From: Miklos Szeredi <miklos@xxxxxxxxxx>
The overlay sb 'copyup_wq' and overlay inode 'copying' condition
variable are about to replace the upper sb rename_lock, as finer
grained synchronization objects for concurrent copy up.
Suggested-by: Miklos Szeredi <miklos@xxxxxxxxxx>
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/overlayfs/overlayfs.h | 2 ++
fs/overlayfs/ovl_entry.h | 2 ++
fs/overlayfs/super.c | 1 +
fs/overlayfs/util.c | 30 ++++++++++++++++++++++++++++++
4 files changed, 35 insertions(+)
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 59d1c38..131efb7 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -180,6 +180,8 @@ struct file *ovl_path_open(struct path *path, int flags);
struct dentry *ovl_alloc_tmpfile(struct dentry *parent, umode_t mode);
int ovl_link_tmpfile(struct dentry *temp, struct inode *dir,
struct dentry *dentry);
+int ovl_copy_up_start(struct dentry *dentry);
+void ovl_copy_up_end(struct dentry *dentry);
/* namei.c */
int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index 65f24000..59614fa 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -28,6 +28,7 @@ struct ovl_fs {
/* creds of process who forced instantiation of super block */
const struct cred *creator_cred;
bool tmpfile;
+ wait_queue_head_t copyup_wq;
};
/* private information held for every overlayfs dentry */
@@ -39,6 +40,7 @@ struct ovl_entry {
u64 version;
const char *redirect;
bool opaque;
+ bool copying;
};
struct rcu_head rcu;
};
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index a6c42f5..4a9f489 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -708,6 +708,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
if (!ufs)
goto out;
+ init_waitqueue_head(&ufs->copyup_wq);
ufs->config.redirect_dir = ovl_redirect_dir_def;
err = ovl_parse_opt((char *) data, &ufs->config);
if (err)
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 0fbf41c..f361b47 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -301,3 +301,33 @@ int ovl_link_tmpfile(struct dentry *temp, struct inode *dir,
return err;
}
+
+int ovl_copy_up_start(struct dentry *dentry)
+{
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ struct ovl_entry *oe = dentry->d_fsdata;
+ int err;
+
+ spin_lock(&ofs->copyup_wq.lock);
+ err = wait_event_interruptible_locked(ofs->copyup_wq, !oe->copying);
+ if (!err) {
+ if (oe->__upperdentry)
+ err = 1; /* Already copied up */
+ else
+ oe->copying = true;
+ }
+ spin_unlock(&ofs->copyup_wq.lock);
+
+ return err;
+}
+
+void ovl_copy_up_end(struct dentry *dentry)
+{
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ spin_lock(&ofs->copyup_wq.lock);
+ oe->copying = false;
+ wake_up_locked(&ofs->copyup_wq);
+ spin_unlock(&ofs->copyup_wq.lock);
+}
--
2.7.4
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