Commit c31f91c6 authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

fuse: don't allow signals to interrupt getdents copying 



When getting the directory contents, the entries are first fetched to a
kernel buffer, then they are copied to userspace with dir_emit().  This
second phase is non-blocking as long as the userspace buffer is not paged
out, making it interruptible makes zero sense.

Overload d_type as flags, since it only uses 4 bits from 32.

Reviewed-by: default avatarBernd Schubert <bschubert@ddn.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent f3cb8bd9

fs/fuse/readdir.c

+2 −2
Original line number Diff line number Diff line
@@ -120,7 +120,7 @@ static bool fuse_emit(struct file *file, struct dir_context *ctx, 
		fuse_add_dirent_to_cache(file, dirent, ctx->pos);



	return dir_emit(ctx, dirent->name, dirent->namelen, dirent->ino,

			dirent->type);

			dirent->type | FILLDIR_FLAG_NOINTR);

}



static int parse_dirfile(char *buf, size_t nbytes, struct file *file,
@@ -422,7 +422,7 @@ static enum fuse_parse_result fuse_parse_cache(struct fuse_file *ff, 
		if (ff->readdir.pos == ctx->pos) {

			res = FOUND_SOME;

			if (!dir_emit(ctx, dirent->name, dirent->namelen,

				      dirent->ino, dirent->type))

				      dirent->ino, dirent->type | FILLDIR_FLAG_NOINTR))

				return FOUND_ALL;

			ctx->pos = dirent->off;

		}

fs/readdir.c

+15 −3
Original line number Diff line number Diff line
@@ -266,6 +266,10 @@ static bool filldir(struct dir_context *ctx, const char *name, int namlen, 
	int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,

		sizeof(long));

	int prev_reclen;

	unsigned int flags = d_type;



	BUILD_BUG_ON(FILLDIR_FLAG_NOINTR & S_DT_MASK);

	d_type &= S_DT_MASK;



	buf->error = verify_dirent_name(name, namlen);

	if (unlikely(buf->error))
@@ -279,7 +283,7 @@ static bool filldir(struct dir_context *ctx, const char *name, int namlen, 
		return false;

	}

	prev_reclen = buf->prev_reclen;

	if (prev_reclen && signal_pending(current))

	if (!(flags & FILLDIR_FLAG_NOINTR) && prev_reclen && signal_pending(current))

		return false;

	dirent = buf->current_dir;

	prev = (void __user *) dirent - prev_reclen;
@@ -351,6 +355,10 @@ static bool filldir64(struct dir_context *ctx, const char *name, int namlen, 
	int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,

		sizeof(u64));

	int prev_reclen;

	unsigned int flags = d_type;



	BUILD_BUG_ON(FILLDIR_FLAG_NOINTR & S_DT_MASK);

	d_type &= S_DT_MASK;



	buf->error = verify_dirent_name(name, namlen);

	if (unlikely(buf->error))
@@ -359,7 +367,7 @@ static bool filldir64(struct dir_context *ctx, const char *name, int namlen, 
	if (reclen > buf->count)

		return false;

	prev_reclen = buf->prev_reclen;

	if (prev_reclen && signal_pending(current))

	if (!(flags & FILLDIR_FLAG_NOINTR) && prev_reclen && signal_pending(current))

		return false;

	dirent = buf->current_dir;

	prev = (void __user *)dirent - prev_reclen;
@@ -513,6 +521,10 @@ static bool compat_filldir(struct dir_context *ctx, const char *name, int namlen 
	int reclen = ALIGN(offsetof(struct compat_linux_dirent, d_name) +

		namlen + 2, sizeof(compat_long_t));

	int prev_reclen;

	unsigned int flags = d_type;



	BUILD_BUG_ON(FILLDIR_FLAG_NOINTR & S_DT_MASK);

	d_type &= S_DT_MASK;



	buf->error = verify_dirent_name(name, namlen);

	if (unlikely(buf->error))
@@ -526,7 +538,7 @@ static bool compat_filldir(struct dir_context *ctx, const char *name, int namlen 
		return false;

	}

	prev_reclen = buf->prev_reclen;

	if (prev_reclen && signal_pending(current))

	if (!(flags & FILLDIR_FLAG_NOINTR) && prev_reclen && signal_pending(current))

		return false;

	dirent = buf->current_dir;

	prev = (void __user *) dirent - prev_reclen;

include/linux/fs.h

+3 −0
Original line number Diff line number Diff line
@@ -2073,6 +2073,9 @@ struct dir_context { 
	loff_t pos;

};



/* If OR-ed with d_type, pending signals are not checked */

#define FILLDIR_FLAG_NOINTR	0x1000



/*

 * These flags let !MMU mmap() govern direct device mapping vs immediate

 * copying more easily for MAP_PRIVATE, especially for ROM filesystems.