For non-samefs case, all directory entries are "impure" because the
st_ino value returned from stat(2) is not the st_ino value of the
real inode.
In order to provide the same d_ino values for the directory type entries,
we never iterate the real dir directly in non-samefs case.
ovl_fill_real() has been modified to return the overlay inode number
as d_ino of the "." and ".." entries.
Build the impure dir cache for non-samefs case even if there is no
"impure" xattr on dir, but if real dir has nlink > 2 or nlink == 1,
which indicates that is has subdirs.
Update non-merge dir cache version on every change in subdir entry
and reset the dir cache after copy up when directory becomes !is_real.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/overlayfs/dir.c | 17 ++++++++++-------
fs/overlayfs/overlayfs.h | 2 +-
fs/overlayfs/readdir.c | 37 +++++++++++++++++++++++++------------
fs/overlayfs/util.c | 9 ++++++---
4 files changed, 42 insertions(+), 23 deletions(-)
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 26aef3b5f007..f2ba8ab99581 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -155,7 +155,7 @@ static int ovl_set_opaque(struct dentry *dentry, struct dentry *upperdentry)
static void ovl_instantiate(struct dentry *dentry, struct inode *inode,
struct dentry *newdentry, bool hardlink)
{
- ovl_dentry_version_inc(dentry->d_parent, false);
+ ovl_dentry_version_inc(dentry->d_parent, false, S_ISDIR(inode->i_mode));
ovl_dentry_set_upper_alias(dentry);
if (!hardlink) {
ovl_inode_update(inode, newdentry);
@@ -676,7 +676,7 @@ static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir)
if (flags)
ovl_cleanup(wdir, upper);
- ovl_dentry_version_inc(dentry->d_parent, true);
+ ovl_dentry_version_inc(dentry->d_parent, true, is_dir);
out_d_drop:
d_drop(dentry);
dput(whiteout);
@@ -727,7 +727,8 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
err = vfs_rmdir(dir, upper);
else
err = vfs_unlink(dir, upper, NULL);
- ovl_dentry_version_inc(dentry->d_parent, ovl_type_origin(dentry));
+ ovl_dentry_version_inc(dentry->d_parent, ovl_type_origin(dentry),
+ is_dir);
/*
* Keeping this dentry hashed would mean having to release
@@ -1075,10 +1076,12 @@ static int ovl_rename(struct inode *olddir, struct dentry *old,
drop_nlink(d_inode(new));
}
- ovl_dentry_version_inc(old->d_parent, ovl_type_origin(old));
- ovl_dentry_version_inc(new->d_parent, ovl_type_origin(old));
- if (!overwrite)
- ovl_dentry_version_inc(old->d_parent, ovl_type_origin(new));
+ ovl_dentry_version_inc(old->d_parent, ovl_type_origin(old), is_dir);
+ ovl_dentry_version_inc(new->d_parent, ovl_type_origin(old), is_dir);
+ if (!overwrite) {
+ ovl_dentry_version_inc(old->d_parent, ovl_type_origin(new),
+ new_is_dir);
+ }
out_dput:
dput(newdentry);
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index cefe5a97d048..17fc4622dfba 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -221,7 +221,7 @@ void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
void ovl_inode_init(struct inode *inode, struct dentry *upperdentry,
struct dentry *lowerdentry);
void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
-void ovl_dentry_version_inc(struct dentry *dentry, bool impurity);
+void ovl_dentry_version_inc(struct dentry *dentry, bool impurity, bool subdir);
u64 ovl_dentry_version_get(struct dentry *dentry);
bool ovl_is_whiteout(struct dentry *dentry);
struct file *ovl_path_open(struct path *path, int flags);
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index 4ec95806285e..56320b927c5d 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -344,14 +344,14 @@ static void ovl_dir_reset(struct file *file)
struct ovl_dir_file *od = file->private_data;
struct ovl_dir_cache *cache = od->cache;
struct dentry *dentry = file->f_path.dentry;
- bool is_real;
+ bool is_real = ovl_dir_is_real(dentry);
- if (cache && ovl_dentry_version_get(dentry) != cache->version) {
+ if (cache && (ovl_dentry_version_get(dentry) != cache->version ||
+ od->is_real != is_real)) {
ovl_cache_put(od, dentry);
od->cache = NULL;
od->cursor = NULL;
}
- is_real = ovl_dir_is_real(dentry);
if (od->is_real != is_real) {
/* is_real can only become false when dir is copied up */
if (WARN_ON(is_real))
@@ -455,7 +455,6 @@ static struct ovl_dir_cache *ovl_cache_get(struct dentry *dentry)
* sure that d_ino will be consistent with st_ino from stat(2).
*/
static int ovl_cache_update_ino(struct path *path, struct ovl_cache_entry *p)
-
{
struct dentry *dir = path->dentry;
struct dentry *this = NULL;
@@ -557,7 +556,7 @@ static int ovl_dir_read_impure(struct path *path, struct list_head *list,
INIT_LIST_HEAD(list);
*root = RB_ROOT;
- ovl_path_upper(path->dentry, &realpath);
+ ovl_path_real(path->dentry, &realpath);
err = ovl_dir_read(&realpath, &rdd);
if (err)
@@ -592,6 +591,7 @@ static struct ovl_dir_cache *ovl_cache_get_impure(struct path *path)
{
int res;
struct dentry *dentry = path->dentry;
+ struct dentry *upper = ovl_dentry_upper(dentry);
struct ovl_dir_cache *cache;
cache = ovl_dir_cache(d_inode(dentry));
@@ -612,9 +612,9 @@ static struct ovl_dir_cache *ovl_cache_get_impure(struct path *path)
kfree(cache);
return ERR_PTR(res);
}
- if (list_empty(&cache->entries)) {
+ if (upper && list_empty(&cache->entries)) {
/* Good oportunity to get rid of an unnecessary "impure" flag */
- ovl_do_removexattr(ovl_dentry_upper(dentry), OVL_XATTR_IMPURE);
+ ovl_do_removexattr(upper, OVL_XATTR_IMPURE);
ovl_clear_flag(OVL_IMPURE, d_inode(dentry));
kfree(cache);
return NULL;
@@ -631,6 +631,7 @@ struct ovl_readdir_translate {
struct ovl_dir_cache *cache;
struct dir_context ctx;
u64 parent_ino;
+ u64 current_ino;
};
static int ovl_fill_real(struct dir_context *ctx, const char *name,
@@ -643,6 +644,8 @@ static int ovl_fill_real(struct dir_context *ctx, const char *name,
if (rdt->parent_ino && strcmp(name, "..") == 0)
ino = rdt->parent_ino;
+ else if (rdt->current_ino && namelen == 1 && name[0] == '.')
+ ino = rdt->current_ino;
else if (rdt->cache) {
struct ovl_cache_entry *p;
@@ -659,12 +662,16 @@ static int ovl_iterate_real(struct file *file, struct dir_context *ctx)
int err;
struct ovl_dir_file *od = file->private_data;
struct dentry *dir = file->f_path.dentry;
+ struct inode *realinode = d_inode(od->realfile->f_path.dentry);
struct ovl_readdir_translate rdt = {
.ctx.actor = ovl_fill_real,
.orig_ctx = ctx,
};
- if (OVL_TYPE_MERGE(ovl_path_type(dir->d_parent))) {
+ if (!ovl_same_sb(dir->d_sb)) {
+ rdt.current_ino = dir->d_inode->i_ino;
+ rdt.parent_ino = dir->d_parent->d_inode->i_ino;
+ } else if (OVL_TYPE_MERGE(ovl_path_type(dir->d_parent))) {
struct kstat stat;
struct path statpath = file->f_path;
@@ -677,7 +684,13 @@ static int ovl_iterate_real(struct file *file, struct dir_context *ctx)
rdt.parent_ino = stat.ino;
}
- if (ovl_test_flag(OVL_IMPURE, d_inode(dir))) {
+ /*
+ * If dir is impure, we need to cache st_ino values of copy up origins.
+ * For non-samefs, if dir nlink is either 1 (=any) or > 2, then it may
+ * have subdirs and we need to cache their non persistent st_ino values.
+ */
+ if (ovl_test_flag(OVL_IMPURE, d_inode(dir)) ||
+ (!ovl_same_sb(dir->d_sb) && realinode->i_nlink != 2)) {
rdt.cache = ovl_cache_get_impure(&file->f_path);
if (IS_ERR(rdt.cache))
return PTR_ERR(rdt.cache);
@@ -703,9 +716,9 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx)
* dir is impure then need to adjust d_ino for copied up
* entries.
*/
- if (ovl_same_sb(dentry->d_sb) &&
- (ovl_test_flag(OVL_IMPURE, d_inode(dentry)) ||
- OVL_TYPE_MERGE(ovl_path_type(dentry->d_parent)))) {
+ if (ovl_test_flag(OVL_IMPURE, d_inode(dentry)) ||
+ OVL_TYPE_MERGE(ovl_path_type(dentry->d_parent)) ||
+ !ovl_same_sb(dentry->d_sb)) {
return ovl_iterate_real(file, ctx);
}
return iterate_dir(od->realfile, ctx);
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index d6bb1c9f5e7a..b4d729dff66b 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -279,7 +279,7 @@ void ovl_inode_update(struct inode *inode, struct dentry *upperdentry)
}
}
-void ovl_dentry_version_inc(struct dentry *dentry, bool impurity)
+void ovl_dentry_version_inc(struct dentry *dentry, bool impurity, bool subdir)
{
struct inode *inode = d_inode(dentry);
@@ -288,9 +288,12 @@ void ovl_dentry_version_inc(struct dentry *dentry, bool impurity)
* Version is used by readdir code to keep cache consistent. For merge
* dirs all changes need to be noted. For non-merge dirs, cache only
* contains impure (ones which have been copied up and have origins)
- * entries, so only need to note changes to impure entries.
+ * entries, so only need to note changes to impure entries. For
+ * non-merge dirs in non-samefs case, we need to also note changes for
+ * all sub-dirs, because we cache all overlay dir inode numbers.
*/
- if (OVL_TYPE_MERGE(ovl_path_type(dentry)) || impurity)
+ if (OVL_TYPE_MERGE(ovl_path_type(dentry)) || impurity ||
+ (subdir && !ovl_same_sb(dentry->d_sb)))
OVL_I(inode)->version++;
}
--
2.7.4
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