/* * 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); } }
/* * 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); }
/* * This is the iodone() function for buffers which have had callbacks * attached to them by xfs_buf_attach_iodone(). It should remove each * log item from the buffer's list and call the callback of each in turn. * When done, the buffer's fsprivate field is set to NULL and the buffer * is unlocked with a call to iodone(). */ void xfs_buf_iodone_callbacks( struct xfs_buf *bp) { struct xfs_log_item *lip = bp->b_fspriv; struct xfs_mount *mp = lip->li_mountp; static ulong lasttime; static xfs_buftarg_t *lasttarg; if (likely(!xfs_buf_geterror(bp))) goto do_callbacks; /* * If we've already decided to shutdown the filesystem because of * I/O errors, there's no point in giving this a retry. */ if (XFS_FORCED_SHUTDOWN(mp)) { xfs_buf_stale(bp); XFS_BUF_DONE(bp); trace_xfs_buf_item_iodone(bp, _RET_IP_); goto do_callbacks; } if (bp->b_target != lasttarg || time_after(jiffies, (lasttime + 5*HZ))) { lasttime = jiffies; xfs_buf_ioerror_alert(bp, __func__); } lasttarg = bp->b_target; /* * If the write was asynchronous then no one will be looking for the * error. Clear the error state and write the buffer out again. * * XXX: This helps against transient write errors, but we need to find * a way to shut the filesystem down if the writes keep failing. * * In practice we'll shut the filesystem down soon as non-transient * erorrs tend to affect the whole device and a failing log write * will make us give up. But we really ought to do better here. */ if (XFS_BUF_ISASYNC(bp)) { ASSERT(bp->b_iodone != NULL); trace_xfs_buf_item_iodone_async(bp, _RET_IP_); xfs_buf_ioerror(bp, 0); /* errno of 0 unsets the flag */ if (!XFS_BUF_ISSTALE(bp)) { bp->b_flags |= XBF_WRITE | XBF_ASYNC | XBF_DONE; xfs_buf_iorequest(bp); } else { xfs_buf_relse(bp); } return; } /* * If the write of the buffer was synchronous, we want to make * sure to return the error to the caller of xfs_bwrite(). */ xfs_buf_stale(bp); XFS_BUF_DONE(bp); trace_xfs_buf_error_relse(bp, _RET_IP_); do_callbacks: xfs_buf_do_callbacks(bp); bp->b_fspriv = NULL; bp->b_iodone = NULL; xfs_buf_ioend(bp, 0); }