From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757262AbdDFJaG (ORCPT ); Thu, 6 Apr 2017 05:30:06 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:51636 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754925AbdDFIk5 (ORCPT ); Thu, 6 Apr 2017 04:40:57 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Brian Foster , Christoph Hellwig , "Darrick J. Wong" Subject: [PATCH 4.9 05/72] xfs: pull up iolock from xfs_free_eofblocks() Date: Thu, 6 Apr 2017 10:37:52 +0200 Message-Id: <20170406083620.023320177@linuxfoundation.org> X-Mailer: git-send-email 2.12.2 In-Reply-To: <20170406083619.775985942@linuxfoundation.org> References: <20170406083619.775985942@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Brian Foster commit a36b926180cda375ac2ec89e1748b47137cfc51c upstream. xfs_free_eofblocks() requires the IOLOCK_EXCL lock, but is called from different contexts where the lock may or may not be held. The need_iolock parameter exists for this reason, to indicate whether xfs_free_eofblocks() must acquire the iolock itself before it can proceed. This is ugly and confusing. Simplify the semantics of xfs_free_eofblocks() to require the caller to acquire the iolock appropriately and kill the need_iolock parameter. While here, the mp param can be removed as well as the xfs_mount is accessible from the xfs_inode structure. This patch does not change behavior. Signed-off-by: Brian Foster Reviewed-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong Signed-off-by: Greg Kroah-Hartman --- fs/xfs/xfs_bmap_util.c | 41 +++++++++++++++------------------------ fs/xfs/xfs_bmap_util.h | 3 -- fs/xfs/xfs_icache.c | 24 ++++++++++++++--------- fs/xfs/xfs_inode.c | 51 ++++++++++++++++++++++++++----------------------- 4 files changed, 60 insertions(+), 59 deletions(-) --- a/fs/xfs/xfs_bmap_util.c +++ b/fs/xfs/xfs_bmap_util.c @@ -917,17 +917,18 @@ xfs_can_free_eofblocks(struct xfs_inode */ int xfs_free_eofblocks( - xfs_mount_t *mp, - xfs_inode_t *ip, - bool need_iolock) + struct xfs_inode *ip) { - xfs_trans_t *tp; - int error; - xfs_fileoff_t end_fsb; - xfs_fileoff_t last_fsb; - xfs_filblks_t map_len; - int nimaps; - xfs_bmbt_irec_t imap; + struct xfs_trans *tp; + int error; + xfs_fileoff_t end_fsb; + xfs_fileoff_t last_fsb; + xfs_filblks_t map_len; + int nimaps; + struct xfs_bmbt_irec imap; + struct xfs_mount *mp = ip->i_mount; + + ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL)); /* * Figure out if there are any blocks beyond the end @@ -944,6 +945,10 @@ xfs_free_eofblocks( error = xfs_bmapi_read(ip, end_fsb, map_len, &imap, &nimaps, 0); xfs_iunlock(ip, XFS_ILOCK_SHARED); + /* + * If there are blocks after the end of file, truncate the file to its + * current size to free them up. + */ if (!error && (nimaps != 0) && (imap.br_startblock != HOLESTARTBLOCK || ip->i_delayed_blks)) { @@ -954,22 +959,10 @@ xfs_free_eofblocks( if (error) return error; - /* - * There are blocks after the end of file. - * Free them up now by truncating the file to - * its current size. - */ - if (need_iolock) { - if (!xfs_ilock_nowait(ip, XFS_IOLOCK_EXCL)) - return -EAGAIN; - } - error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp); if (error) { ASSERT(XFS_FORCED_SHUTDOWN(mp)); - if (need_iolock) - xfs_iunlock(ip, XFS_IOLOCK_EXCL); return error; } @@ -997,8 +990,6 @@ xfs_free_eofblocks( } xfs_iunlock(ip, XFS_ILOCK_EXCL); - if (need_iolock) - xfs_iunlock(ip, XFS_IOLOCK_EXCL); } return error; } @@ -1415,7 +1406,7 @@ xfs_shift_file_space( * into the accessible region of the file. */ if (xfs_can_free_eofblocks(ip, true)) { - error = xfs_free_eofblocks(mp, ip, false); + error = xfs_free_eofblocks(ip); if (error) return error; } --- a/fs/xfs/xfs_bmap_util.h +++ b/fs/xfs/xfs_bmap_util.h @@ -63,8 +63,7 @@ int xfs_insert_file_space(struct xfs_ino /* EOF block manipulation functions */ bool xfs_can_free_eofblocks(struct xfs_inode *ip, bool force); -int xfs_free_eofblocks(struct xfs_mount *mp, struct xfs_inode *ip, - bool need_iolock); +int xfs_free_eofblocks(struct xfs_inode *ip); int xfs_swap_extents(struct xfs_inode *ip, struct xfs_inode *tip, struct xfs_swapext *sx); --- a/fs/xfs/xfs_icache.c +++ b/fs/xfs/xfs_icache.c @@ -1324,7 +1324,7 @@ xfs_inode_free_eofblocks( int flags, void *args) { - int ret; + int ret = 0; struct xfs_eofblocks *eofb = args; bool need_iolock = true; int match; @@ -1360,19 +1360,25 @@ xfs_inode_free_eofblocks( return 0; /* - * A scan owner implies we already hold the iolock. Skip it in - * xfs_free_eofblocks() to avoid deadlock. This also eliminates - * the possibility of EAGAIN being returned. + * A scan owner implies we already hold the iolock. Skip it here + * to avoid deadlock. */ if (eofb->eof_scan_owner == ip->i_ino) need_iolock = false; } - ret = xfs_free_eofblocks(ip->i_mount, ip, need_iolock); - - /* don't revisit the inode if we're not waiting */ - if (ret == -EAGAIN && !(flags & SYNC_WAIT)) - ret = 0; + /* + * If the caller is waiting, return -EAGAIN to keep the background + * scanner moving and revisit the inode in a subsequent pass. + */ + if (need_iolock && !xfs_ilock_nowait(ip, XFS_IOLOCK_EXCL)) { + if (flags & SYNC_WAIT) + ret = -EAGAIN; + return ret; + } + ret = xfs_free_eofblocks(ip); + if (need_iolock) + xfs_iunlock(ip, XFS_IOLOCK_EXCL); return ret; } --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -1701,32 +1701,34 @@ xfs_release( if (xfs_can_free_eofblocks(ip, false)) { /* + * Check if the inode is being opened, written and closed + * frequently and we have delayed allocation blocks outstanding + * (e.g. streaming writes from the NFS server), truncating the + * blocks past EOF will cause fragmentation to occur. + * + * In this case don't do the truncation, but we have to be + * careful how we detect this case. Blocks beyond EOF show up as + * i_delayed_blks even when the inode is clean, so we need to + * truncate them away first before checking for a dirty release. + * Hence on the first dirty close we will still remove the + * speculative allocation, but after that we will leave it in + * place. + */ + if (xfs_iflags_test(ip, XFS_IDIRTY_RELEASE)) + return 0; + /* * If we can't get the iolock just skip truncating the blocks * past EOF because we could deadlock with the mmap_sem - * otherwise. We'll get another chance to drop them once the + * otherwise. We'll get another chance to drop them once the * last reference to the inode is dropped, so we'll never leak * blocks permanently. - * - * Further, check if the inode is being opened, written and - * closed frequently and we have delayed allocation blocks - * outstanding (e.g. streaming writes from the NFS server), - * truncating the blocks past EOF will cause fragmentation to - * occur. - * - * In this case don't do the truncation, either, but we have to - * be careful how we detect this case. Blocks beyond EOF show - * up as i_delayed_blks even when the inode is clean, so we - * need to truncate them away first before checking for a dirty - * release. Hence on the first dirty close we will still remove - * the speculative allocation, but after that we will leave it - * in place. */ - if (xfs_iflags_test(ip, XFS_IDIRTY_RELEASE)) - return 0; - - error = xfs_free_eofblocks(mp, ip, true); - if (error && error != -EAGAIN) - return error; + if (xfs_ilock_nowait(ip, XFS_IOLOCK_EXCL)) { + error = xfs_free_eofblocks(ip); + xfs_iunlock(ip, XFS_IOLOCK_EXCL); + if (error) + return error; + } /* delalloc blocks after truncation means it really is dirty */ if (ip->i_delayed_blks) @@ -1913,8 +1915,11 @@ xfs_inactive( * cache. Post-eof blocks must be freed, lest we end up with * broken free space accounting. */ - if (xfs_can_free_eofblocks(ip, true)) - xfs_free_eofblocks(mp, ip, false); + if (xfs_can_free_eofblocks(ip, true)) { + xfs_ilock(ip, XFS_IOLOCK_EXCL); + xfs_free_eofblocks(ip); + xfs_iunlock(ip, XFS_IOLOCK_EXCL); + } return; }