diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2018-04-09 12:48:05 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-04-09 12:48:05 -0700 |
commit | fd3b36d275660c905da9900b078eea341847d5e4 (patch) | |
tree | 687872bfb4e3dce727d6bab3e8799cd67d4d5108 /fs/namei.c | |
parent | 8ea4a5d84e6c44b3508599fe114ea806e63985a4 (diff) | |
parent | 30ce4d1903e1d8a7ccd110860a5eef3c638ed8be (diff) | |
download | op-kernel-dev-fd3b36d275660c905da9900b078eea341847d5e4.zip op-kernel-dev-fd3b36d275660c905da9900b078eea341847d5e4.tar.gz |
Merge branch 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs namei updates from Al Viro:
- make lookup_one_len() safe with parent locked only shared(incoming
afs series wants that)
- fix of getname_kernel() regression from 2015 (-stable fodder, that
one).
* 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
getname_kernel() needs to make sure that ->name != ->iname in long case
make lookup_one_len() safe to use with directory locked shared
new helper: __lookup_slow()
merge common parts of lookup_one_len{,_unlocked} into common helper
Diffstat (limited to 'fs/namei.c')
-rw-r--r-- | fs/namei.c | 124 |
1 files changed, 57 insertions, 67 deletions
@@ -224,9 +224,10 @@ getname_kernel(const char * filename) if (len <= EMBEDDED_NAME_MAX) { result->name = (char *)result->iname; } else if (len <= PATH_MAX) { + const size_t size = offsetof(struct filename, iname[1]); struct filename *tmp; - tmp = kmalloc(sizeof(*tmp), GFP_KERNEL); + tmp = kmalloc(size, GFP_KERNEL); if (unlikely(!tmp)) { __putname(result); return ERR_PTR(-ENOMEM); @@ -1597,22 +1598,21 @@ static int lookup_fast(struct nameidata *nd, } /* Fast lookup failed, do it the slow way */ -static struct dentry *lookup_slow(const struct qstr *name, - struct dentry *dir, - unsigned int flags) +static struct dentry *__lookup_slow(const struct qstr *name, + struct dentry *dir, + unsigned int flags) { - struct dentry *dentry = ERR_PTR(-ENOENT), *old; + struct dentry *dentry, *old; struct inode *inode = dir->d_inode; DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); - inode_lock_shared(inode); /* Don't go there if it's already dead */ if (unlikely(IS_DEADDIR(inode))) - goto out; + return ERR_PTR(-ENOENT); again: dentry = d_alloc_parallel(dir, name, &wq); if (IS_ERR(dentry)) - goto out; + return dentry; if (unlikely(!d_in_lookup(dentry))) { if (!(flags & LOOKUP_NO_REVAL)) { int error = d_revalidate(dentry, flags); @@ -1634,11 +1634,21 @@ again: dentry = old; } } -out: - inode_unlock_shared(inode); return dentry; } +static struct dentry *lookup_slow(const struct qstr *name, + struct dentry *dir, + unsigned int flags) +{ + struct inode *inode = dir->d_inode; + struct dentry *res; + inode_lock_shared(inode); + res = __lookup_slow(name, dir, flags); + inode_unlock_shared(inode); + return res; +} + static inline int may_lookup(struct nameidata *nd) { if (nd->flags & LOOKUP_RCU) { @@ -2421,56 +2431,63 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt, } EXPORT_SYMBOL(vfs_path_lookup); -/** - * lookup_one_len - filesystem helper to lookup single pathname component - * @name: pathname component to lookup - * @base: base directory to lookup from - * @len: maximum length @len should be interpreted to - * - * Note that this routine is purely a helper for filesystem usage and should - * not be called by generic code. - * - * The caller must hold base->i_mutex. - */ -struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) +static int lookup_one_len_common(const char *name, struct dentry *base, + int len, struct qstr *this) { - struct qstr this; - unsigned int c; - int err; - - WARN_ON_ONCE(!inode_is_locked(base->d_inode)); - - this.name = name; - this.len = len; - this.hash = full_name_hash(base, name, len); + this->name = name; + this->len = len; + this->hash = full_name_hash(base, name, len); if (!len) - return ERR_PTR(-EACCES); + return -EACCES; if (unlikely(name[0] == '.')) { if (len < 2 || (len == 2 && name[1] == '.')) - return ERR_PTR(-EACCES); + return -EACCES; } while (len--) { - c = *(const unsigned char *)name++; + unsigned int c = *(const unsigned char *)name++; if (c == '/' || c == '\0') - return ERR_PTR(-EACCES); + return -EACCES; } /* * See if the low-level filesystem might want * to use its own hash.. */ if (base->d_flags & DCACHE_OP_HASH) { - int err = base->d_op->d_hash(base, &this); + int err = base->d_op->d_hash(base, this); if (err < 0) - return ERR_PTR(err); + return err; } - err = inode_permission(base->d_inode, MAY_EXEC); + return inode_permission(base->d_inode, MAY_EXEC); +} + +/** + * lookup_one_len - filesystem helper to lookup single pathname component + * @name: pathname component to lookup + * @base: base directory to lookup from + * @len: maximum length @len should be interpreted to + * + * Note that this routine is purely a helper for filesystem usage and should + * not be called by generic code. + * + * The caller must hold base->i_mutex. + */ +struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) +{ + struct dentry *dentry; + struct qstr this; + int err; + + WARN_ON_ONCE(!inode_is_locked(base->d_inode)); + + err = lookup_one_len_common(name, base, len, &this); if (err) return ERR_PTR(err); - return __lookup_hash(&this, base, 0); + dentry = lookup_dcache(&this, base, 0); + return dentry ? dentry : __lookup_slow(&this, base, 0); } EXPORT_SYMBOL(lookup_one_len); @@ -2490,37 +2507,10 @@ struct dentry *lookup_one_len_unlocked(const char *name, struct dentry *base, int len) { struct qstr this; - unsigned int c; int err; struct dentry *ret; - this.name = name; - this.len = len; - this.hash = full_name_hash(base, name, len); - if (!len) - return ERR_PTR(-EACCES); - - if (unlikely(name[0] == '.')) { - if (len < 2 || (len == 2 && name[1] == '.')) - return ERR_PTR(-EACCES); - } - - while (len--) { - c = *(const unsigned char *)name++; - if (c == '/' || c == '\0') - return ERR_PTR(-EACCES); - } - /* - * See if the low-level filesystem might want - * to use its own hash.. - */ - if (base->d_flags & DCACHE_OP_HASH) { - int err = base->d_op->d_hash(base, &this); - if (err < 0) - return ERR_PTR(err); - } - - err = inode_permission(base->d_inode, MAY_EXEC); + err = lookup_one_len_common(name, base, len, &this); if (err) return ERR_PTR(err); |