From c4982110ae93d7575503feb81d15e93c0c5f393c Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 7 Aug 2012 02:02:02 -0400 Subject: xfs: unlock the AGI buffer when looping in xfs_dialloc Also update some commens in the area to make the code easier to read. Signed-off-by: Christoph Hellwig Reviewed-by: Mark Tinguely Reviewed-by: Dave Chinner Signed-off-by: Ben Myers --- fs/xfs/xfs_ialloc.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) (limited to 'fs/xfs/xfs_ialloc.c') diff --git a/fs/xfs/xfs_ialloc.c b/fs/xfs/xfs_ialloc.c index 21e37b55f7e..5aceb3f8ecd 100644 --- a/fs/xfs/xfs_ialloc.c +++ b/fs/xfs/xfs_ialloc.c @@ -962,23 +962,22 @@ xfs_dialloc( if (!pag->pagi_freecount && !okalloc) goto nextag; + /* + * Then read in the AGI buffer and recheck with the AGI buffer + * lock held. + */ error = xfs_ialloc_read_agi(mp, tp, agno, &agbp); if (error) goto out_error; - /* - * Once the AGI has been read in we have to recheck - * pagi_freecount with the AGI buffer lock held. - */ if (pag->pagi_freecount) { xfs_perag_put(pag); goto out_alloc; } - if (!okalloc) { - xfs_trans_brelse(tp, agbp); - goto nextag; - } + if (!okalloc) + goto nextag_relse_buffer; + error = xfs_ialloc_ag_alloc(tp, agbp, &ialloced); if (error) { @@ -1007,6 +1006,8 @@ xfs_dialloc( return 0; } +nextag_relse_buffer: + xfs_trans_brelse(tp, agbp); nextag: xfs_perag_put(pag); if (++agno == mp->m_sb.sb_agcount) -- cgit v1.2.3-70-g09d2 From 8aea3ff411b2ce8fe7b46644298ed243a920eb24 Mon Sep 17 00:00:00 2001 From: Carlos Maiolino Date: Thu, 20 Sep 2012 10:32:36 -0300 Subject: xfs: Fix m_agirotor reset during AG selection xfs_ialloc_next_ag() currently resets m_agirotor when it is equal to m_maxagi: if (++mp->m_agirotor == mp->m_maxagi) mp->m_agirotor = 0; But, if for some reason mp->m_maxagi changes to a lower value than current m_agirotor, this condition will never be true, causing m_agirotor to exceed the maximum allowed value (m_maxagi). This implies mainly during lookups for xfs_perag structs in its radix tree, since the agno value used for the lookup is based on m_agirotor. An out-of-range m_agirotor may cause a lookup failure which in case will return NULL. As an example, the value of m_maxagi is decreased during inode64->inode32 remount process, case where I've found this problem. Signed-off-by: Carlos Maiolino Reviewed-by: Christoph Hellwig Reviewed-by: Mark Tinguely Signed-off-by: Ben Myers --- fs/xfs/xfs_ialloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/xfs/xfs_ialloc.c') diff --git a/fs/xfs/xfs_ialloc.c b/fs/xfs/xfs_ialloc.c index 5aceb3f8ecd..445bf1aef31 100644 --- a/fs/xfs/xfs_ialloc.c +++ b/fs/xfs/xfs_ialloc.c @@ -431,7 +431,7 @@ xfs_ialloc_next_ag( spin_lock(&mp->m_agirotor_lock); agno = mp->m_agirotor; - if (++mp->m_agirotor == mp->m_maxagi) + if (++mp->m_agirotor >= mp->m_maxagi) mp->m_agirotor = 0; spin_unlock(&mp->m_agirotor_lock); -- cgit v1.2.3-70-g09d2