Now that gfs2_file_buffered_write is the only remaining user of
ip->i_gh, we can allocate a glock holder on the stack and use that
instead.

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.  Since writing to
the statfs inode isn't very common, allocate the statfs holder
dynamically when needed.

Signed-off-by: Andreas Gruenbacher <agrue...@redhat.com>
---
 fs/gfs2/file.c   | 42 +++++++++++++++++++++++++-----------------
 fs/gfs2/incore.h |  3 +--
 2 files changed, 26 insertions(+), 19 deletions(-)

diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 2cf3466b9dde..9729cb3483c0 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -1010,12 +1010,15 @@ 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;
        size_t prev_count = 0, window_size = 0;
        size_t read = 0;
        ssize_t ret;
@@ -1026,9 +1029,15 @@ static ssize_t gfs2_file_buffered_write(struct kiocb 
*iocb, struct iov_iter *fro
         * inode glock, fault in the pages manually, and retry.
         */
 
-       gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &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);
 retry:
-       ret = gfs2_glock_nq(&ip->i_gh);
+       ret = gfs2_glock_nq(gh);
        if (ret)
                goto out_uninit;
 retry_under_glock:
@@ -1036,7 +1045,7 @@ 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;
        }
@@ -1049,20 +1058,17 @@ static ssize_t gfs2_file_buffered_write(struct kiocb 
*iocb, struct iov_iter *fro
        if (ret > 0)
                read += 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);
        if (unlikely(iov_iter_count(from) && (ret > 0 || ret == -EFAULT)) &&
            should_fault_in_pages(from, &prev_count, &window_size)) {
                size_t leftover;
 
-               gfs2_holder_allow_demote(&ip->i_gh);
+               gfs2_holder_allow_demote(gh);
                leftover = fault_in_iov_iter_readable(from, window_size);
-               gfs2_holder_disallow_demote(&ip->i_gh);
+               gfs2_holder_disallow_demote(gh);
                if (leftover != window_size) {
-                       if (!gfs2_holder_queued(&ip->i_gh)) {
+                       if (!gfs2_holder_queued(gh)) {
                                if (read)
                                        goto out_uninit;
                                goto retry;
@@ -1071,10 +1077,12 @@ static ssize_t gfs2_file_buffered_write(struct kiocb 
*iocb, struct iov_iter *fro
                }
        }
 out_unlock:
-       if (gfs2_holder_queued(&ip->i_gh))
-               gfs2_glock_dq(&ip->i_gh);
+       if (gfs2_holder_queued(gh))
+               gfs2_glock_dq(gh);
 out_uninit:
-       gfs2_holder_uninit(&ip->i_gh);
+       gfs2_holder_uninit(gh);
+       if (statfs_gh)
+               kfree(statfs_gh);
        return read ? read : ret;
 }
 
@@ -1129,7 +1137,7 @@ 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;
@@ -1151,7 +1159,7 @@ 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)) {
                        iocb->ki_pos += ret;
                        ret = generic_write_sync(iocb, ret);
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index e73a81db0714..87abdcc1de0c 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

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