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-rw-r--r--fs/xfs/scrub/tempfile.c851
1 files changed, 851 insertions, 0 deletions
diff --git a/fs/xfs/scrub/tempfile.c b/fs/xfs/scrub/tempfile.c
new file mode 100644
index 0000000000..b747b625c5
--- /dev/null
+++ b/fs/xfs/scrub/tempfile.c
@@ -0,0 +1,851 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2021-2024 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_log_format.h"
+#include "xfs_trans.h"
+#include "xfs_inode.h"
+#include "xfs_ialloc.h"
+#include "xfs_quota.h"
+#include "xfs_bmap.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_trans_space.h"
+#include "xfs_dir2.h"
+#include "xfs_exchrange.h"
+#include "xfs_exchmaps.h"
+#include "xfs_defer.h"
+#include "xfs_symlink_remote.h"
+#include "scrub/scrub.h"
+#include "scrub/common.h"
+#include "scrub/repair.h"
+#include "scrub/trace.h"
+#include "scrub/tempfile.h"
+#include "scrub/tempexch.h"
+#include "scrub/xfile.h"
+
+/*
+ * Create a temporary file for reconstructing metadata, with the intention of
+ * atomically exchanging the temporary file's contents with the file that's
+ * being repaired.
+ */
+int
+xrep_tempfile_create(
+ struct xfs_scrub *sc,
+ uint16_t mode)
+{
+ struct xfs_mount *mp = sc->mp;
+ struct xfs_trans *tp = NULL;
+ struct xfs_dquot *udqp = NULL;
+ struct xfs_dquot *gdqp = NULL;
+ struct xfs_dquot *pdqp = NULL;
+ struct xfs_trans_res *tres;
+ struct xfs_inode *dp = mp->m_rootip;
+ xfs_ino_t ino;
+ unsigned int resblks;
+ bool is_dir = S_ISDIR(mode);
+ int error;
+
+ if (xfs_is_shutdown(mp))
+ return -EIO;
+ if (xfs_is_readonly(mp))
+ return -EROFS;
+
+ ASSERT(sc->tp == NULL);
+ ASSERT(sc->tempip == NULL);
+
+ /*
+ * Make sure that we have allocated dquot(s) on disk. The temporary
+ * inode should be completely root owned so that we don't fail due to
+ * quota limits.
+ */
+ error = xfs_qm_vop_dqalloc(dp, GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, 0,
+ XFS_QMOPT_QUOTALL, &udqp, &gdqp, &pdqp);
+ if (error)
+ return error;
+
+ if (is_dir) {
+ resblks = xfs_mkdir_space_res(mp, 0);
+ tres = &M_RES(mp)->tr_mkdir;
+ } else {
+ resblks = XFS_IALLOC_SPACE_RES(mp);
+ tres = &M_RES(mp)->tr_create_tmpfile;
+ }
+
+ error = xfs_trans_alloc_icreate(mp, tres, udqp, gdqp, pdqp, resblks,
+ &tp);
+ if (error)
+ goto out_release_dquots;
+
+ /* Allocate inode, set up directory. */
+ error = xfs_dialloc(&tp, dp->i_ino, mode, &ino);
+ if (error)
+ goto out_trans_cancel;
+ error = xfs_init_new_inode(&nop_mnt_idmap, tp, dp, ino, mode, 0, 0,
+ 0, false, &sc->tempip);
+ if (error)
+ goto out_trans_cancel;
+
+ /* Change the ownership of the inode to root. */
+ VFS_I(sc->tempip)->i_uid = GLOBAL_ROOT_UID;
+ VFS_I(sc->tempip)->i_gid = GLOBAL_ROOT_GID;
+ sc->tempip->i_diflags &= ~(XFS_DIFLAG_REALTIME | XFS_DIFLAG_RTINHERIT);
+ xfs_trans_log_inode(tp, sc->tempip, XFS_ILOG_CORE);
+
+ /*
+ * Mark our temporary file as private so that LSMs and the ACL code
+ * don't try to add their own metadata or reason about these files.
+ * The file should never be exposed to userspace.
+ */
+ VFS_I(sc->tempip)->i_flags |= S_PRIVATE;
+ VFS_I(sc->tempip)->i_opflags &= ~IOP_XATTR;
+
+ if (is_dir) {
+ error = xfs_dir_init(tp, sc->tempip, dp);
+ if (error)
+ goto out_trans_cancel;
+ } else if (S_ISLNK(VFS_I(sc->tempip)->i_mode)) {
+ /*
+ * Initialize the temporary symlink with a meaningless target
+ * that won't trip the verifiers. Repair must rewrite the
+ * target with meaningful content before swapping with the file
+ * being repaired. A single-byte target will not write a
+ * remote target block, so the owner is irrelevant.
+ */
+ error = xfs_symlink_write_target(tp, sc->tempip,
+ sc->tempip->i_ino, ".", 1, 0, 0);
+ if (error)
+ goto out_trans_cancel;
+ }
+
+ /*
+ * Attach the dquot(s) to the inodes and modify them incore.
+ * These ids of the inode couldn't have changed since the new
+ * inode has been locked ever since it was created.
+ */
+ xfs_qm_vop_create_dqattach(tp, sc->tempip, udqp, gdqp, pdqp);
+
+ /*
+ * Put our temp file on the unlinked list so it's purged automatically.
+ * All file-based metadata being reconstructed using this file must be
+ * atomically exchanged with the original file because the contents
+ * here will be purged when the inode is dropped or log recovery cleans
+ * out the unlinked list.
+ */
+ error = xfs_iunlink(tp, sc->tempip);
+ if (error)
+ goto out_trans_cancel;
+
+ error = xfs_trans_commit(tp);
+ if (error)
+ goto out_release_inode;
+
+ trace_xrep_tempfile_create(sc);
+
+ xfs_qm_dqrele(udqp);
+ xfs_qm_dqrele(gdqp);
+ xfs_qm_dqrele(pdqp);
+
+ /* Finish setting up the incore / vfs context. */
+ xfs_iunlock(sc->tempip, XFS_ILOCK_EXCL);
+ xfs_setup_iops(sc->tempip);
+ xfs_finish_inode_setup(sc->tempip);
+
+ sc->temp_ilock_flags = 0;
+ return error;
+
+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 (sc->tempip) {
+ xfs_iunlock(sc->tempip, XFS_ILOCK_EXCL);
+ xfs_finish_inode_setup(sc->tempip);
+ xchk_irele(sc, sc->tempip);
+ }
+out_release_dquots:
+ xfs_qm_dqrele(udqp);
+ xfs_qm_dqrele(gdqp);
+ xfs_qm_dqrele(pdqp);
+
+ return error;
+}
+
+/* Take IOLOCK_EXCL on the temporary file, maybe. */
+bool
+xrep_tempfile_iolock_nowait(
+ struct xfs_scrub *sc)
+{
+ if (xfs_ilock_nowait(sc->tempip, XFS_IOLOCK_EXCL)) {
+ sc->temp_ilock_flags |= XFS_IOLOCK_EXCL;
+ return true;
+ }
+
+ return false;
+}
+
+/*
+ * Take the temporary file's IOLOCK while holding a different inode's IOLOCK.
+ * In theory nobody else should hold the tempfile's IOLOCK, but we use trylock
+ * to avoid deadlocks and lockdep complaints.
+ */
+int
+xrep_tempfile_iolock_polled(
+ struct xfs_scrub *sc)
+{
+ int error = 0;
+
+ while (!xrep_tempfile_iolock_nowait(sc)) {
+ if (xchk_should_terminate(sc, &error))
+ return error;
+ delay(1);
+ }
+
+ return 0;
+}
+
+/* Release IOLOCK_EXCL on the temporary file. */
+void
+xrep_tempfile_iounlock(
+ struct xfs_scrub *sc)
+{
+ xfs_iunlock(sc->tempip, XFS_IOLOCK_EXCL);
+ sc->temp_ilock_flags &= ~XFS_IOLOCK_EXCL;
+}
+
+/* Prepare the temporary file for metadata updates by grabbing ILOCK_EXCL. */
+void
+xrep_tempfile_ilock(
+ struct xfs_scrub *sc)
+{
+ sc->temp_ilock_flags |= XFS_ILOCK_EXCL;
+ xfs_ilock(sc->tempip, XFS_ILOCK_EXCL);
+}
+
+/* Try to grab ILOCK_EXCL on the temporary file. */
+bool
+xrep_tempfile_ilock_nowait(
+ struct xfs_scrub *sc)
+{
+ if (xfs_ilock_nowait(sc->tempip, XFS_ILOCK_EXCL)) {
+ sc->temp_ilock_flags |= XFS_ILOCK_EXCL;
+ return true;
+ }
+
+ return false;
+}
+
+/* Unlock ILOCK_EXCL on the temporary file after an update. */
+void
+xrep_tempfile_iunlock(
+ struct xfs_scrub *sc)
+{
+ xfs_iunlock(sc->tempip, XFS_ILOCK_EXCL);
+ sc->temp_ilock_flags &= ~XFS_ILOCK_EXCL;
+}
+
+/*
+ * Begin the process of making changes to both the file being scrubbed and
+ * the temporary file by taking ILOCK_EXCL on both.
+ */
+void
+xrep_tempfile_ilock_both(
+ struct xfs_scrub *sc)
+{
+ xfs_lock_two_inodes(sc->ip, XFS_ILOCK_EXCL, sc->tempip, XFS_ILOCK_EXCL);
+ sc->ilock_flags |= XFS_ILOCK_EXCL;
+ sc->temp_ilock_flags |= XFS_ILOCK_EXCL;
+}
+
+/* Unlock ILOCK_EXCL on both files. */
+void
+xrep_tempfile_iunlock_both(
+ struct xfs_scrub *sc)
+{
+ xrep_tempfile_iunlock(sc);
+ xchk_iunlock(sc, XFS_ILOCK_EXCL);
+}
+
+/* Release the temporary file. */
+void
+xrep_tempfile_rele(
+ struct xfs_scrub *sc)
+{
+ if (!sc->tempip)
+ return;
+
+ if (sc->temp_ilock_flags) {
+ xfs_iunlock(sc->tempip, sc->temp_ilock_flags);
+ sc->temp_ilock_flags = 0;
+ }
+
+ xchk_irele(sc, sc->tempip);
+ sc->tempip = NULL;
+}
+
+/*
+ * Make sure that the given range of the data fork of the temporary file is
+ * mapped to written blocks. The caller must ensure that both inodes are
+ * joined to the transaction.
+ */
+int
+xrep_tempfile_prealloc(
+ struct xfs_scrub *sc,
+ xfs_fileoff_t off,
+ xfs_filblks_t len)
+{
+ struct xfs_bmbt_irec map;
+ xfs_fileoff_t end = off + len;
+ int error;
+
+ ASSERT(sc->tempip != NULL);
+ ASSERT(!XFS_NOT_DQATTACHED(sc->mp, sc->tempip));
+
+ for (; off < end; off = map.br_startoff + map.br_blockcount) {
+ int nmaps = 1;
+
+ /*
+ * If we have a real extent mapping this block then we're
+ * in ok shape.
+ */
+ error = xfs_bmapi_read(sc->tempip, off, end - off, &map, &nmaps,
+ XFS_DATA_FORK);
+ if (error)
+ return error;
+ if (nmaps == 0) {
+ ASSERT(nmaps != 0);
+ return -EFSCORRUPTED;
+ }
+
+ if (xfs_bmap_is_written_extent(&map))
+ continue;
+
+ /*
+ * If we find a delalloc reservation then something is very
+ * very wrong. Bail out.
+ */
+ if (map.br_startblock == DELAYSTARTBLOCK)
+ return -EFSCORRUPTED;
+
+ /*
+ * Make sure this block has a real zeroed extent allocated to
+ * it.
+ */
+ nmaps = 1;
+ error = xfs_bmapi_write(sc->tp, sc->tempip, off, end - off,
+ XFS_BMAPI_CONVERT | XFS_BMAPI_ZERO, 0, &map,
+ &nmaps);
+ if (error)
+ return error;
+ if (nmaps != 1)
+ return -EFSCORRUPTED;
+
+ trace_xrep_tempfile_prealloc(sc, XFS_DATA_FORK, &map);
+
+ /* Commit new extent and all deferred work. */
+ error = xfs_defer_finish(&sc->tp);
+ if (error)
+ return error;
+ }
+
+ return 0;
+}
+
+/*
+ * Write data to each block of a file. The given range of the tempfile's data
+ * fork must already be populated with written extents.
+ */
+int
+xrep_tempfile_copyin(
+ struct xfs_scrub *sc,
+ xfs_fileoff_t off,
+ xfs_filblks_t len,
+ xrep_tempfile_copyin_fn prep_fn,
+ void *data)
+{
+ LIST_HEAD(buffers_list);
+ struct xfs_mount *mp = sc->mp;
+ struct xfs_buf *bp;
+ xfs_fileoff_t flush_mask;
+ xfs_fileoff_t end = off + len;
+ loff_t pos = XFS_FSB_TO_B(mp, off);
+ int error = 0;
+
+ ASSERT(S_ISREG(VFS_I(sc->tempip)->i_mode));
+
+ /* Flush buffers to disk every 512K */
+ flush_mask = XFS_B_TO_FSBT(mp, (1U << 19)) - 1;
+
+ for (; off < end; off++, pos += mp->m_sb.sb_blocksize) {
+ struct xfs_bmbt_irec map;
+ int nmaps = 1;
+
+ /* Read block mapping for this file block. */
+ error = xfs_bmapi_read(sc->tempip, off, 1, &map, &nmaps, 0);
+ if (error)
+ goto out_err;
+ if (nmaps == 0 || !xfs_bmap_is_written_extent(&map)) {
+ error = -EFSCORRUPTED;
+ goto out_err;
+ }
+
+ /* Get the metadata buffer for this offset in the file. */
+ error = xfs_trans_get_buf(sc->tp, mp->m_ddev_targp,
+ XFS_FSB_TO_DADDR(mp, map.br_startblock),
+ mp->m_bsize, 0, &bp);
+ if (error)
+ goto out_err;
+
+ trace_xrep_tempfile_copyin(sc, XFS_DATA_FORK, &map);
+
+ /* Read in a block's worth of data from the xfile. */
+ error = prep_fn(sc, bp, data);
+ if (error) {
+ xfs_trans_brelse(sc->tp, bp);
+ goto out_err;
+ }
+
+ /* Queue buffer, and flush if we have too much dirty data. */
+ xfs_buf_delwri_queue_here(bp, &buffers_list);
+ xfs_trans_brelse(sc->tp, bp);
+
+ if (!(off & flush_mask)) {
+ error = xfs_buf_delwri_submit(&buffers_list);
+ if (error)
+ goto out_err;
+ }
+ }
+
+ /*
+ * Write the new blocks to disk. If the ordered list isn't empty after
+ * that, then something went wrong and we have to fail. This should
+ * never happen, but we'll check anyway.
+ */
+ error = xfs_buf_delwri_submit(&buffers_list);
+ if (error)
+ goto out_err;
+
+ if (!list_empty(&buffers_list)) {
+ ASSERT(list_empty(&buffers_list));
+ error = -EIO;
+ goto out_err;
+ }
+
+ return 0;
+
+out_err:
+ xfs_buf_delwri_cancel(&buffers_list);
+ return error;
+}
+
+/*
+ * Set the temporary file's size. Caller must join the tempfile to the scrub
+ * transaction and is responsible for adjusting block mappings as needed.
+ */
+int
+xrep_tempfile_set_isize(
+ struct xfs_scrub *sc,
+ unsigned long long isize)
+{
+ if (sc->tempip->i_disk_size == isize)
+ return 0;
+
+ sc->tempip->i_disk_size = isize;
+ i_size_write(VFS_I(sc->tempip), isize);
+ return xrep_tempfile_roll_trans(sc);
+}
+
+/*
+ * Roll a repair transaction involving the temporary file. Caller must join
+ * both the temporary file and the file being scrubbed to the transaction.
+ * This function return with both inodes joined to a new scrub transaction,
+ * or the usual negative errno.
+ */
+int
+xrep_tempfile_roll_trans(
+ struct xfs_scrub *sc)
+{
+ int error;
+
+ xfs_trans_log_inode(sc->tp, sc->tempip, XFS_ILOG_CORE);
+ error = xrep_roll_trans(sc);
+ if (error)
+ return error;
+
+ xfs_trans_ijoin(sc->tp, sc->tempip, 0);
+ return 0;
+}
+
+/*
+ * Fill out the mapping exchange request in preparation for atomically
+ * committing the contents of a metadata file that we've rebuilt in the temp
+ * file.
+ */
+STATIC int
+xrep_tempexch_prep_request(
+ struct xfs_scrub *sc,
+ int whichfork,
+ struct xrep_tempexch *tx)
+{
+ struct xfs_exchmaps_req *req = &tx->req;
+
+ memset(tx, 0, sizeof(struct xrep_tempexch));
+
+ /* COW forks don't exist on disk. */
+ if (whichfork == XFS_COW_FORK) {
+ ASSERT(0);
+ return -EINVAL;
+ }
+
+ /* Both files should have the relevant forks. */
+ if (!xfs_ifork_ptr(sc->ip, whichfork) ||
+ !xfs_ifork_ptr(sc->tempip, whichfork)) {
+ ASSERT(xfs_ifork_ptr(sc->ip, whichfork) != NULL);
+ ASSERT(xfs_ifork_ptr(sc->tempip, whichfork) != NULL);
+ return -EINVAL;
+ }
+
+ /* Exchange all mappings in both forks. */
+ req->ip1 = sc->tempip;
+ req->ip2 = sc->ip;
+ req->startoff1 = 0;
+ req->startoff2 = 0;
+ switch (whichfork) {
+ case XFS_ATTR_FORK:
+ req->flags |= XFS_EXCHMAPS_ATTR_FORK;
+ break;
+ case XFS_DATA_FORK:
+ /* Always exchange sizes when exchanging data fork mappings. */
+ req->flags |= XFS_EXCHMAPS_SET_SIZES;
+ break;
+ }
+ req->blockcount = XFS_MAX_FILEOFF;
+
+ return 0;
+}
+
+/*
+ * Fill out the mapping exchange resource estimation structures in preparation
+ * for exchanging the contents of a metadata file that we've rebuilt in the
+ * temp file. Caller must hold IOLOCK_EXCL but not ILOCK_EXCL on both files.
+ */
+STATIC int
+xrep_tempexch_estimate(
+ struct xfs_scrub *sc,
+ struct xrep_tempexch *tx)
+{
+ struct xfs_exchmaps_req *req = &tx->req;
+ struct xfs_ifork *ifp;
+ struct xfs_ifork *tifp;
+ int whichfork = xfs_exchmaps_reqfork(req);
+ int state = 0;
+
+ /*
+ * The exchmaps code only knows how to exchange file fork space
+ * mappings. Any fork data in local format must be promoted to a
+ * single block before the exchange can take place.
+ */
+ ifp = xfs_ifork_ptr(sc->ip, whichfork);
+ if (ifp->if_format == XFS_DINODE_FMT_LOCAL)
+ state |= 1;
+
+ tifp = xfs_ifork_ptr(sc->tempip, whichfork);
+ if (tifp->if_format == XFS_DINODE_FMT_LOCAL)
+ state |= 2;
+
+ switch (state) {
+ case 0:
+ /* Both files have mapped extents; use the regular estimate. */
+ return xfs_exchrange_estimate(req);
+ case 1:
+ /*
+ * The file being repaired is in local format, but the temp
+ * file has mapped extents. To perform the exchange, the file
+ * being repaired must have its shorform data converted to an
+ * ondisk block so that the forks will be in extents format.
+ * We need one resblk for the conversion; the number of
+ * exchanges is (worst case) the temporary file's extent count
+ * plus the block we converted.
+ */
+ req->ip1_bcount = sc->tempip->i_nblocks;
+ req->ip2_bcount = 1;
+ req->nr_exchanges = 1 + tifp->if_nextents;
+ req->resblks = 1;
+ break;
+ case 2:
+ /*
+ * The temporary file is in local format, but the file being
+ * repaired has mapped extents. To perform the exchange, the
+ * temp file must have its shortform data converted to an
+ * ondisk block, and the fork changed to extents format. We
+ * need one resblk for the conversion; the number of exchanges
+ * is (worst case) the extent count of the file being repaired
+ * plus the block we converted.
+ */
+ req->ip1_bcount = 1;
+ req->ip2_bcount = sc->ip->i_nblocks;
+ req->nr_exchanges = 1 + ifp->if_nextents;
+ req->resblks = 1;
+ break;
+ case 3:
+ /*
+ * Both forks are in local format. To perform the exchange,
+ * both files must have their shortform data converted to
+ * fsblocks, and both forks must be converted to extents
+ * format. We need two resblks for the two conversions, and
+ * the number of exchanges is 1 since there's only one block at
+ * fileoff 0. Presumably, the caller could not exchange the
+ * two inode fork areas directly.
+ */
+ req->ip1_bcount = 1;
+ req->ip2_bcount = 1;
+ req->nr_exchanges = 1;
+ req->resblks = 2;
+ break;
+ }
+
+ return xfs_exchmaps_estimate_overhead(req);
+}
+
+/*
+ * Obtain a quota reservation to make sure we don't hit EDQUOT. We can skip
+ * this if quota enforcement is disabled or if both inodes' dquots are the
+ * same. The qretry structure must be initialized to zeroes before the first
+ * call to this function.
+ */
+STATIC int
+xrep_tempexch_reserve_quota(
+ struct xfs_scrub *sc,
+ const struct xrep_tempexch *tx)
+{
+ struct xfs_trans *tp = sc->tp;
+ const struct xfs_exchmaps_req *req = &tx->req;
+ int64_t ddelta, rdelta;
+ int error;
+
+ /*
+ * Don't bother with a quota reservation if we're not enforcing them
+ * or the two inodes have the same dquots.
+ */
+ if (!XFS_IS_QUOTA_ON(tp->t_mountp) || req->ip1 == req->ip2 ||
+ (req->ip1->i_udquot == req->ip2->i_udquot &&
+ req->ip1->i_gdquot == req->ip2->i_gdquot &&
+ req->ip1->i_pdquot == req->ip2->i_pdquot))
+ return 0;
+
+ /*
+ * Quota reservation for each file comes from two sources. First, we
+ * need to account for any net gain in mapped blocks during the
+ * exchange. Second, we need reservation for the gross gain in mapped
+ * blocks so that we don't trip over any quota block reservation
+ * assertions. We must reserve the gross gain because the quota code
+ * subtracts from bcount the number of blocks that we unmap; it does
+ * not add that quantity back to the quota block reservation.
+ */
+ ddelta = max_t(int64_t, 0, req->ip2_bcount - req->ip1_bcount);
+ rdelta = max_t(int64_t, 0, req->ip2_rtbcount - req->ip1_rtbcount);
+ error = xfs_trans_reserve_quota_nblks(tp, req->ip1,
+ ddelta + req->ip1_bcount, rdelta + req->ip1_rtbcount,
+ true);
+ if (error)
+ return error;
+
+ ddelta = max_t(int64_t, 0, req->ip1_bcount - req->ip2_bcount);
+ rdelta = max_t(int64_t, 0, req->ip1_rtbcount - req->ip2_rtbcount);
+ return xfs_trans_reserve_quota_nblks(tp, req->ip2,
+ ddelta + req->ip2_bcount, rdelta + req->ip2_rtbcount,
+ true);
+}
+
+/*
+ * Prepare an existing transaction for an atomic file contents exchange.
+ *
+ * This function fills out the mapping exchange request and resource estimation
+ * structures in preparation for exchanging the contents of a metadata file
+ * that has been rebuilt in the temp file. Next, it reserves space and quota
+ * for the transaction.
+ *
+ * The caller must hold ILOCK_EXCL of the scrub target file and the temporary
+ * file. The caller must join both inodes to the transaction with no unlock
+ * flags, and is responsible for dropping both ILOCKs when appropriate. Only
+ * use this when those ILOCKs cannot be dropped.
+ */
+int
+xrep_tempexch_trans_reserve(
+ struct xfs_scrub *sc,
+ int whichfork,
+ struct xrep_tempexch *tx)
+{
+ int error;
+
+ ASSERT(sc->tp != NULL);
+ xfs_assert_ilocked(sc->ip, XFS_ILOCK_EXCL);
+ xfs_assert_ilocked(sc->tempip, XFS_ILOCK_EXCL);
+
+ error = xrep_tempexch_prep_request(sc, whichfork, tx);
+ if (error)
+ return error;
+
+ error = xfs_exchmaps_estimate(&tx->req);
+ if (error)
+ return error;
+
+ error = xfs_trans_reserve_more(sc->tp, tx->req.resblks, 0);
+ if (error)
+ return error;
+
+ return xrep_tempexch_reserve_quota(sc, tx);
+}
+
+/*
+ * Create a new transaction for a file contents exchange.
+ *
+ * This function fills out the mapping excahange request and resource
+ * estimation structures in preparation for exchanging the contents of a
+ * metadata file that has been rebuilt in the temp file. Next, it reserves
+ * space, takes ILOCK_EXCL of both inodes, joins them to the transaction and
+ * reserves quota for the transaction.
+ *
+ * The caller is responsible for dropping both ILOCKs when appropriate.
+ */
+int
+xrep_tempexch_trans_alloc(
+ struct xfs_scrub *sc,
+ int whichfork,
+ struct xrep_tempexch *tx)
+{
+ unsigned int flags = 0;
+ int error;
+
+ ASSERT(sc->tp == NULL);
+ ASSERT(xfs_has_exchange_range(sc->mp));
+
+ error = xrep_tempexch_prep_request(sc, whichfork, tx);
+ if (error)
+ return error;
+
+ error = xrep_tempexch_estimate(sc, tx);
+ if (error)
+ return error;
+
+ if (xfs_has_lazysbcount(sc->mp))
+ flags |= XFS_TRANS_RES_FDBLKS;
+
+ error = xfs_trans_alloc(sc->mp, &M_RES(sc->mp)->tr_itruncate,
+ tx->req.resblks, 0, flags, &sc->tp);
+ if (error)
+ return error;
+
+ sc->temp_ilock_flags |= XFS_ILOCK_EXCL;
+ sc->ilock_flags |= XFS_ILOCK_EXCL;
+ xfs_exchrange_ilock(sc->tp, sc->ip, sc->tempip);
+
+ return xrep_tempexch_reserve_quota(sc, tx);
+}
+
+/*
+ * Exchange file mappings (and hence file contents) between the file being
+ * repaired and the temporary file. Returns with both inodes locked and joined
+ * to a clean scrub transaction.
+ */
+int
+xrep_tempexch_contents(
+ struct xfs_scrub *sc,
+ struct xrep_tempexch *tx)
+{
+ int error;
+
+ ASSERT(xfs_has_exchange_range(sc->mp));
+
+ xfs_exchange_mappings(sc->tp, &tx->req);
+ error = xfs_defer_finish(&sc->tp);
+ if (error)
+ return error;
+
+ /*
+ * If we exchanged the ondisk sizes of two metadata files, we must
+ * exchanged the incore sizes as well.
+ */
+ if (tx->req.flags & XFS_EXCHMAPS_SET_SIZES) {
+ loff_t temp;
+
+ temp = i_size_read(VFS_I(sc->ip));
+ i_size_write(VFS_I(sc->ip), i_size_read(VFS_I(sc->tempip)));
+ i_size_write(VFS_I(sc->tempip), temp);
+ }
+
+ return 0;
+}
+
+/*
+ * Write local format data from one of the temporary file's forks into the same
+ * fork of file being repaired, and exchange the file sizes, if appropriate.
+ * Caller must ensure that the file being repaired has enough fork space to
+ * hold all the bytes.
+ */
+void
+xrep_tempfile_copyout_local(
+ struct xfs_scrub *sc,
+ int whichfork)
+{
+ struct xfs_ifork *temp_ifp;
+ struct xfs_ifork *ifp;
+ unsigned int ilog_flags = XFS_ILOG_CORE;
+
+ temp_ifp = xfs_ifork_ptr(sc->tempip, whichfork);
+ ifp = xfs_ifork_ptr(sc->ip, whichfork);
+
+ ASSERT(temp_ifp != NULL);
+ ASSERT(ifp != NULL);
+ ASSERT(temp_ifp->if_format == XFS_DINODE_FMT_LOCAL);
+ ASSERT(ifp->if_format == XFS_DINODE_FMT_LOCAL);
+
+ switch (whichfork) {
+ case XFS_DATA_FORK:
+ ASSERT(sc->tempip->i_disk_size <=
+ xfs_inode_data_fork_size(sc->ip));
+ break;
+ case XFS_ATTR_FORK:
+ ASSERT(sc->tempip->i_forkoff >= sc->ip->i_forkoff);
+ break;
+ default:
+ ASSERT(0);
+ return;
+ }
+
+ /* Recreate @sc->ip's incore fork (ifp) with data from temp_ifp. */
+ xfs_idestroy_fork(ifp);
+ xfs_init_local_fork(sc->ip, whichfork, temp_ifp->if_data,
+ temp_ifp->if_bytes);
+
+ if (whichfork == XFS_DATA_FORK) {
+ i_size_write(VFS_I(sc->ip), i_size_read(VFS_I(sc->tempip)));
+ sc->ip->i_disk_size = sc->tempip->i_disk_size;
+ }
+
+ ilog_flags |= xfs_ilog_fdata(whichfork);
+ xfs_trans_log_inode(sc->tp, sc->ip, ilog_flags);
+}
+
+/* Decide if a given XFS inode is a temporary file for a repair. */
+bool
+xrep_is_tempfile(
+ const struct xfs_inode *ip)
+{
+ const struct inode *inode = &ip->i_vnode;
+
+ if (IS_PRIVATE(inode) && !(inode->i_opflags & IOP_XATTR))
+ return true;
+
+ return false;
+}