Sharing inode with different whiteout files for saving
inode and speeding up delete opration.
Signed-off-by: Chengguang Xu <cgxu519@xxxxxxxxxxxx>
---
Hi Miklos, Amir
This is another inode sharing approach for whiteout files compare
to Tao's previous patch. I didn't receive feedback from Tao for
further update and this new approach seems more simple and reliable.
Could you have a look at this patch?
fs/overlayfs/dir.c | 53 ++++++++++++++++++++++++++++++++++------
fs/overlayfs/overlayfs.h | 2 +-
fs/overlayfs/ovl_entry.h | 2 ++
fs/overlayfs/readdir.c | 3 ++-
fs/overlayfs/super.c | 3 +++
fs/overlayfs/util.c | 3 ++-
6 files changed, 56 insertions(+), 10 deletions(-)
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 279009dee366..d5c2e1ada624 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -61,36 +61,74 @@ struct dentry *ovl_lookup_temp(struct dentry *workdir)
return temp;
}
+const unsigned int ovl_whiteout_link_max = 60000;
+
+static bool ovl_whiteout_linkable(struct dentry *dentry)
+{
+ unsigned int max;
+
+ max = min_not_zero(dentry->d_sb->s_max_links, ovl_whiteout_link_max);
+ if (dentry->d_inode->i_nlink >= max)
+ return false;
+ return true;
+}
+
/* caller holds i_mutex on workdir */
-static struct dentry *ovl_whiteout(struct dentry *workdir)
+static struct dentry *ovl_whiteout(struct dentry *workdir, struct ovl_fs *ofs)
{
int err;
+ bool again = true;
struct dentry *whiteout;
struct inode *wdir = workdir->d_inode;
+retry:
whiteout = ovl_lookup_temp(workdir);
if (IS_ERR(whiteout))
return whiteout;
+
+ if (ofs->whiteout) {
+ if (ovl_whiteout_linkable(ofs->whiteout)) {
+ err = ovl_do_link(ofs->whiteout, wdir, whiteout);
+ if (!err)
+ return whiteout;
+
+ if (!again)
+ goto out;
+ }
+
+ err = ovl_do_unlink(ofs->workdir->d_inode, ofs->whiteout);
+ ofs->whiteout = NULL;
+ if (err)
+ goto out;
+ }
+
err = ovl_do_whiteout(wdir, whiteout);
- if (err) {
- dput(whiteout);
- whiteout = ERR_PTR(err);
+ if (!err) {
+ ofs->whiteout = whiteout;
+ if (again) {
+ again = false;
+ goto retry;
+ }
+ return ERR_PTR(-EIO);
}
+out:
+ dput(whiteout);
+ whiteout = ERR_PTR(err);
return whiteout;
}
/* Caller must hold i_mutex on both workdir and dir */
int ovl_cleanup_and_whiteout(struct dentry *workdir, struct inode *dir,
- struct dentry *dentry)
+ struct dentry *dentry, struct ovl_fs *ofs)
{
struct inode *wdir = workdir->d_inode;
struct dentry *whiteout;
int err;
int flags = 0;
- whiteout = ovl_whiteout(workdir);
+ whiteout = ovl_whiteout(workdir, ofs);
err = PTR_ERR(whiteout);
if (IS_ERR(whiteout))
return err;
@@ -715,6 +753,7 @@ static bool ovl_matches_upper(struct dentry *dentry, struct dentry *upper)
static int ovl_remove_and_whiteout(struct dentry *dentry,
struct list_head *list)
{
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
struct dentry *workdir = ovl_workdir(dentry);
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
struct dentry *upper;
@@ -748,7 +787,7 @@ static int ovl_remove_and_whiteout(struct dentry *dentry,
goto out_dput_upper;
}
- err = ovl_cleanup_and_whiteout(workdir, d_inode(upperdir), upper);
+ err = ovl_cleanup_and_whiteout(workdir, d_inode(upperdir), upper, ofs);
if (err)
goto out_d_drop;
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index e6f3670146ed..6212feef36c5 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -456,7 +456,7 @@ static inline void ovl_copyflags(struct inode *from, struct inode *to)
/* dir.c */
extern const struct inode_operations ovl_dir_inode_operations;
int ovl_cleanup_and_whiteout(struct dentry *workdir, struct inode *dir,
- struct dentry *dentry);
+ struct dentry *dentry, struct ovl_fs *ofs);
struct ovl_cattr {
dev_t rdev;
umode_t mode;
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index 5762d802fe01..408aa6c7a3bd 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -77,6 +77,8 @@ struct ovl_fs {
int xino_mode;
/* For allocation of non-persistent inode numbers */
atomic_long_t last_ino;
+ /* Whiteout dentry cache */
+ struct dentry *whiteout;
};
static inline struct ovl_fs *OVL_FS(struct super_block *sb)
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index e452ff7d583d..0c8c7ff4fc9e 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -1146,7 +1146,8 @@ int ovl_indexdir_cleanup(struct ovl_fs *ofs)
* Whiteout orphan index to block future open by
* handle after overlay nlink dropped to zero.
*/
- err = ovl_cleanup_and_whiteout(indexdir, dir, index);
+ err = ovl_cleanup_and_whiteout(indexdir, dir, index,
+ ofs);
} else {
/* Cleanup orphan index entries */
err = ovl_cleanup(dir, index);
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 732ad5495c92..fae9729ff018 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -240,6 +240,9 @@ static void ovl_free_fs(struct ovl_fs *ofs)
kfree(ofs->config.redirect_mode);
if (ofs->creator_cred)
put_cred(ofs->creator_cred);
+ if (ofs->whiteout)
+ ovl_do_unlink(ofs->workdir->d_inode,
+ ofs->whiteout);
kfree(ofs);
}
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 36b60788ee47..d05c4028f179 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -669,6 +669,7 @@ bool ovl_need_index(struct dentry *dentry)
/* Caller must hold OVL_I(inode)->lock */
static void ovl_cleanup_index(struct dentry *dentry)
{
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
struct dentry *indexdir = ovl_indexdir(dentry->d_sb);
struct inode *dir = indexdir->d_inode;
struct dentry *lowerdentry = ovl_dentry_lower(dentry);
@@ -707,7 +708,7 @@ static void ovl_cleanup_index(struct dentry *dentry)
index = NULL;
} else if (ovl_index_all(dentry->d_sb)) {
/* Whiteout orphan index to block future open by handle */
- err = ovl_cleanup_and_whiteout(indexdir, dir, index);
+ err = ovl_cleanup_and_whiteout(indexdir, dir, index, ofs);
} else {
/* Cleanup orphan index entries */
err = ovl_cleanup(dir, index);
--
2.20.1
