/* * This is called to unpin the buffer associated with the buf log * item which was previously pinned with a call to xfs_buf_item_pin(). * Just call bunpin() on the buffer to do this. * * Also drop the reference to the buf item for the current transaction. * If the XFS_BLI_STALE flag is set and we are the last reference, * then free up the buf log item and unlock the buffer. */ void xfs_buf_item_unpin( xfs_buf_log_item_t *bip, int stale) { xfs_mount_t *mp; xfs_buf_t *bp; int freed; SPLDECL(s); bp = bip->bli_buf; ASSERT(bp != NULL); ASSERT(XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t *) == bip); ASSERT(atomic_read(&bip->bli_refcount) > 0); xfs_buf_item_trace("UNPIN", bip); xfs_buftrace("XFS_UNPIN", bp); freed = atomic_dec_and_test(&bip->bli_refcount); mp = bip->bli_item.li_mountp; xfs_bunpin(bp); if (freed && stale) { ASSERT(bip->bli_flags & XFS_BLI_STALE); ASSERT(XFS_BUF_VALUSEMA(bp) <= 0); ASSERT(!(XFS_BUF_ISDELAYWRITE(bp))); ASSERT(XFS_BUF_ISSTALE(bp)); ASSERT(bip->bli_format.blf_flags & XFS_BLI_CANCEL); xfs_buf_item_trace("UNPIN STALE", bip); xfs_buftrace("XFS_UNPIN STALE", bp); /* * If we get called here because of an IO error, we may * or may not have the item on the AIL. xfs_trans_delete_ail() * will take care of that situation. * xfs_trans_delete_ail() drops the AIL lock. */ if (bip->bli_flags & XFS_BLI_STALE_INODE) { xfs_buf_do_callbacks(bp, (xfs_log_item_t *)bip); XFS_BUF_SET_FSPRIVATE(bp, NULL); XFS_BUF_CLR_IODONE_FUNC(bp); } else { AIL_LOCK(mp,s); xfs_trans_delete_ail(mp, (xfs_log_item_t *)bip, s); xfs_buf_item_relse(bp); ASSERT(XFS_BUF_FSPRIVATE(bp, void *) == NULL); } xfs_buf_relse(bp); }
/* * Release the buffer associated with the buf log item. If there is no dirty * logged data associated with the buffer recorded in the buf log item, then * free the buf log item and remove the reference to it in the buffer. * * This call ignores the recursion count. It is only called when the buffer * should REALLY be unlocked, regardless of the recursion count. * * We unconditionally drop the transaction's reference to the log item. If the * item was logged, then another reference was taken when it was pinned, so we * can safely drop the transaction reference now. This also allows us to avoid * potential races with the unpin code freeing the bli by not referencing the * bli after we've dropped the reference count. * * If the XFS_BLI_HOLD flag is set in the buf log item, then free the log item * if necessary but do not unlock the buffer. This is for support of * xfs_trans_bhold(). Make sure the XFS_BLI_HOLD field is cleared if we don't * free the item. */ STATIC void xfs_buf_item_unlock( struct xfs_log_item *lip) { struct xfs_buf_log_item *bip = BUF_ITEM(lip); struct xfs_buf *bp = bip->bli_buf; int aborted, clean, i; uint hold; /* Clear the buffer's association with this transaction. */ bp->b_transp = NULL; /* * If this is a transaction abort, don't return early. Instead, allow * the brelse to happen. Normally it would be done for stale * (cancelled) buffers at unpin time, but we'll never go through the * pin/unpin cycle if we abort inside commit. */ aborted = (lip->li_flags & XFS_LI_ABORTED) != 0; /* * Before possibly freeing the buf item, determine if we should * release the buffer at the end of this routine. */ hold = bip->bli_flags & XFS_BLI_HOLD; /* Clear the per transaction state. */ bip->bli_flags &= ~(XFS_BLI_LOGGED | XFS_BLI_HOLD); /* * If the buf item is marked stale, then don't do anything. We'll * unlock the buffer and free the buf item when the buffer is unpinned * for the last time. */ if (bip->bli_flags & XFS_BLI_STALE) { trace_xfs_buf_item_unlock_stale(bip); ASSERT(bip->__bli_format.blf_flags & XFS_BLF_CANCEL); if (!aborted) { atomic_dec(&bip->bli_refcount); return; } } trace_xfs_buf_item_unlock(bip); /* * If the buf item isn't tracking any data, free it, otherwise drop the * reference we hold to it. If we are aborting the transaction, this may * be the only reference to the buf item, so we free it anyway * regardless of whether it is dirty or not. A dirty abort implies a * shutdown, anyway. */ clean = 1; for (i = 0; i < bip->bli_format_count; i++) { if (!xfs_bitmap_empty(bip->bli_formats[i].blf_data_map, bip->bli_formats[i].blf_map_size)) { clean = 0; break; } } if (clean) xfs_buf_item_relse(bp); else if (aborted) { if (atomic_dec_and_test(&bip->bli_refcount)) { ASSERT(XFS_FORCED_SHUTDOWN(lip->li_mountp)); xfs_buf_item_relse(bp); } } else atomic_dec(&bip->bli_refcount); if (!hold) xfs_buf_relse(bp); }
/* * This is called to unpin the buffer associated with the buf log * item which was previously pinned with a call to xfs_buf_item_pin(). * * Also drop the reference to the buf item for the current transaction. * If the XFS_BLI_STALE flag is set and we are the last reference, * then free up the buf log item and unlock the buffer. * * If the remove flag is set we are called from uncommit in the * forced-shutdown path. If that is true and the reference count on * the log item is going to drop to zero we need to free the item's * descriptor in the transaction. */ STATIC void xfs_buf_item_unpin( struct xfs_log_item *lip, int remove) { struct xfs_buf_log_item *bip = BUF_ITEM(lip); xfs_buf_t *bp = bip->bli_buf; struct xfs_ail *ailp = lip->li_ailp; int stale = bip->bli_flags & XFS_BLI_STALE; int freed; ASSERT(bp->b_fspriv == bip); ASSERT(atomic_read(&bip->bli_refcount) > 0); trace_xfs_buf_item_unpin(bip); freed = atomic_dec_and_test(&bip->bli_refcount); if (atomic_dec_and_test(&bp->b_pin_count)) wake_up_all(&bp->b_waiters); if (freed && stale) { ASSERT(bip->bli_flags & XFS_BLI_STALE); ASSERT(xfs_buf_islocked(bp)); ASSERT(XFS_BUF_ISSTALE(bp)); ASSERT(bip->__bli_format.blf_flags & XFS_BLF_CANCEL); trace_xfs_buf_item_unpin_stale(bip); if (remove) { /* * If we are in a transaction context, we have to * remove the log item from the transaction as we are * about to release our reference to the buffer. If we * don't, the unlock that occurs later in * xfs_trans_uncommit() will try to reference the * buffer which we no longer have a hold on. */ if (lip->li_desc) xfs_trans_del_item(lip); /* * Since the transaction no longer refers to the buffer, * the buffer should no longer refer to the transaction. */ bp->b_transp = NULL; } /* * If we get called here because of an IO error, we may * or may not have the item on the AIL. xfs_trans_ail_delete() * will take care of that situation. * xfs_trans_ail_delete() drops the AIL lock. */ if (bip->bli_flags & XFS_BLI_STALE_INODE) { xfs_buf_do_callbacks(bp); bp->b_fspriv = NULL; bp->b_iodone = NULL; } else { spin_lock(&ailp->xa_lock); xfs_trans_ail_delete(ailp, lip, SHUTDOWN_LOG_IO_ERROR); xfs_buf_item_relse(bp); ASSERT(bp->b_fspriv == NULL); } xfs_buf_relse(bp); } else if (freed && remove) { /* * There are currently two references to the buffer - the active * LRU reference and the buf log item. What we are about to do * here - simulate a failed IO completion - requires 3 * references. * * The LRU reference is removed by the xfs_buf_stale() call. The * buf item reference is removed by the xfs_buf_iodone() * callback that is run by xfs_buf_do_callbacks() during ioend * processing (via the bp->b_iodone callback), and then finally * the ioend processing will drop the IO reference if the buffer * is marked XBF_ASYNC. * * Hence we need to take an additional reference here so that IO * completion processing doesn't free the buffer prematurely. */ xfs_buf_lock(bp); xfs_buf_hold(bp); bp->b_flags |= XBF_ASYNC; xfs_buf_ioerror(bp, EIO); XFS_BUF_UNDONE(bp); xfs_buf_stale(bp); xfs_buf_ioend(bp, 0); } }
/* * Release the buffer associated with the buf log item. If there is no dirty * logged data associated with the buffer recorded in the buf log item, then * free the buf log item and remove the reference to it in the buffer. * * This call ignores the recursion count. It is only called when the buffer * should REALLY be unlocked, regardless of the recursion count. * * We unconditionally drop the transaction's reference to the log item. If the * item was logged, then another reference was taken when it was pinned, so we * can safely drop the transaction reference now. This also allows us to avoid * potential races with the unpin code freeing the bli by not referencing the * bli after we've dropped the reference count. * * If the XFS_BLI_HOLD flag is set in the buf log item, then free the log item * if necessary but do not unlock the buffer. This is for support of * xfs_trans_bhold(). Make sure the XFS_BLI_HOLD field is cleared if we don't * free the item. */ STATIC void xfs_buf_item_unlock( struct xfs_log_item *lip) { struct xfs_buf_log_item *bip = BUF_ITEM(lip); struct xfs_buf *bp = bip->bli_buf; bool clean; bool aborted; int flags; /* Clear the buffer's association with this transaction. */ bp->b_transp = NULL; /* * If this is a transaction abort, don't return early. Instead, allow * the brelse to happen. Normally it would be done for stale * (cancelled) buffers at unpin time, but we'll never go through the * pin/unpin cycle if we abort inside commit. */ aborted = (lip->li_flags & XFS_LI_ABORTED) ? true : false; /* * Before possibly freeing the buf item, copy the per-transaction state * so we can reference it safely later after clearing it from the * buffer log item. */ flags = bip->bli_flags; bip->bli_flags &= ~(XFS_BLI_LOGGED | XFS_BLI_HOLD | XFS_BLI_ORDERED); /* * If the buf item is marked stale, then don't do anything. We'll * unlock the buffer and free the buf item when the buffer is unpinned * for the last time. */ if (flags & XFS_BLI_STALE) { trace_xfs_buf_item_unlock_stale(bip); ASSERT(bip->__bli_format.blf_flags & XFS_BLF_CANCEL); if (!aborted) { atomic_dec(&bip->bli_refcount); return; } } trace_xfs_buf_item_unlock(bip); /* * If the buf item isn't tracking any data, free it, otherwise drop the * reference we hold to it. If we are aborting the transaction, this may * be the only reference to the buf item, so we free it anyway * regardless of whether it is dirty or not. A dirty abort implies a * shutdown, anyway. * * Ordered buffers are dirty but may have no recorded changes, so ensure * we only release clean items here. */ clean = (flags & XFS_BLI_DIRTY) ? false : true; if (clean) { int i; for (i = 0; i < bip->bli_format_count; i++) { if (!xfs_bitmap_empty(bip->bli_formats[i].blf_data_map, bip->bli_formats[i].blf_map_size)) { clean = false; break; } } } /* * Clean buffers, by definition, cannot be in the AIL. However, aborted * buffers may be dirty and hence in the AIL. Therefore if we are * aborting a buffer and we've just taken the last refernce away, we * have to check if it is in the AIL before freeing it. We need to free * it in this case, because an aborted transaction has already shut the * filesystem down and this is the last chance we will have to do so. */ if (atomic_dec_and_test(&bip->bli_refcount)) { if (clean) xfs_buf_item_relse(bp); else if (aborted) { ASSERT(XFS_FORCED_SHUTDOWN(lip->li_mountp)); if (lip->li_flags & XFS_LI_IN_AIL) { spin_lock(&lip->li_ailp->xa_lock); xfs_trans_ail_delete(lip->li_ailp, lip, SHUTDOWN_LOG_IO_ERROR); } xfs_buf_item_relse(bp); } } if (!(flags & XFS_BLI_HOLD)) xfs_buf_relse(bp); }
/* * This is called to unpin the buffer associated with the buf log * item which was previously pinned with a call to xfs_buf_item_pin(). * * Also drop the reference to the buf item for the current transaction. * If the XFS_BLI_STALE flag is set and we are the last reference, * then free up the buf log item and unlock the buffer. * * If the remove flag is set we are called from uncommit in the * forced-shutdown path. If that is true and the reference count on * the log item is going to drop to zero we need to free the item's * descriptor in the transaction. */ STATIC void xfs_buf_item_unpin( struct xfs_log_item *lip, int remove) { struct xfs_buf_log_item *bip = BUF_ITEM(lip); xfs_buf_t *bp = bip->bli_buf; struct xfs_ail *ailp = lip->li_ailp; int stale = bip->bli_flags & XFS_BLI_STALE; int freed; ASSERT(XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t *) == bip); ASSERT(atomic_read(&bip->bli_refcount) > 0); trace_xfs_buf_item_unpin(bip); freed = atomic_dec_and_test(&bip->bli_refcount); if (atomic_dec_and_test(&bp->b_pin_count)) wake_up_all(&bp->b_waiters); if (freed && stale) { ASSERT(bip->bli_flags & XFS_BLI_STALE); ASSERT(XFS_BUF_VALUSEMA(bp) <= 0); ASSERT(!(XFS_BUF_ISDELAYWRITE(bp))); ASSERT(XFS_BUF_ISSTALE(bp)); ASSERT(bip->bli_format.blf_flags & XFS_BLF_CANCEL); trace_xfs_buf_item_unpin_stale(bip); if (remove) { /* * If we are in a transaction context, we have to * remove the log item from the transaction as we are * about to release our reference to the buffer. If we * don't, the unlock that occurs later in * xfs_trans_uncommit() will try to reference the * buffer which we no longer have a hold on. */ if (lip->li_desc) xfs_trans_del_item(lip); /* * Since the transaction no longer refers to the buffer, * the buffer should no longer refer to the transaction. */ XFS_BUF_SET_FSPRIVATE2(bp, NULL); } /* * If we get called here because of an IO error, we may * or may not have the item on the AIL. xfs_trans_ail_delete() * will take care of that situation. * xfs_trans_ail_delete() drops the AIL lock. */ if (bip->bli_flags & XFS_BLI_STALE_INODE) { xfs_buf_do_callbacks(bp); XFS_BUF_SET_FSPRIVATE(bp, NULL); XFS_BUF_CLR_IODONE_FUNC(bp); } else { spin_lock(&ailp->xa_lock); xfs_trans_ail_delete(ailp, (xfs_log_item_t *)bip); xfs_buf_item_relse(bp); ASSERT(XFS_BUF_FSPRIVATE(bp, void *) == NULL); } xfs_buf_relse(bp); }