From: Steven Whitehouse <swhiteho@redhat.com> Subject: [RHEL5] [GFS2] Don't flush everything on fdatasync [1/2] Date: Thu, 07 Dec 2006 14:35:25 +0000 Bugzilla: 218770 Message-Id: <1165502125.3752.858.camel@quoit.chygwyn.com> Changelog: GFS2: Don't flush everything on fdatasync Hi, This one is in two bits purely because we are following the upstream patches. The bz is #218770 and the first of the two patches is below, Steve. >From 33c3de32872ef3c075e4dac04c0de8f86ac39f6f Mon Sep 17 00:00:00 2001 The gfs2_fsync() function was doing a journal flush on each and every call. While this is correct, its also a lot of overhead. This patch means that on fdatasync flushes we rely on the VFS to flush the data for us and we don't do a journal flush unless we really need to. We have to do a journal flush for stuffed files though because they have the data and the inode metadata in the same block. Journaled files also need a journal flush too of course. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> --- fs/gfs2/ops_file.c | 30 +++++++++++++++++++++++++++--- 1 files changed, 27 insertions(+), 3 deletions(-) diff --git a/fs/gfs2/ops_file.c b/fs/gfs2/ops_file.c index c2be216..7bd971b 100644 --- a/fs/gfs2/ops_file.c +++ b/fs/gfs2/ops_file.c @@ -22,6 +22,7 @@ #include <linux/gfs2_ondisk.h> #include <linux/ext2_fs.h> #include <linux/crc32.h> #include <linux/lm_interface.h> +#include <linux/writeback.h> #include <asm/uaccess.h> #include "gfs2.h" @@ -503,16 +504,39 @@ static int gfs2_close(struct inode *inod * @file: the file that points to the dentry (we ignore this) * @dentry: the dentry that points to the inode to sync * + * The VFS will flush "normal" data for us. We only need to worry + * about metadata here. For journaled data, we just do a log flush + * as we can't avoid it. Otherwise we can just bale out if datasync + * is set. For stuffed inodes we must flush the log in order to + * ensure that all data is on disk. + * * Returns: errno */ static int gfs2_fsync(struct file *file, struct dentry *dentry, int datasync) { - struct gfs2_inode *ip = GFS2_I(dentry->d_inode); + struct inode *inode = dentry->d_inode; + int sync_state = inode->i_state & (I_DIRTY_SYNC|I_DIRTY_DATASYNC); + int ret = 0; + struct writeback_control wbc = { + .sync_mode = WB_SYNC_ALL, + .nr_to_write = 0, + }; + + if (gfs2_is_jdata(GFS2_I(inode))) { + gfs2_log_flush(GFS2_SB(inode), GFS2_I(inode)->i_gl); + return 0; + } - gfs2_log_flush(ip->i_gl->gl_sbd, ip->i_gl); + if (sync_state != 0) { + if (!datasync) + ret = sync_inode(inode, &wbc); - return 0; + if (gfs2_is_stuffed(GFS2_I(inode))) + gfs2_log_flush(GFS2_SB(inode), GFS2_I(inode)->i_gl); + } + + return ret; } /** -- 1.4.1 >From 34126f9f41901ca9d7d0031c2b11fc0d6c07b72d Mon Sep 17 00:00:00 2001 From: Steven Whitehouse <swhiteho@redhat.com> Date: Thu, 7 Dec 2006 09:13:14 -0500 Subject: [PATCH] [GFS2] Change gfs2_fsync() to use write_inode_now() This is a bit better than the previous version of gfs2_fsync() although it would be better still if we were able to call a function which only wrote the inode & metadata. Its no big deal though that this will potentially write the data as well since the VFS has already done that before calling gfs2_fsync(). I've also added a comment to explain whats going on here. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> Cc: Andrew Morton <akpm@osdl.org> --- fs/gfs2/ops_file.c | 11 ++++++----- 1 files changed, 6 insertions(+), 5 deletions(-) diff --git a/fs/gfs2/ops_file.c b/fs/gfs2/ops_file.c index 7bd971b..b3f1e03 100644 --- a/fs/gfs2/ops_file.c +++ b/fs/gfs2/ops_file.c @@ -510,6 +510,11 @@ static int gfs2_close(struct inode *inod * is set. For stuffed inodes we must flush the log in order to * ensure that all data is on disk. * + * The call to write_inode_now() is there to write back metadata and + * the inode itself. It does also try and write the data, but thats + * (hopefully) a no-op due to the VFS having already called filemap_fdatawrite() + * for us. + * * Returns: errno */ @@ -518,10 +523,6 @@ static int gfs2_fsync(struct file *file, struct inode *inode = dentry->d_inode; int sync_state = inode->i_state & (I_DIRTY_SYNC|I_DIRTY_DATASYNC); int ret = 0; - struct writeback_control wbc = { - .sync_mode = WB_SYNC_ALL, - .nr_to_write = 0, - }; if (gfs2_is_jdata(GFS2_I(inode))) { gfs2_log_flush(GFS2_SB(inode), GFS2_I(inode)->i_gl); @@ -530,7 +531,7 @@ static int gfs2_fsync(struct file *file, if (sync_state != 0) { if (!datasync) - ret = sync_inode(inode, &wbc); + ret = write_inode_now(inode, 0); if (gfs2_is_stuffed(GFS2_I(inode))) gfs2_log_flush(GFS2_SB(inode), GFS2_I(inode)->i_gl); -- 1.4.1