Commit c6be2bd0 authored by Jeffle Xu's avatar Jeffle Xu Committed by Gao Xiang
Browse files

erofs: register fscache volume 



A new fscache based mode is going to be introduced for erofs, in which
case on-demand read semantics is implemented through fscache.

As the first step, register fscache volume for each erofs filesystem.
That means, data blobs can not be shared among erofs filesystems. In the
following iteration, we are going to introduce the domain semantics, in
which case several erofs filesystems can belong to one domain, and data
blobs can be shared among these erofs filesystems of one domain.

Signed-off-by: default avatarJeffle Xu <jefflexu@linux.alibaba.com>
Reviewed-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220425122143.56815-12-jefflexu@linux.alibaba.com


Acked-by: default avatarChao Yu <chao@kernel.org>
Signed-off-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
parent 93b856bb

fs/erofs/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -98,3 +98,13 @@ config EROFS_FS_ZIP_LZMA 
	  systems will be readable without selecting this option.



	  If unsure, say N.



config EROFS_FS_ONDEMAND

	bool "EROFS fscache-based on-demand read support"

	depends on CACHEFILES_ONDEMAND && (EROFS_FS=m && FSCACHE || EROFS_FS=y && FSCACHE=y)

	default n

	help

	  This permits EROFS to use fscache-backed data blobs with on-demand

	  read support.



	  If unsure, say N.

fs/erofs/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -5,3 +5,4 @@ erofs-objs := super.o inode.o data.o namei.o dir.o utils.o pcpubuf.o sysfs.o 
erofs-$(CONFIG_EROFS_FS_XATTR) += xattr.o

erofs-$(CONFIG_EROFS_FS_ZIP) += decompressor.o zmap.o zdata.o

erofs-$(CONFIG_EROFS_FS_ZIP_LZMA) += decompressor_lzma.o

erofs-$(CONFIG_EROFS_FS_ONDEMAND) += fscache.o

fs/erofs/fscache.c

0 → 100644
+37 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-or-later

/*

 * Copyright (C) 2022, Alibaba Cloud

 */

#include <linux/fscache.h>

#include "internal.h"



int erofs_fscache_register_fs(struct super_block *sb)

{

	struct erofs_sb_info *sbi = EROFS_SB(sb);

	struct fscache_volume *volume;

	char *name;

	int ret = 0;



	name = kasprintf(GFP_KERNEL, "erofs,%s", sbi->opt.fsid);

	if (!name)

		return -ENOMEM;



	volume = fscache_acquire_volume(name, NULL, NULL, 0);

	if (IS_ERR_OR_NULL(volume)) {

		erofs_err(sb, "failed to register volume for %s", name);

		ret = volume ? PTR_ERR(volume) : -EOPNOTSUPP;

		volume = NULL;

	}



	sbi->volume = volume;

	kfree(name);

	return ret;

}



void erofs_fscache_unregister_fs(struct super_block *sb)

{

	struct erofs_sb_info *sbi = EROFS_SB(sb);



	fscache_relinquish_volume(sbi->volume, NULL, false);

	sbi->volume = NULL;

}

fs/erofs/internal.h

+16 −0
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ struct erofs_mount_opts { 
	unsigned int max_sync_decompress_pages;

#endif

	unsigned int mount_opt;

	char *fsid;

};



struct erofs_dev_context {
@@ -146,6 +147,9 @@ struct erofs_sb_info { 
	/* sysfs support */

	struct kobject s_kobj;		/* /sys/fs/erofs/<devname> */

	struct completion s_kobj_unregister;



	/* fscache support */

	struct fscache_volume *volume;

};



#define EROFS_SB(sb) ((struct erofs_sb_info *)(sb)->s_fs_info)
@@ -593,6 +597,18 @@ static inline int z_erofs_load_lzma_config(struct super_block *sb, 
}

#endif	/* !CONFIG_EROFS_FS_ZIP */



/* fscache.c */

#ifdef CONFIG_EROFS_FS_ONDEMAND

int erofs_fscache_register_fs(struct super_block *sb);

void erofs_fscache_unregister_fs(struct super_block *sb);

#else

static inline int erofs_fscache_register_fs(struct super_block *sb)

{

	return 0;

}

static inline void erofs_fscache_unregister_fs(struct super_block *sb) {}

#endif



#define EFSCORRUPTED    EUCLEAN         /* Filesystem is corrupted */



#endif	/* __EROFS_INTERNAL_H */

fs/erofs/super.c

+5 −0
Original line number Diff line number Diff line
@@ -641,6 +641,10 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc) 
	if (erofs_is_fscache_mode(sb)) {

		sb->s_blocksize = EROFS_BLKSIZ;

		sb->s_blocksize_bits = LOG_BLOCK_SIZE;



		err = erofs_fscache_register_fs(sb);

		if (err)

			return err;

	} else {

		if (!sb_set_blocksize(sb, EROFS_BLKSIZ)) {

			erofs_err(sb, "failed to set erofs blksize");
@@ -808,6 +812,7 @@ static void erofs_kill_sb(struct super_block *sb) 


	erofs_free_dev_context(sbi->devs);

	fs_put_dax(sbi->dax_dev);

	erofs_fscache_unregister_fs(sb);

	kfree(sbi);

	sb->s_fs_info = NULL;

}