diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/xfs/xfs_trans_ail.c | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c index f31271c30de9..2ffc570679be 100644 --- a/fs/xfs/xfs_trans_ail.c +++ b/fs/xfs/xfs_trans_ail.c @@ -467,6 +467,7 @@ xfs_trans_ail_update( { xfs_log_item_t *dlip = NULL; xfs_log_item_t *mlip; /* ptr to minimum lip */ + xfs_lsn_t tail_lsn; mlip = xfs_ail_min(ailp); @@ -483,8 +484,16 @@ xfs_trans_ail_update( if (mlip == dlip) { mlip = xfs_ail_min(ailp); + /* + * It is not safe to access mlip after the AIL lock is + * dropped, so we must get a copy of li_lsn before we do + * so. This is especially important on 32-bit platforms + * where accessing and updating 64-bit values like li_lsn + * is not atomic. + */ + tail_lsn = mlip->li_lsn; spin_unlock(&ailp->xa_lock); - xfs_log_move_tail(ailp->xa_mount, mlip->li_lsn); + xfs_log_move_tail(ailp->xa_mount, tail_lsn); } else { spin_unlock(&ailp->xa_lock); } @@ -514,6 +523,7 @@ xfs_trans_ail_delete( { xfs_log_item_t *dlip; xfs_log_item_t *mlip; + xfs_lsn_t tail_lsn; if (lip->li_flags & XFS_LI_IN_AIL) { mlip = xfs_ail_min(ailp); @@ -527,9 +537,16 @@ xfs_trans_ail_delete( if (mlip == dlip) { mlip = xfs_ail_min(ailp); + /* + * It is not safe to access mlip after the AIL lock + * is dropped, so we must get a copy of li_lsn + * before we do so. This is especially important + * on 32-bit platforms where accessing and updating + * 64-bit values like li_lsn is not atomic. + */ + tail_lsn = mlip ? mlip->li_lsn : 0; spin_unlock(&ailp->xa_lock); - xfs_log_move_tail(ailp->xa_mount, - (mlip ? mlip->li_lsn : 0)); + xfs_log_move_tail(ailp->xa_mount, tail_lsn); } else { spin_unlock(&ailp->xa_lock); } |