Hi Sage, We are on Dragon Boat Festival holidays. :) I will take a close look and test it next week. -- Henry
2011/6/4 Sage Weil <[email protected]>: > Hi Henry, > > I made a small change to the O_DIRECT path to zero holes properly in > commit 85defe7 (below). Do you mind reviewing the change, and/or testing, > since you are the main O_DIRECT user? The test case that was failing is > here: > > http://tracker.newdream.net/issues/1096#note-19 > > The problem was that the read coming down from the VFS isn't trimmed to > i_size, so the old zero tail check wasn't true, and we would set > *checkeof. Then ceph_aio_read would getattr and loop, since we > didn't actually read eof (due to a hole). > > Actually, I suspect the *checkeof part is still incorrect... does the > zeroing part at least look right to you? > > Thanks! > sage > > > From 85defe76f7e2a0b3d285a3be72fcffce96629b5c Mon Sep 17 00:00:00 2001 > From: Sage Weil <[email protected]> > Date: Wed, 1 Jun 2011 16:08:44 -0700 > Subject: [PATCH] ceph: fix short sync reads from the OSD > > If we get a short read from the OSD because the object is small, we need to > zero the remainder of the buffer. For O_DIRECT reads, the attempted range > is not trimmed to i_size by the VFS, so we were actually looping > indefinitely. > > Fix by trimming by i_size, and the unconditionally zeroing the trailing > range. > > Reported-by: Jeff Wu <[email protected]> > Signed-off-by: Sage Weil <[email protected]> > --- > fs/ceph/file.c | 28 +++++++++++++++------------- > 1 files changed, 15 insertions(+), 13 deletions(-) > > diff --git a/fs/ceph/file.c b/fs/ceph/file.c > index 8c5ac4e..b654f40 100644 > --- a/fs/ceph/file.c > +++ b/fs/ceph/file.c > @@ -283,7 +283,7 @@ int ceph_release(struct inode *inode, struct file *file) > static int striped_read(struct inode *inode, > u64 off, u64 len, > struct page **pages, int num_pages, > - int *checkeof, bool align_to_pages, > + int *checkeof, bool o_direct, > unsigned long buf_align) > { > struct ceph_fs_client *fsc = ceph_inode_to_client(inode); > @@ -308,7 +308,7 @@ static int striped_read(struct inode *inode, > io_align = off & ~PAGE_MASK; > > more: > - if (align_to_pages) > + if (o_direct) > page_align = (pos - io_align + buf_align) & ~PAGE_MASK; > else > page_align = pos & ~PAGE_MASK; > @@ -346,20 +346,22 @@ more: > } > > if (was_short) { > - /* was original extent fully inside i_size? */ > - if (pos + left <= inode->i_size) { > - dout("zero tail\n"); > - ceph_zero_page_vector_range(page_off + read, len - > read, > + /* did we bounce off eof? */ > + if (pos + left > inode->i_size) > + *checkeof = 1; > + > + /* zero trailing bytes (inside i_size) */ > + if (left > 0 && pos < inode->i_size) { > + if (pos + left > inode->i_size) > + left = inode->i_size - pos; > + > + dout("zero tail %d\n", left); > + ceph_zero_page_vector_range(page_off + read, left, > pages); > - read = len; > - goto out; > + read += left; > } > - > - /* check i_size */ > - *checkeof = 1; > } > > -out: > if (ret >= 0) > ret = read; > dout("striped_read returns %d\n", ret); > @@ -659,7 +661,7 @@ out: > > /* hit EOF or hole? */ > if (statret == 0 && *ppos < inode->i_size) { > - dout("aio_read sync_read hit hole, reading more\n"); > + dout("aio_read sync_read hit hole, ppos %lld < size > %lld, reading more\n", *ppos, inode->i_size); > read += ret; > base += ret; > len -= ret; > -- > 1.7.0 > > -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
