From 90fa22da6d6b41dc17435aff7b800f9ca3c00401 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 27 Aug 2024 07:03:21 +0200 Subject: [PATCH] xfs: ensure st_blocks never goes to zero during COW writes COW writes remove the amount overwritten either directly for delalloc reservations, or in earlier deferred transactions than adding the new amount back in the bmap map transaction. This means st_blocks on an inode where all data is overwritten using the COW path can temporarily show a 0 st_blocks. This can easily be reproduced with the pending zoned device support where all writes use this path and trips the check in generic/615, but could also happen on a reflink file without that. Fix this by temporarily add the pending blocks to be mapped to i_delayed_blks while the item is queued. Signed-off-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Reviewed-by: Dave Chinner Signed-off-by: Chandan Babu R --- fs/xfs/libxfs/xfs_bmap.c | 1 + fs/xfs/xfs_bmap_item.c | 17 +++++++++++++++++ 2 files changed, 18 insertions(+) diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c index 28473b6a95cc..8090e8249116 100644 --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -4856,6 +4856,7 @@ xfs_bmapi_remap( } ip->i_nblocks += len; + ip->i_delayed_blks -= len; /* see xfs_bmap_defer_add */ xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); if (ifp->if_format == XFS_DINODE_FMT_BTREE) diff --git a/fs/xfs/xfs_bmap_item.c b/fs/xfs/xfs_bmap_item.c index e224b49b7cff..35a8c1b8b3cb 100644 --- a/fs/xfs/xfs_bmap_item.c +++ b/fs/xfs/xfs_bmap_item.c @@ -346,6 +346,17 @@ xfs_bmap_defer_add( trace_xfs_bmap_defer(bi); xfs_bmap_update_get_group(tp->t_mountp, bi); + + /* + * Ensure the deferred mapping is pre-recorded in i_delayed_blks. + * + * Otherwise stat can report zero blocks for an inode that actually has + * data when the entire mapping is in the process of being overwritten + * using the out of place write path. This is undone in xfs_bmapi_remap + * after it has incremented di_nblocks for a successful operation. + */ + if (bi->bi_type == XFS_BMAP_MAP) + bi->bi_owner->i_delayed_blks += bi->bi_bmap.br_blockcount; xfs_defer_add(tp, &bi->bi_list, &xfs_bmap_update_defer_type); } @@ -367,6 +378,9 @@ xfs_bmap_update_cancel_item( { struct xfs_bmap_intent *bi = bi_entry(item); + if (bi->bi_type == XFS_BMAP_MAP) + bi->bi_owner->i_delayed_blks -= bi->bi_bmap.br_blockcount; + xfs_bmap_update_put_group(bi); kmem_cache_free(xfs_bmap_intent_cache, bi); } @@ -464,6 +478,9 @@ xfs_bui_recover_work( bi->bi_owner = *ipp; xfs_bmap_update_get_group(mp, bi); + /* see xfs_bmap_defer_add for details */ + if (bi->bi_type == XFS_BMAP_MAP) + bi->bi_owner->i_delayed_blks += bi->bi_bmap.br_blockcount; xfs_defer_add_item(dfp, &bi->bi_list); return bi; }