Commit b8e42a65 authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

ovl: get rid of redundant members in struct ovl_fs 



ofs->upper_mnt is copied to ->layers[0].mnt and ->layers[0].trap could be
used instead of a separate ->upperdir_trap.

Split the lowerdir option early to get the number of layers, then allocate
the ->layers array, and finally fill the upper and lower layers, as before.

Get rid of path_put_init() in ovl_lower_dir(), since the only caller will
take care of that.

[Colin Ian King] Fix null pointer dereference on null stack pointer on
error return found by Coverity.

Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 08f4c7c8

fs/overlayfs/ovl_entry.h

+1 −3
Original line number Diff line number Diff line
@@ -46,7 +46,6 @@ struct ovl_path { 


/* private information held for overlayfs's superblock */

struct ovl_fs {

	struct vfsmount *upper_mnt;

	unsigned int numlayer;

	/* Number of unique fs among layers including upper fs */

	unsigned int numfs;
@@ -70,7 +69,6 @@ struct ovl_fs { 
	bool workdir_locked;

	bool share_whiteout;

	/* Traps in ovl inode cache */

	struct inode *upperdir_trap;

	struct inode *workbasedir_trap;

	struct inode *workdir_trap;

	struct inode *indexdir_trap;
@@ -84,7 +82,7 @@ struct ovl_fs { 


static inline struct vfsmount *ovl_upper_mnt(struct ovl_fs *ofs)

{

	return ofs->upper_mnt;

	return ofs->layers[0].mnt;

}



static inline struct ovl_fs *OVL_FS(struct super_block *sb)

fs/overlayfs/super.c

+47 −52
Original line number Diff line number Diff line
@@ -216,7 +216,6 @@ static void ovl_free_fs(struct ovl_fs *ofs) 
	iput(ofs->workbasedir_trap);

	iput(ofs->indexdir_trap);

	iput(ofs->workdir_trap);

	iput(ofs->upperdir_trap);

	dput(ofs->whiteout);

	dput(ofs->indexdir);

	dput(ofs->workdir);
@@ -225,8 +224,7 @@ static void ovl_free_fs(struct ovl_fs *ofs) 
	dput(ofs->workbasedir);

	if (ofs->upperdir_locked)

		ovl_inuse_unlock(ovl_upper_mnt(ofs)->mnt_root);

	mntput(ofs->upper_mnt);

	for (i = 1; i < ofs->numlayer; i++) {

	for (i = 0; i < ofs->numlayer; i++) {

		iput(ofs->layers[i].trap);

		mntput(ofs->layers[i].mnt);

	}
@@ -837,11 +835,11 @@ static int ovl_lower_dir(const char *name, struct path *path, 


	err = ovl_mount_dir_noesc(name, path);

	if (err)

		goto out;

		return err;



	err = ovl_check_namelen(path, ofs, name);

	if (err)

		goto out_put;

		return err;



	*stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth);
@@ -863,11 +861,6 @@ static int ovl_lower_dir(const char *name, struct path *path, 
		ofs->xino_mode = -1;



	return 0;



out_put:

	path_put_init(path);

out:

	return err;

}



/* Workdir should not be subdir of upperdir and vice versa */
@@ -1074,7 +1067,7 @@ static int ovl_report_in_use(struct ovl_fs *ofs, const char *name) 
}



static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs,

			 struct path *upperpath)

			 struct ovl_layer *upper_layer, struct path *upperpath)

{

	struct vfsmount *upper_mnt;

	int err;
@@ -1094,7 +1087,7 @@ static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, 
	if (err)

		goto out;



	err = ovl_setup_trap(sb, upperpath->dentry, &ofs->upperdir_trap,

	err = ovl_setup_trap(sb, upperpath->dentry, &upper_layer->trap,

			     "upperdir");

	if (err)

		goto out;
@@ -1108,7 +1101,9 @@ static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, 


	/* Don't inherit atime flags */

	upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME);

	ofs->upper_mnt = upper_mnt;

	upper_layer->mnt = upper_mnt;

	upper_layer->idx = 0;

	upper_layer->fsid = 0;



	/*

	 * Inherit SB_NOSEC flag from upperdir.
@@ -1458,18 +1453,13 @@ static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path) 
}



static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs,

			  struct path *stack, unsigned int numlower)

			  struct path *stack, unsigned int numlower,

			  struct ovl_layer *layers)

{

	int err;

	unsigned int i;

	struct ovl_layer *layers;



	err = -ENOMEM;

	layers = kcalloc(numlower + 1, sizeof(struct ovl_layer), GFP_KERNEL);

	if (!layers)

		goto out;

	ofs->layers = layers;



	ofs->fs = kcalloc(numlower + 1, sizeof(struct ovl_sb), GFP_KERNEL);

	if (ofs->fs == NULL)

		goto out;
@@ -1477,11 +1467,6 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, 
	/* idx/fsid 0 are reserved for upper fs even with lower only overlay */

	ofs->numfs++;



	layers[0].mnt = ovl_upper_mnt(ofs);

	layers[0].idx = 0;

	layers[0].fsid = 0;

	ofs->numlayer = 1;



	/*

	 * All lower layers that share the same fs as upper layer, use the same

	 * pseudo_dev as upper layer.  Allocate fs[0].pseudo_dev even for lower
@@ -1579,44 +1564,30 @@ out: 
}



static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb,

					    struct ovl_fs *ofs)

				const char *lower, unsigned int numlower,

				struct ovl_fs *ofs, struct ovl_layer *layers)

{

	int err;

	char *lowertmp, *lower;

	struct path *stack = NULL;

	unsigned int stacklen, numlower = 0, i;

	unsigned int i;

	struct ovl_entry *oe;



	err = -ENOMEM;

	lowertmp = kstrdup(ofs->config.lowerdir, GFP_KERNEL);

	if (!lowertmp)

		goto out_err;



	err = -EINVAL;

	stacklen = ovl_split_lowerdirs(lowertmp);

	if (stacklen > OVL_MAX_STACK) {

		pr_err("too many lower directories, limit is %d\n",

		       OVL_MAX_STACK);

		goto out_err;

	} else if (!ofs->config.upperdir && stacklen == 1) {

	if (!ofs->config.upperdir && numlower == 1) {

		pr_err("at least 2 lowerdir are needed while upperdir nonexistent\n");

		goto out_err;

		return ERR_PTR(-EINVAL);

	} else if (!ofs->config.upperdir && ofs->config.nfs_export &&

		   ofs->config.redirect_follow) {

		pr_warn("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n");

		ofs->config.nfs_export = false;

	}



	err = -ENOMEM;

	stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL);

	stack = kcalloc(numlower, sizeof(struct path), GFP_KERNEL);

	if (!stack)

		goto out_err;

		return ERR_PTR(-ENOMEM);



	err = -EINVAL;

	lower = lowertmp;

	for (numlower = 0; numlower < stacklen; numlower++) {

		err = ovl_lower_dir(lower, &stack[numlower], ofs,

				    &sb->s_stack_depth);

	for (i = 0; i < numlower; i++) {

		err = ovl_lower_dir(lower, &stack[i], ofs, &sb->s_stack_depth);

		if (err)

			goto out_err;
@@ -1630,7 +1601,7 @@ static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, 
		goto out_err;

	}



	err = ovl_get_layers(sb, ofs, stack, numlower);

	err = ovl_get_layers(sb, ofs, stack, numlower, layers);

	if (err)

		goto out_err;
@@ -1648,7 +1619,6 @@ out: 
	for (i = 0; i < numlower; i++)

		path_put(&stack[i]);

	kfree(stack);

	kfree(lowertmp);



	return oe;
@@ -1772,7 +1742,10 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) 
	struct dentry *root_dentry;

	struct ovl_entry *oe;

	struct ovl_fs *ofs;

	struct ovl_layer *layers;

	struct cred *cred;

	char *splitlower = NULL;

	unsigned int numlower;

	int err;



	sb->s_d_op = &ovl_dentry_operations;
@@ -1804,6 +1777,26 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) 
		goto out_err;

	}



	err = -ENOMEM;

	splitlower = kstrdup(ofs->config.lowerdir, GFP_KERNEL);

	if (!splitlower)

		goto out_err;



	numlower = ovl_split_lowerdirs(splitlower);

	if (numlower > OVL_MAX_STACK) {

		pr_err("too many lower directories, limit is %d\n",

		       OVL_MAX_STACK);

		goto out_err;

	}



	layers = kcalloc(numlower + 1, sizeof(struct ovl_layer), GFP_KERNEL);

	if (!layers)

		goto out_err;



	ofs->layers = layers;

	/* Layer 0 is reserved for upper even if there's no upper */

	ofs->numlayer = 1;



	sb->s_stack_depth = 0;

	sb->s_maxbytes = MAX_LFS_FILESIZE;

	atomic_long_set(&ofs->last_ino, 1);
@@ -1825,7 +1818,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) 
			goto out_err;

		}



		err = ovl_get_upper(sb, ofs, &upperpath);

		err = ovl_get_upper(sb, ofs, &layers[0], &upperpath);

		if (err)

			goto out_err;
@@ -1840,7 +1833,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) 
		sb->s_time_gran = ovl_upper_mnt(ofs)->mnt_sb->s_time_gran;



	}

	oe = ovl_get_lowerstack(sb, ofs);

	oe = ovl_get_lowerstack(sb, splitlower, numlower, ofs, layers);

	err = PTR_ERR(oe);

	if (IS_ERR(oe))

		goto out_err;
@@ -1903,6 +1896,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) 
		goto out_free_oe;



	mntput(upperpath.mnt);

	kfree(splitlower);



	sb->s_root = root_dentry;
@@ -1912,6 +1906,7 @@ out_free_oe: 
	ovl_entry_stack_free(oe);

	kfree(oe);

out_err:

	kfree(splitlower);

	path_put(&upperpath);

	ovl_free_fs(ofs);

out:

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