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-rw-r--r--fs/overlayfs/copy_up.c56
-rw-r--r--fs/overlayfs/overlayfs.h18
-rw-r--r--fs/overlayfs/super.c1
-rw-r--r--fs/overlayfs/util.c78
4 files changed, 142 insertions, 11 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index aa3c62a4e462..7e6664d6643d 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -180,6 +180,16 @@ out_fput:
return error;
}
+static int ovl_set_size(struct dentry *upperdentry, struct kstat *stat)
+{
+ struct iattr attr = {
+ .ia_valid = ATTR_SIZE,
+ .ia_size = stat->size,
+ };
+
+ return notify_change(upperdentry, &attr, NULL);
+}
+
static int ovl_set_timestamps(struct dentry *upperdentry, struct kstat *stat)
{
struct iattr attr = {
@@ -520,8 +530,18 @@ static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp)
return err;
}
+ if (c->metacopy) {
+ err = ovl_check_setxattr(c->dentry, temp, OVL_XATTR_METACOPY,
+ NULL, 0, -EOPNOTSUPP);
+ if (err)
+ return err;
+ }
+
inode_lock(temp->d_inode);
- err = ovl_set_attr(temp, &c->stat);
+ if (c->metacopy)
+ err = ovl_set_size(temp, &c->stat);
+ if (!err)
+ err = ovl_set_attr(temp, &c->stat);
inode_unlock(temp->d_inode);
return err;
@@ -559,6 +579,8 @@ static int ovl_copy_up_locked(struct ovl_copy_up_ctx *c)
if (err)
goto out;
+ if (!c->metacopy)
+ ovl_set_upperdata(d_inode(c->dentry));
inode = d_inode(c->dentry);
ovl_inode_update(inode, newdentry);
if (S_ISDIR(inode->i_mode))
@@ -681,6 +703,28 @@ static bool ovl_need_meta_copy_up(struct dentry *dentry, umode_t mode,
return true;
}
+/* Copy up data of an inode which was copied up metadata only in the past. */
+static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
+{
+ struct path upperpath;
+ int err;
+
+ ovl_path_upper(c->dentry, &upperpath);
+ if (WARN_ON(upperpath.dentry == NULL))
+ return -EIO;
+
+ err = ovl_copy_up_data(&c->lowerpath, &upperpath, c->stat.size);
+ if (err)
+ return err;
+
+ err = vfs_removexattr(upperpath.dentry, OVL_XATTR_METACOPY);
+ if (err)
+ return err;
+
+ ovl_set_upperdata(d_inode(c->dentry));
+ return err;
+}
+
static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
int flags)
{
@@ -726,7 +770,7 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
return PTR_ERR(ctx.link);
}
- err = ovl_copy_up_start(dentry);
+ err = ovl_copy_up_start(dentry, flags);
/* err < 0: interrupted, err > 0: raced with another copy-up */
if (unlikely(err)) {
if (err > 0)
@@ -736,6 +780,8 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
err = ovl_do_copy_up(&ctx);
if (!err && parent && !ovl_dentry_has_upper_alias(dentry))
err = ovl_link_up(&ctx);
+ if (!err && ovl_dentry_needs_data_copy_up_locked(dentry, flags))
+ err = ovl_copy_up_meta_inode_data(&ctx);
ovl_copy_up_end(dentry);
}
do_delayed_call(&done);
@@ -761,7 +807,7 @@ int ovl_copy_up_flags(struct dentry *dentry, int flags)
struct dentry *next;
struct dentry *parent = NULL;
- if (ovl_already_copied_up(dentry))
+ if (ovl_already_copied_up(dentry, flags))
break;
next = dget(dentry);
@@ -789,13 +835,13 @@ int ovl_copy_up_flags(struct dentry *dentry, int flags)
static bool ovl_open_need_copy_up(struct dentry *dentry, int flags)
{
/* Copy up of disconnected dentry does not set upper alias */
- if (ovl_already_copied_up(dentry))
+ if (ovl_already_copied_up(dentry, flags))
return false;
if (special_file(d_inode(dentry)->i_mode))
return false;
- if (!(OPEN_FMODE(flags) & FMODE_WRITE) && !(flags & O_TRUNC))
+ if (!ovl_open_flags_need_copy_up(flags))
return false;
return true;
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 206e588df095..16a000694c4e 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -29,6 +29,7 @@ enum ovl_path_type {
#define OVL_XATTR_IMPURE OVL_XATTR_PREFIX "impure"
#define OVL_XATTR_NLINK OVL_XATTR_PREFIX "nlink"
#define OVL_XATTR_UPPER OVL_XATTR_PREFIX "upper"
+#define OVL_XATTR_METACOPY OVL_XATTR_PREFIX "metacopy"
enum ovl_inode_flag {
/* Pure upper dir that may contain non pure upper entries */
@@ -36,6 +37,7 @@ enum ovl_inode_flag {
/* Non-merge dir that may contain whiteout entries */
OVL_WHITEOUTS,
OVL_INDEX,
+ OVL_UPPERDATA,
};
enum ovl_entry_flag {
@@ -191,6 +193,14 @@ static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode)
return ret;
}
+static inline bool ovl_open_flags_need_copy_up(int flags)
+{
+ if (!flags)
+ return false;
+
+ return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
+}
+
/* util.c */
int ovl_want_write(struct dentry *dentry);
void ovl_drop_write(struct dentry *dentry);
@@ -226,6 +236,10 @@ bool ovl_dentry_is_whiteout(struct dentry *dentry);
void ovl_dentry_set_opaque(struct dentry *dentry);
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);
+bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags);
+bool ovl_has_upperdata(struct inode *inode);
+void ovl_set_upperdata(struct inode *inode);
bool ovl_redirect_dir(struct super_block *sb);
const char *ovl_dentry_get_redirect(struct dentry *dentry);
void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
@@ -236,9 +250,9 @@ void ovl_dir_modified(struct dentry *dentry, bool impurity);
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);
-int ovl_copy_up_start(struct dentry *dentry);
+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);
+bool ovl_already_copied_up(struct dentry *dentry, int flags);
bool ovl_check_origin_xattr(struct dentry *dentry);
bool ovl_check_dir_xattr(struct dentry *dentry, const char *name);
int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index d4caeee051ee..ab0039161f85 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1485,6 +1485,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
/* Root is always merge -> can have whiteouts */
ovl_set_flag(OVL_WHITEOUTS, d_inode(root_dentry));
ovl_dentry_set_flag(OVL_E_CONNECTED, root_dentry);
+ ovl_set_upperdata(d_inode(root_dentry));
ovl_inode_init(d_inode(root_dentry), upperpath.dentry,
ovl_dentry_lower(root_dentry));
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 43235294e77b..f8e3c95711b8 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -279,6 +279,62 @@ void ovl_dentry_set_upper_alias(struct dentry *dentry)
ovl_dentry_set_flag(OVL_E_UPPER_ALIAS, dentry);
}
+static bool ovl_should_check_upperdata(struct inode *inode)
+{
+ if (!S_ISREG(inode->i_mode))
+ return false;
+
+ if (!ovl_inode_lower(inode))
+ return false;
+
+ return true;
+}
+
+bool ovl_has_upperdata(struct inode *inode)
+{
+ if (!ovl_should_check_upperdata(inode))
+ return true;
+
+ if (!ovl_test_flag(OVL_UPPERDATA, inode))
+ return false;
+ /*
+ * Pairs with smp_wmb() in ovl_set_upperdata(). Main user of
+ * ovl_has_upperdata() is ovl_copy_up_meta_inode_data(). Make sure
+ * if setting of OVL_UPPERDATA is visible, then effects of writes
+ * before that are visible too.
+ */
+ smp_rmb();
+ return true;
+}
+
+void ovl_set_upperdata(struct inode *inode)
+{
+ /*
+ * Pairs with smp_rmb() in ovl_has_upperdata(). Make sure
+ * if OVL_UPPERDATA flag is visible, then effects of write operations
+ * before it are visible as well.
+ */
+ smp_wmb();
+ ovl_set_flag(OVL_UPPERDATA, inode);
+}
+
+/* Caller should hold ovl_inode->lock */
+bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags)
+{
+ if (!ovl_open_flags_need_copy_up(flags))
+ return false;
+
+ return !ovl_test_flag(OVL_UPPERDATA, d_inode(dentry));
+}
+
+bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags)
+{
+ if (!ovl_open_flags_need_copy_up(flags))
+ return false;
+
+ return !ovl_has_upperdata(d_inode(dentry));
+}
+
bool ovl_redirect_dir(struct super_block *sb)
{
struct ovl_fs *ofs = sb->s_fs_info;
@@ -377,7 +433,20 @@ struct file *ovl_path_open(struct path *path, int flags)
return dentry_open(path, flags | O_NOATIME, current_cred());
}
-bool ovl_already_copied_up(struct dentry *dentry)
+/* Caller should hold ovl_inode->lock */
+static bool ovl_already_copied_up_locked(struct dentry *dentry, int flags)
+{
+ bool disconnected = dentry->d_flags & DCACHE_DISCONNECTED;
+
+ if (ovl_dentry_upper(dentry) &&
+ (ovl_dentry_has_upper_alias(dentry) || disconnected) &&
+ !ovl_dentry_needs_data_copy_up_locked(dentry, flags))
+ return true;
+
+ return false;
+}
+
+bool ovl_already_copied_up(struct dentry *dentry, int flags)
{
bool disconnected = dentry->d_flags & DCACHE_DISCONNECTED;
@@ -395,19 +464,20 @@ bool ovl_already_copied_up(struct dentry *dentry)
* with rename.
*/
if (ovl_dentry_upper(dentry) &&
- (ovl_dentry_has_upper_alias(dentry) || disconnected))
+ (ovl_dentry_has_upper_alias(dentry) || disconnected) &&
+ !ovl_dentry_needs_data_copy_up(dentry, flags))
return true;
return false;
}
-int ovl_copy_up_start(struct dentry *dentry)
+int ovl_copy_up_start(struct dentry *dentry, int flags)
{
struct ovl_inode *oi = OVL_I(d_inode(dentry));
int err;
err = mutex_lock_interruptible(&oi->lock);
- if (!err && ovl_already_copied_up(dentry)) {
+ if (!err && ovl_already_copied_up_locked(dentry, flags)) {
err = 1; /* Already copied up */
mutex_unlock(&oi->lock);
}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.