| Message ID | 20200522035029.3022405-21-david@fromorbit.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | xfs: rework inode flushing to make inode reclaim fully asynchronous | expand |
On Fri, May 22, 2020 at 01:50:25PM +1000, Dave Chinner wrote: > From: Dave Chinner <dchinner@redhat.com> > > Now we have a cached buffer on inode log items, we don't need > to do buffer lookups when flushing inodes anymore - all we need > to do is lock the buffer and we are ready to go. > > This largely gets rid of the need for xfs_iflush(), which is > essentially just a mechanism to look up the buffer and flush the > inode to it. Instead, we can just call xfs_iflush_cluster() with a > few modifications to ensure it also flushes the inode we already > hold locked. > > This allows the AIL inode item pushing to be almost entirely > non-blocking in XFS - we won't block unless memory allocation > for the cluster inode lookup blocks or the block device queues are > full. > > Writeback during inode reclaim becomes a little more complex because > we now have to lock the buffer ourselves, but otherwise this change > is largely a functional no-op that removes a whole lot of code. > > Signed-off-by: Dave Chinner <dchinner@redhat.com> /This/ looks pretty straightforward. I always wondered about the fact that the inode item push function would extract a buffer pointer but then imap_to_bp would replace our pointer... Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> --D > --- > fs/xfs/xfs_inode.c | 106 ++++++---------------------------------- > fs/xfs/xfs_inode.h | 2 +- > fs/xfs/xfs_inode_item.c | 51 +++++++------------ > 3 files changed, 32 insertions(+), 127 deletions(-) > > diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c > index 961eef2ce8c4a..a94528d26328b 100644 > --- a/fs/xfs/xfs_inode.c > +++ b/fs/xfs/xfs_inode.c > @@ -3429,7 +3429,18 @@ xfs_rename( > return error; > } > > -STATIC int > +/* > + * Non-blocking flush of dirty inode metadata into the backing buffer. > + * > + * The caller must have a reference to the inode and hold the cluster buffer > + * locked. The function will walk across all the inodes on the cluster buffer it > + * can find and lock without blocking, and flush them to the cluster buffer. > + * > + * On success, the caller must write out the buffer returned in *bp and > + * release it. On failure, the filesystem will be shut down, the buffer will > + * have been unlocked and released, and EFSCORRUPTED will be returned. > + */ > +int > xfs_iflush_cluster( > struct xfs_inode *ip, > struct xfs_buf *bp) > @@ -3464,8 +3475,6 @@ xfs_iflush_cluster( > > for (i = 0; i < nr_found; i++) { > cip = cilist[i]; > - if (cip == ip) > - continue; > > /* > * because this is an RCU protected lookup, we could find a > @@ -3556,99 +3565,11 @@ xfs_iflush_cluster( > kmem_free(cilist); > out_put: > xfs_perag_put(pag); > - return error; > -} > - > -/* > - * 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( > - struct xfs_inode *ip, > - struct xfs_buf **bpp) > -{ > - struct xfs_mount *mp = ip->i_mount; > - struct xfs_buf *bp = NULL; > - struct xfs_dinode *dip; > - int error; > - > - XFS_STATS_INC(mp, xs_iflush_count); > - > - ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)); > - ASSERT(xfs_isiflocked(ip)); > - ASSERT(ip->i_df.if_format != XFS_DINODE_FMT_BTREE || > - ip->i_df.if_nextents > XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK)); > - > - *bpp = NULL; > - > - xfs_iunpin_wait(ip); > - > - /* > - * For stale inodes we cannot rely on the backing buffer remaining > - * stale in cache for the remaining life of the stale inode and so > - * xfs_imap_to_bp() below may give us a buffer that no longer contains > - * inodes below. We have to check this after ensuring the inode is > - * unpinned so that it is safe to reclaim the stale inode after the > - * flush call. > - */ > - if (xfs_iflags_test(ip, XFS_ISTALE)) { > - xfs_ifunlock(ip); > - return 0; > - } > - > - /* > - * Get the buffer containing the on-disk inode. We are doing a try-lock > - * operation here, so we may get an EAGAIN error. In that case, return > - * leaving the inode dirty. > - * > - * If we get any other error, we effectively have a corruption situation > - * and we cannot flush the inode. Abort the flush and shut down. > - */ > - error = xfs_imap_to_bp(mp, NULL, &ip->i_imap, &dip, &bp, XBF_TRYLOCK); > - if (error == -EAGAIN) { > - xfs_ifunlock(ip); > - return error; > - } > - if (error) > - goto abort; > - > - /* > - * If the buffer is pinned then push on the log now so we won't > - * get stuck waiting in the write for too long. > - */ > - if (xfs_buf_ispinned(bp)) > - xfs_log_force(mp, 0); > - > - /* > - * Flush the provided inode then attempt to gather others from the > - * cluster into the write. > - * > - * Note: Once we attempt to flush an inode, we must run buffer > - * completion callbacks on any failure. If this fails, simulate an I/O > - * failure on the buffer and shut down. > - */ > - error = xfs_iflush_int(ip, bp); > - if (!error) > - error = xfs_iflush_cluster(ip, bp); > if (error) { > bp->b_flags |= XBF_ASYNC; > xfs_buf_ioend_fail(bp); > - goto shutdown; > + xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE); > } > - > - *bpp = bp; > - return 0; > - > -abort: > - xfs_iflush_abort(ip); > -shutdown: > - xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE); > return error; > } > > @@ -3667,6 +3588,7 @@ xfs_iflush_int( > ASSERT(ip->i_df.if_format != XFS_DINODE_FMT_BTREE || > ip->i_df.if_nextents > XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK)); > ASSERT(iip != NULL && iip->ili_fields != 0); > + ASSERT(iip->ili_item.li_buf == bp); > > dip = xfs_buf_offset(bp, ip->i_imap.im_boffset); > > diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h > index dadcf19458960..d1109eb13ba2e 100644 > --- a/fs/xfs/xfs_inode.h > +++ b/fs/xfs/xfs_inode.h > @@ -427,7 +427,7 @@ int xfs_log_force_inode(struct xfs_inode *ip); > void xfs_iunpin_wait(xfs_inode_t *); > #define xfs_ipincount(ip) ((unsigned int) atomic_read(&ip->i_pincount)) > > -int xfs_iflush(struct xfs_inode *, struct xfs_buf **); > +int xfs_iflush_cluster(struct xfs_inode *, struct xfs_buf *); > void xfs_lock_two_inodes(struct xfs_inode *ip0, uint ip0_mode, > struct xfs_inode *ip1, uint ip1_mode); > > diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c > index 7718cfc39eec8..42b4b5fe1e2a9 100644 > --- a/fs/xfs/xfs_inode_item.c > +++ b/fs/xfs/xfs_inode_item.c > @@ -504,53 +504,35 @@ xfs_inode_item_push( > uint rval = XFS_ITEM_SUCCESS; > int error; > > - if (xfs_ipincount(ip) > 0) > - return XFS_ITEM_PINNED; > + ASSERT(iip->ili_item.li_buf); > > - if (!xfs_ilock_nowait(ip, XFS_ILOCK_SHARED)) > - return XFS_ITEM_LOCKED; > + if (xfs_ipincount(ip) > 0 || xfs_buf_ispinned(bp) || > + (ip->i_flags & XFS_ISTALE)) > + return XFS_ITEM_PINNED; > > - /* > - * Re-check the pincount now that we stabilized the value by > - * taking the ilock. > - */ > - if (xfs_ipincount(ip) > 0) { > - rval = XFS_ITEM_PINNED; > - goto out_unlock; > - } > + /* If the inode is already flush locked, we're already flushing. */ > + if (xfs_isiflocked(ip)) > + return XFS_ITEM_FLUSHING; > > - /* > - * Stale inode items should force out the iclog. > - */ > - if (ip->i_flags & XFS_ISTALE) { > - rval = XFS_ITEM_PINNED; > - goto out_unlock; > - } > + if (!xfs_buf_trylock(bp)) > + return XFS_ITEM_LOCKED; > > - /* > - * Someone else is already flushing the inode. Nothing we can do > - * here but wait for the flush to finish and remove the item from > - * the AIL. > - */ > - if (!xfs_iflock_nowait(ip)) { > - rval = XFS_ITEM_FLUSHING; > - goto out_unlock; > + if (bp->b_flags & _XBF_DELWRI_Q) { > + xfs_buf_unlock(bp); > + return XFS_ITEM_FLUSHING; > } > - > - ASSERT(iip->ili_fields != 0 || XFS_FORCED_SHUTDOWN(ip->i_mount)); > spin_unlock(&lip->li_ailp->ail_lock); > > - error = xfs_iflush(ip, &bp); > + error = xfs_iflush_cluster(ip, bp); > if (!error) { > if (!xfs_buf_delwri_queue(bp, buffer_list)) > rval = XFS_ITEM_FLUSHING; > - xfs_buf_relse(bp); > - } else if (error == -EAGAIN) > + xfs_buf_unlock(bp); > + } else { > rval = XFS_ITEM_LOCKED; > + } > > spin_lock(&lip->li_ailp->ail_lock); > -out_unlock: > - xfs_iunlock(ip, XFS_ILOCK_SHARED); > return rval; > } > > @@ -567,6 +549,7 @@ xfs_inode_item_release( > > ASSERT(ip->i_itemp != NULL); > ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL)); > + ASSERT(lip->li_buf || !test_bit(XFS_LI_DIRTY, &lip->li_flags)); > > lock_flags = iip->ili_lock_flags; > iip->ili_lock_flags = 0; > -- > 2.26.2.761.g0e0b3e54be >
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index 961eef2ce8c4a..a94528d26328b 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -3429,7 +3429,18 @@ xfs_rename( return error; } -STATIC int +/* + * Non-blocking flush of dirty inode metadata into the backing buffer. + * + * The caller must have a reference to the inode and hold the cluster buffer + * locked. The function will walk across all the inodes on the cluster buffer it + * can find and lock without blocking, and flush them to the cluster buffer. + * + * On success, the caller must write out the buffer returned in *bp and + * release it. On failure, the filesystem will be shut down, the buffer will + * have been unlocked and released, and EFSCORRUPTED will be returned. + */ +int xfs_iflush_cluster( struct xfs_inode *ip, struct xfs_buf *bp) @@ -3464,8 +3475,6 @@ xfs_iflush_cluster( for (i = 0; i < nr_found; i++) { cip = cilist[i]; - if (cip == ip) - continue; /* * because this is an RCU protected lookup, we could find a @@ -3556,99 +3565,11 @@ xfs_iflush_cluster( kmem_free(cilist); out_put: xfs_perag_put(pag); - return error; -} - -/* - * 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( - struct xfs_inode *ip, - struct xfs_buf **bpp) -{ - struct xfs_mount *mp = ip->i_mount; - struct xfs_buf *bp = NULL; - struct xfs_dinode *dip; - int error; - - XFS_STATS_INC(mp, xs_iflush_count); - - ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)); - ASSERT(xfs_isiflocked(ip)); - ASSERT(ip->i_df.if_format != XFS_DINODE_FMT_BTREE || - ip->i_df.if_nextents > XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK)); - - *bpp = NULL; - - xfs_iunpin_wait(ip); - - /* - * For stale inodes we cannot rely on the backing buffer remaining - * stale in cache for the remaining life of the stale inode and so - * xfs_imap_to_bp() below may give us a buffer that no longer contains - * inodes below. We have to check this after ensuring the inode is - * unpinned so that it is safe to reclaim the stale inode after the - * flush call. - */ - if (xfs_iflags_test(ip, XFS_ISTALE)) { - xfs_ifunlock(ip); - return 0; - } - - /* - * Get the buffer containing the on-disk inode. We are doing a try-lock - * operation here, so we may get an EAGAIN error. In that case, return - * leaving the inode dirty. - * - * If we get any other error, we effectively have a corruption situation - * and we cannot flush the inode. Abort the flush and shut down. - */ - error = xfs_imap_to_bp(mp, NULL, &ip->i_imap, &dip, &bp, XBF_TRYLOCK); - if (error == -EAGAIN) { - xfs_ifunlock(ip); - return error; - } - if (error) - goto abort; - - /* - * If the buffer is pinned then push on the log now so we won't - * get stuck waiting in the write for too long. - */ - if (xfs_buf_ispinned(bp)) - xfs_log_force(mp, 0); - - /* - * Flush the provided inode then attempt to gather others from the - * cluster into the write. - * - * Note: Once we attempt to flush an inode, we must run buffer - * completion callbacks on any failure. If this fails, simulate an I/O - * failure on the buffer and shut down. - */ - error = xfs_iflush_int(ip, bp); - if (!error) - error = xfs_iflush_cluster(ip, bp); if (error) { bp->b_flags |= XBF_ASYNC; xfs_buf_ioend_fail(bp); - goto shutdown; + xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE); } - - *bpp = bp; - return 0; - -abort: - xfs_iflush_abort(ip); -shutdown: - xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE); return error; } @@ -3667,6 +3588,7 @@ xfs_iflush_int( ASSERT(ip->i_df.if_format != XFS_DINODE_FMT_BTREE || ip->i_df.if_nextents > XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK)); ASSERT(iip != NULL && iip->ili_fields != 0); + ASSERT(iip->ili_item.li_buf == bp); dip = xfs_buf_offset(bp, ip->i_imap.im_boffset); diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h index dadcf19458960..d1109eb13ba2e 100644 --- a/fs/xfs/xfs_inode.h +++ b/fs/xfs/xfs_inode.h @@ -427,7 +427,7 @@ int xfs_log_force_inode(struct xfs_inode *ip); void xfs_iunpin_wait(xfs_inode_t *); #define xfs_ipincount(ip) ((unsigned int) atomic_read(&ip->i_pincount)) -int xfs_iflush(struct xfs_inode *, struct xfs_buf **); +int xfs_iflush_cluster(struct xfs_inode *, struct xfs_buf *); void xfs_lock_two_inodes(struct xfs_inode *ip0, uint ip0_mode, struct xfs_inode *ip1, uint ip1_mode); diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c index 7718cfc39eec8..42b4b5fe1e2a9 100644 --- a/fs/xfs/xfs_inode_item.c +++ b/fs/xfs/xfs_inode_item.c @@ -504,53 +504,35 @@ xfs_inode_item_push( uint rval = XFS_ITEM_SUCCESS; int error; - if (xfs_ipincount(ip) > 0) - return XFS_ITEM_PINNED; + ASSERT(iip->ili_item.li_buf); - if (!xfs_ilock_nowait(ip, XFS_ILOCK_SHARED)) - return XFS_ITEM_LOCKED; + if (xfs_ipincount(ip) > 0 || xfs_buf_ispinned(bp) || + (ip->i_flags & XFS_ISTALE)) + return XFS_ITEM_PINNED; - /* - * Re-check the pincount now that we stabilized the value by - * taking the ilock. - */ - if (xfs_ipincount(ip) > 0) { - rval = XFS_ITEM_PINNED; - goto out_unlock; - } + /* If the inode is already flush locked, we're already flushing. */ + if (xfs_isiflocked(ip)) + return XFS_ITEM_FLUSHING; - /* - * Stale inode items should force out the iclog. - */ - if (ip->i_flags & XFS_ISTALE) { - rval = XFS_ITEM_PINNED; - goto out_unlock; - } + if (!xfs_buf_trylock(bp)) + return XFS_ITEM_LOCKED; - /* - * Someone else is already flushing the inode. Nothing we can do - * here but wait for the flush to finish and remove the item from - * the AIL. - */ - if (!xfs_iflock_nowait(ip)) { - rval = XFS_ITEM_FLUSHING; - goto out_unlock; + if (bp->b_flags & _XBF_DELWRI_Q) { + xfs_buf_unlock(bp); + return XFS_ITEM_FLUSHING; } - - ASSERT(iip->ili_fields != 0 || XFS_FORCED_SHUTDOWN(ip->i_mount)); spin_unlock(&lip->li_ailp->ail_lock); - error = xfs_iflush(ip, &bp); + error = xfs_iflush_cluster(ip, bp); if (!error) { if (!xfs_buf_delwri_queue(bp, buffer_list)) rval = XFS_ITEM_FLUSHING; - xfs_buf_relse(bp); - } else if (error == -EAGAIN) + xfs_buf_unlock(bp); + } else { rval = XFS_ITEM_LOCKED; + } spin_lock(&lip->li_ailp->ail_lock); -out_unlock: - xfs_iunlock(ip, XFS_ILOCK_SHARED); return rval; } @@ -567,6 +549,7 @@ xfs_inode_item_release( ASSERT(ip->i_itemp != NULL); ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL)); + ASSERT(lip->li_buf || !test_bit(XFS_LI_DIRTY, &lip->li_flags)); lock_flags = iip->ili_lock_flags; iip->ili_lock_flags = 0;