Commit 25885a35 authored by Al Viro's avatar Al Viro
Browse files

Change calling conventions for filldir_t 



filldir_t instances (directory iterators callbacks) used to return 0 for
"OK, keep going" or -E... for "stop".  Note that it's *NOT* how the
error values are reported - the rules for those are callback-dependent
and ->iterate{,_shared}() instances only care about zero vs. non-zero
(look at emit_dir() and friends).

So let's just return bool ("should we keep going?") - it's less confusing
that way.  The choice between "true means keep going" and "true means
stop" is bikesheddable; we have two groups of callbacks -
	do something for everything in directory, until we run into problem
and
	find an entry in directory and do something to it.

The former tended to use 0/-E... conventions - -E<something> on failure.
The latter tended to use 0/1, 1 being "stop, we are done".
The callers treated anything non-zero as "stop", ignoring which
non-zero value did they get.

"true means stop" would be more natural for the second group; "true
means keep going" - for the first one.  I tried both variants and
the things like
	if allocation failed
		something = -ENOMEM;
		return true;
just looked unnatural and asking for trouble.

[folded suggestion from Matthew Wilcox <willy@infradead.org>]
Acked-by: default avatarChristian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent d6da19c9

Documentation/filesystems/porting.rst

+11 −0
Original line number Diff line number Diff line
@@ -922,3 +922,14 @@ is provided - file_open_root_mnt(). In-tree users adjusted. 
no_llseek is gone; don't set .llseek to that - just leave it NULL instead.

Checks for "does that file have llseek(2), or should it fail with ESPIPE"

should be done by looking at FMODE_LSEEK in file->f_mode.



---



*mandatory*



filldir_t (readdir callbacks) calling conventions have changed.  Instead of

returning 0 or -E... it returns bool now.  false means "no more" (as -E... used

to) and true - "keep going" (as 0 in old calling conventions).  Rationale:

callers never looked at specific -E... values anyway.  ->iterate() and

->iterate_shared() instance require no changes at all, all filldir_t ones in

the tree converted.

arch/alpha/kernel/osf_sys.c

+5 −5
Original line number Diff line number Diff line
@@ -108,7 +108,7 @@ struct osf_dirent_callback { 
	int error;

};



static int

static bool

osf_filldir(struct dir_context *ctx, const char *name, int namlen,

	    loff_t offset, u64 ino, unsigned int d_type)

{
@@ -120,11 +120,11 @@ osf_filldir(struct dir_context *ctx, const char *name, int namlen, 


	buf->error = -EINVAL;	/* only used if we fail */

	if (reclen > buf->count)

		return -EINVAL;

		return false;

	d_ino = ino;

	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {

		buf->error = -EOVERFLOW;

		return -EOVERFLOW;

		return false;

	}

	if (buf->basep) {

		if (put_user(offset, buf->basep))
@@ -141,10 +141,10 @@ osf_filldir(struct dir_context *ctx, const char *name, int namlen, 
	dirent = (void __user *)dirent + reclen;

	buf->dirent = dirent;

	buf->count -= reclen;

	return 0;

	return true;

Efault:

	buf->error = -EFAULT;

	return -EFAULT;

	return false;

}



SYSCALL_DEFINE4(osf_getdirentries, unsigned int, fd,

fs/afs/dir.c

+10 −13
Original line number Diff line number Diff line
@@ -24,9 +24,9 @@ static int afs_readdir(struct file *file, struct dir_context *ctx); 
static int afs_d_revalidate(struct dentry *dentry, unsigned int flags);

static int afs_d_delete(const struct dentry *dentry);

static void afs_d_iput(struct dentry *dentry, struct inode *inode);

static int afs_lookup_one_filldir(struct dir_context *ctx, const char *name, int nlen,

static bool afs_lookup_one_filldir(struct dir_context *ctx, 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,

static bool afs_lookup_filldir(struct dir_context *ctx, const char *name, int nlen,

			      loff_t fpos, u64 ino, unsigned dtype);

static int afs_create(struct user_namespace *mnt_userns, struct inode *dir,

		      struct dentry *dentry, umode_t mode, bool excl);
@@ -568,7 +568,7 @@ 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_one_filldir(struct dir_context *ctx, const char *name,

static bool afs_lookup_one_filldir(struct dir_context *ctx, const char *name,

				  int nlen, loff_t fpos, u64 ino, unsigned dtype)

{

	struct afs_lookup_one_cookie *cookie =
@@ -584,16 +584,16 @@ static int afs_lookup_one_filldir(struct dir_context *ctx, const char *name, 


	if (cookie->name.len != nlen ||

	    memcmp(cookie->name.name, name, nlen) != 0) {

		_leave(" = 0 [no]");

		return 0;

		_leave(" = true [keep looking]");

		return true;

	}



	cookie->fid.vnode = ino;

	cookie->fid.unique = dtype;

	cookie->found = 1;



	_leave(" = -1 [found]");

	return -1;

	_leave(" = false [found]");

	return false;

}



/*
@@ -636,12 +636,11 @@ static int afs_do_lookup_one(struct inode *dir, struct dentry *dentry, 
 * - if afs_dir_iterate_block() spots this function, it'll pass the FID

 *   uniquifier through dtype

 */

static int afs_lookup_filldir(struct dir_context *ctx, const char *name,

static bool afs_lookup_filldir(struct dir_context *ctx, const char *name,

			      int nlen, loff_t fpos, u64 ino, unsigned dtype)

{

	struct afs_lookup_cookie *cookie =

		container_of(ctx, struct afs_lookup_cookie, ctx);

	int ret;



	_enter("{%s,%u},%s,%u,,%llu,%u",

	       cookie->name.name, cookie->name.len, name, nlen,
@@ -663,12 +662,10 @@ static int afs_lookup_filldir(struct dir_context *ctx, const char *name, 
		cookie->fids[1].unique	= dtype;

		cookie->found = 1;

		if (cookie->one_only)

			return -1;

			return false;

	}



	ret = cookie->nr_fids >= 50 ? -1 : 0;

	_leave(" = %d", ret);

	return ret;

	return cookie->nr_fids < 50;

}



/*

fs/ecryptfs/file.c

+16 −22
Original line number Diff line number Diff line
@@ -53,7 +53,7 @@ struct ecryptfs_getdents_callback { 
};



/* Inspired by generic filldir in fs/readdir.c */

static int

static bool

ecryptfs_filldir(struct dir_context *ctx, const char *lower_name,

		 int lower_namelen, loff_t offset, u64 ino, unsigned int d_type)

{
@@ -61,18 +61,19 @@ ecryptfs_filldir(struct dir_context *ctx, const char *lower_name, 
		container_of(ctx, struct ecryptfs_getdents_callback, ctx);

	size_t name_size;

	char *name;

	int rc;

	int err;

	bool res;



	buf->filldir_called++;

	rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size,

	err = ecryptfs_decode_and_decrypt_filename(&name, &name_size,

						   buf->sb, lower_name,

						   lower_namelen);

	if (rc) {

		if (rc != -EINVAL) {

	if (err) {

		if (err != -EINVAL) {

			ecryptfs_printk(KERN_DEBUG,

					"%s: Error attempting to decode and decrypt filename [%s]; rc = [%d]\n",

					__func__, lower_name, rc);

			return rc;

					__func__, lower_name, err);

			return false;

		}



		/* Mask -EINVAL errors as these are most likely due a plaintext
@@ -81,16 +82,15 @@ ecryptfs_filldir(struct dir_context *ctx, const char *lower_name, 
		 * the "lost+found" dentry in the root directory of an Ext4

		 * filesystem.

		 */

		return 0;

		return true;

	}



	buf->caller->pos = buf->ctx.pos;

	rc = !dir_emit(buf->caller, name, name_size, ino, d_type);

	res = dir_emit(buf->caller, name, name_size, ino, d_type);

	kfree(name);

	if (!rc)

	if (res)

		buf->entries_written++;



	return rc;

	return res;

}



/**
@@ -111,14 +111,8 @@ static int ecryptfs_readdir(struct file *file, struct dir_context *ctx) 
	lower_file = ecryptfs_file_to_lower(file);

	rc = iterate_dir(lower_file, &buf.ctx);

	ctx->pos = buf.ctx.pos;

	if (rc < 0)

		goto out;

	if (buf.filldir_called && !buf.entries_written)

		goto out;

	if (rc >= 0)

		fsstack_copy_attr_atime(inode,

					file_inode(lower_file));

out:

	if (rc >= 0 && (buf.entries_written || !buf.filldir_called))

		fsstack_copy_attr_atime(inode, file_inode(lower_file));

	return rc;

}

fs/exportfs/expfs.c

+3 −4
Original line number Diff line number Diff line
@@ -248,21 +248,20 @@ struct getdents_callback { 
 * A rather strange filldir function to capture

 * the name matching the specified inode number.

 */

static int filldir_one(struct dir_context *ctx, const char *name, int len,

static bool filldir_one(struct dir_context *ctx, const char *name, int len,

			loff_t pos, u64 ino, unsigned int d_type)

{

	struct getdents_callback *buf =

		container_of(ctx, struct getdents_callback, ctx);

	int result = 0;



	buf->sequence++;

	if (buf->ino == ino && len <= NAME_MAX) {

		memcpy(buf->name, name, len);

		buf->name[len] = '\0';

		buf->found = 1;

		result = -1;

		return false;	// no more

	}

	return result;

	return true;

}



/**