Re: [PATCH 18/47] xfs: refactor redo intent item processing

Brian Foster
2016-08-02T18:47:41Z

On Wed, Jul 20, 2016 at 09:58:04PM -0700, Darrick J. Wong wrote:
> Refactor the EFI intent item recovery (and cancellation) functions
> into a general function that scans the AIL and an intent item type
> specific handler. Move the function that recovers a single EFI item
> into the extent free item code. We'll want the generalized function
> when we start wiring up more redo item types.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
> fs/xfs/xfs_extfree_item.c | 65 ++++++++++++++++
> fs/xfs/xfs_extfree_item.h | 3 +
> fs/xfs/xfs_log_recover.c | 182 +++++++++++++++++++++------------------------
> 3 files changed, 151 insertions(+), 99 deletions(-)
>
>
...
> diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
> index 080b54b..af608aa 100644
> --- a/fs/xfs/xfs_log_recover.c
> +++ b/fs/xfs/xfs_log_recover.c
> @@ -24,7 +24,6 @@
> #include "xfs_bit.h"
> #include "xfs_sb.h"
> #include "xfs_mount.h"
> -#include "xfs_defer.h"
> #include "xfs_da_format.h"
> #include "xfs_da_btree.h"
> #include "xfs_inode.h"
> @@ -4165,126 +4164,112 @@ xlog_recover_process_data(
...
> STATIC int
> -xlog_recover_process_efis(
> +xlog_recover_process_intents(
> struct xlog *log)
> {
> struct xfs_log_item *lip;
> - struct xfs_efi_log_item *efip;
> int error = 0;
> struct xfs_ail_cursor cur;
> struct xfs_ail *ailp;
> + xfs_lsn_t last_lsn;
>
> ailp = log->l_ailp;
> spin_lock(&ailp->xa_lock);
> lip = xfs_trans_ail_cursor_first(ailp, &cur, 0);
> + last_lsn = xlog_assign_lsn(log->l_curr_cycle, log->l_curr_block);
> while (lip != NULL) {
> /*
> - * We're done when we see something other than an EFI.
> - * There should be no EFIs left in the AIL now.
> + * We're done when we see something other than an intent.
> + * There should be no intents left in the AIL now.
> */
> - if (lip->li_type != XFS_LI_EFI) {
> + if (!xlog_item_is_intent(lip)) {
> #ifdef DEBUG
> for (; lip; lip = xfs_trans_ail_cursor_next(ailp, &cur))
> - ASSERT(lip->li_type != XFS_LI_EFI);
> + ASSERT(!xlog_item_is_intent(lip));
> #endif
> break;
> }
>
> /*
> - * Skip EFIs that we've already processed.
> + * We should never see a redo item with a LSN higher than
> + * the last transaction we found in the log at the start
> + * of recovery.
> */
> - efip = container_of(lip, struct xfs_efi_log_item, efi_item);
> - if (test_bit(XFS_EFI_RECOVERED, &efip->efi_flags)) {
> - lip = xfs_trans_ail_cursor_next(ailp, &cur);
> - continue;
> - }
> + ASSERT(XFS_LSN_CMP(last_lsn, lip->li_lsn) >= 0);
>
> - spin_unlock(&ailp->xa_lock);
> - error = xlog_recover_process_efi(log->l_mp, efip);
> - spin_lock(&ailp->xa_lock);
> + switch (lip->li_type) {
> + case XFS_LI_EFI:
> + error = xlog_recover_process_efi(log->l_mp, ailp, lip);
> + break;
> + }

I think I'd prefer to see the locking remain here rather than get buried
in the helper functions. That said, this allows us to check the
recovered bit without a lock cycle. Meh, either way:

Reviewed-by: Brian Foster <bfoster@redhat.com>

> if (error)
> goto out;
> lip = xfs_trans_ail_cursor_next(ailp, &cur);
> @@ -4296,15 +4281,14 @@ out:
> }
>
> /*
> - * A cancel occurs when the mount has failed and we're bailing out. Release all
> - * pending EFIs so they don't pin the AIL.
> + * A cancel occurs when the mount has failed and we're bailing out.
> + * Release all pending log intent items so they don't pin the AIL.
> */
> STATIC int
> -xlog_recover_cancel_efis(
> +xlog_recover_cancel_intents(
> struct xlog *log)
> {
> struct xfs_log_item *lip;
> - struct xfs_efi_log_item *efip;
> int error = 0;
> struct xfs_ail_cursor cur;
> struct xfs_ail *ailp;
> @@ -4314,22 +4298,22 @@ xlog_recover_cancel_efis(
> lip = xfs_trans_ail_cursor_first(ailp, &cur, 0);
> while (lip != NULL) {
> /*
> - * We're done when we see something other than an EFI.
> - * There should be no EFIs left in the AIL now.
> + * We're done when we see something other than an intent.
> + * There should be no intents left in the AIL now.
> */
> - if (lip->li_type != XFS_LI_EFI) {
> + if (!xlog_item_is_intent(lip)) {
> #ifdef DEBUG
> for (; lip; lip = xfs_trans_ail_cursor_next(ailp, &cur))
> - ASSERT(lip->li_type != XFS_LI_EFI);
> + ASSERT(!xlog_item_is_intent(lip));
> #endif
> break;
> }
>
> - efip = container_of(lip, struct xfs_efi_log_item, efi_item);
> -
> - spin_unlock(&ailp->xa_lock);
> - xfs_efi_release(efip);
> - spin_lock(&ailp->xa_lock);
> + switch (lip->li_type) {
> + case XFS_LI_EFI:
> + xlog_recover_cancel_efi(log->l_mp, ailp, lip);
> + break;
> + }
>
> lip = xfs_trans_ail_cursor_next(ailp, &cur);
> }
> @@ -5140,16 +5124,16 @@ xlog_recover_finish(
> */
> if (log->l_flags & XLOG_RECOVERY_NEEDED) {
> int error;
> - error = xlog_recover_process_efis(log);
> + error = xlog_recover_process_intents(log);
> if (error) {
> - xfs_alert(log->l_mp, "Failed to recover EFIs");
> + xfs_alert(log->l_mp, "Failed to recover intents");
> return error;
> }
> /*
> - * Sync the log to get all the EFIs out of the AIL.
> + * Sync the log to get all the intents out of the AIL.
> * This isn't absolutely necessary, but it helps in
> * case the unlink transactions would have problems
> - * pushing the EFIs out of the way.
> + * pushing the intents out of the way.
> */
> xfs_log_force(log->l_mp, XFS_LOG_SYNC);
>
> @@ -5174,7 +5158,7 @@ xlog_recover_cancel(
> int error = 0;
>
> if (log->l_flags & XLOG_RECOVERY_NEEDED)
> - error = xlog_recover_cancel_efis(log);
> + error = xlog_recover_cancel_intents(log);
>
> return error;
> }
>
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