From: Amir Goldstein <amir73il@gmail.com> mainline inclusion from mainline-v6.7-rc1 commit 162d06444070c12827d604a2cb6b6bd98d48cbb0 category: feature bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBHLU4 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Make the locking order of ovl_inode_lock() strictly between the two vfs stacked layers, i.e.: - ovl vfs locks: sb_writers, inode_lock, ... - ovl_inode_lock - upper vfs locks: sb_writers, inode_lock, ... To that effect, move ovl_want_write() into the helpers ovl_nlink_start() and ovl_copy_up_start which currently take the ovl_inode_lock() after ovl_want_write(). Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Yifan Qiao <qiaoyifan4@huawei.com> --- fs/overlayfs/copy_up.c | 13 +++------ fs/overlayfs/dir.c | 60 ++++++++++++++++++------------------------ fs/overlayfs/export.c | 7 +---- fs/overlayfs/inode.c | 57 +++++++++++++++++++-------------------- fs/overlayfs/util.c | 34 +++++++++++++++++++----- 5 files changed, 84 insertions(+), 87 deletions(-) diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index dbf7b3cd70ca..cc5fe472d6e3 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -1170,17 +1170,10 @@ static bool ovl_open_need_copy_up(struct dentry *dentry, int flags) int ovl_maybe_copy_up(struct dentry *dentry, int flags) { - int err = 0; - - if (ovl_open_need_copy_up(dentry, flags)) { - err = ovl_want_write(dentry); - if (!err) { - err = ovl_copy_up_flags(dentry, flags); - ovl_drop_write(dentry); - } - } + if (!ovl_open_need_copy_up(dentry, flags)) + return 0; - return err; + return ovl_copy_up_flags(dentry, flags); } int ovl_copy_up_with_data(struct dentry *dentry) diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c index 54602f0bed8b..68cfb2959f75 100644 --- a/fs/overlayfs/dir.c +++ b/fs/overlayfs/dir.c @@ -556,10 +556,6 @@ static int ovl_create_or_link(struct dentry *dentry, struct inode *inode, struct cred *override_cred; struct dentry *parent = dentry->d_parent; - err = ovl_copy_up(parent); - if (err) - return err; - old_cred = ovl_override_creds(dentry->d_sb); /* @@ -623,6 +619,10 @@ static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev, .link = link, }; + err = ovl_copy_up(dentry->d_parent); + if (err) + return err; + err = ovl_want_write(dentry); if (err) goto out; @@ -697,28 +697,24 @@ static int ovl_link(struct dentry *old, struct inode *newdir, int err; struct inode *inode; - err = ovl_want_write(old); + err = ovl_copy_up(old); if (err) goto out; - err = ovl_copy_up(old); + err = ovl_copy_up(new->d_parent); if (err) - goto out_drop_write; + goto out; - err = ovl_copy_up(new->d_parent); + err = ovl_nlink_start(old); if (err) - goto out_drop_write; + goto out; if (ovl_is_metacopy_dentry(old)) { err = ovl_set_link_redirect(old); if (err) - goto out_drop_write; + goto out_nlink_end; } - err = ovl_nlink_start(old); - if (err) - goto out_drop_write; - inode = d_inode(old); ihold(inode); @@ -728,9 +724,8 @@ static int ovl_link(struct dentry *old, struct inode *newdir, if (err) iput(inode); +out_nlink_end: ovl_nlink_end(old); -out_drop_write: - ovl_drop_write(old); out: return err; } @@ -888,17 +883,13 @@ static int ovl_do_remove(struct dentry *dentry, bool is_dir) goto out; } - err = ovl_want_write(dentry); - if (err) - goto out; - err = ovl_copy_up(dentry->d_parent); if (err) - goto out_drop_write; + goto out; err = ovl_nlink_start(dentry); if (err) - goto out_drop_write; + goto out; old_cred = ovl_override_creds(dentry->d_sb); if (!lower_positive) @@ -923,8 +914,6 @@ static int ovl_do_remove(struct dentry *dentry, bool is_dir) if (ovl_dentry_upper(dentry)) ovl_copyattr(d_inode(dentry)); -out_drop_write: - ovl_drop_write(dentry); out: ovl_cache_free(&list); return err; @@ -1128,29 +1117,32 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir, } } - err = ovl_want_write(old); - if (err) - goto out; - err = ovl_copy_up(old); if (err) - goto out_drop_write; + goto out; err = ovl_copy_up(new->d_parent); if (err) - goto out_drop_write; + goto out; if (!overwrite) { err = ovl_copy_up(new); if (err) - goto out_drop_write; + goto out; } else if (d_inode(new)) { err = ovl_nlink_start(new); if (err) - goto out_drop_write; + goto out; update_nlink = true; } + if (!update_nlink) { + /* ovl_nlink_start() took ovl_want_write() */ + err = ovl_want_write(old); + if (err) + goto out; + } + old_cred = ovl_override_creds(old->d_sb); if (!list_empty(&list)) { @@ -1283,8 +1275,8 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir, revert_creds(old_cred); if (update_nlink) ovl_nlink_end(new); -out_drop_write: - ovl_drop_write(old); + else + ovl_drop_write(old); out: dput(opaquedir); ovl_cache_free(&list); diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c index 3a17e4366f28..19df4efbf148 100644 --- a/fs/overlayfs/export.c +++ b/fs/overlayfs/export.c @@ -23,12 +23,7 @@ static int ovl_encode_maybe_copy_up(struct dentry *dentry) if (ovl_dentry_upper(dentry)) return 0; - err = ovl_want_write(dentry); - if (!err) { - err = ovl_copy_up(dentry); - ovl_drop_write(dentry); - } - + err = ovl_copy_up(dentry); if (err) { pr_warn_ratelimited("failed to copy up on encode (%pd2, err=%i)\n", dentry, err); diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 9c42a30317d5..64a18913b1d6 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -32,10 +32,6 @@ int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry, if (err) return err; - err = ovl_want_write(dentry); - if (err) - goto out; - if (attr->ia_valid & ATTR_SIZE) { /* Truncate should trigger data copy up as well */ full_copy_up = true; @@ -54,7 +50,7 @@ int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry, winode = d_inode(upperdentry); err = get_write_access(winode); if (err) - goto out_drop_write; + goto out; } if (attr->ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID)) @@ -78,6 +74,10 @@ int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry, */ attr->ia_valid &= ~ATTR_OPEN; + err = ovl_want_write(dentry); + if (err) + goto out_put_write; + inode_lock(upperdentry->d_inode); old_cred = ovl_override_creds(dentry->d_sb); err = ovl_do_notify_change(ofs, upperdentry, attr); @@ -85,12 +85,12 @@ int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry, if (!err) ovl_copyattr(dentry->d_inode); inode_unlock(upperdentry->d_inode); + ovl_drop_write(dentry); +out_put_write: if (winode) put_write_access(winode); } -out_drop_write: - ovl_drop_write(dentry); out: return err; } @@ -361,27 +361,27 @@ int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, struct path realpath; const struct cred *old_cred; - err = ovl_want_write(dentry); - if (err) - goto out; - if (!value && !upperdentry) { ovl_path_lower(dentry, &realpath); old_cred = ovl_override_creds(dentry->d_sb); err = vfs_getxattr(mnt_idmap(realpath.mnt), realdentry, name, NULL, 0); revert_creds(old_cred); if (err < 0) - goto out_drop_write; + goto out; } if (!upperdentry) { err = ovl_copy_up(dentry); if (err) - goto out_drop_write; + goto out; realdentry = ovl_dentry_upper(dentry); } + err = ovl_want_write(dentry); + if (err) + goto out; + old_cred = ovl_override_creds(dentry->d_sb); if (value) { err = ovl_do_setxattr(ofs, realdentry, name, value, size, @@ -391,12 +391,10 @@ int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, err = ovl_do_removexattr(ofs, realdentry, name); } revert_creds(old_cred); + ovl_drop_write(dentry); /* copy c/mtime */ ovl_copyattr(inode); - -out_drop_write: - ovl_drop_write(dentry); out: return err; } @@ -611,10 +609,6 @@ static int ovl_set_or_remove_acl(struct dentry *dentry, struct inode *inode, struct dentry *upperdentry = ovl_dentry_upper(dentry); struct dentry *realdentry = upperdentry ?: ovl_dentry_lower(dentry); - err = ovl_want_write(dentry); - if (err) - return err; - /* * If ACL is to be removed from a lower file, check if it exists in * the first place before copying it up. @@ -630,7 +624,7 @@ static int ovl_set_or_remove_acl(struct dentry *dentry, struct inode *inode, revert_creds(old_cred); if (IS_ERR(real_acl)) { err = PTR_ERR(real_acl); - goto out_drop_write; + goto out; } posix_acl_release(real_acl); } @@ -638,23 +632,26 @@ static int ovl_set_or_remove_acl(struct dentry *dentry, struct inode *inode, if (!upperdentry) { err = ovl_copy_up(dentry); if (err) - goto out_drop_write; + goto out; realdentry = ovl_dentry_upper(dentry); } + err = ovl_want_write(dentry); + if (err) + goto out; + old_cred = ovl_override_creds(dentry->d_sb); if (acl) err = ovl_do_set_acl(ofs, realdentry, acl_name, acl); else err = ovl_do_remove_acl(ofs, realdentry, acl_name); revert_creds(old_cred); + ovl_drop_write(dentry); /* copy c/mtime */ ovl_copyattr(inode); - -out_drop_write: - ovl_drop_write(dentry); +out: return err; } @@ -782,14 +779,14 @@ int ovl_fileattr_set(struct mnt_idmap *idmap, unsigned int flags; int err; - err = ovl_want_write(dentry); - if (err) - goto out; - err = ovl_copy_up(dentry); if (!err) { ovl_path_real(dentry, &upperpath); + err = ovl_want_write(dentry); + if (err) + goto out; + old_cred = ovl_override_creds(inode->i_sb); /* * Store immutable/append-only flags in xattr and clear them @@ -802,6 +799,7 @@ int ovl_fileattr_set(struct mnt_idmap *idmap, if (!err) err = ovl_real_fileattr_set(&upperpath, fa); revert_creds(old_cred); + ovl_drop_write(dentry); /* * Merge real inode flags with inode flags read from @@ -816,7 +814,6 @@ int ovl_fileattr_set(struct mnt_idmap *idmap, /* Update ctime */ ovl_copyattr(inode); } - ovl_drop_write(dentry); out: return err; } diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c index f543956d23b4..e9e867119f34 100644 --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -679,16 +679,26 @@ int ovl_copy_up_start(struct dentry *dentry, int flags) int err; err = ovl_inode_lock_interruptible(inode); - if (!err && ovl_already_copied_up_locked(dentry, flags)) { + if (err) + return err; + + if (ovl_already_copied_up_locked(dentry, flags)) err = 1; /* Already copied up */ - ovl_inode_unlock(inode); - } + else + err = ovl_want_write(dentry); + if (err) + goto out_unlock; + + return 0; +out_unlock: + ovl_inode_unlock(inode); return err; } void ovl_copy_up_end(struct dentry *dentry) { + ovl_drop_write(dentry); ovl_inode_unlock(d_inode(dentry)); } @@ -1091,8 +1101,12 @@ int ovl_nlink_start(struct dentry *dentry) if (err) return err; + err = ovl_want_write(dentry); + if (err) + goto out_unlock; + if (d_is_dir(dentry) || !ovl_test_flag(OVL_INDEX, inode)) - goto out; + return 0; old_cred = ovl_override_creds(dentry->d_sb); /* @@ -1103,10 +1117,15 @@ int ovl_nlink_start(struct dentry *dentry) */ err = ovl_set_nlink_upper(dentry); revert_creds(old_cred); - -out: if (err) - ovl_inode_unlock(inode); + goto out_drop_write; + + return 0; + +out_drop_write: + ovl_drop_write(dentry); +out_unlock: + ovl_inode_unlock(inode); return err; } @@ -1123,6 +1142,7 @@ void ovl_nlink_end(struct dentry *dentry) revert_creds(old_cred); } + ovl_drop_write(dentry); ovl_inode_unlock(inode); } -- 2.39.2