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authorMiklos Szeredi <mszeredi@redhat.com>2016-12-16 11:02:57 +0100
committerMiklos Szeredi <mszeredi@redhat.com>2016-12-16 11:02:57 +0100
commit688ea0e5a0e2278e2fcd0014324ab1ba68e70ad7 (patch)
treee3e8c4924f694e485253ee5a2b512b30b4bcef7a /fs/overlayfs
parentd15951198eaccb92c6b49e62cb72f5ff62da2236 (diff)
downloadblackbird-op-linux-688ea0e5a0e2278e2fcd0014324ab1ba68e70ad7.tar.gz
blackbird-op-linux-688ea0e5a0e2278e2fcd0014324ab1ba68e70ad7.zip
ovl: allow redirect_dir to default to "on"
This patch introduces a kernel config option and a module param. Both can be used independently to turn the default value of redirect_dir on or off. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/overlayfs')
-rw-r--r--fs/overlayfs/Kconfig14
-rw-r--r--fs/overlayfs/super.c5
2 files changed, 19 insertions, 0 deletions
diff --git a/fs/overlayfs/Kconfig b/fs/overlayfs/Kconfig
index 34355818a2e0..0daac5112f7a 100644
--- a/fs/overlayfs/Kconfig
+++ b/fs/overlayfs/Kconfig
@@ -8,3 +8,17 @@ config OVERLAY_FS
merged with the 'upper' object.
For more information see Documentation/filesystems/overlayfs.txt
+
+config OVERLAY_FS_REDIRECT_DIR
+ bool "Overlayfs: turn on redirect dir feature by default"
+ depends on OVERLAY_FS
+ help
+ If this config option is enabled then overlay filesystems will use
+ redirects when renaming directories by default. In this case it is
+ still possible to turn off redirects globally with the
+ "redirect_dir=off" module option or on a filesystem instance basis
+ with the "redirect_dir=off" mount option.
+
+ Note, that redirects are not backward compatible. That is, mounting
+ an overlay which has redirects on a kernel that doesn't support this
+ feature will have unexpected results.
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 520f9ab0e9ef..2750aef24d16 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -28,6 +28,10 @@ struct ovl_dir_cache;
#define OVL_MAX_STACK 500
+static bool ovl_redirect_dir_def = IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_DIR);
+module_param_named(redirect_dir, ovl_redirect_dir_def, bool, 0644);
+MODULE_PARM_DESC(ovl_redirect_dir_def,
+ "Default to on or off for the redirect_dir feature");
static void ovl_dentry_release(struct dentry *dentry)
{
@@ -702,6 +706,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
if (!ufs)
goto out;
+ ufs->config.redirect_dir = ovl_redirect_dir_def;
err = ovl_parse_opt((char *) data, &ufs->config);
if (err)
goto out_free_config;
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