If a directory only exist in low layer, create a new file in it trigger
directory copy-up. Permission lost of the new directory in upper layer
was observed during power-cut stress test.
Fix by adding new mount opion "upsync=strict", make sure data/metadata of
copied up directory written to disk before renaming from tmp to final
destination.
Signed-off-by: Fei Lv <feilv@xxxxxxxxxxxx>
---
OPT_sync changed to OPT_upsync since mount option "sync" already used.
fs/overlayfs/copy_up.c | 21 +++++++++++++++++++++
fs/overlayfs/ovl_entry.h | 20 ++++++++++++++++++--
fs/overlayfs/params.c | 33 +++++++++++++++++++++++++++++----
fs/overlayfs/super.c | 2 +-
4 files changed, 69 insertions(+), 7 deletions(-)
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index a5ef2005a2cc..b6f021ad7a43 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -243,6 +243,21 @@ static int ovl_verify_area(loff_t pos, loff_t pos2, loff_t len, loff_t totlen)
return 0;
}
+static int ovl_copy_up_sync(struct path *path)
+{
+ struct file *new_file;
+ int err;
+
+ new_file = ovl_path_open(path, O_LARGEFILE | O_WRONLY);
+ if (IS_ERR(new_file))
+ return PTR_ERR(new_file);
+
+ err = vfs_fsync(new_file, 0);
+ fput(new_file);
+
+ return err;
+}
+
static int ovl_copy_up_file(struct ovl_fs *ofs, struct dentry *dentry,
struct file *new_file, loff_t len)
{
@@ -701,6 +716,9 @@ static int ovl_copy_up_metadata(struct ovl_copy_up_ctx *c, struct dentry *temp)
err = ovl_set_attr(ofs, temp, &c->stat);
inode_unlock(temp->d_inode);
+ if (!err && ovl_should_sync_strict(ofs))
+ err = ovl_copy_up_sync(&upperpath);
+
return err;
}
@@ -1104,6 +1122,9 @@ static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
ovl_clear_flag(OVL_HAS_DIGEST, d_inode(c->dentry));
ovl_clear_flag(OVL_VERIFIED_DIGEST, d_inode(c->dentry));
ovl_set_upperdata(d_inode(c->dentry));
+
+ if (!err && ovl_should_sync_strict(ofs))
+ err = ovl_copy_up_sync(&upperpath);
out_free:
kfree(capability);
out:
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index cb449ab310a7..4592e6f7dcf7 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -5,6 +5,12 @@
* Copyright (C) 2016 Red Hat, Inc.
*/
+enum {
+ OVL_SYNC_DATA,
+ OVL_SYNC_STRICT,
+ OVL_SYNC_OFF,
+};
+
struct ovl_config {
char *upperdir;
char *workdir;
@@ -18,7 +24,7 @@ struct ovl_config {
int xino;
bool metacopy;
bool userxattr;
- bool ovl_volatile;
+ int sync_mode;
};
struct ovl_sb {
@@ -120,7 +126,17 @@ static inline struct ovl_fs *OVL_FS(struct super_block *sb)
static inline bool ovl_should_sync(struct ovl_fs *ofs)
{
- return !ofs->config.ovl_volatile;
+ return ofs->config.sync_mode == OVL_SYNC_DATA;
+}
+
+static inline bool ovl_should_sync_strict(struct ovl_fs *ofs)
+{
+ return ofs->config.sync_mode == OVL_SYNC_STRICT;
+}
+
+static inline bool ovl_is_volatile(struct ovl_config *config)
+{
+ return config->sync_mode == OVL_SYNC_OFF;
}
static inline unsigned int ovl_numlower(struct ovl_entry *oe)
diff --git a/fs/overlayfs/params.c b/fs/overlayfs/params.c
index 4860fcc4611b..5d5538dd3de7 100644
--- a/fs/overlayfs/params.c
+++ b/fs/overlayfs/params.c
@@ -58,6 +58,7 @@ enum ovl_opt {
Opt_xino,
Opt_metacopy,
Opt_verity,
+ Opt_upsync,
Opt_volatile,
};
@@ -139,6 +140,23 @@ static int ovl_verity_mode_def(void)
return OVL_VERITY_OFF;
}
+static const struct constant_table ovl_parameter_upsync[] = {
+ { "data", OVL_SYNC_DATA },
+ { "strict", OVL_SYNC_STRICT },
+ { "off", OVL_SYNC_OFF },
+ {}
+};
+
+static const char *ovl_upsync_mode(struct ovl_config *config)
+{
+ return ovl_parameter_upsync[config->sync_mode].name;
+}
+
+static int ovl_upsync_mode_def(void)
+{
+ return OVL_SYNC_DATA;
+}
+
const struct fs_parameter_spec ovl_parameter_spec[] = {
fsparam_string_empty("lowerdir", Opt_lowerdir),
fsparam_string("lowerdir+", Opt_lowerdir_add),
@@ -154,6 +172,7 @@ const struct fs_parameter_spec ovl_parameter_spec[] = {
fsparam_enum("xino", Opt_xino, ovl_parameter_xino),
fsparam_enum("metacopy", Opt_metacopy, ovl_parameter_bool),
fsparam_enum("verity", Opt_verity, ovl_parameter_verity),
+ fsparam_enum("upsync", Opt_upsync, ovl_parameter_upsync),
fsparam_flag("volatile", Opt_volatile),
{}
};
@@ -617,8 +636,11 @@ static int ovl_parse_param(struct fs_context *fc, struct fs_parameter *param)
case Opt_verity:
config->verity_mode = result.uint_32;
break;
+ case Opt_upsync:
+ config->sync_mode = result.uint_32;
+ break;
case Opt_volatile:
- config->ovl_volatile = true;
+ config->sync_mode = OVL_SYNC_OFF;
break;
case Opt_userxattr:
config->userxattr = true;
@@ -802,9 +824,9 @@ int ovl_fs_params_verify(const struct ovl_fs_context *ctx,
config->index = false;
}
- if (!config->upperdir && config->ovl_volatile) {
+ if (!config->upperdir && ovl_is_volatile(config)) {
pr_info("option \"volatile\" is meaningless in a non-upper mount, ignoring it.\n");
- config->ovl_volatile = false;
+ config->sync_mode = ovl_upsync_mode_def();
}
if (!config->upperdir && config->uuid == OVL_UUID_ON) {
@@ -997,8 +1019,11 @@ int ovl_show_options(struct seq_file *m, struct dentry *dentry)
if (ofs->config.metacopy != ovl_metacopy_def)
seq_printf(m, ",metacopy=%s",
ofs->config.metacopy ? "on" : "off");
- if (ofs->config.ovl_volatile)
+ if (ovl_is_volatile(&ofs->config))
seq_puts(m, ",volatile");
+ else if (ofs->config.sync_mode != ovl_upsync_mode_def())
+ seq_printf(m, ",upsync=%s",
+ ovl_upsync_mode(&ofs->config));
if (ofs->config.userxattr)
seq_puts(m, ",userxattr");
if (ofs->config.verity_mode != ovl_verity_mode_def())
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 06a231970cb5..824cbcf40523 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -750,7 +750,7 @@ static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
* For volatile mount, create a incompat/volatile/dirty file to keep
* track of it.
*/
- if (ofs->config.ovl_volatile) {
+ if (ovl_is_volatile(&ofs->config)) {
err = ovl_create_volatile_dirty(ofs);
if (err < 0) {
pr_err("Failed to create volatile/dirty file.\n");
base-commit: 0c3836482481200ead7b416ca80c68a29cfdaabd
--
2.45.2
