diff options
author | Amir Goldstein <amir73il@gmail.com> | 2017-05-16 01:26:49 +0300 |
---|---|---|
committer | Miklos Szeredi <mszeredi@redhat.com> | 2017-07-04 23:03:18 +0300 |
commit | 15932c415b3ed20bd1c1e05d071b4ad498656280 (patch) | |
tree | 9a5c7e198c8529323c57534720791e232a64ddb4 /fs/overlayfs/copy_up.c | |
parent | b9ac5c274b8c9d642567022c0e319bca4db31956 (diff) | |
download | linux-15932c415b3ed20bd1c1e05d071b4ad498656280.tar.xz |
ovl: defer upper dir lock to tempfile link
On copy up of regular file using an O_TMPFILE, lock upper dir only
before linking the tempfile in place.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/overlayfs/copy_up.c')
-rw-r--r-- | fs/overlayfs/copy_up.c | 67 |
1 files changed, 38 insertions, 29 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index 5e8fd99557e1..28711af7f9db 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -316,6 +316,35 @@ static int ovl_set_origin(struct dentry *dentry, struct dentry *lower, return err; } +static int ovl_install_temp(struct dentry *workdir, struct dentry *upperdir, + struct dentry *dentry, + struct dentry *temp, struct kstat *pstat, + bool tmpfile, struct dentry **newdentry) +{ + int err; + struct dentry *upper; + struct inode *udir = d_inode(upperdir); + + upper = lookup_one_len(dentry->d_name.name, upperdir, + dentry->d_name.len); + if (IS_ERR(upper)) + return PTR_ERR(upper); + + if (tmpfile) + err = ovl_do_link(temp, udir, upper, true); + else + err = ovl_do_rename(d_inode(workdir), temp, udir, upper, 0); + + /* Restore timestamps on parent (best effort) */ + if (!err) { + ovl_set_timestamps(upperdir, pstat); + *newdentry = dget(tmpfile ? upper : temp); + } + dput(upper); + + return err; +} + static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir, struct dentry *dentry, struct path *lowerpath, struct kstat *stat, const char *link, @@ -324,7 +353,6 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir, 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; @@ -371,16 +399,7 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir, BUG_ON(upperpath.dentry != NULL); 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; } @@ -408,29 +427,21 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir, goto out_cleanup; } - upper = lookup_one_len(dentry->d_name.name, upperdir, - dentry->d_name.len); - if (IS_ERR(upper)) { - err = PTR_ERR(upper); - upper = NULL; - goto out_cleanup; + if (tmpfile) { + inode_lock_nested(udir, I_MUTEX_PARENT); + err = ovl_install_temp(workdir, upperdir, dentry, temp, pstat, + tmpfile, &newdentry); + inode_unlock(udir); + } else { + err = ovl_install_temp(workdir, upperdir, dentry, temp, pstat, + tmpfile, &newdentry); } - - 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_inode_update(d_inode(dentry), newdentry); - - /* Restore timestamps on parent (best effort) */ - ovl_set_timestamps(upperdir, pstat); out: dput(temp); - dput(upper); return err; out_cleanup: @@ -496,10 +507,8 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry, 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; } |