From: Andreas Gruenbacher <agruenba@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andreas Gruenbacher <agruenba@redhat.com>,
cluster-devel@redhat.com, linux-kernel@vger.kernel.org,
Alexander Viro <viro@zeniv.linux.org.uk>, Jan Kara <jack@suse.cz>,
Matthew Wilcox <willy@infradead.org>
Subject: [RFC 7/9] gfs2: Encode glock holding and retry flags in journal_info
Date: Mon, 31 May 2021 19:01:21 +0200 [thread overview]
Message-ID: <20210531170123.243771-8-agruenba@redhat.com> (raw)
In-Reply-To: <20210531170123.243771-1-agruenba@redhat.com>
Use the lowest two bits in current->journal_info to encode when
we're holding a glock, and when an operation holding a glock
needs to be retried.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
fs/gfs2/incore.h | 35 +++++++++++++++++++++++++++++++++--
1 file changed, 33 insertions(+), 2 deletions(-)
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index aa8d1a23132d..e32433df119c 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -871,14 +871,45 @@ static inline unsigned gfs2_max_stuffed_size(const struct gfs2_inode *ip)
return GFS2_SB(&ip->i_inode)->sd_sb.sb_bsize - sizeof(struct gfs2_dinode);
}
+/*
+ * Transactions are always memory aligned, so we use bit 0 of
+ * current->journal_info to indicate when we're holding a glock and so taking
+ * random additional glocks might deadlock, and bit 1 to indicate when such an
+ * operation needs to be retried after dropping and re-acquiring that "outer"
+ * glock.
+ */
+
static inline struct gfs2_trans *current_trans(void)
{
- return current->journal_info;
+ return (void *)((long)current->journal_info & ~3);
}
static inline void set_current_trans(struct gfs2_trans *tr)
{
- current->journal_info = tr;
+ long flags = (long)current->journal_info & 3;
+ current->journal_info = (void *)((long)tr | flags);
+}
+
+static inline bool current_holds_glock(void)
+{
+ return (long)current->journal_info & 1;
+}
+
+static inline bool current_needs_retry(void)
+{
+ return (long)current->journal_info & 2;
+}
+
+static inline void set_current_holds_glock(bool b)
+{
+ current->journal_info =
+ (void *)(((long)current->journal_info & ~1) | b);
+}
+
+static inline void set_current_needs_retry(bool b)
+{
+ current->journal_info =
+ (void *)(((long)current->journal_info & ~2) | (b << 1));
}
#endif /* __INCORE_DOT_H__ */
--
2.26.3
WARNING: multiple messages have this Message-ID (diff)
From: Andreas Gruenbacher <agruenba@redhat.com>
To: cluster-devel.redhat.com
Subject: [Cluster-devel] [RFC 7/9] gfs2: Encode glock holding and retry flags in journal_info
Date: Mon, 31 May 2021 19:01:21 +0200 [thread overview]
Message-ID: <20210531170123.243771-8-agruenba@redhat.com> (raw)
In-Reply-To: <20210531170123.243771-1-agruenba@redhat.com>
Use the lowest two bits in current->journal_info to encode when
we're holding a glock, and when an operation holding a glock
needs to be retried.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
fs/gfs2/incore.h | 35 +++++++++++++++++++++++++++++++++--
1 file changed, 33 insertions(+), 2 deletions(-)
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index aa8d1a23132d..e32433df119c 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -871,14 +871,45 @@ static inline unsigned gfs2_max_stuffed_size(const struct gfs2_inode *ip)
return GFS2_SB(&ip->i_inode)->sd_sb.sb_bsize - sizeof(struct gfs2_dinode);
}
+/*
+ * Transactions are always memory aligned, so we use bit 0 of
+ * current->journal_info to indicate when we're holding a glock and so taking
+ * random additional glocks might deadlock, and bit 1 to indicate when such an
+ * operation needs to be retried after dropping and re-acquiring that "outer"
+ * glock.
+ */
+
static inline struct gfs2_trans *current_trans(void)
{
- return current->journal_info;
+ return (void *)((long)current->journal_info & ~3);
}
static inline void set_current_trans(struct gfs2_trans *tr)
{
- current->journal_info = tr;
+ long flags = (long)current->journal_info & 3;
+ current->journal_info = (void *)((long)tr | flags);
+}
+
+static inline bool current_holds_glock(void)
+{
+ return (long)current->journal_info & 1;
+}
+
+static inline bool current_needs_retry(void)
+{
+ return (long)current->journal_info & 2;
+}
+
+static inline void set_current_holds_glock(bool b)
+{
+ current->journal_info =
+ (void *)(((long)current->journal_info & ~1) | b);
+}
+
+static inline void set_current_needs_retry(bool b)
+{
+ current->journal_info =
+ (void *)(((long)current->journal_info & ~2) | (b << 1));
}
#endif /* __INCORE_DOT_H__ */
--
2.26.3
next prev parent reply other threads:[~2021-05-31 17:10 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-31 17:01 [RFC 0/9] gfs2: handle page faults during read and write Andreas Gruenbacher
2021-05-31 17:01 ` [Cluster-devel] " Andreas Gruenbacher
2021-05-31 17:01 ` [RFC 1/9] gfs2: Clean up the error handling in gfs2_page_mkwrite Andreas Gruenbacher
2021-05-31 17:01 ` [Cluster-devel] " Andreas Gruenbacher
2021-05-31 17:01 ` [RFC 2/9] gfs2: Add wrapper for iomap_file_buffered_write Andreas Gruenbacher
2021-05-31 17:01 ` [Cluster-devel] " Andreas Gruenbacher
2021-05-31 17:01 ` [RFC 3/9] gfs2: Add gfs2_holder_is_compatible helper Andreas Gruenbacher
2021-05-31 17:01 ` [Cluster-devel] " Andreas Gruenbacher
2021-05-31 17:01 ` [RFC 4/9] gfs2: Fix mmap + page fault deadlocks (part 1) Andreas Gruenbacher
2021-05-31 17:01 ` [Cluster-devel] " Andreas Gruenbacher
2021-06-01 6:00 ` Linus Torvalds
2021-06-01 6:00 ` [Cluster-devel] " Linus Torvalds
2021-06-02 11:16 ` Andreas Gruenbacher
2021-06-02 11:16 ` [Cluster-devel] " Andreas Gruenbacher
2021-06-11 16:25 ` Al Viro
2021-06-11 16:25 ` [Cluster-devel] " Al Viro
2021-06-12 21:05 ` Al Viro
2021-06-12 21:05 ` [Cluster-devel] " Al Viro
2021-06-12 21:35 ` Al Viro
2021-06-12 21:35 ` [Cluster-devel] " Al Viro
2021-06-13 8:44 ` Steven Whitehouse
2021-06-13 8:44 ` Steven Whitehouse
2021-05-31 17:01 ` [RFC 5/9] iov_iter: Add iov_iter_fault_in_writeable() Andreas Gruenbacher
2021-05-31 17:01 ` [Cluster-devel] " Andreas Gruenbacher
2021-05-31 17:12 ` Al Viro
2021-05-31 17:12 ` [Cluster-devel] " Al Viro
2021-06-12 21:12 ` Al Viro
2021-06-12 21:12 ` [Cluster-devel] " Al Viro
2021-06-12 21:33 ` Linus Torvalds
2021-06-12 21:33 ` [Cluster-devel] " Linus Torvalds
2021-06-12 21:47 ` Al Viro
2021-06-12 21:47 ` [Cluster-devel] " Al Viro
2021-06-12 23:17 ` Linus Torvalds
2021-06-12 23:17 ` [Cluster-devel] " Linus Torvalds
2021-06-12 23:38 ` Al Viro
2021-06-12 23:38 ` [Cluster-devel] " Al Viro
2021-05-31 17:01 ` [RFC 6/9] gfs2: Add wrappers for accessing journal_info Andreas Gruenbacher
2021-05-31 17:01 ` [Cluster-devel] " Andreas Gruenbacher
2021-05-31 17:01 ` Andreas Gruenbacher [this message]
2021-05-31 17:01 ` [Cluster-devel] [RFC 7/9] gfs2: Encode glock holding and retry flags in journal_info Andreas Gruenbacher
2021-05-31 17:01 ` [RFC 8/9] gfs2: Add LM_FLAG_OUTER glock holder flag Andreas Gruenbacher
2021-05-31 17:01 ` [Cluster-devel] " Andreas Gruenbacher
2021-05-31 17:01 ` [RFC 9/9] gfs2: Fix mmap + page fault deadlocks (part 2) Andreas Gruenbacher
2021-05-31 17:01 ` [Cluster-devel] " Andreas Gruenbacher
2021-06-01 5:47 ` Linus Torvalds
2021-06-01 5:47 ` [Cluster-devel] " Linus Torvalds
2021-05-31 17:57 ` [Cluster-devel] [RFC 0/9] gfs2: handle page faults during read and write Linus Torvalds
2021-05-31 20:35 ` Andreas Gruenbacher
2021-05-31 20:35 ` [Cluster-devel] " Andreas Gruenbacher
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