Re: [PATCH] Overlayfs: ovl_fill_merge() should use container_of() rather than direct cast

From: Miklos Szeredi
Date: Thu Oct 30 2014 - 12:37:48 EST


On Thu, Oct 30, 2014 at 02:47:06PM +0000, David Howells wrote:
> Miklos Szeredi <miklos@xxxxxxxxxx> wrote:
>
> > Okay, but why don't we have a typed argument of actor then?
>
> You should ask that one to Al.


Subject: vfs: make first argument of dir_context.actor typed
From: Miklos Szeredi <mszeredi@xxxxxxx>

Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxx>
---
diff --git a/arch/alpha/kernel/osf_sys.c b/arch/alpha/kernel/osf_sys.c
index f9c732e18284..e51f578636a5 100644
--- a/arch/alpha/kernel/osf_sys.c
+++ b/arch/alpha/kernel/osf_sys.c
@@ -104,11 +104,12 @@ struct osf_dirent_callback {
};

static int
-osf_filldir(void *__buf, const char *name, int namlen, loff_t offset,
- u64 ino, unsigned int d_type)
+osf_filldir(struct dir_context *ctx, const char *name, int namlen,
+ loff_t offset, u64 ino, unsigned int d_type)
{
struct osf_dirent __user *dirent;
- struct osf_dirent_callback *buf = (struct osf_dirent_callback *) __buf;
+ struct osf_dirent_callback *buf =
+ container_of(ctx, struct osf_dirent_callback, ctx);
unsigned int reclen = ALIGN(NAME_OFFSET + namlen + 1, sizeof(u32));
unsigned int d_ino;

diff --git a/arch/parisc/hpux/fs.c b/arch/parisc/hpux/fs.c
index 2bedafea3d94..97a7bf8df348 100644
--- a/arch/parisc/hpux/fs.c
+++ b/arch/parisc/hpux/fs.c
@@ -56,11 +56,12 @@ struct getdents_callback {

#define NAME_OFFSET(de) ((int) ((de)->d_name - (char __user *) (de)))

-static int filldir(void * __buf, const char * name, int namlen, loff_t offset,
- u64 ino, unsigned d_type)
+static int filldir(struct dir_context *ctx, const char *name, int namlen,
+ loff_t offset, u64 ino, unsigned d_type)
{
struct hpux_dirent __user * dirent;
- struct getdents_callback * buf = (struct getdents_callback *) __buf;
+ struct getdents_callback *buf =
+ container_of(ctx, struct getdents_callback, ctx);
ino_t d_ino;
int reclen = ALIGN(NAME_OFFSET(dirent) + namlen + 1, sizeof(long));

diff --git a/drivers/staging/lustre/lustre/llite/llite_nfs.c b/drivers/staging/lustre/lustre/llite/llite_nfs.c
index ae3a12ab7fa1..243a7840457f 100644
--- a/drivers/staging/lustre/lustre/llite/llite_nfs.c
+++ b/drivers/staging/lustre/lustre/llite/llite_nfs.c
@@ -207,13 +207,15 @@ static int ll_encode_fh(struct inode *inode, __u32 *fh, int *plen,
return LUSTRE_NFS_FID;
}

-static int ll_nfs_get_name_filldir(void *cookie, const char *name, int namelen,
- loff_t hash, u64 ino, unsigned type)
+static int ll_nfs_get_name_filldir(struct dir_context *ctx, const char *name,
+ int namelen, loff_t hash, u64 ino,
+ unsigned type)
{
/* It is hack to access lde_fid for comparison with lgd_fid.
* So the input 'name' must be part of the 'lu_dirent'. */
struct lu_dirent *lde = container_of0(name, struct lu_dirent, lde_name);
- struct ll_getname_data *lgd = cookie;
+ struct ll_getname_data *lgd =
+ container_of(ctx, struct ll_getname_data, ctx);
struct lu_fid fid;

fid_le_to_cpu(&fid, &lde->lde_fid);
diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index a1645b88fe8a..5c835c2fd9d4 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -391,10 +391,11 @@ static int afs_readdir(struct file *file, struct dir_context *ctx)
* - if afs_dir_iterate_block() spots this function, it'll pass the FID
* uniquifier through dtype
*/
-static int afs_lookup_filldir(void *_cookie, const char *name, int nlen,
- loff_t fpos, u64 ino, unsigned dtype)
+static int afs_lookup_filldir(struct dir_context *ctx, const char *name,
+ int nlen, loff_t fpos, u64 ino, unsigned dtype)
{
- struct afs_lookup_cookie *cookie = _cookie;
+ struct afs_lookup_cookie *cookie =
+ container_of(ctx, struct afs_lookup_cookie, ctx);

_enter("{%s,%u},%s,%u,,%llu,%u",
cookie->name.name, cookie->name.len, name, nlen,
diff --git a/fs/compat.c b/fs/compat.c
index b13df99f3534..6fd272d455e4 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -847,10 +847,12 @@ struct compat_readdir_callback {
int result;
};

-static int compat_fillonedir(void *__buf, const char *name, int namlen,
- loff_t offset, u64 ino, unsigned int d_type)
+static int compat_fillonedir(struct dir_context *ctx, const char *name,
+ int namlen, loff_t offset, u64 ino,
+ unsigned int d_type)
{
- struct compat_readdir_callback *buf = __buf;
+ struct compat_readdir_callback *buf =
+ container_of(ctx, struct compat_readdir_callback, ctx);
struct compat_old_linux_dirent __user *dirent;
compat_ulong_t d_ino;

@@ -915,11 +917,12 @@ struct compat_getdents_callback {
int error;
};

-static int compat_filldir(void *__buf, const char *name, int namlen,
+static int compat_filldir(struct dir_context *ctx, const char *name, int namlen,
loff_t offset, u64 ino, unsigned int d_type)
{
struct compat_linux_dirent __user * dirent;
- struct compat_getdents_callback *buf = __buf;
+ struct compat_getdents_callback *buf =
+ container_of(ctx, struct compat_getdents_callback, ctx);
compat_ulong_t d_ino;
int reclen = ALIGN(offsetof(struct compat_linux_dirent, d_name) +
namlen + 2, sizeof(compat_long_t));
@@ -1001,11 +1004,13 @@ struct compat_getdents_callback64 {
int error;
};

-static int compat_filldir64(void * __buf, const char * name, int namlen, loff_t offset,
- u64 ino, unsigned int d_type)
+static int compat_filldir64(struct dir_context *ctx, const char *name,
+ int namlen, loff_t offset, u64 ino,
+ unsigned int d_type)
{
struct linux_dirent64 __user *dirent;
- struct compat_getdents_callback64 *buf = __buf;
+ struct compat_getdents_callback64 *buf =
+ container_of(ctx, struct compat_getdents_callback64, ctx);
int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
sizeof(u64));
u64 off;
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index f5bce9096555..80154ec4f8c2 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -75,11 +75,11 @@ struct ecryptfs_getdents_callback {

/* Inspired by generic filldir in fs/readdir.c */
static int
-ecryptfs_filldir(void *dirent, const char *lower_name, int lower_namelen,
- loff_t offset, u64 ino, unsigned int d_type)
+ecryptfs_filldir(struct dir_context *ctx, const char *lower_name,
+ int lower_namelen, loff_t offset, u64 ino, unsigned int d_type)
{
struct ecryptfs_getdents_callback *buf =
- (struct ecryptfs_getdents_callback *)dirent;
+ container_of(ctx, struct ecryptfs_getdents_callback, ctx);
size_t name_size;
char *name;
int rc;
diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index b01fbfb51f43..a2b350ddd402 100644
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -241,10 +241,11 @@ struct getdents_callback {
* A rather strange filldir function to capture
* the name matching the specified inode number.
*/
-static int filldir_one(void * __buf, const char * name, int len,
+static int filldir_one(struct dir_context *ctx, const char *name, int len,
loff_t pos, u64 ino, unsigned int d_type)
{
- struct getdents_callback *buf = __buf;
+ struct getdents_callback *buf =
+ container_of(ctx, struct getdents_callback, ctx);
int result = 0;

buf->sequence++;
diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index 3963ede84eb0..c5d6bb939d19 100644
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c
@@ -702,10 +702,11 @@ static int fat_readdir(struct file *file, struct dir_context *ctx)
}

#define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type) \
-static int func(void *__buf, const char *name, int name_len, \
+static int func(struct dir_context *ctx, const char *name, int name_len, \
loff_t offset, u64 ino, unsigned int d_type) \
{ \
- struct fat_ioctl_filldir_callback *buf = __buf; \
+ struct fat_ioctl_filldir_callback *buf = \
+ container_of(ctx, struct fat_ioctl_filldir_callback, ctx); \
struct dirent_type __user *d1 = buf->dirent; \
struct dirent_type __user *d2 = d1 + 1; \
\
diff --git a/fs/gfs2/export.c b/fs/gfs2/export.c
index 8b9b3775e2e7..c41d255b6a7b 100644
--- a/fs/gfs2/export.c
+++ b/fs/gfs2/export.c
@@ -69,10 +69,12 @@ struct get_name_filldir {
char *name;
};

-static int get_name_filldir(void *opaque, const char *name, int length,
- loff_t offset, u64 inum, unsigned int type)
+static int get_name_filldir(struct dir_context *ctx, const char *name,
+ int length, loff_t offset, u64 inum,
+ unsigned int type)
{
- struct get_name_filldir *gnfd = opaque;
+ struct get_name_filldir *gnfd =
+ container_of(ctx, struct get_name_filldir, ctx);

if (inum != gnfd->inum.no_addr)
return 0;
diff --git a/fs/hppfs/hppfs.c b/fs/hppfs/hppfs.c
index 4338ff32959d..5f2755117ce7 100644
--- a/fs/hppfs/hppfs.c
+++ b/fs/hppfs/hppfs.c
@@ -548,10 +548,11 @@ struct hppfs_dirent {
struct dentry *dentry;
};

-static int hppfs_filldir(void *d, const char *name, int size,
+static int hppfs_filldir(struct dir_context *ctx, const char *name, int size,
loff_t offset, u64 inode, unsigned int type)
{
- struct hppfs_dirent *dirent = d;
+ struct hppfs_dirent *dirent =
+ container_of(ctx, struct hppfs_dirent, ctx);

if (file_removed(dirent->dentry, name))
return 0;
diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index a25490ae6c62..0e71a0dd58ca 100644
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -245,10 +245,11 @@ struct nfs4_dir_ctx {
};

static int
-nfsd4_build_namelist(void *arg, const char *name, int namlen,
+nfsd4_build_namelist(struct dir_context *__ctx, const char *name, int namlen,
loff_t offset, u64 ino, unsigned int d_type)
{
- struct nfs4_dir_ctx *ctx = arg;
+ struct nfs4_dir_ctx *ctx =
+ container_of(__ctx, struct nfs4_dir_ctx, ctx);
struct name_list *entry;

if (namlen != HEXDIR_LEN - 1)
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 989129e2d6ea..161d2d51b6f2 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1819,10 +1819,12 @@ struct readdir_data {
int full;
};

-static int nfsd_buffered_filldir(void *__buf, const char *name, int namlen,
- loff_t offset, u64 ino, unsigned int d_type)
+static int nfsd_buffered_filldir(struct dir_context *ctx, const char *name,
+ int namlen, loff_t offset, u64 ino,
+ unsigned int d_type)
{
- struct readdir_data *buf = __buf;
+ struct readdir_data *buf =
+ container_of(ctx, struct readdir_data, ctx);
struct buffered_dirent *de = (void *)(buf->dirent + buf->used);
unsigned int reclen;

@@ -1842,7 +1844,7 @@ static int nfsd_buffered_filldir(void *__buf, const char *name, int namlen,
return 0;
}

-static __be32 nfsd_buffered_readdir(struct file *file, filldir_t func,
+static __be32 nfsd_buffered_readdir(struct file *file, nfsd_filldir_t func,
struct readdir_cd *cdp, loff_t *offsetp)
{
struct buffered_dirent *de;
@@ -1926,7 +1928,7 @@ static __be32 nfsd_buffered_readdir(struct file *file, filldir_t func,
*/
__be32
nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp,
- struct readdir_cd *cdp, filldir_t func)
+ struct readdir_cd *cdp, nfsd_filldir_t func)
{
__be32 err;
struct file *file;
diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
index c2ff3f14e5f6..b1796d6ee538 100644
--- a/fs/nfsd/vfs.h
+++ b/fs/nfsd/vfs.h
@@ -36,7 +36,7 @@
/*
* Callback function for readdir
*/
-typedef int (*nfsd_dirop_t)(struct inode *, struct dentry *, int, int);
+typedef int (*nfsd_filldir_t)(void *, const char *, int, loff_t, u64, unsigned);

/* nfsd/vfs.c */
int nfsd_racache_init(int);
@@ -95,7 +95,7 @@ __be32 nfsd_rename(struct svc_rqst *,
__be32 nfsd_unlink(struct svc_rqst *, struct svc_fh *, int type,
char *name, int len);
__be32 nfsd_readdir(struct svc_rqst *, struct svc_fh *,
- loff_t *, struct readdir_cd *, filldir_t);
+ loff_t *, struct readdir_cd *, nfsd_filldir_t);
__be32 nfsd_statfs(struct svc_rqst *, struct svc_fh *,
struct kstatfs *, int access);

diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index 0717662b4aef..c43d9b4a1ec0 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -2073,10 +2073,12 @@ struct ocfs2_empty_dir_priv {
unsigned seen_other;
unsigned dx_dir;
};
-static int ocfs2_empty_dir_filldir(void *priv, const char *name, int name_len,
- loff_t pos, u64 ino, unsigned type)
+static int ocfs2_empty_dir_filldir(struct dir_context *ctx, const char *name,
+ int name_len, loff_t pos, u64 ino,
+ unsigned type)
{
- struct ocfs2_empty_dir_priv *p = priv;
+ struct ocfs2_empty_dir_priv *p =
+ container_of(ctx, struct ocfs2_empty_dir_priv, ctx);

/*
* Check the positions of "." and ".." records to be sure
diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
index 4b0c68849b36..4f502382180f 100644
--- a/fs/ocfs2/journal.c
+++ b/fs/ocfs2/journal.c
@@ -1982,10 +1982,12 @@ struct ocfs2_orphan_filldir_priv {
struct ocfs2_super *osb;
};

-static int ocfs2_orphan_filldir(void *priv, const char *name, int name_len,
- loff_t pos, u64 ino, unsigned type)
+static int ocfs2_orphan_filldir(struct dir_context *ctx, const char *name,
+ int name_len, loff_t pos, u64 ino,
+ unsigned type)
{
- struct ocfs2_orphan_filldir_priv *p = priv;
+ struct ocfs2_orphan_filldir_priv *p =
+ container_of(ctx, struct ocfs2_orphan_filldir_priv, ctx);
struct inode *iter;

if (name_len == 1 && !strncmp(".", name, 1))
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index 910553f37aca..a5f8a81317cd 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -178,10 +178,12 @@ static void ovl_cache_put(struct ovl_dir_file *od, struct dentry *dentry)
}
}

-static int ovl_fill_merge(void *buf, const char *name, int namelen,
- loff_t offset, u64 ino, unsigned int d_type)
+static int ovl_fill_merge(struct dir_context *ctx, const char *name,
+ int namelen, loff_t offset, u64 ino,
+ unsigned int d_type)
{
- struct ovl_readdir_data *rdd = buf;
+ struct ovl_readdir_data *rdd =
+ container_of(ctx, struct ovl_readdir_data, ctx);

rdd->count++;
if (!rdd->is_merge)
diff --git a/fs/readdir.c b/fs/readdir.c
index 33fd92208cb7..dc68bf15ed28 100644
--- a/fs/readdir.c
+++ b/fs/readdir.c
@@ -74,10 +74,11 @@ struct readdir_callback {
int result;
};

-static int fillonedir(void * __buf, const char * name, int namlen, loff_t offset,
- u64 ino, unsigned int d_type)
+static int fillonedir(struct dir_context *ctx, const char *name, int namlen,
+ loff_t offset, u64 ino, unsigned int d_type)
{
- struct readdir_callback *buf = (struct readdir_callback *) __buf;
+ struct readdir_callback *buf =
+ container_of(ctx, struct readdir_callback, ctx);
struct old_linux_dirent __user * dirent;
unsigned long d_ino;

@@ -148,11 +149,12 @@ struct getdents_callback {
int error;
};

-static int filldir(void * __buf, const char * name, int namlen, loff_t offset,
- u64 ino, unsigned int d_type)
+static int filldir(struct dir_context *ctx, const char *name, int namlen,
+ loff_t offset, u64 ino, unsigned int d_type)
{
struct linux_dirent __user * dirent;
- struct getdents_callback * buf = (struct getdents_callback *) __buf;
+ struct getdents_callback *buf =
+ container_of(ctx, struct getdents_callback, ctx);
unsigned long d_ino;
int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
sizeof(long));
@@ -232,11 +234,12 @@ struct getdents_callback64 {
int error;
};

-static int filldir64(void * __buf, const char * name, int namlen, loff_t offset,
- u64 ino, unsigned int d_type)
+static int filldir64(struct dir_context ctx, const char *name, int namlen,
+ loff_t offset, u64 ino, unsigned int d_type)
{
struct linux_dirent64 __user *dirent;
- struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf;
+ struct getdents_callback64 *buf =
+ container_of(ctx, struct getdents_callback64, ctx);
int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
sizeof(u64));

diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c
index 7c36898af402..628248ce2f8b 100644
--- a/fs/reiserfs/xattr.c
+++ b/fs/reiserfs/xattr.c
@@ -188,10 +188,11 @@ struct reiserfs_dentry_buf {
};

static int
-fill_with_dentries(void *buf, const char *name, int namelen, loff_t offset,
- u64 ino, unsigned int d_type)
+fill_with_dentries(struct dir_context *ctx, const char *name, int namelen,
+ loff_t offset, u64 ino, unsigned int d_type)
{
- struct reiserfs_dentry_buf *dbuf = buf;
+ struct reiserfs_dentry_buf *dbuf =
+ container_of(ctx, struct reiserfs_dentry_buf, ctx);
struct dentry *dentry;

WARN_ON_ONCE(!mutex_is_locked(&dbuf->xadir->d_inode->i_mutex));
@@ -824,10 +825,12 @@ struct listxattr_buf {
struct dentry *dentry;
};

-static int listxattr_filler(void *buf, const char *name, int namelen,
- loff_t offset, u64 ino, unsigned int d_type)
+static int listxattr_filler(struct dir_context *ctx, const char *name,
+ int namelen, loff_t offset, u64 ino,
+ unsigned int d_type)
{
- struct listxattr_buf *b = (struct listxattr_buf *)buf;
+ struct listxattr_buf *b =
+ container_of(ctx, struct listxattr_buf, ctx);
size_t size;

if (name[0] != '.' ||
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 4e41a4a331bb..59dd37ec6a62 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1464,7 +1464,10 @@ int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags);
* This allows the kernel to read directories into kernel space or
* to have different dirent layouts depending on the binary type.
*/
-typedef int (*filldir_t)(void *, const char *, int, loff_t, u64, unsigned);
+struct dir_context;
+typedef int (*filldir_t)(struct dir_context *, const char *, int, loff_t, u64,
+ unsigned);
+
struct dir_context {
const filldir_t actor;
loff_t pos;
--
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