xfs: implement deferred bmbt map/unmap operations

Source kernel commit: 9f3afb57d5f1e7145986132106c6ca91f8136cc2

Implement deferred versions of the inode block map/unmap functions.
These will be used in subsequent patches to make reflink operations
atomic.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/include/xfs_trace.h b/include/xfs_trace.h
index e16eee3a1df03fd9e2592b4e1118a869289d003f..c634f997b395aa04d758398982d3253cef9de6a5 100644 (file)
--- a/include/xfs_trace.h
+++ b/include/xfs_trace.h
@@ -273,6 +273,9 @@
 
 #define trace_xfs_bmap_remap_alloc(...)                ((void) 0)
 #define trace_xfs_bmap_remap_alloc_error(...)  ((void) 0)
+#define trace_xfs_bmap_deferred(...)           ((void) 0)
+#define trace_xfs_bmap_defer(...)              ((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_bmap.c b/libxfs/xfs_bmap.c
index 575bd5220de6cee4b0ca21af5822341a4a10f85d..4c3b4a33ab36c9f20c886d0e453c963e1fade5b2 100644 (file)
--- a/libxfs/xfs_bmap.c
+++ b/libxfs/xfs_bmap.c
@@ -6054,3 +6054,146 @@ out:
        xfs_trans_cancel(tp);
        return error;
 }
+
+/* Deferred mapping is only for real extents in the data fork. */
+static bool
+xfs_bmap_is_update_needed(
+       struct xfs_bmbt_irec    *bmap)
+{
+       return  bmap->br_startblock != HOLESTARTBLOCK &&
+               bmap->br_startblock != DELAYSTARTBLOCK;
+}
+
+/* Record a bmap intent. */
+static int
+__xfs_bmap_add(
+       struct xfs_mount                *mp,
+       struct xfs_defer_ops            *dfops,
+       enum xfs_bmap_intent_type       type,
+       struct xfs_inode                *ip,
+       int                             whichfork,
+       struct xfs_bmbt_irec            *bmap)
+{
+       int                             error;
+       struct xfs_bmap_intent          *bi;
+
+       trace_xfs_bmap_defer(mp,
+                       XFS_FSB_TO_AGNO(mp, bmap->br_startblock),
+                       type,
+                       XFS_FSB_TO_AGBNO(mp, bmap->br_startblock),
+                       ip->i_ino, whichfork,
+                       bmap->br_startoff,
+                       bmap->br_blockcount,
+                       bmap->br_state);
+
+       bi = kmem_alloc(sizeof(struct xfs_bmap_intent), KM_SLEEP | KM_NOFS);
+       INIT_LIST_HEAD(&bi->bi_list);
+       bi->bi_type = type;
+       bi->bi_owner = ip;
+       bi->bi_whichfork = whichfork;
+       bi->bi_bmap = *bmap;
+
+       error = xfs_defer_join(dfops, bi->bi_owner);
+       if (error) {
+               kmem_free(bi);
+               return error;
+       }
+
+       xfs_defer_add(dfops, XFS_DEFER_OPS_TYPE_BMAP, &bi->bi_list);
+       return 0;
+}
+
+/* Map an extent into a file. */
+int
+xfs_bmap_map_extent(
+       struct xfs_mount        *mp,
+       struct xfs_defer_ops    *dfops,
+       struct xfs_inode        *ip,
+       struct xfs_bmbt_irec    *PREV)
+{
+       if (!xfs_bmap_is_update_needed(PREV))
+               return 0;
+
+       return __xfs_bmap_add(mp, dfops, XFS_BMAP_MAP, ip,
+                       XFS_DATA_FORK, PREV);
+}
+
+/* Unmap an extent out of a file. */
+int
+xfs_bmap_unmap_extent(
+       struct xfs_mount        *mp,
+       struct xfs_defer_ops    *dfops,
+       struct xfs_inode        *ip,
+       struct xfs_bmbt_irec    *PREV)
+{
+       if (!xfs_bmap_is_update_needed(PREV))
+               return 0;
+
+       return __xfs_bmap_add(mp, dfops, XFS_BMAP_UNMAP, ip,
+                       XFS_DATA_FORK, PREV);
+}
+
+/*
+ * Process one of the deferred bmap operations.  We pass back the
+ * btree cursor to maintain our lock on the bmapbt between calls.
+ */
+int
+xfs_bmap_finish_one(
+       struct xfs_trans                *tp,
+       struct xfs_defer_ops            *dfops,
+       struct xfs_inode                *ip,
+       enum xfs_bmap_intent_type       type,
+       int                             whichfork,
+       xfs_fileoff_t                   startoff,
+       xfs_fsblock_t                   startblock,
+       xfs_filblks_t                   blockcount,
+       xfs_exntst_t                    state)
+{
+       struct xfs_bmbt_irec            bmap;
+       int                             nimaps = 1;
+       xfs_fsblock_t                   firstfsb;
+       int                             flags = XFS_BMAPI_REMAP;
+       int                             done;
+       int                             error = 0;
+
+       bmap.br_startblock = startblock;
+       bmap.br_startoff = startoff;
+       bmap.br_blockcount = blockcount;
+       bmap.br_state = state;
+
+       trace_xfs_bmap_deferred(tp->t_mountp,
+                       XFS_FSB_TO_AGNO(tp->t_mountp, startblock), type,
+                       XFS_FSB_TO_AGBNO(tp->t_mountp, startblock),
+                       ip->i_ino, whichfork, startoff, blockcount, state);
+
+       if (whichfork != XFS_DATA_FORK && whichfork != XFS_ATTR_FORK)
+               return -EFSCORRUPTED;
+       if (whichfork == XFS_ATTR_FORK)
+               flags |= XFS_BMAPI_ATTRFORK;
+
+       if (XFS_TEST_ERROR(false, tp->t_mountp,
+                       XFS_ERRTAG_BMAP_FINISH_ONE,
+                       XFS_RANDOM_BMAP_FINISH_ONE))
+               return -EIO;
+
+       switch (type) {
+       case XFS_BMAP_MAP:
+               firstfsb = bmap.br_startblock;
+               error = xfs_bmapi_write(tp, ip, bmap.br_startoff,
+                                       bmap.br_blockcount, flags, &firstfsb,
+                                       bmap.br_blockcount, &bmap, &nimaps,
+                                       dfops);
+               break;
+       case XFS_BMAP_UNMAP:
+               error = xfs_bunmapi(tp, ip, bmap.br_startoff,
+                               bmap.br_blockcount, flags, 1, &firstfsb,
+                               dfops, &done);
+               ASSERT(done);
+               break;
+       default:
+               ASSERT(0);
+               error = -EFSCORRUPTED;
+       }
+
+       return error;
+}

diff --git a/libxfs/xfs_bmap.h b/libxfs/xfs_bmap.h
index 27cfa1d11342bb518bffd438fdaa67ffb543816c..2c2f8833d85a4c1cd501b78c8a301fc027675bf7 100644 (file)
--- a/libxfs/xfs_bmap.h
+++ b/libxfs/xfs_bmap.h
@@ -238,4 +238,13 @@ struct xfs_bmap_intent {
        struct xfs_bmbt_irec                    bi_bmap;
 };
 
+int    xfs_bmap_finish_one(struct xfs_trans *tp, struct xfs_defer_ops *dfops,
+               struct xfs_inode *ip, enum xfs_bmap_intent_type type,
+               int whichfork, xfs_fileoff_t startoff, xfs_fsblock_t startblock,
+               xfs_filblks_t blockcount, xfs_exntst_t state);
+int    xfs_bmap_map_extent(struct xfs_mount *mp, struct xfs_defer_ops *dfops,
+               struct xfs_inode *ip, struct xfs_bmbt_irec *imap);
+int    xfs_bmap_unmap_extent(struct xfs_mount *mp, struct xfs_defer_ops *dfops,
+               struct xfs_inode *ip, struct xfs_bmbt_irec *imap);
+
 #endif /* __XFS_BMAP_H__ */

diff --git a/libxfs/xfs_defer.h b/libxfs/xfs_defer.h
index 4d94a869e581caff0bdd67b9468b90a760351664..f6e93ef0bffe8a4620a136b1e7f523bb1343a941 100644 (file)
--- a/libxfs/xfs_defer.h
+++ b/libxfs/xfs_defer.h
@@ -51,6 +51,7 @@ struct xfs_defer_pending {
  * find all the space it needs.
  */
 enum xfs_defer_ops_type {
+       XFS_DEFER_OPS_TYPE_BMAP,
        XFS_DEFER_OPS_TYPE_REFCOUNT,
        XFS_DEFER_OPS_TYPE_RMAP,
        XFS_DEFER_OPS_TYPE_FREE,