From: Andreas Gruenbacher <agruenba@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Christoph Hellwig <hch@infradead.org>,
"Darrick J. Wong" <djwong@kernel.org>
Cc: Jan Kara <jack@suse.cz>, Matthew Wilcox <willy@infradead.org>,
cluster-devel@redhat.com, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, ocfs2-devel@oss.oracle.com,
Andreas Gruenbacher <agruenba@redhat.com>
Subject: [PATCH v6 11/19] gfs2: Move the inode glock locking to gfs2_file_buffered_write
Date: Thu, 19 Aug 2021 21:40:54 +0200 [thread overview]
Message-ID: <20210819194102.1491495-12-agruenba@redhat.com> (raw)
In-Reply-To: <20210819194102.1491495-1-agruenba@redhat.com>
So far, for buffered writes, we were taking the inode glock in
gfs2_iomap_begin and dropping it in gfs2_iomap_end with the intention of
not holding the inode glock while iomap_write_actor faults in user
pages. It turns out that iomap_write_actor is called inside iomap_begin
... iomap_end, so the user pages were still faulted in while holding the
inode glock and the locking code in iomap_begin / iomap_end was
completely pointless.
Move the locking into gfs2_file_buffered_write instead. We'll take care
of the potential deadlocks due to faulting user pages while holding a
glock in a subsequent patch.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
fs/gfs2/bmap.c | 60 +-------------------------------------------------
fs/gfs2/file.c | 27 +++++++++++++++++++++++
2 files changed, 28 insertions(+), 59 deletions(-)
diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index ed8b67b21718..0d90f1809efb 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -961,46 +961,6 @@ static int __gfs2_iomap_get(struct inode *inode, loff_t pos, loff_t length,
goto out;
}
-static int gfs2_write_lock(struct inode *inode)
-{
- struct gfs2_inode *ip = GFS2_I(inode);
- struct gfs2_sbd *sdp = GFS2_SB(inode);
- int error;
-
- gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &ip->i_gh);
- error = gfs2_glock_nq(&ip->i_gh);
- if (error)
- goto out_uninit;
- if (&ip->i_inode == sdp->sd_rindex) {
- struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
-
- error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE,
- GL_NOCACHE, &m_ip->i_gh);
- if (error)
- goto out_unlock;
- }
- return 0;
-
-out_unlock:
- gfs2_glock_dq(&ip->i_gh);
-out_uninit:
- gfs2_holder_uninit(&ip->i_gh);
- return error;
-}
-
-static void gfs2_write_unlock(struct inode *inode)
-{
- struct gfs2_inode *ip = GFS2_I(inode);
- struct gfs2_sbd *sdp = GFS2_SB(inode);
-
- if (&ip->i_inode == sdp->sd_rindex) {
- struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
-
- gfs2_glock_dq_uninit(&m_ip->i_gh);
- }
- gfs2_glock_dq_uninit(&ip->i_gh);
-}
-
static int gfs2_iomap_page_prepare(struct inode *inode, loff_t pos,
unsigned len, struct iomap *iomap)
{
@@ -1119,11 +1079,6 @@ static int gfs2_iomap_begin_write(struct inode *inode, loff_t pos,
return ret;
}
-static inline bool gfs2_iomap_need_write_lock(unsigned flags)
-{
- return (flags & IOMAP_WRITE) && !(flags & IOMAP_DIRECT);
-}
-
static int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
unsigned flags, struct iomap *iomap,
struct iomap *srcmap)
@@ -1136,12 +1091,6 @@ static int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
iomap->flags |= IOMAP_F_BUFFER_HEAD;
trace_gfs2_iomap_start(ip, pos, length, flags);
- if (gfs2_iomap_need_write_lock(flags)) {
- ret = gfs2_write_lock(inode);
- if (ret)
- goto out;
- }
-
ret = __gfs2_iomap_get(inode, pos, length, flags, iomap, &mp);
if (ret)
goto out_unlock;
@@ -1169,10 +1118,7 @@ static int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
ret = gfs2_iomap_begin_write(inode, pos, length, flags, iomap, &mp);
out_unlock:
- if (ret && gfs2_iomap_need_write_lock(flags))
- gfs2_write_unlock(inode);
release_metapath(&mp);
-out:
trace_gfs2_iomap_end(ip, iomap, ret);
return ret;
}
@@ -1220,15 +1166,11 @@ static int gfs2_iomap_end(struct inode *inode, loff_t pos, loff_t length,
}
if (unlikely(!written))
- goto out_unlock;
+ return 0;
if (iomap->flags & IOMAP_F_SIZE_CHANGED)
mark_inode_dirty(inode);
set_bit(GLF_DIRTY, &ip->i_gl->gl_flags);
-
-out_unlock:
- if (gfs2_iomap_need_write_lock(flags))
- gfs2_write_unlock(inode);
return 0;
}
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 55ec1cadc9e6..813154d60834 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -880,11 +880,38 @@ static ssize_t gfs2_file_buffered_write(struct kiocb *iocb, struct iov_iter *fro
{
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
+ struct gfs2_inode *ip = GFS2_I(inode);
+ struct gfs2_sbd *sdp = GFS2_SB(inode);
ssize_t ret;
+ gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &ip->i_gh);
+ ret = gfs2_glock_nq(&ip->i_gh);
+ if (ret)
+ goto out_uninit;
+
+ if (inode == sdp->sd_rindex) {
+ struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
+
+ ret = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE,
+ GL_NOCACHE, &m_ip->i_gh);
+ if (ret)
+ goto out_unlock;
+ }
+
current->backing_dev_info = inode_to_bdi(inode);
ret = iomap_file_buffered_write(iocb, from, &gfs2_iomap_ops);
current->backing_dev_info = NULL;
+
+ if (inode == sdp->sd_rindex) {
+ struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
+
+ gfs2_glock_dq_uninit(&m_ip->i_gh);
+ }
+
+out_unlock:
+ gfs2_glock_dq(&ip->i_gh);
+out_uninit:
+ gfs2_holder_uninit(&ip->i_gh);
return ret;
}
--
2.26.3
next prev parent reply other threads:[~2021-08-19 19:42 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-19 19:40 [PATCH v6 00/19] gfs2: Fix mmap + page fault deadlocks Andreas Gruenbacher
2021-08-19 19:40 ` [PATCH v6 01/19] iov_iter: Fix iov_iter_get_pages{,_alloc} page fault return value Andreas Gruenbacher
2021-08-19 19:40 ` [PATCH v6 02/19] powerpc/kvm: Fix kvm_use_magic_page Andreas Gruenbacher
2021-08-19 19:40 ` [PATCH v6 03/19] Turn fault_in_pages_{readable,writeable} into fault_in_{readable,writeable} Andreas Gruenbacher
2021-08-19 19:40 ` [PATCH v6 04/19] Turn iov_iter_fault_in_readable into fault_in_iov_iter_readable Andreas Gruenbacher
2021-08-19 19:40 ` [PATCH v6 05/19] iov_iter: Introduce fault_in_iov_iter_writeable Andreas Gruenbacher
2021-08-19 19:40 ` [PATCH v6 06/19] gfs2: Add wrapper for iomap_file_buffered_write Andreas Gruenbacher
2021-08-19 19:40 ` [PATCH v6 07/19] gfs2: Clean up function may_grant Andreas Gruenbacher
2021-08-19 19:40 ` [PATCH v6 08/19] gfs2: Eliminate vestigial HIF_FIRST Andreas Gruenbacher
2021-08-19 19:40 ` [PATCH v6 09/19] gfs2: Remove redundant check from gfs2_glock_dq Andreas Gruenbacher
2021-08-19 19:40 ` [PATCH v6 10/19] gfs2: Introduce flag for glock holder auto-demotion Andreas Gruenbacher
2021-08-20 9:35 ` [Cluster-devel] " Steven Whitehouse
2021-08-20 13:11 ` Bob Peterson
2021-08-20 13:41 ` Steven Whitehouse
2021-08-20 15:22 ` Andreas Gruenbacher
2021-08-23 8:14 ` Steven Whitehouse
2021-08-23 15:18 ` Andreas Gruenbacher
2021-08-23 16:05 ` Matthew Wilcox
2021-08-23 16:36 ` Bob Peterson
2021-08-23 19:12 ` Andreas Gruenbacher
2021-08-24 7:59 ` Steven Whitehouse
2021-08-20 13:17 ` Andreas Gruenbacher
2021-08-20 13:47 ` Steven Whitehouse
2021-08-20 14:43 ` Andreas Grünbacher
2021-08-19 19:40 ` Andreas Gruenbacher [this message]
2021-08-19 19:40 ` [PATCH v6 12/19] gfs2: Fix mmap + page fault deadlocks for buffered I/O Andreas Gruenbacher
2021-08-19 19:40 ` [PATCH v6 13/19] iomap: Fix iomap_dio_rw return value for user copies Andreas Gruenbacher
2021-08-19 19:40 ` [PATCH v6 14/19] iomap: Support partial direct I/O on user copy failures Andreas Gruenbacher
2021-08-19 19:40 ` [PATCH v6 15/19] iomap: Add done_before argument to iomap_dio_rw Andreas Gruenbacher
2021-08-19 19:40 ` [PATCH v6 16/19] gup: Introduce FOLL_NOFAULT flag to disable page faults Andreas Gruenbacher
2021-08-19 19:41 ` [PATCH v6 17/19] iov_iter: Introduce nofault " Andreas Gruenbacher
2021-08-19 19:41 ` [PATCH v6 18/19] gfs2: Fix mmap + page fault deadlocks for direct I/O Andreas Gruenbacher
2021-08-19 19:41 ` [PATCH v6 19/19] gfs2: Eliminate ip->i_gh Andreas Gruenbacher
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