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-rw-r--r--fs/overlayfs/namei.c43
-rw-r--r--fs/overlayfs/overlayfs.h23
-rw-r--r--fs/overlayfs/ovl_entry.h4
-rw-r--r--fs/overlayfs/readdir.c7
-rw-r--r--fs/overlayfs/super.c15
-rw-r--r--fs/overlayfs/util.c53
6 files changed, 97 insertions, 48 deletions
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 984ffdaeed6c..5764f91d283e 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -18,10 +18,11 @@
struct ovl_lookup_data {
struct super_block *sb;
- struct vfsmount *mnt;
+ const struct ovl_layer *layer;
struct qstr name;
bool is_dir;
bool opaque;
+ bool xwhiteouts;
bool stop;
bool last;
char *redirect;
@@ -201,17 +202,13 @@ struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh,
return real;
}
-static bool ovl_is_opaquedir(struct ovl_fs *ofs, const struct path *path)
-{
- return ovl_path_check_dir_xattr(ofs, path, OVL_XATTR_OPAQUE);
-}
-
static struct dentry *ovl_lookup_positive_unlocked(struct ovl_lookup_data *d,
const char *name,
struct dentry *base, int len,
bool drop_negative)
{
- struct dentry *ret = lookup_one_unlocked(mnt_idmap(d->mnt), name, base, len);
+ struct dentry *ret = lookup_one_unlocked(mnt_idmap(d->layer->mnt), name,
+ base, len);
if (!IS_ERR(ret) && d_flags_negative(smp_load_acquire(&ret->d_flags))) {
if (drop_negative && ret->d_lockref.count == 1) {
@@ -232,10 +229,13 @@ static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d,
size_t prelen, const char *post,
struct dentry **ret, bool drop_negative)
{
+ struct ovl_fs *ofs = OVL_FS(d->sb);
struct dentry *this;
struct path path;
int err;
bool last_element = !post[0];
+ bool is_upper = d->layer->idx == 0;
+ char val;
this = ovl_lookup_positive_unlocked(d, name, base, namelen, drop_negative);
if (IS_ERR(this)) {
@@ -253,8 +253,8 @@ static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d,
}
path.dentry = this;
- path.mnt = d->mnt;
- if (ovl_path_is_whiteout(OVL_FS(d->sb), &path)) {
+ path.mnt = d->layer->mnt;
+ if (ovl_path_is_whiteout(ofs, &path)) {
d->stop = d->opaque = true;
goto put_and_out;
}
@@ -272,7 +272,7 @@ static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d,
d->stop = true;
goto put_and_out;
}
- err = ovl_check_metacopy_xattr(OVL_FS(d->sb), &path, NULL);
+ err = ovl_check_metacopy_xattr(ofs, &path, NULL);
if (err < 0)
goto out_err;
@@ -292,7 +292,12 @@ static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d,
if (d->last)
goto out;
- if (ovl_is_opaquedir(OVL_FS(d->sb), &path)) {
+ /* overlay.opaque=x means xwhiteouts directory */
+ val = ovl_get_opaquedir_val(ofs, &path);
+ if (last_element && !is_upper && val == 'x') {
+ d->xwhiteouts = true;
+ ovl_layer_set_xwhiteouts(ofs, d->layer);
+ } else if (val == 'y') {
d->stop = true;
if (last_element)
d->opaque = true;
@@ -863,7 +868,8 @@ fail:
* Returns next layer in stack starting from top.
* Returns -1 if this is the last layer.
*/
-int ovl_path_next(int idx, struct dentry *dentry, struct path *path)
+int ovl_path_next(int idx, struct dentry *dentry, struct path *path,
+ const struct ovl_layer **layer)
{
struct ovl_entry *oe = OVL_E(dentry);
struct ovl_path *lowerstack = ovl_lowerstack(oe);
@@ -871,13 +877,16 @@ int ovl_path_next(int idx, struct dentry *dentry, struct path *path)
BUG_ON(idx < 0);
if (idx == 0) {
ovl_path_upper(dentry, path);
- if (path->dentry)
+ if (path->dentry) {
+ *layer = &OVL_FS(dentry->d_sb)->layers[0];
return ovl_numlower(oe) ? 1 : -1;
+ }
idx++;
}
BUG_ON(idx > ovl_numlower(oe));
path->dentry = lowerstack[idx - 1].dentry;
- path->mnt = lowerstack[idx - 1].layer->mnt;
+ *layer = lowerstack[idx - 1].layer;
+ path->mnt = (*layer)->mnt;
return (idx < ovl_numlower(oe)) ? idx + 1 : -1;
}
@@ -1055,7 +1064,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
old_cred = ovl_override_creds(dentry->d_sb);
upperdir = ovl_dentry_upper(dentry->d_parent);
if (upperdir) {
- d.mnt = ovl_upper_mnt(ofs);
+ d.layer = &ofs->layers[0];
err = ovl_lookup_layer(upperdir, &d, &upperdentry, true);
if (err)
goto out;
@@ -1111,7 +1120,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
else if (d.is_dir || !ofs->numdatalayer)
d.last = lower.layer->idx == ovl_numlower(roe);
- d.mnt = lower.layer->mnt;
+ d.layer = lower.layer;
err = ovl_lookup_layer(lower.dentry, &d, &this, false);
if (err)
goto out_put;
@@ -1278,6 +1287,8 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
if (upperopaque)
ovl_dentry_set_opaque(dentry);
+ if (d.xwhiteouts)
+ ovl_dentry_set_xwhiteouts(dentry);
if (upperdentry)
ovl_dentry_set_upper_alias(dentry);
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 5ba11eb43767..ee949f3e7c77 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -50,7 +50,6 @@ enum ovl_xattr {
OVL_XATTR_METACOPY,
OVL_XATTR_PROTATTR,
OVL_XATTR_XWHITEOUT,
- OVL_XATTR_XWHITEOUTS,
};
enum ovl_inode_flag {
@@ -70,6 +69,8 @@ enum ovl_entry_flag {
OVL_E_UPPER_ALIAS,
OVL_E_OPAQUE,
OVL_E_CONNECTED,
+ /* Lower stack may contain xwhiteout entries */
+ OVL_E_XWHITEOUTS,
};
enum {
@@ -477,6 +478,10 @@ bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry);
bool ovl_dentry_is_opaque(struct dentry *dentry);
bool ovl_dentry_is_whiteout(struct dentry *dentry);
void ovl_dentry_set_opaque(struct dentry *dentry);
+bool ovl_dentry_has_xwhiteouts(struct dentry *dentry);
+void ovl_dentry_set_xwhiteouts(struct dentry *dentry);
+void ovl_layer_set_xwhiteouts(struct ovl_fs *ofs,
+ const struct ovl_layer *layer);
bool ovl_dentry_has_upper_alias(struct dentry *dentry);
void ovl_dentry_set_upper_alias(struct dentry *dentry);
bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags);
@@ -494,11 +499,10 @@ struct file *ovl_path_open(const struct path *path, int flags);
int ovl_copy_up_start(struct dentry *dentry, int flags);
void ovl_copy_up_end(struct dentry *dentry);
bool ovl_already_copied_up(struct dentry *dentry, int flags);
-bool ovl_path_check_dir_xattr(struct ovl_fs *ofs, const struct path *path,
- enum ovl_xattr ox);
+char ovl_get_dir_xattr_val(struct ovl_fs *ofs, const struct path *path,
+ enum ovl_xattr ox);
bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, const struct path *path);
bool ovl_path_check_xwhiteout_xattr(struct ovl_fs *ofs, const struct path *path);
-bool ovl_path_check_xwhiteouts_xattr(struct ovl_fs *ofs, const struct path *path);
bool ovl_init_uuid_xattr(struct super_block *sb, struct ovl_fs *ofs,
const struct path *upperpath);
@@ -573,7 +577,13 @@ static inline bool ovl_is_impuredir(struct super_block *sb,
.mnt = ovl_upper_mnt(ofs),
};
- return ovl_path_check_dir_xattr(ofs, &upperpath, OVL_XATTR_IMPURE);
+ return ovl_get_dir_xattr_val(ofs, &upperpath, OVL_XATTR_IMPURE) == 'y';
+}
+
+static inline char ovl_get_opaquedir_val(struct ovl_fs *ofs,
+ const struct path *path)
+{
+ return ovl_get_dir_xattr_val(ofs, path, OVL_XATTR_OPAQUE);
}
static inline bool ovl_redirect_follow(struct ovl_fs *ofs)
@@ -680,7 +690,8 @@ int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin,
struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
struct dentry *origin, bool verify);
-int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
+int ovl_path_next(int idx, struct dentry *dentry, struct path *path,
+ const struct ovl_layer **layer);
int ovl_verify_lowerdata(struct dentry *dentry);
struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags);
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index 5fa9c58af65f..cb449ab310a7 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -40,6 +40,8 @@ struct ovl_layer {
int idx;
/* One fsid per unique underlying sb (upper fsid == 0) */
int fsid;
+ /* xwhiteouts were found on this layer */
+ bool has_xwhiteouts;
};
struct ovl_path {
@@ -59,7 +61,7 @@ struct ovl_fs {
unsigned int numfs;
/* Number of data-only lower layers */
unsigned int numdatalayer;
- const struct ovl_layer *layers;
+ struct ovl_layer *layers;
struct ovl_sb *fs;
/* workbasedir is the path at workdir= mount option */
struct dentry *workbasedir;
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index e71156baa7bc..0ca8af060b0c 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -305,8 +305,6 @@ static inline int ovl_dir_read(const struct path *realpath,
if (IS_ERR(realfile))
return PTR_ERR(realfile);
- rdd->in_xwhiteouts_dir = rdd->dentry &&
- ovl_path_check_xwhiteouts_xattr(OVL_FS(rdd->dentry->d_sb), realpath);
rdd->first_maybe_whiteout = NULL;
rdd->ctx.pos = 0;
do {
@@ -359,10 +357,13 @@ static int ovl_dir_read_merged(struct dentry *dentry, struct list_head *list,
.is_lowest = false,
};
int idx, next;
+ const struct ovl_layer *layer;
for (idx = 0; idx != -1; idx = next) {
- next = ovl_path_next(idx, dentry, &realpath);
+ next = ovl_path_next(idx, dentry, &realpath, &layer);
rdd.is_upper = ovl_dentry_upper(dentry) == realpath.dentry;
+ rdd.in_xwhiteouts_dir = layer->has_xwhiteouts &&
+ ovl_dentry_has_xwhiteouts(dentry);
if (next != -1) {
err = ovl_dir_read(&realpath, &rdd);
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 4ab66e3d4cff..2eef6c70b2ae 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1249,6 +1249,7 @@ static struct dentry *ovl_get_root(struct super_block *sb,
struct ovl_entry *oe)
{
struct dentry *root;
+ struct ovl_fs *ofs = OVL_FS(sb);
struct ovl_path *lowerpath = ovl_lowerstack(oe);
unsigned long ino = d_inode(lowerpath->dentry)->i_ino;
int fsid = lowerpath->layer->fsid;
@@ -1270,6 +1271,20 @@ static struct dentry *ovl_get_root(struct super_block *sb,
ovl_set_flag(OVL_IMPURE, d_inode(root));
}
+ /* Look for xwhiteouts marker except in the lowermost layer */
+ for (int i = 0; i < ovl_numlower(oe) - 1; i++, lowerpath++) {
+ struct path path = {
+ .mnt = lowerpath->layer->mnt,
+ .dentry = lowerpath->dentry,
+ };
+
+ /* overlay.opaque=x means xwhiteouts directory */
+ if (ovl_get_opaquedir_val(ofs, &path) == 'x') {
+ ovl_layer_set_xwhiteouts(ofs, lowerpath->layer);
+ ovl_dentry_set_xwhiteouts(root);
+ }
+ }
+
/* Root is always merge -> can have whiteouts */
ovl_set_flag(OVL_WHITEOUTS, d_inode(root));
ovl_dentry_set_flag(OVL_E_CONNECTED, root);
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 0217094c23ea..a8e17f14d7a2 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -461,6 +461,33 @@ void ovl_dentry_set_opaque(struct dentry *dentry)
ovl_dentry_set_flag(OVL_E_OPAQUE, dentry);
}
+bool ovl_dentry_has_xwhiteouts(struct dentry *dentry)
+{
+ return ovl_dentry_test_flag(OVL_E_XWHITEOUTS, dentry);
+}
+
+void ovl_dentry_set_xwhiteouts(struct dentry *dentry)
+{
+ ovl_dentry_set_flag(OVL_E_XWHITEOUTS, dentry);
+}
+
+/*
+ * ovl_layer_set_xwhiteouts() is called before adding the overlay dir
+ * dentry to dcache, while readdir of that same directory happens after
+ * the overlay dir dentry is in dcache, so if some cpu observes that
+ * ovl_dentry_is_xwhiteouts(), it will also observe layer->has_xwhiteouts
+ * for the layers where xwhiteouts marker was found in that merge dir.
+ */
+void ovl_layer_set_xwhiteouts(struct ovl_fs *ofs,
+ const struct ovl_layer *layer)
+{
+ if (layer->has_xwhiteouts)
+ return;
+
+ /* Write once to read-mostly layer properties */
+ ofs->layers[layer->idx].has_xwhiteouts = true;
+}
+
/*
* For hard links and decoded file handles, it's possible for ovl_dentry_upper()
* to return positive, while there's no actual upper alias for the inode.
@@ -739,19 +766,6 @@ bool ovl_path_check_xwhiteout_xattr(struct ovl_fs *ofs, const struct path *path)
return res >= 0;
}
-bool ovl_path_check_xwhiteouts_xattr(struct ovl_fs *ofs, const struct path *path)
-{
- struct dentry *dentry = path->dentry;
- int res;
-
- /* xattr.whiteouts must be a directory */
- if (!d_is_dir(dentry))
- return false;
-
- res = ovl_path_getxattr(ofs, path, OVL_XATTR_XWHITEOUTS, NULL, 0);
- return res >= 0;
-}
-
/*
* Load persistent uuid from xattr into s_uuid if found, or store a new
* random generated value in s_uuid and in xattr.
@@ -811,20 +825,17 @@ fail:
return false;
}
-bool ovl_path_check_dir_xattr(struct ovl_fs *ofs, const struct path *path,
- enum ovl_xattr ox)
+char ovl_get_dir_xattr_val(struct ovl_fs *ofs, const struct path *path,
+ enum ovl_xattr ox)
{
int res;
char val;
if (!d_is_dir(path->dentry))
- return false;
+ return 0;
res = ovl_path_getxattr(ofs, path, ox, &val, 1);
- if (res == 1 && val == 'y')
- return true;
-
- return false;
+ return res == 1 ? val : 0;
}
#define OVL_XATTR_OPAQUE_POSTFIX "opaque"
@@ -837,7 +848,6 @@ bool ovl_path_check_dir_xattr(struct ovl_fs *ofs, const struct path *path,
#define OVL_XATTR_METACOPY_POSTFIX "metacopy"
#define OVL_XATTR_PROTATTR_POSTFIX "protattr"
#define OVL_XATTR_XWHITEOUT_POSTFIX "whiteout"
-#define OVL_XATTR_XWHITEOUTS_POSTFIX "whiteouts"
#define OVL_XATTR_TAB_ENTRY(x) \
[x] = { [false] = OVL_XATTR_TRUSTED_PREFIX x ## _POSTFIX, \
@@ -854,7 +864,6 @@ const char *const ovl_xattr_table[][2] = {
OVL_XATTR_TAB_ENTRY(OVL_XATTR_METACOPY),
OVL_XATTR_TAB_ENTRY(OVL_XATTR_PROTATTR),
OVL_XATTR_TAB_ENTRY(OVL_XATTR_XWHITEOUT),
- OVL_XATTR_TAB_ENTRY(OVL_XATTR_XWHITEOUTS),
};
int ovl_check_setxattr(struct ovl_fs *ofs, struct dentry *upperdentry,
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-03 05:12:29 +0000