Merge remote-tracking branch 'jk/vfs' into work.misc

[cascardo/linux.git] / fs / overlayfs / inode.c

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 990388d..251e525 100644 (file)
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -10,6 +10,7 @@
 #include <linux/fs.h>
 #include <linux/slab.h>
 #include <linux/xattr.h>
+#include <linux/posix_acl.h>
 #include "overlayfs.h"
 
 static int ovl_copy_up_truncate(struct dentry *dentry)
@@ -191,32 +192,44 @@ static int ovl_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
        return err;
 }
 
-static bool ovl_is_private_xattr(const char *name)
+bool ovl_is_private_xattr(const char *name)
 {
-#define OVL_XATTR_PRE_NAME OVL_XATTR_PREFIX "."
-       return strncmp(name, OVL_XATTR_PRE_NAME,
-                      sizeof(OVL_XATTR_PRE_NAME) - 1) == 0;
+       return strncmp(name, OVL_XATTR_PREFIX,
+                      sizeof(OVL_XATTR_PREFIX) - 1) == 0;
 }
 
-int ovl_setxattr(struct dentry *dentry, struct inode *inode,
-                const char *name, const void *value,
-                size_t size, int flags)
+int ovl_xattr_set(struct dentry *dentry, const char *name, const void *value,
+                 size_t size, int flags)
 {
        int err;
-       struct dentry *upperdentry;
+       struct path realpath;
+       enum ovl_path_type type = ovl_path_real(dentry, &realpath);
        const struct cred *old_cred;
 
        err = ovl_want_write(dentry);
        if (err)
                goto out;
 
+       if (!value && !OVL_TYPE_UPPER(type)) {
+               err = vfs_getxattr(realpath.dentry, name, NULL, 0);
+               if (err < 0)
+                       goto out_drop_write;
+       }
+
        err = ovl_copy_up(dentry);
        if (err)
                goto out_drop_write;
 
-       upperdentry = ovl_dentry_upper(dentry);
+       if (!OVL_TYPE_UPPER(type))
+               ovl_path_upper(dentry, &realpath);
+
        old_cred = ovl_override_creds(dentry->d_sb);
-       err = vfs_setxattr(upperdentry, name, value, size, flags);
+       if (value)
+               err = vfs_setxattr(realpath.dentry, name, value, size, flags);
+       else {
+               WARN_ON(flags != XATTR_REPLACE);
+               err = vfs_removexattr(realpath.dentry, name);
+       }
        revert_creds(old_cred);
 
 out_drop_write:
@@ -225,16 +238,13 @@ out:
        return err;
 }
 
-ssize_t ovl_getxattr(struct dentry *dentry, struct inode *inode,
-                    const char *name, void *value, size_t size)
+int ovl_xattr_get(struct dentry *dentry, const char *name,
+                 void *value, size_t size)
 {
        struct dentry *realdentry = ovl_dentry_real(dentry);
        ssize_t res;
        const struct cred *old_cred;
 
-       if (ovl_is_private_xattr(name))
-               return -ENODATA;
-
        old_cred = ovl_override_creds(dentry->d_sb);
        res = vfs_getxattr(realdentry, name, value, size);
        revert_creds(old_cred);
@@ -245,7 +255,8 @@ ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
 {
        struct dentry *realdentry = ovl_dentry_real(dentry);
        ssize_t res;
-       int off;
+       size_t len;
+       char *s;
        const struct cred *old_cred;
 
        old_cred = ovl_override_creds(dentry->d_sb);
@@ -255,73 +266,39 @@ ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
                return res;
 
        /* filter out private xattrs */
-       for (off = 0; off < res;) {
-               char *s = list + off;
-               size_t slen = strlen(s) + 1;
+       for (s = list, len = res; len;) {
+               size_t slen = strnlen(s, len) + 1;
 
-               BUG_ON(off + slen > res);
+               /* underlying fs providing us with an broken xattr list? */
+               if (WARN_ON(slen > len))
+                       return -EIO;
 
+               len -= slen;
                if (ovl_is_private_xattr(s)) {
                        res -= slen;
-                       memmove(s, s + slen, res - off);
+                       memmove(s, s + slen, len);
                } else {
-                       off += slen;
+                       s += slen;
                }
        }
 
        return res;
 }
 
-int ovl_removexattr(struct dentry *dentry, const char *name)
-{
-       int err;
-       struct path realpath;
-       enum ovl_path_type type = ovl_path_real(dentry, &realpath);
-       const struct cred *old_cred;
-
-       err = ovl_want_write(dentry);
-       if (err)
-               goto out;
-
-       err = -ENODATA;
-       if (ovl_is_private_xattr(name))
-               goto out_drop_write;
-
-       if (!OVL_TYPE_UPPER(type)) {
-               err = vfs_getxattr(realpath.dentry, name, NULL, 0);
-               if (err < 0)
-                       goto out_drop_write;
-
-               err = ovl_copy_up(dentry);
-               if (err)
-                       goto out_drop_write;
-
-               ovl_path_upper(dentry, &realpath);
-       }
-
-       old_cred = ovl_override_creds(dentry->d_sb);
-       err = vfs_removexattr(realpath.dentry, name);
-       revert_creds(old_cred);
-out_drop_write:
-       ovl_drop_write(dentry);
-out:
-       return err;
-}
-
 struct posix_acl *ovl_get_acl(struct inode *inode, int type)
 {
        struct inode *realinode = ovl_inode_real(inode, NULL);
        const struct cred *old_cred;
        struct posix_acl *acl;
 
-       if (!IS_POSIXACL(realinode))
+       if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !IS_POSIXACL(realinode))
                return NULL;
 
        if (!realinode->i_op->get_acl)
                return NULL;
 
        old_cred = ovl_override_creds(inode->i_sb);
-       acl = realinode->i_op->get_acl(realinode, type);
+       acl = get_acl(realinode, type);
        revert_creds(old_cred);
 
        return acl;
@@ -391,9 +368,9 @@ static const struct inode_operations ovl_file_inode_operations = {
        .permission     = ovl_permission,
        .getattr        = ovl_getattr,
        .setxattr       = generic_setxattr,
-       .getxattr       = ovl_getxattr,
+       .getxattr       = generic_getxattr,
        .listxattr      = ovl_listxattr,
-       .removexattr    = ovl_removexattr,
+       .removexattr    = generic_removexattr,
        .get_acl        = ovl_get_acl,
        .update_time    = ovl_update_time,
 };
@@ -404,9 +381,9 @@ static const struct inode_operations ovl_symlink_inode_operations = {
        .readlink       = ovl_readlink,
        .getattr        = ovl_getattr,
        .setxattr       = generic_setxattr,
-       .getxattr       = ovl_getxattr,
+       .getxattr       = generic_getxattr,
        .listxattr      = ovl_listxattr,
-       .removexattr    = ovl_removexattr,
+       .removexattr    = generic_removexattr,
        .update_time    = ovl_update_time,
 };
 
@@ -415,6 +392,9 @@ static void ovl_fill_inode(struct inode *inode, umode_t mode)
        inode->i_ino = get_next_ino();
        inode->i_mode = mode;
        inode->i_flags |= S_NOCMTIME;
+#ifdef CONFIG_FS_POSIX_ACL
+       inode->i_acl = inode->i_default_acl = ACL_DONT_CACHE;
+#endif
 
        mode &= S_IFMT;
        switch (mode) {