An upper dir is marked "impure" to let ovl_iterate() know that this
directory may contain non pure upper entries whose d_ino may need to be
read from the origin inode.
We already mark a non-merge dir "impure" when moving a non-pure child
entry inside it, to let ovl_iterate() know not to iterate the non-merge
dir directly.
Mark also a merge dir "impure" when moving a non-pure child entry inside
it and when copying up a child entry inside it.
This can be used to optimize ovl_iterate() to perform a "pure merge" of
upper and lower directories, merging the content of the directories,
without having to read d_ino from origin inodes.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/overlayfs/copy_up.c | 7 +++++++
fs/overlayfs/dir.c | 31 ++++++-------------------------
fs/overlayfs/overlayfs.h | 7 ++++---
fs/overlayfs/util.c | 16 ++++++++++++++++
4 files changed, 33 insertions(+), 28 deletions(-)
Miklos,
w.r.t. the clause in constant d_ino commit message:
"There is an overhead of lookup per upper entry in readdir.
That overhead is a waste for a merge dir with only pure upper
entries (i.e. no copy ups), but that can be optimized later."
Please consider this patch for v4.12 on top of the one already in
overlayfs-next.
Not sure how common the use case of "pure merge" is, but the optimization
of not doing the origin lookup in ovl_interate() is trivial, so better have
the merge dir marked "impure" now when introducing overlay.origin.
Amir.
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 843ed2a..1ae1790 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -459,6 +459,13 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
ovl_path_upper(parent, &parentpath);
upperdir = parentpath.dentry;
+ /* Mark parent "impure" because it may now contain non-pure upper */
+ if (!ovl_dentry_is_impure(parent)) {
+ err = ovl_set_impure(parent, upperdir);
+ if (err)
+ return err;
+ }
+
err = vfs_getattr(&parentpath, &pstat,
STATX_ATIME | STATX_MTIME, AT_STATX_SYNC_AS_STAT);
if (err)
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index f2a118b..c9efc54 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -149,22 +149,6 @@ static int ovl_set_opaque(struct dentry *dentry, struct dentry *upperdentry)
return ovl_set_opaque_xerr(dentry, upperdentry, -EIO);
}
-static int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry)
-{
- int err;
-
- /*
- * Do not fail when upper doesn't support xattrs.
- * Upper inodes won't have origin nor redirect xattr anyway.
- */
- err = ovl_check_setxattr(dentry, upperdentry, OVL_XATTR_IMPURE,
- "y", 1, 0);
- if (!err)
- ovl_dentry_set_impure(dentry);
-
- return err;
-}
-
/* Common operations required to be done after creation of file on upper */
static void ovl_instantiate(struct dentry *dentry, struct inode *inode,
struct dentry *newdentry, bool hardlink)
@@ -976,21 +960,18 @@ static int ovl_rename(struct inode *olddir, struct dentry *old,
if (!samedir) {
/*
* When moving a merge dir or non-dir with copy up origin into
- * a non-merge upper dir (a.k.a pure upper dir), we are making
- * the target parent dir "impure". ovl_iterate() iterates pure
- * upper dirs directly, because there is no need to filter out
- * whiteouts and merge dir content with lower dir. But for the
- * case of an "impure" upper dir, ovl_iterate() cannot iterate
- * the real directory directly, because it looks for the inode
- * numbers to fill d_ino in the entries origin inode.
+ * a new parent, we are marking the new parent dir "impure".
+ * When ovl_iterate() iterates an "impure" upper dir, it will
+ * lookup the origin inodes of the entries to fill d_ino.
*/
- if (ovl_type_origin(old) && !ovl_type_merge(new->d_parent)) {
+ if (ovl_type_origin(old) &&
+ !ovl_dentry_is_impure(new->d_parent)) {
err = ovl_set_impure(new->d_parent, new_upperdir);
if (err)
goto out_revert_creds;
}
if (!overwrite && ovl_type_origin(new) &&
- !ovl_type_merge(old->d_parent)) {
+ !ovl_dentry_is_impure(old->d_parent)) {
err = ovl_set_impure(old->d_parent, old_upperdir);
if (err)
goto out_revert_creds;
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index a9fb958..a62139f 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -221,6 +221,10 @@ bool ovl_is_whiteout(struct dentry *dentry);
struct file *ovl_path_open(struct path *path, int flags);
int ovl_copy_up_start(struct dentry *dentry);
void ovl_copy_up_end(struct dentry *dentry);
+int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
+ const char *name, const void *value, size_t size,
+ int xerr);
+int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
/* namei.c */
int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
@@ -281,6 +285,3 @@ int ovl_copy_up(struct dentry *dentry);
int ovl_copy_up_flags(struct dentry *dentry, int flags);
int ovl_copy_xattr(struct dentry *old, struct dentry *new);
int ovl_set_attr(struct dentry *upper, struct kstat *stat);
-int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
- const char *name, const void *value, size_t size,
- int xerr);
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index e0dfb07..816769c 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -331,3 +331,19 @@ int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
return err;
}
+
+int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry)
+{
+ int err;
+
+ /*
+ * Do not fail when upper doesn't support xattrs.
+ * Upper inodes won't have origin nor redirect xattr anyway.
+ */
+ err = ovl_check_setxattr(dentry, upperdentry, OVL_XATTR_IMPURE,
+ "y", 1, 0);
+ if (!err)
+ ovl_dentry_set_impure(dentry);
+
+ return err;
+}
--
2.7.4
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