Commit e58bc927 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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
parents 590dce2d 51f8f3c4
......@@ -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;
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);
}
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;
......
......@@ -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);
......
......@@ -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;
};
......
......@@ -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)
......
......@@ -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);
}
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