[PATCH 1/3] xfs: support preallocating and copying content into temporary files

Darrick J. Wong
2023-12-31T20:32:04Z

Create the routines we need to preallocate space in a temporary ondisk
file and then copy the contents of an xfile into the tempfile. The
upcoming rtsummary repair feature will construct the contents of a
realtime summary file in memory, after which it will want to copy all
that into the ondisk temporary file before atomically committing the new
rtsummary contents.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/scrub/tempfile.c | 197 +++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/scrub/tempfile.h | 15 ++++
fs/xfs/scrub/trace.h | 39 +++++++++
3 files changed, 251 insertions(+)

diff --git a/fs/xfs/scrub/tempfile.c b/fs/xfs/scrub/tempfile.c
index 5f4a931b1967c..936107d083545 100644
--- a/fs/xfs/scrub/tempfile.c
+++ b/fs/xfs/scrub/tempfile.c
@@ -14,14 +14,18 @@
#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_xchgrange.h"
+#include "xfs_defer.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
+#include "scrub/repair.h"
#include "scrub/trace.h"
#include "scrub/tempfile.h"
+#include "scrub/xfile.h"

/*
* Create a temporary file for reconstructing metadata, with the intention of
@@ -249,3 +253,196 @@ xrep_tempfile_rele(
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;
+}
diff --git a/fs/xfs/scrub/tempfile.h b/fs/xfs/scrub/tempfile.h
index e165e0a3faf63..7980f9c4de552 100644
--- a/fs/xfs/scrub/tempfile.h
+++ b/fs/xfs/scrub/tempfile.h
@@ -17,6 +17,21 @@ void xrep_tempfile_iounlock(struct xfs_scrub *sc);
void xrep_tempfile_ilock(struct xfs_scrub *sc);
bool xrep_tempfile_ilock_nowait(struct xfs_scrub *sc);
void xrep_tempfile_iunlock(struct xfs_scrub *sc);
+
+int xrep_tempfile_prealloc(struct xfs_scrub *sc, xfs_fileoff_t off,
+ xfs_filblks_t len);
+
+enum xfs_blft;
+
+typedef int (*xrep_tempfile_copyin_fn)(struct xfs_scrub *sc,
+ struct xfs_buf *bp, void *data);
+
+int xrep_tempfile_copyin(struct xfs_scrub *sc, xfs_fileoff_t off,
+ xfs_filblks_t len, xrep_tempfile_copyin_fn fn, void *data);
+
+int xrep_tempfile_set_isize(struct xfs_scrub *sc, unsigned long long isize);
+
+int xrep_tempfile_roll_trans(struct xfs_scrub *sc);
#else
static inline void xrep_tempfile_iolock_both(struct xfs_scrub *sc)
{
diff --git a/fs/xfs/scrub/trace.h b/fs/xfs/scrub/trace.h
index 691c91c9a5853..73ddaaadd2414 100644
--- a/fs/xfs/scrub/trace.h
+++ b/fs/xfs/scrub/trace.h
@@ -2396,6 +2396,45 @@ TRACE_EVENT(xrep_tempfile_create,
__entry->temp_inum)
);

+DECLARE_EVENT_CLASS(xrep_tempfile_class,
+ TP_PROTO(struct xfs_scrub *sc, int whichfork,
+ struct xfs_bmbt_irec *irec),
+ TP_ARGS(sc, whichfork, irec),
+ TP_STRUCT__entry(
+ __field(dev_t, dev)
+ __field(xfs_ino_t, ino)
+ __field(int, whichfork)
+ __field(xfs_fileoff_t, lblk)
+ __field(xfs_filblks_t, len)
+ __field(xfs_fsblock_t, pblk)
+ __field(int, state)
+ ),
+ TP_fast_assign(
+ __entry->dev = sc->mp->m_super->s_dev;
+ __entry->ino = sc->tempip->i_ino;
+ __entry->whichfork = whichfork;
+ __entry->lblk = irec->br_startoff;
+ __entry->len = irec->br_blockcount;
+ __entry->pblk = irec->br_startblock;
+ __entry->state = irec->br_state;
+ ),
+ TP_printk("dev %d:%d ino 0x%llx whichfork %s fileoff 0x%llx fsbcount 0x%llx startblock 0x%llx state %d",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ __entry->ino,
+ __print_symbolic(__entry->whichfork, XFS_WHICHFORK_STRINGS),
+ __entry->lblk,
+ __entry->len,
+ __entry->pblk,
+ __entry->state)
+);
+#define DEFINE_XREP_TEMPFILE_EVENT(name) \
+DEFINE_EVENT(xrep_tempfile_class, name, \
+ TP_PROTO(struct xfs_scrub *sc, int whichfork, \
+ struct xfs_bmbt_irec *irec), \
+ TP_ARGS(sc, whichfork, irec))
+DEFINE_XREP_TEMPFILE_EVENT(xrep_tempfile_prealloc);
+DEFINE_XREP_TEMPFILE_EVENT(xrep_tempfile_copyin);
+
TRACE_EVENT(xreap_ifork_extent,
TP_PROTO(struct xfs_scrub *sc, struct xfs_inode *ip, int whichfork,
const struct xfs_bmbt_irec *irec),