[PATCH v8 10/17] gfs2: Eliminate ip->i_gh

Andreas Gruenbacher
2021-10-19T13:43:23Z

Now that gfs2_file_buffered_write is the only remaining user of
ip->i_gh, we can move the glock holder to the stack (or rather, use the
one we already have on the stack); there is no need for keeping the
holder in the inode anymore.

This is slightly complicated by the fact that we're using ip->i_gh for
the statfs inode in gfs2_file_buffered_write as well. Writing to the
statfs inode isn't very common, so allocate the statfs holder
dynamically when needed.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
fs/gfs2/file.c | 34 +++++++++++++++++++++-------------
fs/gfs2/incore.h | 3 +--
2 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 13282f57da37..8f37e4bab995 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -876,16 +876,25 @@ static ssize_t gfs2_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
return written ? written : ret;
}

-static ssize_t gfs2_file_buffered_write(struct kiocb *iocb, struct iov_iter *from)
+static ssize_t gfs2_file_buffered_write(struct kiocb *iocb,
+ struct iov_iter *from,
+ struct gfs2_holder *gh)
{
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);
+ struct gfs2_holder *statfs_gh = NULL;
ssize_t ret;

- gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &ip->i_gh);
- ret = gfs2_glock_nq(&ip->i_gh);
+ if (inode == sdp->sd_rindex) {
+ statfs_gh = kmalloc(sizeof(*statfs_gh), GFP_NOFS);
+ if (!statfs_gh)
+ return -ENOMEM;
+ }
+
+ gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, gh);
+ ret = gfs2_glock_nq(gh);
if (ret)
goto out_uninit;

@@ -893,7 +902,7 @@ static ssize_t gfs2_file_buffered_write(struct kiocb *iocb, struct iov_iter *fro
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);
+ GL_NOCACHE, statfs_gh);
if (ret)
goto out_unlock;
}
@@ -904,16 +913,15 @@ static ssize_t gfs2_file_buffered_write(struct kiocb *iocb, struct iov_iter *fro
if (ret > 0)
iocb->ki_pos += ret;

- if (inode == sdp->sd_rindex) {
- struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
-
- gfs2_glock_dq_uninit(&m_ip->i_gh);
- }
+ if (inode == sdp->sd_rindex)
+ gfs2_glock_dq_uninit(statfs_gh);

out_unlock:
- gfs2_glock_dq(&ip->i_gh);
+ gfs2_glock_dq(gh);
out_uninit:
- gfs2_holder_uninit(&ip->i_gh);
+ gfs2_holder_uninit(gh);
+ if (statfs_gh)
+ kfree(statfs_gh);
return ret;
}

@@ -968,7 +976,7 @@ static ssize_t gfs2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
goto out_unlock;

iocb->ki_flags |= IOCB_DSYNC;
- buffered = gfs2_file_buffered_write(iocb, from);
+ buffered = gfs2_file_buffered_write(iocb, from, &gh);
if (unlikely(buffered <= 0)) {
if (!ret)
ret = buffered;
@@ -989,7 +997,7 @@ static ssize_t gfs2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
if (!ret || ret2 > 0)
ret += ret2;
} else {
- ret = gfs2_file_buffered_write(iocb, from);
+ ret = gfs2_file_buffered_write(iocb, from, &gh);
if (likely(ret > 0))
ret = generic_write_sync(iocb, ret);
}
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 58b7bac501e4..ca42d310fd4d 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -387,9 +387,8 @@ struct gfs2_inode {
u64 i_generation;
u64 i_eattr;
unsigned long i_flags; /* GIF_... */
- struct gfs2_glock *i_gl; /* Move into i_gh? */
+ struct gfs2_glock *i_gl;
struct gfs2_holder i_iopen_gh;
- struct gfs2_holder i_gh; /* for prepare/commit_write only */
struct gfs2_qadata *i_qadata; /* quota allocation data */
struct gfs2_holder i_rgd_gh;
struct gfs2_blkreserv i_res; /* rgrp multi-block reservation */
--
2.26.3