From 0af32fb468b4a4434dd759d68611763658650b59 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 17 Aug 2016 08:30:28 +1000 Subject: [PATCH] xfs: fix bogus space reservation in xfs_iomap_write_allocate The space reservations was without an explaination in commit "Add error reporting calls in error paths that return EFSCORRUPTED" back in 2003. There is no reason to reserve disk blocks in the transaction when allocating blocks for delalloc space as we already reserved the space when creating the delalloc extent. With this fix we stop running out of the reserved pool in generic/229, which has happened for long time with small blocksize file systems, and has increased in severity with the new buffered write path. [ dchinner: we still need to pass the block reservation into xfs_bmapi_write() to ensure we don't deadlock during AG selection. See commit dbd5c8c ("xfs: pass total block res. as total xfs_bmapi_write() parameter") for more details on why this is necessary. ] Signed-off-by: Christoph Hellwig Reviewed-by: Dave Chinner Signed-off-by: Dave Chinner --- fs/xfs/xfs_iomap.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index 2114d53df433..4398932a7d1b 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -715,12 +715,16 @@ xfs_iomap_write_allocate( * is in the delayed allocation extent on which we sit * but before our buffer starts. */ - nimaps = 0; while (nimaps == 0) { nres = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK); - - error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, nres, + /* + * We have already reserved space for the extent and any + * indirect blocks when creating the delalloc extent, + * there is no need to reserve space in this transaction + * again. + */ + error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, XFS_TRANS_RESERVE, &tp); if (error) return error; -- 2.20.1