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authorChengguang Xu <cgxu519@mykernel.net>2020-04-24 05:55:17 +0300
committerMiklos Szeredi <mszeredi@redhat.com>2020-05-13 12:11:24 +0300
commitc21c839b8448dd4b1e37ffc1bde928f57d34c0db (patch)
tree72887c93eebea1c78fbd61d032cbc06191d082f4 /fs/overlayfs
parent654255fa205cb2b010e9abb34b0c8afcca9c78c7 (diff)
downloadlinux-c21c839b8448dd4b1e37ffc1bde928f57d34c0db.tar.xz
ovl: whiteout inode sharing
Share inode with different whiteout files for saving inode and speeding up delete operation. If EMLINK is encountered when linking a shared whiteout, create a new one. In case of any other error, disable sharing for this super block. Note: ofs->whiteout is protected by inode lock on workdir. Signed-off-by: Chengguang Xu <cgxu519@mykernel.net> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/overlayfs')
-rw-r--r--fs/overlayfs/dir.c49
-rw-r--r--fs/overlayfs/overlayfs.h2
-rw-r--r--fs/overlayfs/ovl_entry.h3
-rw-r--r--fs/overlayfs/readdir.c2
-rw-r--r--fs/overlayfs/super.c4
-rw-r--r--fs/overlayfs/util.c3
6 files changed, 48 insertions, 15 deletions
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 279009dee366..09faa63cf24d 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -62,35 +62,59 @@ struct dentry *ovl_lookup_temp(struct dentry *workdir)
}
/* caller holds i_mutex on workdir */
-static struct dentry *ovl_whiteout(struct dentry *workdir)
+static struct dentry *ovl_whiteout(struct ovl_fs *ofs)
{
int err;
struct dentry *whiteout;
+ struct dentry *workdir = ofs->workdir;
struct inode *wdir = workdir->d_inode;
- whiteout = ovl_lookup_temp(workdir);
- if (IS_ERR(whiteout))
- return whiteout;
+ if (!ofs->whiteout) {
+ whiteout = ovl_lookup_temp(workdir);
+ if (IS_ERR(whiteout))
+ goto out;
- err = ovl_do_whiteout(wdir, whiteout);
- if (err) {
- dput(whiteout);
- whiteout = ERR_PTR(err);
+ err = ovl_do_whiteout(wdir, whiteout);
+ if (err) {
+ dput(whiteout);
+ whiteout = ERR_PTR(err);
+ goto out;
+ }
+ ofs->whiteout = whiteout;
}
+ if (ofs->share_whiteout) {
+ whiteout = ovl_lookup_temp(workdir);
+ if (IS_ERR(whiteout))
+ goto out;
+
+ err = ovl_do_link(ofs->whiteout, wdir, whiteout);
+ if (!err)
+ goto out;
+
+ if (err != -EMLINK) {
+ pr_warn("Failed to link whiteout - disabling whiteout inode sharing(nlink=%u, err=%i)\n",
+ ofs->whiteout->d_inode->i_nlink, err);
+ ofs->share_whiteout = false;
+ }
+ dput(whiteout);
+ }
+ whiteout = ofs->whiteout;
+ ofs->whiteout = NULL;
+out:
return whiteout;
}
/* Caller must hold i_mutex on both workdir and dir */
-int ovl_cleanup_and_whiteout(struct dentry *workdir, struct inode *dir,
+int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir,
struct dentry *dentry)
{
- struct inode *wdir = workdir->d_inode;
+ struct inode *wdir = ofs->workdir->d_inode;
struct dentry *whiteout;
int err;
int flags = 0;
- whiteout = ovl_whiteout(workdir);
+ whiteout = ovl_whiteout(ofs);
err = PTR_ERR(whiteout);
if (IS_ERR(whiteout))
return err;
@@ -715,6 +739,7 @@ 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 = OVL_FS(dentry->d_sb);
struct dentry *workdir = ovl_workdir(dentry);
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
struct dentry *upper;
@@ -748,7 +773,7 @@ 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(ofs, d_inode(upperdir), upper);
if (err)
goto out_d_drop;
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index e00b1ff6dea9..76747f5b0517 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -455,7 +455,7 @@ 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,
+int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir,
struct dentry *dentry);
struct ovl_cattr {
dev_t rdev;
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index 5762d802fe01..a8f82fb7ffb4 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -68,6 +68,7 @@ struct ovl_fs {
/* Did we take the inuse lock? */
bool upperdir_locked;
bool workdir_locked;
+ bool share_whiteout;
/* Traps in ovl inode cache */
struct inode *upperdir_trap;
struct inode *workbasedir_trap;
@@ -77,6 +78,8 @@ 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 20f5310d3ee4..a10b21b562ad 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -1154,7 +1154,7 @@ 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(ofs, dir, index);
} else {
/* Cleanup orphan index entries */
err = ovl_cleanup(dir, index);
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index af69f41f564d..a88a7badf444 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -217,6 +217,7 @@ static void ovl_free_fs(struct ovl_fs *ofs)
iput(ofs->indexdir_trap);
iput(ofs->workdir_trap);
iput(ofs->upperdir_trap);
+ dput(ofs->whiteout);
dput(ofs->indexdir);
dput(ofs->workdir);
if (ofs->workdir_locked)
@@ -1776,6 +1777,9 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
if (!cred)
goto out_err;
+ /* Is there a reason anyone would want not to share whiteouts? */
+ ofs->share_whiteout = true;
+
ofs->config.index = ovl_index_def;
ofs->config.nfs_export = ovl_nfs_export_def;
ofs->config.xino = ovl_xino_def();
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 36b60788ee47..01755bc186c9 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -707,7 +707,8 @@ 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(OVL_FS(dentry->d_sb),
+ dir, index);
} else {
/* Cleanup orphan index entries */
err = ovl_cleanup(dir, index);