From f48e2df8a877ca1c19d92cfd7e74cc5956fa84cb Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Thu, 23 Jan 2020 17:01:19 -0800 Subject: xfs: make xfs_*read_agf return EAGAIN to ALLOC_FLAG_TRYLOCK callers Refactor xfs_read_agf and xfs_alloc_read_agf to return EAGAIN if the caller passed TRYLOCK and we weren't able to get the lock; and change the callers to recognize this. Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Reviewed-by: Dave Chinner --- fs/xfs/libxfs/xfs_alloc.c | 36 ++++++++++++++---------------------- fs/xfs/libxfs/xfs_bmap.c | 11 ++++++----- fs/xfs/xfs_filestream.c | 11 +++++------ 3 files changed, 25 insertions(+), 33 deletions(-) diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c index 34b65635ee34..d8053bc96c4d 100644 --- a/fs/xfs/libxfs/xfs_alloc.c +++ b/fs/xfs/libxfs/xfs_alloc.c @@ -2502,12 +2502,11 @@ xfs_alloc_fix_freelist( if (!pag->pagf_init) { error = xfs_alloc_read_agf(mp, tp, args->agno, flags, &agbp); - if (error) + if (error) { + /* Couldn't lock the AGF so skip this AG. */ + if (error == -EAGAIN) + error = 0; goto out_no_agbp; - if (!pag->pagf_init) { - ASSERT(flags & XFS_ALLOC_FLAG_TRYLOCK); - ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING)); - goto out_agbp_relse; } } @@ -2533,11 +2532,10 @@ xfs_alloc_fix_freelist( */ if (!agbp) { error = xfs_alloc_read_agf(mp, tp, args->agno, flags, &agbp); - if (error) - goto out_no_agbp; - if (!agbp) { - ASSERT(flags & XFS_ALLOC_FLAG_TRYLOCK); - ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING)); + if (error) { + /* Couldn't lock the AGF so skip this AG. */ + if (error == -EAGAIN) + error = 0; goto out_no_agbp; } } @@ -2768,11 +2766,10 @@ xfs_alloc_pagf_init( xfs_buf_t *bp; int error; - if ((error = xfs_alloc_read_agf(mp, tp, agno, flags, &bp))) - return error; - if (bp) + error = xfs_alloc_read_agf(mp, tp, agno, flags, &bp); + if (!error) xfs_trans_brelse(tp, bp); - return 0; + return error; } /* @@ -2961,12 +2958,6 @@ xfs_read_agf( error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp)), XFS_FSS_TO_BB(mp, 1), flags, bpp, &xfs_agf_buf_ops); - /* - * Callers of xfs_read_agf() currently interpret a NULL bpp as EAGAIN - * and need to be converted to check for EAGAIN specifically. - */ - if (error == -EAGAIN) - return 0; if (error) return error; @@ -2992,14 +2983,15 @@ xfs_alloc_read_agf( trace_xfs_alloc_read_agf(mp, agno); + /* We don't support trylock when freeing. */ + ASSERT((flags & (XFS_ALLOC_FLAG_FREEING | XFS_ALLOC_FLAG_TRYLOCK)) != + (XFS_ALLOC_FLAG_FREEING | XFS_ALLOC_FLAG_TRYLOCK)); ASSERT(agno != NULLAGNUMBER); error = xfs_read_agf(mp, tp, agno, (flags & XFS_ALLOC_FLAG_TRYLOCK) ? XBF_TRYLOCK : 0, bpp); if (error) return error; - if (!*bpp) - return 0; ASSERT(!(*bpp)->b_error); agf = XFS_BUF_TO_AGF(*bpp); diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c index cfcef076c72f..9a6d7a84689a 100644 --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -3311,11 +3311,12 @@ xfs_bmap_longest_free_extent( pag = xfs_perag_get(mp, ag); if (!pag->pagf_init) { error = xfs_alloc_pagf_init(mp, tp, ag, XFS_ALLOC_FLAG_TRYLOCK); - if (error) - goto out; - - if (!pag->pagf_init) { - *notinit = 1; + if (error) { + /* Couldn't lock the AGF, so skip this AG. */ + if (error == -EAGAIN) { + *notinit = 1; + error = 0; + } goto out; } } diff --git a/fs/xfs/xfs_filestream.c b/fs/xfs/xfs_filestream.c index 5f12b5d8527a..1a88025e68a3 100644 --- a/fs/xfs/xfs_filestream.c +++ b/fs/xfs/xfs_filestream.c @@ -159,16 +159,15 @@ xfs_filestream_pick_ag( if (!pag->pagf_init) { err = xfs_alloc_pagf_init(mp, NULL, ag, trylock); - if (err && !trylock) { + if (err) { xfs_perag_put(pag); - return err; + if (err != -EAGAIN) + return err; + /* Couldn't lock the AGF, skip this AG. */ + continue; } } - /* Might fail sometimes during the 1st pass with trylock set. */ - if (!pag->pagf_init) - goto next_ag; - /* Keep track of the AG with the most free blocks. */ if (pag->pagf_freeblks > maxfree) { maxfree = pag->pagf_freeblks; -- cgit v1.2.3-59-g8ed1b