Unverified Commit 93570c65 authored by Joanne Koong's avatar Joanne Koong Committed by Christian Brauner
Browse files

fuse: remove fc->blkbits workaround for partial writes 



Now that fuse is integrated with iomap for read/readahead, we can remove
the workaround that was added in commit bd24d210 ("fuse: fix fuseblk
i_blkbits for iomap partial writes"), which was previously needed to
avoid a race condition where an iomap partial write may be overwritten
by a read if blocksize < PAGE_SIZE. Now that fuse does iomap
read/readahead, this is protected against since there is granular
uptodate tracking of blocks, which means this workaround can be removed.

Signed-off-by: default avatarJoanne Koong <joannelkoong@gmail.com>
Tested-by: default avatar <syzbot@syzkaller.appspotmail.com>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 4ea90710

fs/fuse/dir.c

+1 −1
Original line number Diff line number Diff line
@@ -1192,7 +1192,7 @@ static void fuse_fillattr(struct mnt_idmap *idmap, struct inode *inode, 
	if (attr->blksize != 0)

		blkbits = ilog2(attr->blksize);

	else

		blkbits = fc->blkbits;

		blkbits = inode->i_sb->s_blocksize_bits;



	stat->blksize = 1 << blkbits;

}

fs/fuse/fuse_i.h

+0 −8
Original line number Diff line number Diff line
@@ -981,14 +981,6 @@ struct fuse_conn { 
		/* Request timeout (in jiffies). 0 = no timeout */

		unsigned int req_timeout;

	} timeout;



	/*

	 * This is a workaround until fuse uses iomap for reads.

	 * For fuseblk servers, this represents the blocksize passed in at

	 * mount time and for regular fuse servers, this is equivalent to

	 * inode->i_blkbits.

	 */

	u8 blkbits;

};



/*

fs/fuse/inode.c

+1 −12
Original line number Diff line number Diff line
@@ -291,7 +291,7 @@ void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr, 
	if (attr->blksize)

		fi->cached_i_blkbits = ilog2(attr->blksize);

	else

		fi->cached_i_blkbits = fc->blkbits;

		fi->cached_i_blkbits = inode->i_sb->s_blocksize_bits;



	/*

	 * Don't set the sticky bit in i_mode, unless we want the VFS
@@ -1838,22 +1838,11 @@ int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx) 
		err = -EINVAL;

		if (!sb_set_blocksize(sb, ctx->blksize))

			goto err;

		/*

		 * This is a workaround until fuse hooks into iomap for reads.

		 * Use PAGE_SIZE for the blocksize else if the writeback cache

		 * is enabled, buffered writes go through iomap and a read may

		 * overwrite partially written data if blocksize < PAGE_SIZE

		 */

		fc->blkbits = sb->s_blocksize_bits;

		if (ctx->blksize != PAGE_SIZE &&

		    !sb_set_blocksize(sb, PAGE_SIZE))

			goto err;

#endif

		fc->sync_fs = 1;

	} else {

		sb->s_blocksize = PAGE_SIZE;

		sb->s_blocksize_bits = PAGE_SHIFT;

		fc->blkbits = sb->s_blocksize_bits;

	}



	sb->s_subtype = ctx->subtype;