With NFS export, some operations on decoded file handles (e.g. open,
link, setattr, xattr_set) may call copy up with a disconnected non-dir.
In this case, we will copy up lower inode to index dir without
linking it to upper dir.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/overlayfs/copy_up.c | 56 ++++++++++++++++++++++++++++++++++++--------------
fs/overlayfs/inode.c | 4 +++-
fs/overlayfs/util.c | 7 ++++---
3 files changed, 48 insertions(+), 19 deletions(-)
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index df1ce2d5a20e..0a2c2c3743b1 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -452,7 +452,10 @@ static int ovl_link_up(struct ovl_copy_up_ctx *c)
}
}
inode_unlock(udir);
- ovl_set_nlink_upper(c->dentry);
+ if (err)
+ return err;
+
+ err = ovl_set_nlink_upper(c->dentry);
return err;
}
@@ -647,6 +650,9 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c)
err = ovl_get_index_name(c->lowerpath.dentry, &c->destname);
if (err)
return err;
+ } else if (WARN_ON(!c->parent)) {
+ /* Disconnected dentry must be copied up to index dir */
+ return -EIO;
} else {
/*
* Mark parent "impure" because it may now contain non-pure
@@ -669,12 +675,17 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c)
}
}
- if (!err && c->indexed)
+
+ if (err)
+ goto out;
+
+ if (c->indexed)
ovl_set_flag(OVL_INDEX, d_inode(c->dentry));
if (to_index) {
- kfree(c->destname.name);
- } else if (!err) {
+ /* Initialize nlink for copy up of disconnected dentry */
+ err = ovl_set_nlink_upper(c->dentry);
+ } else {
struct inode *udir = d_inode(c->destdir);
/* Restore timestamps on parent (best effort) */
@@ -685,6 +696,9 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c)
ovl_dentry_set_upper_alias(c->dentry);
}
+out:
+ if (to_index)
+ kfree(c->destname.name);
return err;
}
@@ -709,14 +723,17 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
if (err)
return err;
- ovl_path_upper(parent, &parentpath);
- ctx.destdir = parentpath.dentry;
- ctx.destname = dentry->d_name;
+ if (parent) {
+ ovl_path_upper(parent, &parentpath);
+ ctx.destdir = parentpath.dentry;
+ ctx.destname = dentry->d_name;
- err = vfs_getattr(&parentpath, &ctx.pstat,
- STATX_ATIME | STATX_MTIME, AT_STATX_SYNC_AS_STAT);
- if (err)
- return err;
+ err = vfs_getattr(&parentpath, &ctx.pstat,
+ STATX_ATIME | STATX_MTIME,
+ AT_STATX_SYNC_AS_STAT);
+ if (err)
+ return err;
+ }
/* maybe truncate regular file. this has no effect on dirs */
if (flags & O_TRUNC)
@@ -737,7 +754,7 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
} else {
if (!ovl_dentry_upper(dentry))
err = ovl_do_copy_up(&ctx);
- if (!err && !ovl_dentry_has_upper_alias(dentry))
+ if (!err && parent && !ovl_dentry_has_upper_alias(dentry))
err = ovl_link_up(&ctx);
ovl_copy_up_end(dentry);
}
@@ -750,10 +767,19 @@ int ovl_copy_up_flags(struct dentry *dentry, int flags)
{
int err = 0;
const struct cred *old_cred = ovl_override_creds(dentry->d_sb);
+ bool disconnected = (dentry->d_flags & DCACHE_DISCONNECTED);
+
+ /*
+ * With NFS export, copy up can get called for a disconnected non-dir.
+ * In this case, we will copy up lower inode to index dir without
+ * linking it to upper dir.
+ */
+ if (WARN_ON(disconnected && d_is_dir(dentry)))
+ return -EIO;
while (!err) {
struct dentry *next;
- struct dentry *parent;
+ struct dentry *parent = NULL;
/*
* Check if copy-up has happened as well as for upper alias (in
@@ -769,12 +795,12 @@ int ovl_copy_up_flags(struct dentry *dentry, int flags)
* with rename.
*/
if (ovl_dentry_upper(dentry) &&
- ovl_dentry_has_upper_alias(dentry))
+ (ovl_dentry_has_upper_alias(dentry) || disconnected))
break;
next = dget(dentry);
/* find the topmost dentry not yet copied up */
- for (;;) {
+ for (; !disconnected;) {
parent = dget_parent(next);
if (ovl_dentry_upper(parent))
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index a792c088c2b4..5959293f8e70 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -319,8 +319,10 @@ struct posix_acl *ovl_get_acl(struct inode *inode, int type)
static bool ovl_open_need_copy_up(struct dentry *dentry, int flags)
{
+ /* Copy up of disconnected dentry does not set upper alias */
if (ovl_dentry_upper(dentry) &&
- ovl_dentry_has_upper_alias(dentry))
+ (ovl_dentry_has_upper_alias(dentry) ||
+ (dentry->d_flags & DCACHE_DISCONNECTED)))
return false;
if (special_file(d_inode(dentry)->i_mode))
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 568ea4d4529d..b71c5d1af5d1 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -209,9 +209,10 @@ void ovl_dentry_set_opaque(struct dentry *dentry)
}
/*
- * For hard links it's possible for ovl_dentry_upper() to return positive, while
- * there's no actual upper alias for the inode. Copy up code needs to know
- * about the existence of the upper alias, so it can't use ovl_dentry_upper().
+ * For hard links and decoded file handles, it's possible for ovl_dentry_upper()
+ * to return positive, while there's no actual upper alias for the inode.
+ * Copy up code needs to know about the existence of the upper alias, so it
+ * can't use ovl_dentry_upper().
*/
bool ovl_dentry_has_upper_alias(struct dentry *dentry)
{
--
2.7.4
--
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