The growdata transaction is used by growfs operations to increase the data size of the filesystem. Part of this sequence involves extending the size of the last preexisting AG in the fs, if necessary. This is implemented by freeing the newly available physical range to the AG. tr_growdata is not a permanent transaction, however, and block allocation transactions must be permanent to handle deferred frees of AGFL blocks. If the grow operation extends an existing AG that requires AGFL fixing, assert failures occur due to a populated dfops list on a non-permanent transaction and the AGFL free does not occur. This is reproduced (rarely) by xfs/104. Change tr_growdata to a permanent transaction with a default log count. This increases initial transaction reservation size, but growfs is an infrequent and non-performance critical operation and so should have minimal impact. Also add an assert in the block allocation path to make this transaction requirement explicit and obvious to future callers. Reported-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx> --- This is motivated by Darrick's recent xfs/104 failure report[1]. Note that I made the assert a bit more explicit than originally suggested because I think any transaction that performs block allocation should be expected to be able to handle arbitrary AGFL fixups. This survives an fstests auto run without any regressions[2] or assert failures. Brian [1] https://marc.info/?l=linux-xfs&m=155537961822223&w=2 [2] Note that I was never able to reproduce the original xfs/104 failure. fs/xfs/libxfs/xfs_alloc.c | 2 ++ fs/xfs/libxfs/xfs_trans_resv.c | 6 +++++- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c index bc3367b8b7bb..e4df1866f949 100644 --- a/fs/xfs/libxfs/xfs_alloc.c +++ b/fs/xfs/libxfs/xfs_alloc.c @@ -2237,6 +2237,8 @@ xfs_alloc_fix_freelist( xfs_extlen_t need; /* total blocks needed in freelist */ int error = 0; + ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES); + if (!pag->pagf_init) { error = xfs_alloc_read_agf(mp, tp, args->agno, flags, &agbp); if (error) diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c index f99a7aefe418..83f4ee2afc49 100644 --- a/fs/xfs/libxfs/xfs_trans_resv.c +++ b/fs/xfs/libxfs/xfs_trans_resv.c @@ -876,9 +876,13 @@ xfs_trans_resv_calc( resp->tr_sb.tr_logres = xfs_calc_sb_reservation(mp); resp->tr_sb.tr_logcount = XFS_DEFAULT_LOG_COUNT; + /* growdata requires permanent res; it can free space to the last AG */ + resp->tr_growdata.tr_logres = xfs_calc_growdata_reservation(mp); + resp->tr_growdata.tr_logcount = XFS_DEFAULT_PERM_LOG_COUNT; + resp->tr_growdata.tr_logflags |= XFS_TRANS_PERM_LOG_RES; + /* The following transaction are logged in logical format */ resp->tr_ichange.tr_logres = xfs_calc_ichange_reservation(mp); - resp->tr_growdata.tr_logres = xfs_calc_growdata_reservation(mp); resp->tr_fsyncts.tr_logres = xfs_calc_swrite_reservation(mp); resp->tr_writeid.tr_logres = xfs_calc_writeid_reservation(mp); resp->tr_attrsetrt.tr_logres = xfs_calc_attrsetrt_reservation(mp); -- 2.17.2
