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[PATCH 041/145] xfs: convert unwritten status of reverse mappings

To: david@xxxxxxxxxxxxx, darrick.wong@xxxxxxxxxx
Subject: [PATCH 041/145] xfs: convert unwritten status of reverse mappings
From: "Darrick J. Wong" <darrick.wong@xxxxxxxxxx>
Date: Thu, 16 Jun 2016 18:35:02 -0700
Cc: xfs@xxxxxxxxxxx
Delivered-to: xfs@xxxxxxxxxxx
In-reply-to: <146612704434.16048.12932915166928562654.stgit@xxxxxxxxxxxxxxxx>
References: <146612704434.16048.12932915166928562654.stgit@xxxxxxxxxxxxxxxx>
User-agent: StGit/0.17.1-dirty
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@xxxxxxxxxx>
---
 include/xfs_trace.h |    6 +
 libxfs/xfs_rmap.c   |  442 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 448 insertions(+)


diff --git a/include/xfs_trace.h b/include/xfs_trace.h
index 45b5284..55df410 100644
--- a/include/xfs_trace.h
+++ b/include/xfs_trace.h
@@ -203,6 +203,12 @@
 
 #define trace_xfs_rmap_lookup_le_range_result(...)             ((void) 0)
 #define trace_xfs_rmap_map_gtrec(...)          ((void) 0)
+#define trace_xfs_rmap_convert(...)            ((void) 0)
+#define trace_xfs_rmap_convert_gtrec(...)      ((void) 0)
+#define trace_xfs_rmap_convert_state(...)      ((void) 0)
+#define trace_xfs_rmap_convert_done(...)       ((void) 0)
+#define trace_xfs_rmap_convert_error(...)      ((void) 0)
+#define trace_xfs_rmap_find_left_neighbor_result(...)          ((void) 0)
 
 /* set c = c to avoid unused var warnings */
 #define trace_xfs_perag_get(a,b,c,d)   ((c) = (c))
diff --git a/libxfs/xfs_rmap.c b/libxfs/xfs_rmap.c
index cc82824..1e25285 100644
--- a/libxfs/xfs_rmap.c
+++ b/libxfs/xfs_rmap.c
@@ -608,6 +608,448 @@ 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;

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