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authorAmir Goldstein <amir73il@gmail.com>2017-10-15 18:00:20 +0300
committerMiklos Szeredi <mszeredi@redhat.com>2018-01-24 11:25:58 +0100
commitaa3ff3c152ff94ef045ed802db7535167f8a21ab (patch)
treebdeb25cc1784bf8bf2862d654b8a9ea5b0134b33 /fs/overlayfs
parent829c28be9bb9a05aa7eeb8a68a4536cca2d3d694 (diff)
downloadlinux-aa3ff3c152ff94ef045ed802db7535167f8a21ab.tar.bz2
ovl: copy up of disconnected dentries
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@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/overlayfs')
-rw-r--r--fs/overlayfs/copy_up.c56
-rw-r--r--fs/overlayfs/inode.c4
-rw-r--r--fs/overlayfs/util.c7
3 files changed, 48 insertions, 19 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 8ef25d8c3cfe..d855f508fa20 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -450,7 +450,10 @@ 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;
}
@@ -655,6 +658,9 @@ 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
@@ -677,12 +683,17 @@ 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) */
@@ -693,6 +704,9 @@ 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;
}
@@ -717,14 +731,17 @@ 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)
@@ -745,7 +762,7 @@ 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);
}
@@ -758,10 +775,19 @@ 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
@@ -777,12 +803,12 @@ 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 f8f7facb7331..bfd7c766b5cd 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -351,8 +351,10 @@ 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 aa2234d52007..68541eb5be8e 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -229,9 +229,10 @@ 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)
{