Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs updates from Miklos Szeredi:
"Because copy up can take a long time, serialized copy ups could be a
big performance bottleneck. This update allows concurrent copy up of
regular files eliminating this potential problem.
There are also minor fixes"
* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
ovl: drop CAP_SYS_RESOURCE from saved mounter's credentials
ovl: properly implement sync_filesystem()
ovl: concurrent copy up of regular files
ovl: introduce copy up waitqueue
ovl: copy up regular file using O_TMPFILE
ovl: rearrange code in ovl_copy_up_locked()
ovl: check if upperdir fs supports O_TMPFILE
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 2d49850..906ea6c 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -21,6 +21,7 @@
#include <linux/fdtable.h>
#include <linux/ratelimit.h>
#include "overlayfs.h"
+#include "ovl_entry.h"
#define OVL_COPY_UP_CHUNK_SIZE (1 << 20)
@@ -233,12 +234,14 @@ int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat)
static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
struct dentry *dentry, struct path *lowerpath,
- struct kstat *stat, const char *link)
+ struct kstat *stat, const char *link,
+ struct kstat *pstat, bool tmpfile)
{
struct inode *wdir = workdir->d_inode;
struct inode *udir = upperdir->d_inode;
struct dentry *newdentry = NULL;
struct dentry *upper = NULL;
+ struct dentry *temp = NULL;
int err;
const struct cred *old_creds = NULL;
struct cred *new_creds = NULL;
@@ -249,25 +252,30 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
.link = link
};
- newdentry = ovl_lookup_temp(workdir, dentry);
- err = PTR_ERR(newdentry);
- if (IS_ERR(newdentry))
- goto out;
-
upper = lookup_one_len(dentry->d_name.name, upperdir,
dentry->d_name.len);
err = PTR_ERR(upper);
if (IS_ERR(upper))
- goto out1;
+ goto out;
err = security_inode_copy_up(dentry, &new_creds);
if (err < 0)
- goto out2;
+ goto out1;
if (new_creds)
old_creds = override_creds(new_creds);
- err = ovl_create_real(wdir, newdentry, &cattr, NULL, true);
+ if (tmpfile)
+ temp = ovl_do_tmpfile(upperdir, stat->mode);
+ else
+ temp = ovl_lookup_temp(workdir, dentry);
+ err = PTR_ERR(temp);
+ if (IS_ERR(temp))
+ goto out1;
+
+ err = 0;
+ if (!tmpfile)
+ err = ovl_create_real(wdir, temp, &cattr, NULL, true);
if (new_creds) {
revert_creds(old_creds);
@@ -282,39 +290,55 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
ovl_path_upper(dentry, &upperpath);
BUG_ON(upperpath.dentry != NULL);
- upperpath.dentry = newdentry;
+ upperpath.dentry = temp;
- err = ovl_copy_up_data(lowerpath, &upperpath, stat->size);
+ if (tmpfile) {
+ inode_unlock(udir);
+ err = ovl_copy_up_data(lowerpath, &upperpath,
+ stat->size);
+ inode_lock_nested(udir, I_MUTEX_PARENT);
+ } else {
+ err = ovl_copy_up_data(lowerpath, &upperpath,
+ stat->size);
+ }
+
if (err)
goto out_cleanup;
}
- err = ovl_copy_xattr(lowerpath->dentry, newdentry);
+ err = ovl_copy_xattr(lowerpath->dentry, temp);
if (err)
goto out_cleanup;
- inode_lock(newdentry->d_inode);
- err = ovl_set_attr(newdentry, stat);
- inode_unlock(newdentry->d_inode);
+ inode_lock(temp->d_inode);
+ err = ovl_set_attr(temp, stat);
+ inode_unlock(temp->d_inode);
if (err)
goto out_cleanup;
- err = ovl_do_rename(wdir, newdentry, udir, upper, 0);
+ if (tmpfile)
+ err = ovl_do_link(temp, udir, upper, true);
+ else
+ err = ovl_do_rename(wdir, temp, udir, upper, 0);
if (err)
goto out_cleanup;
+ newdentry = dget(tmpfile ? upper : temp);
ovl_dentry_update(dentry, newdentry);
ovl_inode_update(d_inode(dentry), d_inode(newdentry));
- newdentry = NULL;
+
+ /* Restore timestamps on parent (best effort) */
+ ovl_set_timestamps(upperdir, pstat);
out2:
- dput(upper);
+ dput(temp);
out1:
- dput(newdentry);
+ dput(upper);
out:
return err;
out_cleanup:
- ovl_cleanup(wdir, newdentry);
+ if (!tmpfile)
+ ovl_cleanup(wdir, temp);
goto out2;
}
@@ -338,6 +362,7 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
struct dentry *lowerdentry = lowerpath->dentry;
struct dentry *upperdir;
const char *link = NULL;
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
if (WARN_ON(!workdir))
return -EROFS;
@@ -358,6 +383,25 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
return PTR_ERR(link);
}
+ /* Should we copyup with O_TMPFILE or with workdir? */
+ if (S_ISREG(stat->mode) && ofs->tmpfile) {
+ err = ovl_copy_up_start(dentry);
+ /* err < 0: interrupted, err > 0: raced with another copy-up */
+ if (unlikely(err)) {
+ pr_debug("ovl_copy_up_start(%pd2) = %i\n", dentry, err);
+ if (err > 0)
+ err = 0;
+ goto out_done;
+ }
+
+ inode_lock_nested(upperdir->d_inode, I_MUTEX_PARENT);
+ err = ovl_copy_up_locked(workdir, upperdir, dentry, lowerpath,
+ stat, link, &pstat, true);
+ inode_unlock(upperdir->d_inode);
+ ovl_copy_up_end(dentry);
+ goto out_done;
+ }
+
err = -EIO;
if (lock_rename(workdir, upperdir) != NULL) {
pr_err("overlayfs: failed to lock workdir+upperdir\n");
@@ -370,13 +414,10 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
}
err = ovl_copy_up_locked(workdir, upperdir, dentry, lowerpath,
- stat, link);
- if (!err) {
- /* Restore timestamps on parent (best effort) */
- ovl_set_timestamps(upperdir, &pstat);
- }
+ stat, link, &pstat, false);
out_unlock:
unlock_rename(workdir, upperdir);
+out_done:
do_delayed_call(&done);
return err;
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 8af450b..741dc0b 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -127,6 +127,15 @@ static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry)
return err;
}
+static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode)
+{
+ struct dentry *ret = vfs_tmpfile(dentry, mode, 0);
+ int err = IS_ERR(ret) ? PTR_ERR(ret) : 0;
+
+ pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
+ return ret;
+}
+
static inline struct inode *ovl_inode_real(struct inode *inode, bool *is_upper)
{
unsigned long x = (unsigned long) READ_ONCE(inode->i_private);
@@ -169,6 +178,8 @@ void ovl_dentry_version_inc(struct dentry *dentry);
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);
+void ovl_copy_up_end(struct dentry *dentry);
/* namei.c */
int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index d14bca1..59614fa 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -27,6 +27,8 @@ struct ovl_fs {
struct ovl_config config;
/* creds of process who forced instantiation of super block */
const struct cred *creator_cred;
+ bool tmpfile;
+ wait_queue_head_t copyup_wq;
};
/* private information held for every overlayfs dentry */
@@ -38,6 +40,7 @@ struct ovl_entry {
u64 version;
const char *redirect;
bool opaque;
+ bool copying;
};
struct rcu_head rcu;
};
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 9aa37c2..c9e70d3 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -161,6 +161,25 @@ static void ovl_put_super(struct super_block *sb)
kfree(ufs);
}
+static int ovl_sync_fs(struct super_block *sb, int wait)
+{
+ struct ovl_fs *ufs = sb->s_fs_info;
+ struct super_block *upper_sb;
+ int ret;
+
+ if (!ufs->upper_mnt)
+ return 0;
+ upper_sb = ufs->upper_mnt->mnt_sb;
+ if (!upper_sb->s_op->sync_fs)
+ return 0;
+
+ /* real inodes have already been synced by sync_filesystem(ovl_sb) */
+ down_read(&upper_sb->s_umount);
+ ret = upper_sb->s_op->sync_fs(upper_sb, wait);
+ up_read(&upper_sb->s_umount);
+ return ret;
+}
+
/**
* ovl_statfs
* @sb: The overlayfs super block
@@ -223,6 +242,7 @@ static int ovl_remount(struct super_block *sb, int *flags, char *data)
static const struct super_operations ovl_super_operations = {
.put_super = ovl_put_super,
+ .sync_fs = ovl_sync_fs,
.statfs = ovl_statfs,
.show_options = ovl_show_options,
.remount_fs = ovl_remount,
@@ -702,6 +722,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
unsigned int stacklen = 0;
unsigned int i;
bool remote = false;
+ struct cred *cred;
int err;
err = -ENOMEM;
@@ -709,6 +730,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
if (!ufs)
goto out;
+ init_waitqueue_head(&ufs->copyup_wq);
ufs->config.redirect_dir = ovl_redirect_dir_def;
err = ovl_parse_opt((char *) data, &ufs->config);
if (err)
@@ -826,6 +848,8 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
* creation of workdir in previous step.
*/
if (ufs->workdir) {
+ struct dentry *temp;
+
err = ovl_check_d_type_supported(&workpath);
if (err < 0)
goto out_put_workdir;
@@ -837,6 +861,14 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
*/
if (!err)
pr_warn("overlayfs: upper fs needs to support d_type.\n");
+
+ /* Check if upper/work fs supports O_TMPFILE */
+ temp = ovl_do_tmpfile(ufs->workdir, S_IFREG | 0);
+ ufs->tmpfile = !IS_ERR(temp);
+ if (ufs->tmpfile)
+ dput(temp);
+ else
+ pr_warn("overlayfs: upper fs does not support tmpfile.\n");
}
}
@@ -871,10 +903,13 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
else
sb->s_d_op = &ovl_dentry_operations;
- ufs->creator_cred = prepare_creds();
- if (!ufs->creator_cred)
+ ufs->creator_cred = cred = prepare_creds();
+ if (!cred)
goto out_put_lower_mnt;
+ /* Never override disk quota limits or use reserved space */
+ cap_lower(cred->cap_effective, CAP_SYS_RESOURCE);
+
err = -ENOMEM;
oe = ovl_alloc_entry(numlower);
if (!oe)
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 9dc1c0a..1953986 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -12,6 +12,7 @@
#include <linux/slab.h>
#include <linux/cred.h>
#include <linux/xattr.h>
+#include <linux/sched/signal.h>
#include "overlayfs.h"
#include "ovl_entry.h"
@@ -264,3 +265,33 @@ struct file *ovl_path_open(struct path *path, int flags)
{
return dentry_open(path, flags | O_NOATIME, current_cred());
}
+
+int ovl_copy_up_start(struct dentry *dentry)
+{
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ struct ovl_entry *oe = dentry->d_fsdata;
+ int err;
+
+ spin_lock(&ofs->copyup_wq.lock);
+ err = wait_event_interruptible_locked(ofs->copyup_wq, !oe->copying);
+ if (!err) {
+ if (oe->__upperdentry)
+ err = 1; /* Already copied up */
+ else
+ oe->copying = true;
+ }
+ spin_unlock(&ofs->copyup_wq.lock);
+
+ return err;
+}
+
+void ovl_copy_up_end(struct dentry *dentry)
+{
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ spin_lock(&ofs->copyup_wq.lock);
+ oe->copying = false;
+ wake_up_locked(&ofs->copyup_wq);
+ spin_unlock(&ofs->copyup_wq.lock);
+}