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authorTrond Myklebust <trond.myklebust@hammerspace.com>2018-09-02 15:57:01 -0400
committerTrond Myklebust <trond.myklebust@hammerspace.com>2018-09-30 15:35:17 -0400
commit0de43976fbe716379084f954b1e370c35aa87bf0 (patch)
tree64a6ea935fc8015c7369b9ece308771585cd3053 /fs/nfs/pnfs.c
parentNFS: Simplify internal check for whether file is open for write (diff)
downloadlinux-dev-0de43976fbe716379084f954b1e370c35aa87bf0.tar.xz
linux-dev-0de43976fbe716379084f954b1e370c35aa87bf0.zip
NFS: Convert lookups of the open context to RCU
Reduce contention on the inode->i_lock by ensuring that we use RCU when looking up the NFS open context. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Diffstat (limited to 'fs/nfs/pnfs.c')
-rw-r--r--fs/nfs/pnfs.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index c5672c02afd6..06cb90e9bc6e 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1339,6 +1339,7 @@ bool pnfs_roc(struct inode *ino,
if (!nfs_have_layout(ino))
return false;
retry:
+ rcu_read_lock();
spin_lock(&ino->i_lock);
lo = nfsi->layout;
if (!lo || !pnfs_layout_is_valid(lo) ||
@@ -1349,6 +1350,7 @@ retry:
pnfs_get_layout_hdr(lo);
if (test_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags)) {
spin_unlock(&ino->i_lock);
+ rcu_read_unlock();
wait_on_bit(&lo->plh_flags, NFS_LAYOUT_RETURN,
TASK_UNINTERRUPTIBLE);
pnfs_put_layout_hdr(lo);
@@ -1362,7 +1364,7 @@ retry:
skip_read = true;
}
- list_for_each_entry(ctx, &nfsi->open_files, list) {
+ list_for_each_entry_rcu(ctx, &nfsi->open_files, list) {
state = ctx->state;
if (state == NULL)
continue;
@@ -1410,6 +1412,7 @@ retry:
out_noroc:
spin_unlock(&ino->i_lock);
+ rcu_read_unlock();
pnfs_layoutcommit_inode(ino, true);
if (roc) {
struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;