--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2018-2024 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#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 "xfs_attr_sf.h"
+#include "xfs_attr_remote.h"
+#include "xfs_bmap.h"
+#include "xfs_bmap_util.h"
+#include "xfs_exchmaps.h"
+#include "xfs_exchrange.h"
+#include "xfs_acl.h"
+#include "scrub/xfs_scrub.h"
+#include "scrub/scrub.h"
+#include "scrub/common.h"
+#include "scrub/trace.h"
+#include "scrub/repair.h"
+#include "scrub/tempfile.h"
+#include "scrub/tempexch.h"
+#include "scrub/xfile.h"
+#include "scrub/xfarray.h"
+#include "scrub/xfblob.h"
+#include "scrub/attr.h"
+#include "scrub/reap.h"
+#include "scrub/attr_repair.h"
+
+/*
+ * Extended Attribute Repair
+ * =========================
+ *
+ * We repair extended attributes by reading the attr leaf blocks looking for
+ * attributes entries that look salvageable (name passes verifiers, value can
+ * be retrieved, etc). Each extended attribute worth salvaging is stashed in
+ * memory, and the stashed entries are periodically replayed into a temporary
+ * file to constrain memory use. Batching the construction of the temporary
+ * extended attribute structure in this fashion reduces lock cycling of the
+ * file being repaired and the temporary file.
+ *
+ * When salvaging completes, the remaining stashed attributes are replayed to
+ * the temporary file. An atomic file contents exchange is used to commit the
+ * new xattr blocks to the file being repaired. This will disrupt attrmulti
+ * cursors.
+ */
+
+struct xrep_xattr_key {
+ /* Cookie for retrieval of the xattr name. */
+ xfblob_cookie name_cookie;
+
+ /* Cookie for retrieval of the xattr value. */
+ xfblob_cookie value_cookie;
+
+ /* XFS_ATTR_* flags */
+ int flags;
+
+ /* Length of the value and name. */
+ uint32_t valuelen;
+ uint16_t namelen;
+};
+
+/*
+ * Stash up to 8 pages of attrs in xattr_records/xattr_blobs before we write
+ * them to the temp file.
+ */
+#define XREP_XATTR_MAX_STASH_BYTES (PAGE_SIZE * 8)
+
+struct xrep_xattr {
+ struct xfs_scrub *sc;
+
+ /* Information for exchanging attr fork mappings at the end. */
+ struct xrep_tempexch tx;
+
+ /* xattr keys */
+ struct xfarray *xattr_records;
+
+ /* xattr values */
+ struct xfblob *xattr_blobs;
+
+ /* Number of attributes that we are salvaging. */
+ unsigned long long attrs_found;
+};
+
+/* Set up to recreate the extended attributes. */
+int
+xrep_setup_xattr(
+ struct xfs_scrub *sc)
+{
+ return xrep_tempfile_create(sc, S_IFREG);
+}
+
+/*
+ * Decide if we want to salvage this attribute. We don't bother with
+ * incomplete or oversized keys or values. The @value parameter can be null
+ * for remote attrs.
+ */
+STATIC int
+xrep_xattr_want_salvage(
+ struct xrep_xattr *rx,
+ unsigned int attr_flags,
+ const void *name,
+ int namelen,
+ const void *value,
+ int valuelen)
+{
+ if (attr_flags & XFS_ATTR_INCOMPLETE)
+ return false;
+ if (namelen > XATTR_NAME_MAX || namelen <= 0)
+ return false;
+ if (!xfs_attr_namecheck(name, namelen))
+ return false;
+ if (valuelen > XATTR_SIZE_MAX || valuelen < 0)
+ return false;
+ if (hweight32(attr_flags & XFS_ATTR_NSP_ONDISK_MASK) > 1)
+ return false;
+ return true;
+}
+
+/* Allocate an in-core record to hold xattrs while we rebuild the xattr data. */
+STATIC int
+xrep_xattr_salvage_key(
+ struct xrep_xattr *rx,
+ int flags,
+ unsigned char *name,
+ int namelen,
+ unsigned char *value,
+ int valuelen)
+{
+ struct xrep_xattr_key key = {
+ .valuelen = valuelen,
+ .flags = flags & XFS_ATTR_NSP_ONDISK_MASK,
+ };
+ unsigned int i = 0;
+ int error = 0;
+
+ if (xchk_should_terminate(rx->sc, &error))
+ return error;
+
+ /*
+ * Truncate the name to the first character that would trip namecheck.
+ * If we no longer have a name after that, ignore this attribute.
+ */
+ while (i < namelen && name[i] != 0)
+ i++;
+ if (i == 0)
+ return 0;
+ key.namelen = i;
+
+ trace_xrep_xattr_salvage_rec(rx->sc->ip, flags, name, key.namelen,
+ valuelen);
+
+ error = xfblob_store(rx->xattr_blobs, &key.name_cookie, name,
+ key.namelen);
+ if (error)
+ return error;
+
+ error = xfblob_store(rx->xattr_blobs, &key.value_cookie, value,
+ key.valuelen);
+ if (error)
+ return error;
+
+ error = xfarray_append(rx->xattr_records, &key);
+ if (error)
+ return error;
+
+ rx->attrs_found++;
+ return 0;
+}
+
+/*
+ * Record a shortform extended attribute key & value for later reinsertion
+ * into the inode.
+ */
+STATIC int
+xrep_xattr_salvage_sf_attr(
+ struct xrep_xattr *rx,
+ struct xfs_attr_sf_hdr *hdr,
+ struct xfs_attr_sf_entry *sfe)
+{
+ struct xfs_scrub *sc = rx->sc;
+ struct xchk_xattr_buf *ab = sc->buf;
+ unsigned char *name = sfe->nameval;
+ unsigned char *value = &sfe->nameval[sfe->namelen];
+
+ if (!xchk_xattr_set_map(sc, ab->usedmap, (char *)name - (char *)hdr,
+ sfe->namelen))
+ return 0;
+
+ if (!xchk_xattr_set_map(sc, ab->usedmap, (char *)value - (char *)hdr,
+ sfe->valuelen))
+ return 0;
+
+ if (!xrep_xattr_want_salvage(rx, sfe->flags, sfe->nameval,
+ sfe->namelen, value, sfe->valuelen))
+ return 0;
+
+ return xrep_xattr_salvage_key(rx, sfe->flags, sfe->nameval,
+ sfe->namelen, value, sfe->valuelen);
+}
+
+/*
+ * Record a local format extended attribute key & value for later reinsertion
+ * into the inode.
+ */
+STATIC int
+xrep_xattr_salvage_local_attr(
+ struct xrep_xattr *rx,
+ struct xfs_attr_leaf_entry *ent,
+ unsigned int nameidx,
+ const char *buf_end,
+ struct xfs_attr_leaf_name_local *lentry)
+{
+ struct xchk_xattr_buf *ab = rx->sc->buf;
+ unsigned char *value;
+ unsigned int valuelen;
+ unsigned int namesize;
+
+ /*
+ * Decode the leaf local entry format. If something seems wrong, we
+ * junk the attribute.
+ */
+ value = &lentry->nameval[lentry->namelen];
+ valuelen = be16_to_cpu(lentry->valuelen);
+ namesize = xfs_attr_leaf_entsize_local(lentry->namelen, valuelen);
+ if ((char *)lentry + namesize > buf_end)
+ return 0;
+ if (!xrep_xattr_want_salvage(rx, ent->flags, lentry->nameval,
+ lentry->namelen, value, valuelen))
+ return 0;
+ if (!xchk_xattr_set_map(rx->sc, ab->usedmap, nameidx, namesize))
+ return 0;
+
+ /* Try to save this attribute. */
+ return xrep_xattr_salvage_key(rx, ent->flags, lentry->nameval,
+ lentry->namelen, value, valuelen);
+}
+
+/*
+ * Record a remote format extended attribute key & value for later reinsertion
+ * into the inode.
+ */
+STATIC int
+xrep_xattr_salvage_remote_attr(
+ struct xrep_xattr *rx,
+ struct xfs_attr_leaf_entry *ent,
+ unsigned int nameidx,
+ const char *buf_end,
+ struct xfs_attr_leaf_name_remote *rentry,
+ unsigned int ent_idx,
+ struct xfs_buf *leaf_bp)
+{
+ struct xchk_xattr_buf *ab = rx->sc->buf;
+ struct xfs_da_args args = {
+ .trans = rx->sc->tp,
+ .dp = rx->sc->ip,
+ .index = ent_idx,
+ .geo = rx->sc->mp->m_attr_geo,
+ .owner = rx->sc->ip->i_ino,
+ .attr_filter = ent->flags & XFS_ATTR_NSP_ONDISK_MASK,
+ .namelen = rentry->namelen,
+ .name = rentry->name,
+ .value = ab->value,
+ .valuelen = be32_to_cpu(rentry->valuelen),
+ };
+ unsigned int namesize;
+ int error;
+
+ /*
+ * Decode the leaf remote entry format. If something seems wrong, we
+ * junk the attribute. Note that we should never find a zero-length
+ * remote attribute value.
+ */
+ namesize = xfs_attr_leaf_entsize_remote(rentry->namelen);
+ if ((char *)rentry + namesize > buf_end)
+ return 0;
+ if (args.valuelen == 0 ||
+ !xrep_xattr_want_salvage(rx, ent->flags, rentry->name,
+ rentry->namelen, NULL, args.valuelen))
+ return 0;
+ if (!xchk_xattr_set_map(rx->sc, ab->usedmap, nameidx, namesize))
+ return 0;
+
+ /*
+ * Enlarge the buffer (if needed) to hold the value that we're trying
+ * to salvage from the old extended attribute data.
+ */
+ error = xchk_setup_xattr_buf(rx->sc, args.valuelen);
+ if (error == -ENOMEM)
+ error = -EDEADLOCK;
+ if (error)
+ return error;
+
+ /* Look up the remote value and stash it for reconstruction. */
+ error = xfs_attr3_leaf_getvalue(leaf_bp, &args);
+ if (error || args.rmtblkno == 0)
+ goto err_free;
+
+ error = xfs_attr_rmtval_get(&args);
+ if (error)
+ goto err_free;
+
+ /* Try to save this attribute. */
+ error = xrep_xattr_salvage_key(rx, ent->flags, rentry->name,
+ rentry->namelen, ab->value, args.valuelen);
+err_free:
+ /* remote value was garbage, junk it */
+ if (error == -EFSBADCRC || error == -EFSCORRUPTED)
+ error = 0;
+ return error;
+}
+
+/* Extract every xattr key that we can from this attr fork block. */
+STATIC int
+xrep_xattr_recover_leaf(
+ struct xrep_xattr *rx,
+ struct xfs_buf *bp)
+{
+ struct xfs_attr3_icleaf_hdr leafhdr;
+ struct xfs_scrub *sc = rx->sc;
+ struct xfs_mount *mp = sc->mp;
+ struct xfs_attr_leafblock *leaf;
+ struct xfs_attr_leaf_name_local *lentry;
+ struct xfs_attr_leaf_name_remote *rentry;
+ struct xfs_attr_leaf_entry *ent;
+ struct xfs_attr_leaf_entry *entries;
+ struct xchk_xattr_buf *ab = rx->sc->buf;
+ char *buf_end;
+ size_t off;
+ unsigned int nameidx;
+ unsigned int hdrsize;
+ int i;
+ int error = 0;
+
+ bitmap_zero(ab->usedmap, mp->m_attr_geo->blksize);
+
+ /* Check the leaf header */
+ leaf = bp->b_addr;
+ xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &leafhdr, leaf);
+ hdrsize = xfs_attr3_leaf_hdr_size(leaf);
+ xchk_xattr_set_map(sc, ab->usedmap, 0, hdrsize);
+ entries = xfs_attr3_leaf_entryp(leaf);
+
+ buf_end = (char *)bp->b_addr + mp->m_attr_geo->blksize;
+ for (i = 0, ent = entries; i < leafhdr.count; ent++, i++) {
+ if (xchk_should_terminate(sc, &error))
+ return error;
+
+ /* Skip key if it conflicts with something else? */
+ off = (char *)ent - (char *)leaf;
+ if (!xchk_xattr_set_map(sc, ab->usedmap, off,
+ sizeof(xfs_attr_leaf_entry_t)))
+ continue;
+
+ /* Check the name information. */
+ nameidx = be16_to_cpu(ent->nameidx);
+ if (nameidx < leafhdr.firstused ||
+ nameidx >= mp->m_attr_geo->blksize)
+ continue;
+
+ if (ent->flags & XFS_ATTR_LOCAL) {
+ lentry = xfs_attr3_leaf_name_local(leaf, i);
+ error = xrep_xattr_salvage_local_attr(rx, ent, nameidx,
+ buf_end, lentry);
+ } else {
+ rentry = xfs_attr3_leaf_name_remote(leaf, i);
+ error = xrep_xattr_salvage_remote_attr(rx, ent, nameidx,
+ buf_end, rentry, i, bp);
+ }
+ if (error)
+ return error;
+ }
+
+ return 0;
+}
+
+/* Try to recover shortform attrs. */
+STATIC int
+xrep_xattr_recover_sf(
+ struct xrep_xattr *rx)
+{
+ struct xfs_scrub *sc = rx->sc;
+ struct xchk_xattr_buf *ab = sc->buf;
+ struct xfs_attr_sf_hdr *hdr;
+ struct xfs_attr_sf_entry *sfe;
+ struct xfs_attr_sf_entry *next;
+ struct xfs_ifork *ifp;
+ unsigned char *end;
+ int i;
+ int error = 0;
+
+ ifp = xfs_ifork_ptr(rx->sc->ip, XFS_ATTR_FORK);
+ hdr = ifp->if_data;
+
+ bitmap_zero(ab->usedmap, ifp->if_bytes);
+ end = (unsigned char *)ifp->if_data + ifp->if_bytes;
+ xchk_xattr_set_map(sc, ab->usedmap, 0, sizeof(*hdr));
+
+ sfe = xfs_attr_sf_firstentry(hdr);
+ if ((unsigned char *)sfe > end)
+ return 0;
+
+ for (i = 0; i < hdr->count; i++) {
+ if (xchk_should_terminate(sc, &error))
+ return error;
+
+ next = xfs_attr_sf_nextentry(sfe);
+ if ((unsigned char *)next > end)
+ break;
+
+ if (xchk_xattr_set_map(sc, ab->usedmap,
+ (char *)sfe - (char *)hdr,
+ sizeof(struct xfs_attr_sf_entry))) {
+ /*
+ * No conflicts with the sf entry; let's save this
+ * attribute.
+ */
+ error = xrep_xattr_salvage_sf_attr(rx, hdr, sfe);
+ if (error)
+ return error;
+ }
+
+ sfe = next;
+ }
+
+ return 0;
+}
+
+/*
+ * Try to return a buffer of xattr data for a given physical extent.
+ *
+ * Because the buffer cache get function complains if it finds a buffer
+ * matching the block number but not matching the length, we must be careful to
+ * look for incore buffers (up to the maximum length of a remote value) that
+ * could be hiding anywhere in the physical range. If we find an incore
+ * buffer, we can pass that to the caller. Optionally, read a single block and
+ * pass that back.
+ *
+ * Note the subtlety that remote attr value blocks for which there is no incore
+ * buffer will be passed to the callback one block at a time. These buffers
+ * will not have any ops attached and must be staled to prevent aliasing with
+ * multiblock buffers once we drop the ILOCK.
+ */
+STATIC int
+xrep_xattr_find_buf(
+ struct xfs_mount *mp,
+ xfs_fsblock_t fsbno,
+ xfs_extlen_t max_len,
+ bool can_read,
+ struct xfs_buf **bpp)
+{
+ struct xrep_bufscan scan = {
+ .daddr = XFS_FSB_TO_DADDR(mp, fsbno),
+ .max_sectors = xrep_bufscan_max_sectors(mp, max_len),
+ .daddr_step = XFS_FSB_TO_BB(mp, 1),
+ };
+ struct xfs_buf *bp;
+
+ while ((bp = xrep_bufscan_advance(mp, &scan)) != NULL) {
+ *bpp = bp;
+ return 0;
+ }
+
+ if (!can_read) {
+ *bpp = NULL;
+ return 0;
+ }
+
+ return xfs_buf_read(mp->m_ddev_targp, scan.daddr, XFS_FSB_TO_BB(mp, 1),
+ XBF_TRYLOCK, bpp, NULL);
+}
+
+/*
+ * Deal with a buffer that we found during our walk of the attr fork.
+ *
+ * Attribute leaf and node blocks are simple -- they're a single block, so we
+ * can walk them one at a time and we never have to worry about discontiguous
+ * multiblock buffers like we do for directories.
+ *
+ * Unfortunately, remote attr blocks add a lot of complexity here. Each disk
+ * block is totally self contained, in the sense that the v5 header provides no
+ * indication that there could be more data in the next block. The incore
+ * buffers can span multiple blocks, though they never cross extent records.
+ * However, they don't necessarily start or end on an extent record boundary.
+ * Therefore, we need a special buffer find function to walk the buffer cache
+ * for us.
+ *
+ * The caller must hold the ILOCK on the file being repaired. We use
+ * XBF_TRYLOCK here to skip any locked buffer on the assumption that we don't
+ * own the block and don't want to hang the system on a potentially garbage
+ * buffer.
+ */
+STATIC int
+xrep_xattr_recover_block(
+ struct xrep_xattr *rx,
+ xfs_dablk_t dabno,
+ xfs_fsblock_t fsbno,
+ xfs_extlen_t max_len,
+ xfs_extlen_t *actual_len)
+{
+ struct xfs_da_blkinfo *info;
+ struct xfs_buf *bp;
+ int error;
+
+ error = xrep_xattr_find_buf(rx->sc->mp, fsbno, max_len, true, &bp);
+ if (error)
+ return error;
+ info = bp->b_addr;
+ *actual_len = XFS_BB_TO_FSB(rx->sc->mp, bp->b_length);
+
+ trace_xrep_xattr_recover_leafblock(rx->sc->ip, dabno,
+ be16_to_cpu(info->magic));
+
+ /*
+ * If the buffer has the right magic number for an attr leaf block and
+ * passes a structure check (we don't care about checksums), salvage
+ * as much as we can from the block. */
+ if (info->magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC) &&
+ xrep_buf_verify_struct(bp, &xfs_attr3_leaf_buf_ops) &&
+ xfs_attr3_leaf_header_check(bp, rx->sc->ip->i_ino) == NULL)
+ error = xrep_xattr_recover_leaf(rx, bp);
+
+ /*
+ * If the buffer didn't already have buffer ops set, it was read in by
+ * the _find_buf function and could very well be /part/ of a multiblock
+ * remote block. Mark it stale so that it doesn't hang around in
+ * memory to cause problems.
+ */
+ if (bp->b_ops == NULL)
+ xfs_buf_stale(bp);
+
+ xfs_buf_relse(bp);
+ return error;
+}
+
+/* Insert one xattr key/value. */
+STATIC int
+xrep_xattr_insert_rec(
+ struct xrep_xattr *rx,
+ const struct xrep_xattr_key *key)
+{
+ struct xfs_da_args args = {
+ .dp = rx->sc->tempip,
+ .attr_filter = key->flags,
+ .attr_flags = XATTR_CREATE,
+ .namelen = key->namelen,
+ .valuelen = key->valuelen,
+ .owner = rx->sc->ip->i_ino,
+ };
+ struct xchk_xattr_buf *ab = rx->sc->buf;
+ int error;
+
+ /*
+ * Grab pointers to the scrub buffer so that we can use them to insert
+ * attrs into the temp file.
+ */
+ args.name = ab->name;
+ args.value = ab->value;
+
+ /*
+ * The attribute name is stored near the end of the in-core buffer,
+ * though we reserve one more byte to ensure null termination.
+ */
+ ab->name[XATTR_NAME_MAX] = 0;
+
+ error = xfblob_load(rx->xattr_blobs, key->name_cookie, ab->name,
+ key->namelen);
+ if (error)
+ return error;
+
+ error = xfblob_free(rx->xattr_blobs, key->name_cookie);
+ if (error)
+ return error;
+
+ error = xfblob_load(rx->xattr_blobs, key->value_cookie, args.value,
+ key->valuelen);
+ if (error)
+ return error;
+
+ error = xfblob_free(rx->xattr_blobs, key->value_cookie);
+ if (error)
+ return error;
+
+ ab->name[key->namelen] = 0;
+
+ trace_xrep_xattr_insert_rec(rx->sc->tempip, key->flags, ab->name,
+ key->namelen, key->valuelen);
+
+ /*
+ * xfs_attr_set creates and commits its own transaction. If the attr
+ * already exists, we'll just drop it during the rebuild.
+ */
+ error = xfs_attr_set(&args);
+ if (error == -EEXIST)
+ error = 0;
+
+ return error;
+}
+
+/*
+ * Periodically flush salvaged attributes to the temporary file. This is done
+ * to reduce the memory requirements of the xattr rebuild because files can
+ * contain millions of attributes.
+ */
+STATIC int
+xrep_xattr_flush_stashed(
+ struct xrep_xattr *rx)
+{
+ xfarray_idx_t array_cur;
+ int error;
+
+ /*
+ * Entering this function, the scrub context has a reference to the
+ * inode being repaired, the temporary file, and a scrub transaction
+ * that we use during xattr salvaging to avoid livelocking if there
+ * are cycles in the xattr structures. We hold ILOCK_EXCL on both
+ * the inode being repaired, though it is not ijoined to the scrub
+ * transaction.
+ *
+ * To constrain kernel memory use, we occasionally flush salvaged
+ * xattrs from the xfarray and xfblob structures into the temporary
+ * file in preparation for exchanging the xattr structures at the end.
+ * Updating the temporary file requires a transaction, so we commit the
+ * scrub transaction and drop the two ILOCKs so that xfs_attr_set can
+ * allocate whatever transaction it wants.
+ *
+ * We still hold IOLOCK_EXCL on the inode being repaired, which
+ * prevents anyone from modifying the damaged xattr data while we
+ * repair it.
+ */
+ error = xrep_trans_commit(rx->sc);
+ if (error)
+ return error;
+ xchk_iunlock(rx->sc, XFS_ILOCK_EXCL);
+
+ /*
+ * Take the IOLOCK of the temporary file while we modify xattrs. This
+ * isn't strictly required because the temporary file is never revealed
+ * to userspace, but we follow the same locking rules. We still hold
+ * sc->ip's IOLOCK.
+ */
+ error = xrep_tempfile_iolock_polled(rx->sc);
+ if (error)
+ return error;
+
+ /* Add all the salvaged attrs to the temporary file. */
+ foreach_xfarray_idx(rx->xattr_records, array_cur) {
+ struct xrep_xattr_key key;
+
+ error = xfarray_load(rx->xattr_records, array_cur, &key);
+ if (error)
+ return error;
+
+ error = xrep_xattr_insert_rec(rx, &key);
+ if (error)
+ return error;
+ }
+
+ /* Empty out both arrays now that we've added the entries. */
+ xfarray_truncate(rx->xattr_records);
+ xfblob_truncate(rx->xattr_blobs);
+
+ xrep_tempfile_iounlock(rx->sc);
+
+ /* Recreate the salvage transaction and relock the inode. */
+ error = xchk_trans_alloc(rx->sc, 0);
+ if (error)
+ return error;
+ xchk_ilock(rx->sc, XFS_ILOCK_EXCL);
+ return 0;
+}
+
+/* Decide if we've stashed too much xattr data in memory. */
+static inline bool
+xrep_xattr_want_flush_stashed(
+ struct xrep_xattr *rx)
+{
+ unsigned long long bytes;
+
+ bytes = xfarray_bytes(rx->xattr_records) +
+ xfblob_bytes(rx->xattr_blobs);
+ return bytes > XREP_XATTR_MAX_STASH_BYTES;
+}
+
+/* Extract as many attribute keys and values as we can. */
+STATIC int
+xrep_xattr_recover(
+ struct xrep_xattr *rx)
+{
+ struct xfs_bmbt_irec got;
+ struct xfs_scrub *sc = rx->sc;
+ struct xfs_da_geometry *geo = sc->mp->m_attr_geo;
+ xfs_fileoff_t offset;
+ xfs_extlen_t len;
+ xfs_dablk_t dabno;
+ int nmap;
+ int error;
+
+ /*
+ * Iterate each xattr leaf block in the attr fork to scan them for any
+ * attributes that we might salvage.
+ */
+ for (offset = 0;
+ offset < XFS_MAX_FILEOFF;
+ offset = got.br_startoff + got.br_blockcount) {
+ nmap = 1;
+ error = xfs_bmapi_read(sc->ip, offset, XFS_MAX_FILEOFF - offset,
+ &got, &nmap, XFS_BMAPI_ATTRFORK);
+ if (error)
+ return error;
+ if (nmap != 1)
+ return -EFSCORRUPTED;
+ if (!xfs_bmap_is_written_extent(&got))
+ continue;
+
+ for (dabno = round_up(got.br_startoff, geo->fsbcount);
+ dabno < got.br_startoff + got.br_blockcount;
+ dabno += len) {
+ xfs_fileoff_t curr_offset = dabno - got.br_startoff;
+ xfs_extlen_t maxlen;
+
+ if (xchk_should_terminate(rx->sc, &error))
+ return error;
+
+ maxlen = min_t(xfs_filblks_t, INT_MAX,
+ got.br_blockcount - curr_offset);
+ error = xrep_xattr_recover_block(rx, dabno,
+ curr_offset + got.br_startblock,
+ maxlen, &len);
+ if (error)
+ return error;
+
+ if (xrep_xattr_want_flush_stashed(rx)) {
+ error = xrep_xattr_flush_stashed(rx);
+ if (error)
+ return error;
+ }
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Reset the extended attribute fork to a state where we can start re-adding
+ * the salvaged attributes.
+ */
+STATIC int
+xrep_xattr_fork_remove(
+ struct xfs_scrub *sc,
+ struct xfs_inode *ip)
+{
+ struct xfs_attr_sf_hdr *hdr;
+ struct xfs_ifork *ifp = xfs_ifork_ptr(ip, XFS_ATTR_FORK);
+
+ /*
+ * If the data fork is in btree format, we can't change di_forkoff
+ * because we could run afoul of the rule that the data fork isn't
+ * supposed to be in btree format if there's enough space in the fork
+ * that it could have used extents format. Instead, reinitialize the
+ * attr fork to have a shortform structure with zero attributes.
+ */
+ if (ip->i_df.if_format == XFS_DINODE_FMT_BTREE) {
+ ifp->if_format = XFS_DINODE_FMT_LOCAL;
+ hdr = xfs_idata_realloc(ip, (int)sizeof(*hdr) - ifp->if_bytes,
+ XFS_ATTR_FORK);
+ hdr->count = 0;
+ hdr->totsize = cpu_to_be16(sizeof(*hdr));
+ xfs_trans_log_inode(sc->tp, ip,
+ XFS_ILOG_CORE | XFS_ILOG_ADATA);
+ return 0;
+ }
+
+ /* If we still have attr fork extents, something's wrong. */
+ if (ifp->if_nextents != 0) {
+ struct xfs_iext_cursor icur;
+ struct xfs_bmbt_irec irec;
+ unsigned int i = 0;
+
+ xfs_emerg(sc->mp,
+ "inode 0x%llx attr fork still has %llu attr extents, format %d?!",
+ ip->i_ino, ifp->if_nextents, ifp->if_format);
+ for_each_xfs_iext(ifp, &icur, &irec) {
+ xfs_err(sc->mp,
+ "[%u]: startoff %llu startblock %llu blockcount %llu state %u",
+ i++, irec.br_startoff,
+ irec.br_startblock, irec.br_blockcount,
+ irec.br_state);
+ }
+ ASSERT(0);
+ return -EFSCORRUPTED;
+ }
+
+ xfs_attr_fork_remove(ip, sc->tp);
+ return 0;
+}
+
+/*
+ * Free all the attribute fork blocks of the file being repaired and delete the
+ * fork. The caller must ILOCK the scrub file and join it to the transaction.
+ * This function returns with the inode joined to a clean transaction.
+ */
+int
+xrep_xattr_reset_fork(
+ struct xfs_scrub *sc)
+{
+ int error;
+
+ trace_xrep_xattr_reset_fork(sc->ip, sc->ip);
+
+ /* Unmap all the attr blocks. */
+ if (xfs_ifork_has_extents(&sc->ip->i_af)) {
+ error = xrep_reap_ifork(sc, sc->ip, XFS_ATTR_FORK);
+ if (error)
+ return error;
+ }
+
+ error = xrep_xattr_fork_remove(sc, sc->ip);
+ if (error)
+ return error;
+
+ return xfs_trans_roll_inode(&sc->tp, sc->ip);
+}
+
+/*
+ * Free all the attribute fork blocks of the temporary file and delete the attr
+ * fork. The caller must ILOCK the tempfile and join it to the transaction.
+ * This function returns with the inode joined to a clean scrub transaction.
+ */
+STATIC int
+xrep_xattr_reset_tempfile_fork(
+ struct xfs_scrub *sc)
+{
+ int error;
+
+ trace_xrep_xattr_reset_fork(sc->ip, sc->tempip);
+
+ /*
+ * Wipe out the attr fork of the temp file so that regular inode
+ * inactivation won't trip over the corrupt attr fork.
+ */
+ if (xfs_ifork_has_extents(&sc->tempip->i_af)) {
+ error = xrep_reap_ifork(sc, sc->tempip, XFS_ATTR_FORK);
+ if (error)
+ return error;
+ }
+
+ return xrep_xattr_fork_remove(sc, sc->tempip);
+}
+
+/*
+ * Find all the extended attributes for this inode by scraping them out of the
+ * attribute key blocks by hand, and flushing them into the temp file.
+ * When we're done, free the staging memory before exchanging the xattr
+ * structures to reduce memory usage.
+ */
+STATIC int
+xrep_xattr_salvage_attributes(
+ struct xrep_xattr *rx)
+{
+ struct xfs_inode *ip = rx->sc->ip;
+ int error;
+
+ /* Short format xattrs are easy! */
+ if (rx->sc->ip->i_af.if_format == XFS_DINODE_FMT_LOCAL) {
+ error = xrep_xattr_recover_sf(rx);
+ if (error)
+ return error;
+
+ return xrep_xattr_flush_stashed(rx);
+ }
+
+ /*
+ * For non-inline xattr structures, the salvage function scans the
+ * buffer cache looking for potential attr leaf blocks. The scan
+ * requires the ability to lock any buffer found and runs independently
+ * of any transaction <-> buffer item <-> buffer linkage. Therefore,
+ * roll the transaction to ensure there are no buffers joined. We hold
+ * the ILOCK independently of the transaction.
+ */
+ error = xfs_trans_roll(&rx->sc->tp);
+ if (error)
+ return error;
+
+ error = xfs_iread_extents(rx->sc->tp, ip, XFS_ATTR_FORK);
+ if (error)
+ return error;
+
+ error = xrep_xattr_recover(rx);
+ if (error)
+ return error;
+
+ return xrep_xattr_flush_stashed(rx);
+}
+
+/*
+ * Prepare both inodes' attribute forks for an exchange. Promote the tempfile
+ * from short format to leaf format, and if the file being repaired has a short
+ * format attr fork, turn it into an empty extent list.
+ */
+STATIC int
+xrep_xattr_swap_prep(
+ struct xfs_scrub *sc,
+ bool temp_local,
+ bool ip_local)
+{
+ int error;
+
+ /*
+ * If the tempfile's attributes are in shortform format, convert that
+ * to a single leaf extent so that we can use the atomic mapping
+ * exchange.
+ */
+ if (temp_local) {
+ struct xfs_da_args args = {
+ .dp = sc->tempip,
+ .geo = sc->mp->m_attr_geo,
+ .whichfork = XFS_ATTR_FORK,
+ .trans = sc->tp,
+ .total = 1,
+ .owner = sc->ip->i_ino,
+ };
+
+ error = xfs_attr_shortform_to_leaf(&args);
+ if (error)
+ return error;
+
+ /*
+ * Roll the deferred log items to get us back to a clean
+ * transaction.
+ */
+ error = xfs_defer_finish(&sc->tp);
+ if (error)
+ return error;
+ }
+
+ /*
+ * If the file being repaired had a shortform attribute fork, convert
+ * that to an empty extent list in preparation for the atomic mapping
+ * exchange.
+ */
+ if (ip_local) {
+ struct xfs_ifork *ifp;
+
+ ifp = xfs_ifork_ptr(sc->ip, XFS_ATTR_FORK);
+
+ xfs_idestroy_fork(ifp);
+ ifp->if_format = XFS_DINODE_FMT_EXTENTS;
+ ifp->if_nextents = 0;
+ ifp->if_bytes = 0;
+ ifp->if_data = NULL;
+ ifp->if_height = 0;
+
+ xfs_trans_log_inode(sc->tp, sc->ip,
+ XFS_ILOG_CORE | XFS_ILOG_ADATA);
+ }
+
+ return 0;
+}
+
+/* Exchange the temporary file's attribute fork with the one being repaired. */
+STATIC int
+xrep_xattr_swap(
+ struct xfs_scrub *sc,
+ struct xrep_tempexch *tx)
+{
+ bool ip_local, temp_local;
+ int error = 0;
+
+ ip_local = sc->ip->i_af.if_format == XFS_DINODE_FMT_LOCAL;
+ temp_local = sc->tempip->i_af.if_format == XFS_DINODE_FMT_LOCAL;
+
+ /*
+ * If the both files have a local format attr fork and the rebuilt
+ * xattr data would fit in the repaired file's attr fork, just copy
+ * the contents from the tempfile and declare ourselves done.
+ */
+ if (ip_local && temp_local) {
+ int forkoff;
+ int newsize;
+
+ newsize = xfs_attr_sf_totsize(sc->tempip);
+ forkoff = xfs_attr_shortform_bytesfit(sc->ip, newsize);
+ if (forkoff > 0) {
+ sc->ip->i_forkoff = forkoff;
+ xrep_tempfile_copyout_local(sc, XFS_ATTR_FORK);
+ return 0;
+ }
+ }
+
+ /* Otherwise, make sure both attr forks are in block-mapping mode. */
+ error = xrep_xattr_swap_prep(sc, temp_local, ip_local);
+ if (error)
+ return error;
+
+ return xrep_tempexch_contents(sc, tx);
+}
+
+/*
+ * Exchange the new extended attribute data (which we created in the tempfile)
+ * with the file being repaired.
+ */
+STATIC int
+xrep_xattr_rebuild_tree(
+ struct xrep_xattr *rx)
+{
+ struct xfs_scrub *sc = rx->sc;
+ int error;
+
+ /*
+ * If we didn't find any attributes to salvage, repair the file by
+ * zapping its attr fork.
+ */
+ if (rx->attrs_found == 0) {
+ xfs_trans_ijoin(sc->tp, sc->ip, 0);
+ error = xrep_xattr_reset_fork(sc);
+ if (error)
+ return error;
+
+ goto forget_acls;
+ }
+
+ trace_xrep_xattr_rebuild_tree(sc->ip, sc->tempip);
+
+ /*
+ * Commit the repair transaction and drop the ILOCKs so that we can use
+ * the atomic file content exchange helper functions to compute the
+ * correct resource reservations.
+ *
+ * We still hold IOLOCK_EXCL (aka i_rwsem) which will prevent xattr
+ * modifications, but there's nothing to prevent userspace from reading
+ * the attributes until we're ready for the exchange operation. Reads
+ * will return -EIO without shutting down the fs, so we're ok with
+ * that.
+ */
+ error = xrep_trans_commit(sc);
+ if (error)
+ return error;
+
+ xchk_iunlock(sc, XFS_ILOCK_EXCL);
+
+ /*
+ * Take the IOLOCK on the temporary file so that we can run xattr
+ * operations with the same locks held as we would for a normal file.
+ * We still hold sc->ip's IOLOCK.
+ */
+ error = xrep_tempfile_iolock_polled(rx->sc);
+ if (error)
+ return error;
+
+ /* Allocate exchange transaction and lock both inodes. */
+ error = xrep_tempexch_trans_alloc(rx->sc, XFS_ATTR_FORK, &rx->tx);
+ if (error)
+ return error;
+
+ /*
+ * Exchange the blocks mapped by the tempfile's attr fork with the file
+ * being repaired. The old attr blocks will then be attached to the
+ * tempfile, so reap its attr fork.
+ */
+ error = xrep_xattr_swap(sc, &rx->tx);
+ if (error)
+ return error;
+
+ error = xrep_xattr_reset_tempfile_fork(sc);
+ if (error)
+ return error;
+
+ /*
+ * Roll to get a transaction without any inodes joined to it. Then we
+ * can drop the tempfile's ILOCK and IOLOCK before doing more work on
+ * the scrub target file.
+ */
+ error = xfs_trans_roll(&sc->tp);
+ if (error)
+ return error;
+
+ xrep_tempfile_iunlock(sc);
+ xrep_tempfile_iounlock(sc);
+
+forget_acls:
+ /* Invalidate cached ACLs now that we've reloaded all the xattrs. */
+ xfs_forget_acl(VFS_I(sc->ip), SGI_ACL_FILE);
+ xfs_forget_acl(VFS_I(sc->ip), SGI_ACL_DEFAULT);
+ return 0;
+}
+
+/* Tear down all the incore scan stuff we created. */
+STATIC void
+xrep_xattr_teardown(
+ struct xrep_xattr *rx)
+{
+ xfblob_destroy(rx->xattr_blobs);
+ xfarray_destroy(rx->xattr_records);
+ kfree(rx);
+}
+
+/* Set up the filesystem scan so we can regenerate extended attributes. */
+STATIC int
+xrep_xattr_setup_scan(
+ struct xfs_scrub *sc,
+ struct xrep_xattr **rxp)
+{
+ struct xrep_xattr *rx;
+ char *descr;
+ int max_len;
+ int error;
+
+ rx = kzalloc(sizeof(struct xrep_xattr), XCHK_GFP_FLAGS);
+ if (!rx)
+ return -ENOMEM;
+ rx->sc = sc;
+
+ /*
+ * Allocate enough memory to handle loading local attr values from the
+ * xfblob data while flushing stashed attrs to the temporary file.
+ * We only realloc the buffer when salvaging remote attr values.
+ */
+ max_len = xfs_attr_leaf_entsize_local_max(sc->mp->m_attr_geo->blksize);
+ error = xchk_setup_xattr_buf(rx->sc, max_len);
+ if (error == -ENOMEM)
+ error = -EDEADLOCK;
+ if (error)
+ goto out_rx;
+
+ /* Set up some staging for salvaged attribute keys and values */
+ descr = xchk_xfile_ino_descr(sc, "xattr keys");
+ error = xfarray_create(descr, 0, sizeof(struct xrep_xattr_key),
+ &rx->xattr_records);
+ kfree(descr);
+ if (error)
+ goto out_rx;
+
+ descr = xchk_xfile_ino_descr(sc, "xattr names");
+ error = xfblob_create(descr, &rx->xattr_blobs);
+ kfree(descr);
+ if (error)
+ goto out_keys;
+
+ *rxp = rx;
+ return 0;
+out_keys:
+ xfarray_destroy(rx->xattr_records);
+out_rx:
+ kfree(rx);
+ return error;
+}
+
+/*
+ * Repair the extended attribute metadata.
+ *
+ * XXX: Remote attribute value buffers encompass the entire (up to 64k) buffer.
+ * The buffer cache in XFS can't handle aliased multiblock buffers, so this
+ * might misbehave if the attr fork is crosslinked with other filesystem
+ * metadata.
+ */
+int
+xrep_xattr(
+ struct xfs_scrub *sc)
+{
+ struct xrep_xattr *rx = NULL;
+ int error;
+
+ if (!xfs_inode_hasattr(sc->ip))
+ return -ENOENT;
+
+ /* The rmapbt is required to reap the old attr fork. */
+ if (!xfs_has_rmapbt(sc->mp))
+ return -EOPNOTSUPP;
+
+ error = xrep_xattr_setup_scan(sc, &rx);
+ if (error)
+ return error;
+
+ ASSERT(sc->ilock_flags & XFS_ILOCK_EXCL);
+
+ error = xrep_xattr_salvage_attributes(rx);
+ if (error)
+ goto out_scan;
+
+ /* Last chance to abort before we start committing fixes. */
+ if (xchk_should_terminate(sc, &error))
+ goto out_scan;
+
+ error = xrep_xattr_rebuild_tree(rx);
+ if (error)
+ goto out_scan;
+
+out_scan:
+ xrep_xattr_teardown(rx);
+ return error;
+}
projects / linux-block.git / commitdiff