From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 24 May 2018 10:59:43 -0400 From: Brian Foster To: Christoph Hellwig Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 25/34] xfs: remove xfs_reflink_trim_irec_to_next_cow Message-ID: <20180524145943.GB84959@bfoster.bfoster> References: <20180523144357.18985-1-hch@lst.de> <20180523144357.18985-26-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180523144357.18985-26-hch@lst.de> Sender: owner-linux-mm@kvack.org List-ID: On Wed, May 23, 2018 at 04:43:48PM +0200, Christoph Hellwig wrote: > In the only caller we just did a lookup in the COW extent tree for > the same offset. Reuse that result and save a lookup, as well as > shortening the ilock hold time. > > Signed-off-by: Christoph Hellwig > --- > fs/xfs/xfs_aops.c | 25 +++++++++++++++++-------- > fs/xfs/xfs_reflink.c | 33 --------------------------------- > fs/xfs/xfs_reflink.h | 2 -- > 3 files changed, 17 insertions(+), 43 deletions(-) > > diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c > index a4b4a7037deb..354d26d66c12 100644 > --- a/fs/xfs/xfs_aops.c > +++ b/fs/xfs/xfs_aops.c > @@ -383,11 +383,12 @@ xfs_map_blocks( > struct xfs_inode *ip = XFS_I(inode); > struct xfs_mount *mp = ip->i_mount; > ssize_t count = i_blocksize(inode); > - xfs_fileoff_t offset_fsb, end_fsb; > + xfs_fileoff_t offset_fsb, end_fsb, cow_fsb = 0; cow_fsb should probably be initialized to NULLFSBLOCK rather than 0. With that, you also shouldn't need cow_valid. Otherwise looks Ok to me. Brian > int whichfork = XFS_DATA_FORK; > struct xfs_iext_cursor icur; > int error = 0; > int nimaps = 1; > + bool cow_valid = false; > > if (XFS_FORCED_SHUTDOWN(mp)) > return -EIO; > @@ -407,8 +408,11 @@ xfs_map_blocks( > * it directly instead of looking up anything in the data fork. > */ > if (xfs_is_reflink_inode(ip) && > - xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, imap) && > - imap->br_startoff <= offset_fsb) { > + xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, imap)) { > + cow_fsb = imap->br_startoff; > + cow_valid = true; > + } > + if (cow_valid && cow_fsb <= offset_fsb) { > xfs_iunlock(ip, XFS_ILOCK_SHARED); > /* > * Truncate can race with writeback since writeback doesn't > @@ -430,6 +434,10 @@ xfs_map_blocks( > > error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, > imap, &nimaps, XFS_BMAPI_ENTIRE); > + xfs_iunlock(ip, XFS_ILOCK_SHARED); > + if (error) > + return error; > + > if (!nimaps) { > /* > * Lookup returns no match? Beyond eof? regardless, > @@ -451,16 +459,17 @@ xfs_map_blocks( > * is a pending CoW reservation before the end of this extent, > * so that we pick up the COW extents in the next iteration. > */ > - xfs_reflink_trim_irec_to_next_cow(ip, offset_fsb, imap); > + if (cow_valid && > + cow_fsb < imap->br_startoff + imap->br_blockcount) { > + imap->br_blockcount = cow_fsb - imap->br_startoff; > + trace_xfs_reflink_trim_irec(ip, imap); > + } > + > if (imap->br_state == XFS_EXT_UNWRITTEN) > *type = XFS_IO_UNWRITTEN; > else > *type = XFS_IO_OVERWRITE; > } > - xfs_iunlock(ip, XFS_ILOCK_SHARED); > - if (error) > - return error; > - > done: > switch (*type) { > case XFS_IO_HOLE: > diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c > index 8e5eb8e70c89..ff76bc56ff3d 100644 > --- a/fs/xfs/xfs_reflink.c > +++ b/fs/xfs/xfs_reflink.c > @@ -484,39 +484,6 @@ xfs_reflink_allocate_cow( > return error; > } > > -/* > - * Trim an extent to end at the next CoW reservation past offset_fsb. > - */ > -void > -xfs_reflink_trim_irec_to_next_cow( > - struct xfs_inode *ip, > - xfs_fileoff_t offset_fsb, > - struct xfs_bmbt_irec *imap) > -{ > - struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK); > - struct xfs_bmbt_irec got; > - struct xfs_iext_cursor icur; > - > - if (!xfs_is_reflink_inode(ip)) > - return; > - > - /* Find the extent in the CoW fork. */ > - if (!xfs_iext_lookup_extent(ip, ifp, offset_fsb, &icur, &got)) > - return; > - > - /* This is the extent before; try sliding up one. */ > - if (got.br_startoff < offset_fsb) { > - if (!xfs_iext_next_extent(ifp, &icur, &got)) > - return; > - } > - > - if (got.br_startoff >= imap->br_startoff + imap->br_blockcount) > - return; > - > - imap->br_blockcount = got.br_startoff - imap->br_startoff; > - trace_xfs_reflink_trim_irec(ip, imap); > -} > - > /* > * Cancel CoW reservations for some block range of an inode. > * > diff --git a/fs/xfs/xfs_reflink.h b/fs/xfs/xfs_reflink.h > index 15a456492667..e8d4d50c629f 100644 > --- a/fs/xfs/xfs_reflink.h > +++ b/fs/xfs/xfs_reflink.h > @@ -32,8 +32,6 @@ extern int xfs_reflink_allocate_cow(struct xfs_inode *ip, > struct xfs_bmbt_irec *imap, bool *shared, uint *lockmode); > extern int xfs_reflink_convert_cow(struct xfs_inode *ip, xfs_off_t offset, > xfs_off_t count); > -extern void xfs_reflink_trim_irec_to_next_cow(struct xfs_inode *ip, > - xfs_fileoff_t offset_fsb, struct xfs_bmbt_irec *imap); > > extern int xfs_reflink_cancel_cow_blocks(struct xfs_inode *ip, > struct xfs_trans **tpp, xfs_fileoff_t offset_fsb, > -- > 2.17.0 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html