct xfs_attr_leaf_name_local *lentry; + struct xfs_attr_leaf_name_remote *rentry; + struct xfs_buf *bp; + xfs_dahash_t calc_hash; + xfs_dahash_t hash; + int nameidx; + int hdrsize; + unsigned int badflags; + int error; + + blk = &ds->state->path.blk[level]; + + /* Check the whole block, if necessary. */ + error = xfs_scrub_xattr_block(ds, level); + if (error) + goto out; + if (ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT) + goto out; + + /* Check the hash of the entry. */ + error = xfs_scrub_da_btree_hash(ds, level, &ent->hashval); + if (error) + goto out; + + /* Find the attr entry's location. */ + bp = blk->bp; + hdrsize = xfs_attr3_leaf_hdr_size(bp->b_addr); + nameidx = be16_to_cpu(ent->nameidx); + if (nameidx < hdrsize || nameidx >= mp->m_attr_geo->blksize) { + xfs_scrub_da_set_corrupt(ds, level); + goto out; + } + + /* Retrieve the entry and check it. */ + hash = be32_to_cpu(ent->hashval); + badflags = ~(XFS_ATTR_LOCAL | XFS_ATTR_ROOT | XFS_ATTR_SECURE | + XFS_ATTR_INCOMPLETE); + if ((ent->flags & badflags) != 0) + xfs_scrub_da_set_corrupt(ds, level); + if (ent->flags & XFS_ATTR_LOCAL) { + lentry = (struct xfs_attr_leaf_name_local *) + (((char *)bp->b_addr) + nameidx); + if (lentry->namelen <= 0) { + xfs_scrub_da_set_corrupt(ds, level); + goto out; + } + calc_hash = xfs_da_hashname(lentry->nameval, lentry->namelen); + } else { + rentry = (struct xfs_attr_leaf_name_remote *) + (((char *)bp->b_addr) + nameidx); + if (rentry->namelen <= 0) { + xfs_scrub_da_set_corrupt(ds, level); + goto out; + } + calc_hash = xfs_da_hashname(rentry->name, rentry->namelen); + } + if (calc_hash != hash) + xfs_scrub_da_set_corrupt(ds, level); + +out: + return error; +} + +/* Scrub the extended attribute metadata. */ +int +xfs_scrub_xattr( + struct xfs_scrub_context *sc) +{ + struct xfs_scrub_xattr sx; + struct attrlist_cursor_kern cursor = { 0 }; + xfs_dablk_t last_checked = -1U; + int error = 0; + + if (!xfs_inode_hasattr(sc->ip)) + return -ENOENT; + + memset(&sx, 0, sizeof(sx)); + /* Check attribute tree structure */ + error = xfs_scrub_da_btree(sc, XFS_ATTR_FORK, xfs_scrub_xattr_rec, + &last_checked); + if (error) + goto out; + + if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT) + goto out; + + /* Check that every attr key can also be looked up by hash. */ + sx.context.dp = sc->ip; + sx.context.cursor = &cursor; + sx.context.resynch = 1; + sx.context.put_listent = xfs_scrub_xattr_listent; + sx.context.tp = sc->tp; + sx.context.flags = ATTR_INCOMPLETE; + sx.sc = sc; + + /* + * Look up every xattr in this file by name. + * + * Use the backend implementation of xfs_attr_list to call + * xfs_scrub_xattr_listent on every attribute key in this inode. + * In other words, we use the same iterator/callback mechanism + * that listattr uses to scrub extended attributes, though in our + * _listent function, we check the value of the attribute. + * + * The VFS only locks i_rwsem when modifying attrs, so keep all + * three locks held because that's the only way to ensure we're + * the only thread poking into the da btree. We traverse the da + * btree while holding a leaf buffer locked for the xattr name + * iteration, which doesn't really follow the usual buffer + * locking order. + */ + error = xfs_attr_list_int_ilocked(&sx.context); + if (!xfs_scrub_fblock_process_error(sc, XFS_ATTR_FORK, 0, &error)) + goto out; +out: + return error; +} |