[PATCH 038/119] xfs: convert unwritten status of reverse mappings

Darrick J. Wong
2016-06-17T01:22:05Z

Provide a function to convert an unwritten extent to a real one and
vice versa.

v2: Move unwritten bit to rm_offset.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/libxfs/xfs_rmap.c | 442 ++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/xfs_trace.h | 6 +
2 files changed, 448 insertions(+)

diff --git a/fs/xfs/libxfs/xfs_rmap.c b/fs/xfs/libxfs/xfs_rmap.c
index 1043c63..53ba14e 100644
--- a/fs/xfs/libxfs/xfs_rmap.c
+++ b/fs/xfs/libxfs/xfs_rmap.c
@@ -610,6 +610,448 @@ out_error:
return error;
}

+#define RMAP_LEFT_CONTIG (1 << 0)
+#define RMAP_RIGHT_CONTIG (1 << 1)
+#define RMAP_LEFT_FILLING (1 << 2)
+#define RMAP_RIGHT_FILLING (1 << 3)
+#define RMAP_LEFT_VALID (1 << 6)
+#define RMAP_RIGHT_VALID (1 << 7)
+
+#define LEFT r[0]
+#define RIGHT r[1]
+#define PREV r[2]
+#define NEW r[3]
+
+/*
+ * Convert an unwritten extent to a real extent or vice versa.
+ * Does not handle overlapping extents.
+ */
+STATIC int
+__xfs_rmap_convert(
+ struct xfs_btree_cur *cur,
+ xfs_agblock_t bno,
+ xfs_extlen_t len,
+ bool unwritten,
+ struct xfs_owner_info *oinfo)
+{
+ struct xfs_mount *mp = cur->bc_mp;
+ struct xfs_rmap_irec r[4]; /* neighbor extent entries */
+ /* left is 0, right is 1, prev is 2 */
+ /* new is 3 */
+ uint64_t owner;
+ uint64_t offset;
+ uint64_t new_endoff;
+ unsigned int oldext;
+ unsigned int newext;
+ unsigned int flags = 0;
+ int i;
+ int state = 0;
+ int error;
+
+ xfs_owner_info_unpack(oinfo, &owner, &offset, &flags);
+ ASSERT(!(XFS_RMAP_NON_INODE_OWNER(owner) ||
+ (flags & (XFS_RMAP_ATTR_FORK | XFS_RMAP_BMBT_BLOCK))));
+ oldext = unwritten ? XFS_RMAP_UNWRITTEN : 0;
+ new_endoff = offset + len;
+ trace_xfs_rmap_convert(mp, cur->bc_private.a.agno, bno, len,
+ unwritten, oinfo);
+
+ /*
+ * For the initial lookup, look for and exact match or the left-adjacent
+ * record for our insertion point. This will also give us the record for
+ * start block contiguity tests.
+ */
+ error = xfs_rmap_lookup_le(cur, bno, len, owner, offset, oldext, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
+
+ error = xfs_rmap_get_rec(cur, &PREV, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
+ trace_xfs_rmap_lookup_le_range_result(cur->bc_mp,
+ cur->bc_private.a.agno, PREV.rm_startblock,
+ PREV.rm_blockcount, PREV.rm_owner,
+ PREV.rm_offset, PREV.rm_flags);
+
+ ASSERT(PREV.rm_offset <= offset);
+ ASSERT(PREV.rm_offset + PREV.rm_blockcount >= new_endoff);
+ ASSERT((PREV.rm_flags & XFS_RMAP_UNWRITTEN) == oldext);
+ newext = ~oldext & XFS_RMAP_UNWRITTEN;
+
+ /*
+ * Set flags determining what part of the previous oldext allocation
+ * extent is being replaced by a newext allocation.
+ */
+ if (PREV.rm_offset == offset)
+ state |= RMAP_LEFT_FILLING;
+ if (PREV.rm_offset + PREV.rm_blockcount == new_endoff)
+ state |= RMAP_RIGHT_FILLING;
+
+ /*
+ * Decrement the cursor to see if we have a left-adjacent record to our
+ * insertion point. This will give us the record for end block
+ * contiguity tests.
+ */
+ error = xfs_btree_decrement(cur, 0, &i);
+ if (error)
+ goto done;
+ if (i) {
+ state |= RMAP_LEFT_VALID;
+ error = xfs_rmap_get_rec(cur, &LEFT, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
+ XFS_WANT_CORRUPTED_GOTO(mp,
+ LEFT.rm_startblock + LEFT.rm_blockcount <= bno,
+ done);
+ trace_xfs_rmap_find_left_neighbor_result(cur->bc_mp,
+ cur->bc_private.a.agno, LEFT.rm_startblock,
+ LEFT.rm_blockcount, LEFT.rm_owner,
+ LEFT.rm_offset, LEFT.rm_flags);
+ if (LEFT.rm_startblock + LEFT.rm_blockcount == bno &&
+ LEFT.rm_offset + LEFT.rm_blockcount == offset &&
+ xfs_rmap_is_mergeable(&LEFT, owner, offset, len, newext))
+ state |= RMAP_LEFT_CONTIG;
+ }
+
+ /*
+ * Increment the cursor to see if we have a right-adjacent record to our
+ * insertion point. This will give us the record for end block
+ * contiguity tests.
+ */
+ error = xfs_btree_increment(cur, 0, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
+ error = xfs_btree_increment(cur, 0, &i);
+ if (error)
+ goto done;
+ if (i) {
+ state |= RMAP_RIGHT_VALID;
+ error = xfs_rmap_get_rec(cur, &RIGHT, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
+ XFS_WANT_CORRUPTED_GOTO(mp, bno + len <= RIGHT.rm_startblock,
+ done);
+ trace_xfs_rmap_convert_gtrec(cur->bc_mp,
+ cur->bc_private.a.agno, RIGHT.rm_startblock,
+ RIGHT.rm_blockcount, RIGHT.rm_owner,
+ RIGHT.rm_offset, RIGHT.rm_flags);
+ if (bno + len == RIGHT.rm_startblock &&
+ offset + len == RIGHT.rm_offset &&
+ xfs_rmap_is_mergeable(&RIGHT, owner, offset, len, newext))
+ state |= RMAP_RIGHT_CONTIG;
+ }
+
+ /* check that left + prev + right is not too long */
+ if ((state & (RMAP_LEFT_FILLING | RMAP_LEFT_CONTIG |
+ RMAP_RIGHT_FILLING | RMAP_RIGHT_CONTIG)) ==
+ (RMAP_LEFT_FILLING | RMAP_LEFT_CONTIG |
+ RMAP_RIGHT_FILLING | RMAP_RIGHT_CONTIG) &&
+ (unsigned long)LEFT.rm_blockcount + len +
+ RIGHT.rm_blockcount > XFS_RMAP_LEN_MAX)
+ state &= ~RMAP_RIGHT_CONTIG;
+
+ trace_xfs_rmap_convert_state(mp, cur->bc_private.a.agno, state,
+ _RET_IP_);
+
+ /* reset the cursor back to PREV */
+ error = xfs_rmap_lookup_le(cur, bno, len, owner, offset, oldext, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
+
+ /*
+ * Switch out based on the FILLING and CONTIG state bits.
+ */
+ switch (state & (RMAP_LEFT_FILLING | RMAP_LEFT_CONTIG |
+ RMAP_RIGHT_FILLING | RMAP_RIGHT_CONTIG)) {
+ case RMAP_LEFT_FILLING | RMAP_LEFT_CONTIG |
+ RMAP_RIGHT_FILLING | RMAP_RIGHT_CONTIG:
+ /*
+ * Setting all of a previous oldext extent to newext.
+ * The left and right neighbors are both contiguous with new.
+ */
+ error = xfs_btree_increment(cur, 0, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
+ trace_xfs_rmapbt_delete(mp, cur->bc_private.a.agno,
+ RIGHT.rm_startblock, RIGHT.rm_blockcount,
+ RIGHT.rm_owner, RIGHT.rm_offset,
+ RIGHT.rm_flags);
+ error = xfs_btree_delete(cur, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
+ error = xfs_btree_decrement(cur, 0, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
+ trace_xfs_rmapbt_delete(mp, cur->bc_private.a.agno,
+ PREV.rm_startblock, PREV.rm_blockcount,
+ PREV.rm_owner, PREV.rm_offset,
+ PREV.rm_flags);
+ error = xfs_btree_delete(cur, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
+ error = xfs_btree_decrement(cur, 0, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
+ NEW = LEFT;
+ NEW.rm_blockcount += PREV.rm_blockcount + RIGHT.rm_blockcount;
+ error = xfs_rmap_update(cur, &NEW);
+ if (error)
+ goto done;
+ break;
+
+ case RMAP_LEFT_FILLING | RMAP_RIGHT_FILLING | RMAP_LEFT_CONTIG:
+ /*
+ * Setting all of a previous oldext extent to newext.
+ * The left neighbor is contiguous, the right is not.
+ */
+ trace_xfs_rmapbt_delete(mp, cur->bc_private.a.agno,
+ PREV.rm_startblock, PREV.rm_blockcount,
+ PREV.rm_owner, PREV.rm_offset,
+ PREV.rm_flags);
+ error = xfs_btree_delete(cur, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
+ error = xfs_btree_decrement(cur, 0, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
+ NEW = LEFT;
+ NEW.rm_blockcount += PREV.rm_blockcount;
+ error = xfs_rmap_update(cur, &NEW);
+ if (error)
+ goto done;
+ break;
+
+ case RMAP_LEFT_FILLING | RMAP_RIGHT_FILLING | RMAP_RIGHT_CONTIG:
+ /*
+ * Setting all of a previous oldext extent to newext.
+ * The right neighbor is contiguous, the left is not.
+ */
+ error = xfs_btree_increment(cur, 0, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
+ trace_xfs_rmapbt_delete(mp, cur->bc_private.a.agno,
+ RIGHT.rm_startblock, RIGHT.rm_blockcount,
+ RIGHT.rm_owner, RIGHT.rm_offset,
+ RIGHT.rm_flags);
+ error = xfs_btree_delete(cur, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
+ error = xfs_btree_decrement(cur, 0, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
+ NEW.rm_startblock = bno;
+ NEW.rm_owner = owner;
+ NEW.rm_offset = offset;
+ NEW.rm_blockcount = len + RIGHT.rm_blockcount;
+ NEW.rm_flags = newext;
+ error = xfs_rmap_update(cur, &NEW);
+ if (error)
+ goto done;
+ break;
+
+ case RMAP_LEFT_FILLING | RMAP_RIGHT_FILLING:
+ /*
+ * Setting all of a previous oldext extent to newext.
+ * Neither the left nor right neighbors are contiguous with
+ * the new one.
+ */
+ NEW = PREV;
+ NEW.rm_flags = newext;
+ error = xfs_rmap_update(cur, &NEW);
+ if (error)
+ goto done;
+ break;
+
+ case RMAP_LEFT_FILLING | RMAP_LEFT_CONTIG:
+ /*
+ * Setting the first part of a previous oldext extent to newext.
+ * The left neighbor is contiguous.
+ */
+ NEW = PREV;
+ NEW.rm_offset += len;
+ NEW.rm_startblock += len;
+ NEW.rm_blockcount -= len;
+ error = xfs_rmap_update(cur, &NEW);
+ if (error)
+ goto done;
+ error = xfs_btree_decrement(cur, 0, &i);
+ if (error)
+ goto done;
+ NEW = LEFT;
+ NEW.rm_blockcount += len;
+ error = xfs_rmap_update(cur, &NEW);
+ if (error)
+ goto done;
+ break;
+
+ case RMAP_LEFT_FILLING:
+ /*
+ * Setting the first part of a previous oldext extent to newext.
+ * The left neighbor is not contiguous.
+ */
+ NEW = PREV;
+ NEW.rm_startblock += len;
+ NEW.rm_offset += len;
+ NEW.rm_blockcount -= len;
+ error = xfs_rmap_update(cur, &NEW);
+ if (error)
+ goto done;
+ NEW.rm_startblock = bno;
+ NEW.rm_owner = owner;
+ NEW.rm_offset = offset;
+ NEW.rm_blockcount = len;
+ NEW.rm_flags = newext;
+ cur->bc_rec.r = NEW;
+ trace_xfs_rmapbt_insert(mp, cur->bc_private.a.agno, bno,
+ len, owner, offset, newext);
+ error = xfs_btree_insert(cur, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
+ break;
+
+ case RMAP_RIGHT_FILLING | RMAP_RIGHT_CONTIG:
+ /*
+ * Setting the last part of a previous oldext extent to newext.
+ * The right neighbor is contiguous with the new allocation.
+ */
+ NEW = PREV;
+ NEW.rm_blockcount -= len;
+ error = xfs_rmap_update(cur, &NEW);
+ if (error)
+ goto done;
+ error = xfs_btree_increment(cur, 0, &i);
+ if (error)
+ goto done;
+ NEW = RIGHT;
+ NEW.rm_offset = offset;
+ NEW.rm_startblock = bno;
+ NEW.rm_blockcount += len;
+ error = xfs_rmap_update(cur, &NEW);
+ if (error)
+ goto done;
+ break;
+
+ case RMAP_RIGHT_FILLING:
+ /*
+ * Setting the last part of a previous oldext extent to newext.
+ * The right neighbor is not contiguous.
+ */
+ NEW = PREV;
+ NEW.rm_blockcount -= len;
+ error = xfs_rmap_update(cur, &NEW);
+ if (error)
+ goto done;
+ error = xfs_rmap_lookup_eq(cur, bno, len, owner, offset,
+ oldext, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 0, done);
+ NEW.rm_startblock = bno;
+ NEW.rm_owner = owner;
+ NEW.rm_offset = offset;
+ NEW.rm_blockcount = len;
+ NEW.rm_flags = newext;
+ cur->bc_rec.r = NEW;
+ trace_xfs_rmapbt_insert(mp, cur->bc_private.a.agno, bno,
+ len, owner, offset, newext);
+ error = xfs_btree_insert(cur, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
+ break;
+
+ case 0:
+ /*
+ * Setting the middle part of a previous oldext extent to
+ * newext. Contiguity is impossible here.
+ * One extent becomes three extents.
+ */
+ /* new right extent - oldext */
+ NEW.rm_startblock = bno + len;
+ NEW.rm_owner = owner;
+ NEW.rm_offset = new_endoff;
+ NEW.rm_blockcount = PREV.rm_offset + PREV.rm_blockcount -
+ new_endoff;
+ NEW.rm_flags = PREV.rm_flags;
+ error = xfs_rmap_update(cur, &NEW);
+ if (error)
+ goto done;
+ /* new left extent - oldext */
+ NEW = PREV;
+ NEW.rm_blockcount = offset - PREV.rm_offset;
+ cur->bc_rec.r = NEW;
+ trace_xfs_rmapbt_insert(mp, cur->bc_private.a.agno,
+ NEW.rm_startblock, NEW.rm_blockcount,
+ NEW.rm_owner, NEW.rm_offset,
+ NEW.rm_flags);
+ error = xfs_btree_insert(cur, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
+ /*
+ * Reset the cursor to the position of the new extent
+ * we are about to insert as we can't trust it after
+ * the previous insert.
+ */
+ error = xfs_rmap_lookup_eq(cur, bno, len, owner, offset,
+ oldext, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 0, done);
+ /* new middle extent - newext */
+ cur->bc_rec.b.br_state = newext;
+ trace_xfs_rmapbt_insert(mp, cur->bc_private.a.agno, bno, len,
+ owner, offset, newext);
+ error = xfs_btree_insert(cur, &i);
+ if (error)
+ goto done;
+ XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
+ break;
+
+ case RMAP_LEFT_FILLING | RMAP_LEFT_CONTIG | RMAP_RIGHT_CONTIG:
+ case RMAP_RIGHT_FILLING | RMAP_LEFT_CONTIG | RMAP_RIGHT_CONTIG:
+ case RMAP_LEFT_FILLING | RMAP_RIGHT_CONTIG:
+ case RMAP_RIGHT_FILLING | RMAP_LEFT_CONTIG:
+ case RMAP_LEFT_CONTIG | RMAP_RIGHT_CONTIG:
+ case RMAP_LEFT_CONTIG:
+ case RMAP_RIGHT_CONTIG:
+ /*
+ * These cases are all impossible.
+ */
+ ASSERT(0);
+ }
+
+ trace_xfs_rmap_convert_done(mp, cur->bc_private.a.agno, bno, len,
+ unwritten, oinfo);
+done:
+ if (error)
+ trace_xfs_rmap_convert_error(cur->bc_mp,
+ cur->bc_private.a.agno, error, _RET_IP_);
+ return error;
+}
+
+#undef NEW
+#undef LEFT
+#undef RIGHT
+#undef PREV
+
struct xfs_rmapbt_query_range_info {
xfs_rmapbt_query_range_fn fn;
void *priv;
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 3ebceb0..6466adc 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -2497,6 +2497,10 @@ DEFINE_RMAP_EVENT(xfs_rmap_free_extent_error);
DEFINE_RMAP_EVENT(xfs_rmap_alloc_extent);
DEFINE_RMAP_EVENT(xfs_rmap_alloc_extent_done);
DEFINE_RMAP_EVENT(xfs_rmap_alloc_extent_error);
+DEFINE_RMAP_EVENT(xfs_rmap_convert);
+DEFINE_RMAP_EVENT(xfs_rmap_convert_done);
+DEFINE_AG_ERROR_EVENT(xfs_rmap_convert_error);
+DEFINE_AG_ERROR_EVENT(xfs_rmap_convert_state);

DECLARE_EVENT_CLASS(xfs_rmapbt_class,
TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno,
@@ -2551,6 +2555,8 @@ DEFINE_AG_ERROR_EVENT(xfs_rmapbt_delete_error);
DEFINE_AG_ERROR_EVENT(xfs_rmapbt_update_error);
DEFINE_RMAPBT_EVENT(xfs_rmap_lookup_le_range_result);
DEFINE_RMAPBT_EVENT(xfs_rmap_map_gtrec);
+DEFINE_RMAPBT_EVENT(xfs_rmap_convert_gtrec);
+DEFINE_RMAPBT_EVENT(xfs_rmap_find_left_neighbor_result);

#endif /* _TRACE_XFS_H */