Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszer...

[sfrench/cifs-2.6.git] / fs / overlayfs / super.c

diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 20f48abbb82fd3972cd58d7eecf09a2b37a70579..c9e70d39c1ea1cafd730be5caaea6924a29e7c58 100644 (file)
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -7,6 +7,7 @@
  * the Free Software Foundation.
  */
 
+#include <uapi/linux/magic.h>
 #include <linux/fs.h>
 #include <linux/namei.h>
 #include <linux/xattr.h>
@@ -160,6 +161,25 @@ static void ovl_put_super(struct super_block *sb)
        kfree(ufs);
 }
 
+static int ovl_sync_fs(struct super_block *sb, int wait)
+{
+       struct ovl_fs *ufs = sb->s_fs_info;
+       struct super_block *upper_sb;
+       int ret;
+
+       if (!ufs->upper_mnt)
+               return 0;
+       upper_sb = ufs->upper_mnt->mnt_sb;
+       if (!upper_sb->s_op->sync_fs)
+               return 0;
+
+       /* real inodes have already been synced by sync_filesystem(ovl_sb) */
+       down_read(&upper_sb->s_umount);
+       ret = upper_sb->s_op->sync_fs(upper_sb, wait);
+       up_read(&upper_sb->s_umount);
+       return ret;
+}
+
 /**
  * ovl_statfs
  * @sb: The overlayfs super block
@@ -222,6 +242,7 @@ static int ovl_remount(struct super_block *sb, int *flags, char *data)
 
 static const struct super_operations ovl_super_operations = {
        .put_super      = ovl_put_super,
+       .sync_fs        = ovl_sync_fs,
        .statfs         = ovl_statfs,
        .show_options   = ovl_show_options,
        .remount_fs     = ovl_remount,
@@ -701,6 +722,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
        unsigned int stacklen = 0;
        unsigned int i;
        bool remote = false;
+       struct cred *cred;
        int err;
 
        err = -ENOMEM;
@@ -708,6 +730,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
        if (!ufs)
                goto out;
 
+       init_waitqueue_head(&ufs->copyup_wq);
        ufs->config.redirect_dir = ovl_redirect_dir_def;
        err = ovl_parse_opt((char *) data, &ufs->config);
        if (err)
@@ -825,6 +848,8 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
                 * creation of workdir in previous step.
                 */
                if (ufs->workdir) {
+                       struct dentry *temp;
+
                        err = ovl_check_d_type_supported(&workpath);
                        if (err < 0)
                                goto out_put_workdir;
@@ -836,6 +861,14 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
                         */
                        if (!err)
                                pr_warn("overlayfs: upper fs needs to support d_type.\n");
+
+                       /* Check if upper/work fs supports O_TMPFILE */
+                       temp = ovl_do_tmpfile(ufs->workdir, S_IFREG | 0);
+                       ufs->tmpfile = !IS_ERR(temp);
+                       if (ufs->tmpfile)
+                               dput(temp);
+                       else
+                               pr_warn("overlayfs: upper fs does not support tmpfile.\n");
                }
        }
 
@@ -870,10 +903,13 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
        else
                sb->s_d_op = &ovl_dentry_operations;
 
-       ufs->creator_cred = prepare_creds();
-       if (!ufs->creator_cred)
+       ufs->creator_cred = cred = prepare_creds();
+       if (!cred)
                goto out_put_lower_mnt;
 
+       /* Never override disk quota limits or use reserved space */
+       cap_lower(cred->cap_effective, CAP_SYS_RESOURCE);
+
        err = -ENOMEM;
        oe = ovl_alloc_entry(numlower);
        if (!oe)