4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: "Darrick J. Wong" <[email protected]> commit 4c1a67bd3606540b9b42caff34a1d5cd94b1cf65 upstream. We must initialize the firstfsb parameter to _bmapi_write so that it doesn't incorrectly treat stack garbage as a restriction on which AGs it can search for free space. Fixes-coverity-id: 1402025 Fixes-coverity-id: 1415167 Signed-off-by: Darrick J. Wong <[email protected]> Reviewed-by: Brian Foster <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- fs/xfs/libxfs/xfs_bmap.c | 9 +++++++++ fs/xfs/xfs_reflink.c | 2 +- 2 files changed, 10 insertions(+), 1 deletion(-) --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -6639,6 +6639,15 @@ xfs_bmap_finish_one( bmap.br_blockcount = *blockcount; bmap.br_state = state; + /* + * firstfsb is tied to the transaction lifetime and is used to + * ensure correct AG locking order and schedule work item + * continuations. XFS_BUI_MAX_FAST_EXTENTS (== 1) restricts us + * to only making one bmap call per transaction, so it should + * be safe to have it as a local variable here. + */ + firstfsb = NULLFSBLOCK; + trace_xfs_bmap_deferred(tp->t_mountp, XFS_FSB_TO_AGNO(tp->t_mountp, startblock), type, XFS_FSB_TO_AGBNO(tp->t_mountp, startblock), --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -333,7 +333,7 @@ xfs_reflink_convert_cow_extent( struct xfs_defer_ops *dfops) { struct xfs_bmbt_irec irec = *imap; - xfs_fsblock_t first_block; + xfs_fsblock_t first_block = NULLFSBLOCK; int nimaps = 1; if (imap->br_state == XFS_EXT_NORM)
