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authorDave Chinner <dchinner@redhat.com>2010-12-20 03:59:49 +0300
committerDave Chinner <david@fromorbit.com>2010-12-20 03:59:49 +0300
commitb199c8a4ba11879df87daad496ceee41fdc6aa82 (patch)
tree8652785ca70788e3cc43272be72f21123adafbe7 /fs/xfs/xfs_trans_extfree.c
parent9c5f8414efd5eeed9f498d4170337a3eb126341f (diff)
downloadlinux-b199c8a4ba11879df87daad496ceee41fdc6aa82.tar.xz
xfs: Pull EFI/EFD handling out from under the AIL lock
EFI/EFD interactions are protected from races by the AIL lock. They are the only type of log items that require the the AIL lock to serialise internal state, so they need to be separated from the AIL lock before we can do bulk insert operations on the AIL. To acheive this, convert the counter of the number of extents in the EFI to an atomic so it can be safely manipulated by EFD processing without locks. Also, convert the EFI state flag manipulations to use atomic bit operations so no locks are needed to record state changes. Finally, use the state bits to determine when it is safe to free the EFI and clean up the code to do this neatly. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'fs/xfs/xfs_trans_extfree.c')
-rw-r--r--fs/xfs/xfs_trans_extfree.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/fs/xfs/xfs_trans_extfree.c b/fs/xfs/xfs_trans_extfree.c
index f783d5e9fa70..f7590f5badea 100644
--- a/fs/xfs/xfs_trans_extfree.c
+++ b/fs/xfs/xfs_trans_extfree.c
@@ -69,12 +69,16 @@ xfs_trans_log_efi_extent(xfs_trans_t *tp,
tp->t_flags |= XFS_TRANS_DIRTY;
efip->efi_item.li_desc->lid_flags |= XFS_LID_DIRTY;
- next_extent = efip->efi_next_extent;
+ /*
+ * atomic_inc_return gives us the value after the increment;
+ * we want to use it as an array index so we need to subtract 1 from
+ * it.
+ */
+ next_extent = atomic_inc_return(&efip->efi_next_extent) - 1;
ASSERT(next_extent < efip->efi_format.efi_nextents);
extp = &(efip->efi_format.efi_extents[next_extent]);
extp->ext_start = start_block;
extp->ext_len = ext_len;
- efip->efi_next_extent++;
}