From: Christoph Hellwig Date: Mon, 23 Apr 2012 05:58:36 +0000 (+1000) Subject: xfs: do not write the buffer from xfs_iflush X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=4c46819a8097a75d3b378c5e56d2bcf47bb7408d;p=linux-beck.git xfs: do not write the buffer from xfs_iflush Instead of writing the buffer directly from inside xfs_iflush return it to the caller and let the caller decide what to do with the buffer. Also remove the pincount check in xfs_iflush that all non-blocking callers already implement and the now unused flags parameter. Signed-off-by: Christoph Hellwig Reviewed-by: Dave Chinner Reviewed-by: Mark Tinguely Signed-off-by: Ben Myers --- diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index 00f9c2f34e1f..0fa987dea242 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -2384,22 +2384,22 @@ cluster_corrupt_out: } /* - * xfs_iflush() will write a modified inode's changes out to the - * inode's on disk home. The caller must have the inode lock held - * in at least shared mode and the inode flush completion must be - * active as well. The inode lock will still be held upon return from - * the call and the caller is free to unlock it. - * The inode flush will be completed when the inode reaches the disk. - * The flags indicate how the inode's buffer should be written out. + * Flush dirty inode metadata into the backing buffer. + * + * The caller must have the inode lock and the inode flush lock held. The + * inode lock will still be held upon return to the caller, and the inode + * flush lock will be released after the inode has reached the disk. + * + * The caller must write out the buffer returned in *bpp and release it. */ int xfs_iflush( - xfs_inode_t *ip, - uint flags) + struct xfs_inode *ip, + struct xfs_buf **bpp) { - xfs_buf_t *bp; - xfs_dinode_t *dip; - xfs_mount_t *mp; + struct xfs_mount *mp = ip->i_mount; + struct xfs_buf *bp; + struct xfs_dinode *dip; int error; XFS_STATS_INC(xs_iflush_count); @@ -2409,24 +2409,8 @@ xfs_iflush( ASSERT(ip->i_d.di_format != XFS_DINODE_FMT_BTREE || ip->i_d.di_nextents > XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK)); - mp = ip->i_mount; + *bpp = NULL; - /* - * We can't flush the inode until it is unpinned, so wait for it if we - * are allowed to block. We know no one new can pin it, because we are - * holding the inode lock shared and you need to hold it exclusively to - * pin the inode. - * - * If we are not allowed to block, force the log out asynchronously so - * that when we come back the inode will be unpinned. If other inodes - * in the same cluster are dirty, they will probably write the inode - * out for us if they occur after the log force completes. - */ - if (!(flags & SYNC_WAIT) && xfs_ipincount(ip)) { - xfs_iunpin(ip); - xfs_ifunlock(ip); - return EAGAIN; - } xfs_iunpin_wait(ip); /* @@ -2458,8 +2442,7 @@ xfs_iflush( /* * Get the buffer containing the on-disk inode. */ - error = xfs_itobp(mp, NULL, ip, &dip, &bp, - (flags & SYNC_TRYLOCK) ? XBF_TRYLOCK : XBF_LOCK); + error = xfs_itobp(mp, NULL, ip, &dip, &bp, XBF_TRYLOCK); if (error || !bp) { xfs_ifunlock(ip); return error; @@ -2487,13 +2470,8 @@ xfs_iflush( if (error) goto cluster_corrupt_out; - if (flags & SYNC_WAIT) - error = xfs_bwrite(bp); - else - xfs_buf_delwri_queue(bp); - - xfs_buf_relse(bp); - return error; + *bpp = bp; + return 0; corrupt_out: xfs_buf_relse(bp); diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h index 7fee3387e1c8..a2fa79ae410f 100644 --- a/fs/xfs/xfs_inode.h +++ b/fs/xfs/xfs_inode.h @@ -529,7 +529,7 @@ int xfs_iunlink(struct xfs_trans *, xfs_inode_t *); void xfs_iext_realloc(xfs_inode_t *, int, int); void xfs_iunpin_wait(xfs_inode_t *); -int xfs_iflush(xfs_inode_t *, uint); +int xfs_iflush(struct xfs_inode *, struct xfs_buf **); void xfs_promote_inode(struct xfs_inode *); void xfs_lock_inodes(xfs_inode_t **, int, uint); void xfs_lock_two_inodes(xfs_inode_t *, xfs_inode_t *, uint); diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c index 05d924efceaf..d3601ab75dd3 100644 --- a/fs/xfs/xfs_inode_item.c +++ b/fs/xfs/xfs_inode_item.c @@ -506,6 +506,15 @@ xfs_inode_item_trylock( if (!xfs_ilock_nowait(ip, XFS_ILOCK_SHARED)) return XFS_ITEM_LOCKED; + /* + * Re-check the pincount now that we stabilized the value by + * taking the ilock. + */ + if (xfs_ipincount(ip) > 0) { + xfs_iunlock(ip, XFS_ILOCK_SHARED); + return XFS_ITEM_PINNED; + } + if (!xfs_iflock_nowait(ip)) { /* * inode has already been flushed to the backing buffer, @@ -666,6 +675,8 @@ xfs_inode_item_push( { struct xfs_inode_log_item *iip = INODE_ITEM(lip); struct xfs_inode *ip = iip->ili_inode; + struct xfs_buf *bp = NULL; + int error; ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED)); ASSERT(xfs_isiflocked(ip)); @@ -689,7 +700,11 @@ xfs_inode_item_push( * will pull the inode from the AIL, mark it clean and unlock the flush * lock. */ - (void) xfs_iflush(ip, SYNC_TRYLOCK); + error = xfs_iflush(ip, &bp); + if (!error) { + xfs_buf_delwri_queue(bp); + xfs_buf_relse(bp); + } xfs_iunlock(ip, XFS_ILOCK_SHARED); } diff --git a/fs/xfs/xfs_sync.c b/fs/xfs/xfs_sync.c index 7b2bccc4d67b..468c3c0a4f9f 100644 --- a/fs/xfs/xfs_sync.c +++ b/fs/xfs/xfs_sync.c @@ -648,10 +648,6 @@ xfs_reclaim_inode_grab( * (*) dgc: I don't think the clean, pinned state is possible but it gets * handled anyway given the order of checks implemented. * - * As can be seen from the table, the return value of xfs_iflush() is not - * sufficient to correctly decide the reclaim action here. The checks in - * xfs_iflush() might look like duplicates, but they are not. - * * Also, because we get the flush lock first, we know that any inode that has * been flushed delwri has had the flush completed by the time we check that * the inode is clean. @@ -679,7 +675,8 @@ xfs_reclaim_inode( struct xfs_perag *pag, int sync_mode) { - int error; + struct xfs_buf *bp = NULL; + int error; restart: error = 0; @@ -728,29 +725,33 @@ restart: /* * Now we have an inode that needs flushing. * - * We do a nonblocking flush here even if we are doing a SYNC_WAIT - * reclaim as we can deadlock with inode cluster removal. + * Note that xfs_iflush will never block on the inode buffer lock, as * xfs_ifree_cluster() can lock the inode buffer before it locks the - * ip->i_lock, and we are doing the exact opposite here. As a result, - * doing a blocking xfs_itobp() to get the cluster buffer will result + * ip->i_lock, and we are doing the exact opposite here. As a result, + * doing a blocking xfs_itobp() to get the cluster buffer would result * in an ABBA deadlock with xfs_ifree_cluster(). * * As xfs_ifree_cluser() must gather all inodes that are active in the * cache to mark them stale, if we hit this case we don't actually want * to do IO here - we want the inode marked stale so we can simply - * reclaim it. Hence if we get an EAGAIN error on a SYNC_WAIT flush, - * just unlock the inode, back off and try again. Hopefully the next - * pass through will see the stale flag set on the inode. + * reclaim it. Hence if we get an EAGAIN error here, just unlock the + * inode, back off and try again. Hopefully the next pass through will + * see the stale flag set on the inode. */ - error = xfs_iflush(ip, SYNC_TRYLOCK | sync_mode); + error = xfs_iflush(ip, &bp); if (error == EAGAIN) { xfs_iunlock(ip, XFS_ILOCK_EXCL); /* backoff longer than in xfs_ifree_cluster */ delay(2); goto restart; } - xfs_iflock(ip); + if (!error) { + error = xfs_bwrite(bp); + xfs_buf_relse(bp); + } + + xfs_iflock(ip); reclaim: xfs_ifunlock(ip); xfs_iunlock(ip, XFS_ILOCK_EXCL);