| Message ID | 1563758631-29550-3-git-send-email-jsimmons@infradead.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ldiskfs patches against 5.2-rc2+ | expand |
On Sun, Jul 21 2019, James Simmons wrote: > From: James Simmons <uja.ornl@yahoo.com> > > Really old bug that might not even exist anymore? If there is a bug, it is somewhere else. ext4_lookup() should never be called on "." or "..". Whatever calls ext4_lookup must filter those out if there are a possibility. NeilBrown > > Signed-off-by: James Simmons <jsimmons@infradead.org> > --- > fs/ext4/namei.c | 29 +++++++++++++++++++++++++++++ > 1 file changed, 29 insertions(+) > > diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c > index cd01c4a..a616f58 100644 > --- a/fs/ext4/namei.c > +++ b/fs/ext4/namei.c > @@ -1664,6 +1664,35 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsi > } > } > > + /* ".." shouldn't go into dcache to preserve dcache hierarchy > + * otherwise we'll get parent being a child of actual child. > + * see bug 10458 for details -bzzz > + */ > + if (inode && (dentry->d_name.name[0] == '.' && > + (dentry->d_name.len == 1 || (dentry->d_name.len == 2 && > + dentry->d_name.name[1] == '.')))) { > + struct dentry *goal = NULL; > + > + /* first, look for an existing dentry - any one is good */ > + goal = d_find_any_alias(inode); > + if (!goal) { > + spin_lock(&dentry->d_lock); > + /* there is no alias, we need to make current dentry: > + * a) inaccessible for __d_lookup() > + * b) inaccessible for iopen > + */ > + J_ASSERT(hlist_unhashed(&dentry->d_u.d_alias)); > + dentry->d_flags |= DCACHE_NFSFS_RENAMED; > + /* this is d_instantiate() ... */ > + hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry); > + dentry->d_inode = inode; > + spin_unlock(&dentry->d_lock); > + } > + if (goal) > + iput(inode); > + return goal; > + } > + > #ifdef CONFIG_UNICODE > if (!inode && IS_CASEFOLDED(dir)) { > /* Eventually we want to call d_add_ci(dentry, NULL) > -- > 1.8.3.1
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index cd01c4a..a616f58 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -1664,6 +1664,35 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsi } } + /* ".." shouldn't go into dcache to preserve dcache hierarchy + * otherwise we'll get parent being a child of actual child. + * see bug 10458 for details -bzzz + */ + if (inode && (dentry->d_name.name[0] == '.' && + (dentry->d_name.len == 1 || (dentry->d_name.len == 2 && + dentry->d_name.name[1] == '.')))) { + struct dentry *goal = NULL; + + /* first, look for an existing dentry - any one is good */ + goal = d_find_any_alias(inode); + if (!goal) { + spin_lock(&dentry->d_lock); + /* there is no alias, we need to make current dentry: + * a) inaccessible for __d_lookup() + * b) inaccessible for iopen + */ + J_ASSERT(hlist_unhashed(&dentry->d_u.d_alias)); + dentry->d_flags |= DCACHE_NFSFS_RENAMED; + /* this is d_instantiate() ... */ + hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry); + dentry->d_inode = inode; + spin_unlock(&dentry->d_lock); + } + if (goal) + iput(inode); + return goal; + } + #ifdef CONFIG_UNICODE if (!inode && IS_CASEFOLDED(dir)) { /* Eventually we want to call d_add_ci(dentry, NULL)