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authorLinus Torvalds2016-03-22 13:11:15 -0700
committerLinus Torvalds2016-03-22 13:11:15 -0700
commit243d50678583100855862bc084b8b307eea67f68 (patch)
tree41beaa15e0a099211904f685c8fdb91382087656 /fs
parent9f15dec81339a76d91daebc53021daf56b8b15b9 (diff)
parent6986c012faa480fb0fda74eaae9abb22f7ad1004 (diff)
Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs updates from Miklos Szeredi: "Various fixes and tweaks" * 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: cleanup unused var in rename2 ovl: rename is_merge to is_lowest ovl: fixed coding style warning ovl: Ensure upper filesystem supports d_type ovl: Warn on copy up if a process has a R/O fd open to the lower file ovl: honor flag MS_SILENT at mount ovl: verify upper dentry before unlink and rename
Diffstat (limited to 'fs')
-rw-r--r--fs/overlayfs/copy_up.c35
-rw-r--r--fs/overlayfs/dir.c61
-rw-r--r--fs/overlayfs/overlayfs.h1
-rw-r--r--fs/overlayfs/readdir.c53
-rw-r--r--fs/overlayfs/super.c18
5 files changed, 136 insertions, 32 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index d894e7cd9a86..cc514da6f3e7 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -7,6 +7,7 @@
* the Free Software Foundation.
*/
+#include <linux/module.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/file.h>
@@ -16,10 +17,41 @@
#include <linux/uaccess.h>
#include <linux/sched.h>
#include <linux/namei.h>
+#include <linux/fdtable.h>
+#include <linux/ratelimit.h>
#include "overlayfs.h"
#define OVL_COPY_UP_CHUNK_SIZE (1 << 20)
+static bool __read_mostly ovl_check_copy_up;
+module_param_named(check_copy_up, ovl_check_copy_up, bool,
+ S_IWUSR | S_IRUGO);
+MODULE_PARM_DESC(ovl_check_copy_up,
+ "Warn on copy-up when causing process also has a R/O fd open");
+
+static int ovl_check_fd(const void *data, struct file *f, unsigned int fd)
+{
+ const struct dentry *dentry = data;
+
+ if (f->f_inode == d_inode(dentry))
+ pr_warn_ratelimited("overlayfs: Warning: Copying up %pD, but open R/O on fd %u which will cease to be coherent [pid=%d %s]\n",
+ f, fd, current->pid, current->comm);
+ return 0;
+}
+
+/*
+ * Check the fds open by this process and warn if something like the following
+ * scenario is about to occur:
+ *
+ * fd1 = open("foo", O_RDONLY);
+ * fd2 = open("foo", O_RDWR);
+ */
+static void ovl_do_check_copy_up(struct dentry *dentry)
+{
+ if (ovl_check_copy_up)
+ iterate_fd(current->files, 0, ovl_check_fd, dentry);
+}
+
int ovl_copy_xattr(struct dentry *old, struct dentry *new)
{
ssize_t list_size, size, value_size = 0;
@@ -235,6 +267,7 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
if (S_ISREG(stat->mode)) {
struct path upperpath;
+
ovl_path_upper(dentry, &upperpath);
BUG_ON(upperpath.dentry != NULL);
upperpath.dentry = newdentry;
@@ -309,6 +342,8 @@ int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
if (WARN_ON(!workdir))
return -EROFS;
+ ovl_do_check_copy_up(lowerpath->dentry);
+
ovl_path_upper(parent, &parentpath);
upperdir = parentpath.dentry;
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 52f6de5d40a9..b3fc0a35bf62 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -596,21 +596,25 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
{
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
struct inode *dir = upperdir->d_inode;
- struct dentry *upper = ovl_dentry_upper(dentry);
+ struct dentry *upper;
int err;
inode_lock_nested(dir, I_MUTEX_PARENT);
+ upper = lookup_one_len(dentry->d_name.name, upperdir,
+ dentry->d_name.len);
+ err = PTR_ERR(upper);
+ if (IS_ERR(upper))
+ goto out_unlock;
+
err = -ESTALE;
- if (upper->d_parent == upperdir) {
- /* Don't let d_delete() think it can reset d_inode */
- dget(upper);
+ if (upper == ovl_dentry_upper(dentry)) {
if (is_dir)
err = vfs_rmdir(dir, upper);
else
err = vfs_unlink(dir, upper, NULL);
- dput(upper);
ovl_dentry_version_inc(dentry->d_parent);
}
+ dput(upper);
/*
* Keeping this dentry hashed would mean having to release
@@ -620,6 +624,7 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
*/
if (!err)
d_drop(dentry);
+out_unlock:
inode_unlock(dir);
return err;
@@ -714,7 +719,6 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old,
struct dentry *trap;
bool old_opaque;
bool new_opaque;
- bool new_create = false;
bool cleanup_whiteout = false;
bool overwrite = !(flags & RENAME_EXCHANGE);
bool is_dir = d_is_dir(old);
@@ -840,29 +844,38 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old,
trap = lock_rename(new_upperdir, old_upperdir);
- olddentry = ovl_dentry_upper(old);
- newdentry = ovl_dentry_upper(new);
- if (newdentry) {
+
+ olddentry = lookup_one_len(old->d_name.name, old_upperdir,
+ old->d_name.len);
+ err = PTR_ERR(olddentry);
+ if (IS_ERR(olddentry))
+ goto out_unlock;
+
+ err = -ESTALE;
+ if (olddentry != ovl_dentry_upper(old))
+ goto out_dput_old;
+
+ newdentry = lookup_one_len(new->d_name.name, new_upperdir,
+ new->d_name.len);
+ err = PTR_ERR(newdentry);
+ if (IS_ERR(newdentry))
+ goto out_dput_old;
+
+ err = -ESTALE;
+ if (ovl_dentry_upper(new)) {
if (opaquedir) {
- newdentry = opaquedir;
- opaquedir = NULL;
+ if (newdentry != opaquedir)
+ goto out_dput;
} else {
- dget(newdentry);
+ if (newdentry != ovl_dentry_upper(new))
+ goto out_dput;
}
} else {
- new_create = true;
- newdentry = lookup_one_len(new->d_name.name, new_upperdir,
- new->d_name.len);
- err = PTR_ERR(newdentry);
- if (IS_ERR(newdentry))
- goto out_unlock;
+ if (!d_is_negative(newdentry) &&
+ (!new_opaque || !ovl_is_whiteout(newdentry)))
+ goto out_dput;
}
- err = -ESTALE;
- if (olddentry->d_parent != old_upperdir)
- goto out_dput;
- if (newdentry->d_parent != new_upperdir)
- goto out_dput;
if (olddentry == trap)
goto out_dput;
if (newdentry == trap)
@@ -925,6 +938,8 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old,
out_dput:
dput(newdentry);
+out_dput_old:
+ dput(olddentry);
out_unlock:
unlock_rename(new_upperdir, old_upperdir);
out_revert_creds:
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 99b4168c36ff..6a7090f4a441 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -166,6 +166,7 @@ extern const struct file_operations ovl_dir_operations;
int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
void ovl_cache_free(struct list_head *list);
+int ovl_check_d_type_supported(struct path *realpath);
/* inode.c */
int ovl_setattr(struct dentry *dentry, struct iattr *attr);
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index fdaf28f75e12..6ec1e43a9a54 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -36,13 +36,14 @@ struct ovl_dir_cache {
struct ovl_readdir_data {
struct dir_context ctx;
- bool is_merge;
+ bool is_lowest;
struct rb_root root;
struct list_head *list;
struct list_head middle;
struct ovl_cache_entry *first_maybe_whiteout;
int count;
int err;
+ bool d_type_supported;
};
struct ovl_dir_file {
@@ -139,9 +140,9 @@ static int ovl_cache_entry_add_rb(struct ovl_readdir_data *rdd,
return 0;
}
-static int ovl_fill_lower(struct ovl_readdir_data *rdd,
- const char *name, int namelen,
- loff_t offset, u64 ino, unsigned int d_type)
+static int ovl_fill_lowest(struct ovl_readdir_data *rdd,
+ const char *name, int namelen,
+ loff_t offset, u64 ino, unsigned int d_type)
{
struct ovl_cache_entry *p;
@@ -193,10 +194,10 @@ static int ovl_fill_merge(struct dir_context *ctx, const char *name,
container_of(ctx, struct ovl_readdir_data, ctx);
rdd->count++;
- if (!rdd->is_merge)
+ if (!rdd->is_lowest)
return ovl_cache_entry_add_rb(rdd, name, namelen, ino, d_type);
else
- return ovl_fill_lower(rdd, name, namelen, offset, ino, d_type);
+ return ovl_fill_lowest(rdd, name, namelen, offset, ino, d_type);
}
static int ovl_check_whiteouts(struct dentry *dir, struct ovl_readdir_data *rdd)
@@ -289,7 +290,7 @@ static int ovl_dir_read_merged(struct dentry *dentry, struct list_head *list)
.ctx.actor = ovl_fill_merge,
.list = list,
.root = RB_ROOT,
- .is_merge = false,
+ .is_lowest = false,
};
int idx, next;
@@ -306,7 +307,7 @@ static int ovl_dir_read_merged(struct dentry *dentry, struct list_head *list)
* allows offsets to be reasonably constant
*/
list_add(&rdd.middle, rdd.list);
- rdd.is_merge = true;
+ rdd.is_lowest = true;
err = ovl_dir_read(&realpath, &rdd);
list_del(&rdd.middle);
}
@@ -577,3 +578,39 @@ void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list)
}
inode_unlock(upper->d_inode);
}
+
+static int ovl_check_d_type(struct dir_context *ctx, const char *name,
+ int namelen, loff_t offset, u64 ino,
+ unsigned int d_type)
+{
+ struct ovl_readdir_data *rdd =
+ container_of(ctx, struct ovl_readdir_data, ctx);
+
+ /* Even if d_type is not supported, DT_DIR is returned for . and .. */
+ if (!strncmp(name, ".", namelen) || !strncmp(name, "..", namelen))
+ return 0;
+
+ if (d_type != DT_UNKNOWN)
+ rdd->d_type_supported = true;
+
+ return 0;
+}
+
+/*
+ * Returns 1 if d_type is supported, 0 not supported/unknown. Negative values
+ * if error is encountered.
+ */
+int ovl_check_d_type_supported(struct path *realpath)
+{
+ int err;
+ struct ovl_readdir_data rdd = {
+ .ctx.actor = ovl_check_d_type,
+ .d_type_supported = false,
+ };
+
+ err = ovl_dir_read(realpath, &rdd);
+ if (err)
+ return err;
+
+ return rdd.d_type_supported;
+}
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 619ad4b016d2..ef64984c9bbc 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -936,7 +936,8 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
err = -EINVAL;
if (!ufs->config.lowerdir) {
- pr_err("overlayfs: missing 'lowerdir'\n");
+ if (!silent)
+ pr_err("overlayfs: missing 'lowerdir'\n");
goto out_free_config;
}
@@ -1028,6 +1029,21 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
sb->s_flags |= MS_RDONLY;
ufs->workdir = NULL;
}
+
+ /*
+ * Upper should support d_type, else whiteouts are visible.
+ * Given workdir and upper are on same fs, we can do
+ * iterate_dir() on workdir.
+ */
+ err = ovl_check_d_type_supported(&workpath);
+ if (err < 0)
+ goto out_put_workdir;
+
+ if (!err) {
+ pr_err("overlayfs: upper fs needs to support d_type.\n");
+ err = -EINVAL;
+ goto out_put_workdir;
+ }
}
err = -ENOMEM;