immutable and bit-for-bit identical to the official golden image for
their releases due to security and other considerations and
- - hope to save some extra storage space with guaranteed end-to-end performance
- by using reduced metadata and transparent file compression, especially
- for those embedded devices with limited memory (ex, smartphone);
+ - hope to minimize extra storage space with guaranteed end-to-end performance
+ by using compact layout, transparent file compression and direct access,
+ especially for those embedded devices with limited memory and high-density
+ hosts with numerous containers;
Here is the main features of EROFS:
- Support POSIX.1e ACLs by using xattrs;
- Support transparent data compression as an option:
- LZ4 algorithm with the fixed-sized output compression for high performance.
+ LZ4 algorithm with the fixed-sized output compression for high performance;
+
+ - Multiple device support for multi-layer container images.
The following git tree provides the file system user-space tools under
development (ex, formatting tool mkfs.erofs):
dax={always,never} Use direct access (no page cache). See
Documentation/filesystems/dax.rst.
dax A legacy option which is an alias for ``dax=always``.
+device=%s Specify a path to an extra device to be used together.
=================== =========================================================
On-disk details
select FS_IOMAP
select LIBCRC32C
help
- EROFS (Enhanced Read-Only File System) is a lightweight
- read-only file system with modern designs (eg. page-sized
- blocks, inline xattrs/data, etc.) for scenarios which need
- high-performance read-only requirements, e.g. Android OS
- for mobile phones and LIVECDs.
+ EROFS (Enhanced Read-Only File System) is a lightweight read-only
+ file system with modern designs (e.g. no buffer heads, inline
+ xattrs/data, chunk-based deduplication, multiple devices, etc.) for
+ scenarios which need high-performance read-only solutions, e.g.
+ smartphones with Android OS, LiveCDs and high-density hosts with
+ numerous containers;
- It also provides fixed-sized output compression support,
- which improves storage density, keeps relatively higher
- compression ratios, which is more useful to achieve high
- performance for embedded devices with limited memory.
+ It also provides fixed-sized output compression support in order to
+ improve storage density as well as keep relatively higher compression
+ ratios and implements in-place decompression to reuse the file page
+ for compressed data temporarily with proper strategies, which is
+ quite useful to ensure guaranteed end-to-end runtime decompression
+ performance under extremely memory pressure without extra cost.
+
+ See the documentation at <file:Documentation/filesystems/erofs.rst>
+ for more details.
If unsure, say N.
erofs_off_t pos;
int err = 0;
+ map->m_deviceid = 0;
if (map->m_la >= inode->i_size) {
/* leave out-of-bound access unmapped */
map->m_flags = 0;
map->m_flags = 0;
break;
default:
- /* only one device is supported for now */
- if (idx->device_id) {
- erofs_err(sb, "invalid device id %u @ %llu for nid %llu",
- le16_to_cpu(idx->device_id),
- chunknr, vi->nid);
- err = -EFSCORRUPTED;
- goto out_unlock;
- }
+ map->m_deviceid = le16_to_cpu(idx->device_id) &
+ EROFS_SB(sb)->device_id_mask;
map->m_pa = blknr_to_addr(le32_to_cpu(idx->blkaddr));
map->m_flags = EROFS_MAP_MAPPED;
break;
return err;
}
+int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
+{
+ struct erofs_dev_context *devs = EROFS_SB(sb)->devs;
+ struct erofs_device_info *dif;
+ int id;
+
+ /* primary device by default */
+ map->m_bdev = sb->s_bdev;
+ map->m_daxdev = EROFS_SB(sb)->dax_dev;
+
+ if (map->m_deviceid) {
+ down_read(&devs->rwsem);
+ dif = idr_find(&devs->tree, map->m_deviceid - 1);
+ if (!dif) {
+ up_read(&devs->rwsem);
+ return -ENODEV;
+ }
+ map->m_bdev = dif->bdev;
+ map->m_daxdev = dif->dax_dev;
+ up_read(&devs->rwsem);
+ } else if (devs->extra_devices) {
+ down_read(&devs->rwsem);
+ idr_for_each_entry(&devs->tree, dif, id) {
+ erofs_off_t startoff, length;
+
+ if (!dif->mapped_blkaddr)
+ continue;
+ startoff = blknr_to_addr(dif->mapped_blkaddr);
+ length = blknr_to_addr(dif->blocks);
+
+ if (map->m_pa >= startoff &&
+ map->m_pa < startoff + length) {
+ map->m_pa -= startoff;
+ map->m_bdev = dif->bdev;
+ map->m_daxdev = dif->dax_dev;
+ break;
+ }
+ }
+ up_read(&devs->rwsem);
+ }
+ return 0;
+}
+
static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
unsigned int flags, struct iomap *iomap, struct iomap *srcmap)
{
int ret;
struct erofs_map_blocks map;
+ struct erofs_map_dev mdev;
map.m_la = offset;
map.m_llen = length;
if (ret < 0)
return ret;
- iomap->bdev = inode->i_sb->s_bdev;
- iomap->dax_dev = EROFS_I_SB(inode)->dax_dev;
+ mdev = (struct erofs_map_dev) {
+ .m_deviceid = map.m_deviceid,
+ .m_pa = map.m_pa,
+ };
+ ret = erofs_map_dev(inode->i_sb, &mdev);
+ if (ret)
+ return ret;
+
+ iomap->bdev = mdev.m_bdev;
+ iomap->dax_dev = mdev.m_daxdev;
iomap->offset = map.m_la;
iomap->length = map.m_llen;
iomap->flags = 0;
iomap->type = IOMAP_INLINE;
ipage = erofs_get_meta_page(inode->i_sb,
- erofs_blknr(map.m_pa));
+ erofs_blknr(mdev.m_pa));
if (IS_ERR(ipage))
return PTR_ERR(ipage);
iomap->inline_data = page_address(ipage) +
- erofs_blkoff(map.m_pa);
+ erofs_blkoff(mdev.m_pa);
iomap->private = ipage;
} else {
iomap->type = IOMAP_MAPPED;
- iomap->addr = map.m_pa;
+ iomap->addr = mdev.m_pa;
}
return 0;
}
#define EROFS_FEATURE_INCOMPAT_COMPR_CFGS 0x00000002
#define EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER 0x00000002
#define EROFS_FEATURE_INCOMPAT_CHUNKED_FILE 0x00000004
+#define EROFS_FEATURE_INCOMPAT_DEVICE_TABLE 0x00000008
#define EROFS_ALL_FEATURE_INCOMPAT \
(EROFS_FEATURE_INCOMPAT_LZ4_0PADDING | \
EROFS_FEATURE_INCOMPAT_COMPR_CFGS | \
EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER | \
- EROFS_FEATURE_INCOMPAT_CHUNKED_FILE)
+ EROFS_FEATURE_INCOMPAT_CHUNKED_FILE | \
+ EROFS_FEATURE_INCOMPAT_DEVICE_TABLE)
#define EROFS_SB_EXTSLOT_SIZE 16
+struct erofs_deviceslot {
+ union {
+ u8 uuid[16]; /* used for device manager later */
+ u8 userdata[64]; /* digest(sha256), etc. */
+ } u;
+ __le32 blocks; /* total fs blocks of this device */
+ __le32 mapped_blkaddr; /* map starting at mapped_blkaddr */
+ u8 reserved[56];
+};
+#define EROFS_DEVT_SLOT_SIZE sizeof(struct erofs_deviceslot)
+
/* erofs on-disk super block (currently 128 bytes) */
struct erofs_super_block {
__le32 magic; /* file system magic number */
/* customized sliding window size instead of 64k by default */
__le16 lz4_max_distance;
} __packed u1;
- __u8 reserved2[42];
+ __le16 extra_devices; /* # of devices besides the primary device */
+ __le16 devt_slotoff; /* startoff = devt_slotoff * devt_slotsize */
+ __u8 reserved2[38];
};
/*
/* 8-byte inode chunk indexes */
struct erofs_inode_chunk_index {
__le16 advise; /* always 0, don't care for now */
- __le16 device_id; /* back-end storage id, always 0 for now */
+ __le16 device_id; /* back-end storage id (with bits masked) */
__le32 blkaddr; /* start block address of this inode chunk */
};
/* keep in sync between 2 index structures for better extendibility */
BUILD_BUG_ON(sizeof(struct erofs_inode_chunk_index) !=
sizeof(struct z_erofs_vle_decompressed_index));
+ BUILD_BUG_ON(sizeof(struct erofs_deviceslot) != 128);
BUILD_BUG_ON(BIT(Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS) <
Z_EROFS_VLE_CLUSTER_TYPE_MAX - 1);
/* data type for filesystem-wide blocks number */
typedef u32 erofs_blk_t;
+struct erofs_device_info {
+ char *path;
+ struct block_device *bdev;
+ struct dax_device *dax_dev;
+
+ u32 blocks;
+ u32 mapped_blkaddr;
+};
+
struct erofs_mount_opts {
#ifdef CONFIG_EROFS_FS_ZIP
/* current strategy of how to use managed cache */
unsigned int mount_opt;
};
+struct erofs_dev_context {
+ struct idr tree;
+ struct rw_semaphore rwsem;
+
+ unsigned int extra_devices;
+};
+
struct erofs_fs_context {
struct erofs_mount_opts opt;
+ struct erofs_dev_context *devs;
};
/* all filesystem-wide lz4 configurations */
struct erofs_sb_info {
struct erofs_mount_opts opt; /* options */
-
#ifdef CONFIG_EROFS_FS_ZIP
/* list for all registered superblocks, mainly for shrinker */
struct list_head list;
struct erofs_sb_lz4_info lz4;
#endif /* CONFIG_EROFS_FS_ZIP */
+ struct erofs_dev_context *devs;
struct dax_device *dax_dev;
- u32 blocks;
+ u64 total_blocks;
+ u32 primarydevice_blocks;
+
u32 meta_blkaddr;
#ifdef CONFIG_EROFS_FS_XATTR
u32 xattr_blkaddr;
#endif
+ u16 device_id_mask; /* valid bits of device id to be used */
/* inode slot unit size in bit shift */
unsigned char islotbits;
EROFS_FEATURE_FUNCS(lz4_0padding, incompat, INCOMPAT_LZ4_0PADDING)
EROFS_FEATURE_FUNCS(compr_cfgs, incompat, INCOMPAT_COMPR_CFGS)
EROFS_FEATURE_FUNCS(big_pcluster, incompat, INCOMPAT_BIG_PCLUSTER)
+EROFS_FEATURE_FUNCS(device_table, incompat, INCOMPAT_DEVICE_TABLE)
EROFS_FEATURE_FUNCS(sb_chksum, compat, COMPAT_SB_CHKSUM)
/* atomic flag definitions */
erofs_off_t m_pa, m_la;
u64 m_plen, m_llen;
+ unsigned short m_deviceid;
unsigned int m_flags;
struct page *mpage;
}
#endif /* !CONFIG_EROFS_FS_ZIP */
+struct erofs_map_dev {
+ struct block_device *m_bdev;
+ struct dax_device *m_daxdev;
+
+ erofs_off_t m_pa;
+ unsigned int m_deviceid;
+};
+
/* data.c */
extern const struct file_operations erofs_file_fops;
struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr);
+int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *dev);
int erofs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
u64 start, u64 len);
}
#endif
+static int erofs_init_devices(struct super_block *sb,
+ struct erofs_super_block *dsb)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ unsigned int ondisk_extradevs;
+ erofs_off_t pos;
+ struct page *page = NULL;
+ struct erofs_device_info *dif;
+ struct erofs_deviceslot *dis;
+ void *ptr;
+ int id, err = 0;
+
+ sbi->total_blocks = sbi->primarydevice_blocks;
+ if (!erofs_sb_has_device_table(sbi))
+ ondisk_extradevs = 0;
+ else
+ ondisk_extradevs = le16_to_cpu(dsb->extra_devices);
+
+ if (ondisk_extradevs != sbi->devs->extra_devices) {
+ erofs_err(sb, "extra devices don't match (ondisk %u, given %u)",
+ ondisk_extradevs, sbi->devs->extra_devices);
+ return -EINVAL;
+ }
+ if (!ondisk_extradevs)
+ return 0;
+
+ sbi->device_id_mask = roundup_pow_of_two(ondisk_extradevs + 1) - 1;
+ pos = le16_to_cpu(dsb->devt_slotoff) * EROFS_DEVT_SLOT_SIZE;
+ down_read(&sbi->devs->rwsem);
+ idr_for_each_entry(&sbi->devs->tree, dif, id) {
+ erofs_blk_t blk = erofs_blknr(pos);
+ struct block_device *bdev;
+
+ if (!page || page->index != blk) {
+ if (page) {
+ kunmap(page);
+ unlock_page(page);
+ put_page(page);
+ }
+
+ page = erofs_get_meta_page(sb, blk);
+ if (IS_ERR(page)) {
+ up_read(&sbi->devs->rwsem);
+ return PTR_ERR(page);
+ }
+ ptr = kmap(page);
+ }
+ dis = ptr + erofs_blkoff(pos);
+
+ bdev = blkdev_get_by_path(dif->path,
+ FMODE_READ | FMODE_EXCL,
+ sb->s_type);
+ if (IS_ERR(bdev)) {
+ err = PTR_ERR(bdev);
+ goto err_out;
+ }
+ dif->bdev = bdev;
+ dif->dax_dev = fs_dax_get_by_bdev(bdev);
+ dif->blocks = le32_to_cpu(dis->blocks);
+ dif->mapped_blkaddr = le32_to_cpu(dis->mapped_blkaddr);
+ sbi->total_blocks += dif->blocks;
+ pos += EROFS_DEVT_SLOT_SIZE;
+ }
+err_out:
+ up_read(&sbi->devs->rwsem);
+ if (page) {
+ kunmap(page);
+ unlock_page(page);
+ put_page(page);
+ }
+ return err;
+}
+
static int erofs_read_superblock(struct super_block *sb)
{
struct erofs_sb_info *sbi;
sbi->sb_size);
goto out;
}
- sbi->blocks = le32_to_cpu(dsb->blocks);
+ sbi->primarydevice_blocks = le32_to_cpu(dsb->blocks);
sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
#ifdef CONFIG_EROFS_FS_XATTR
sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
ret = erofs_load_compr_cfgs(sb, dsb);
else
ret = z_erofs_load_lz4_config(sb, dsb, NULL, 0);
+ if (ret < 0)
+ goto out;
+
+ /* handle multiple devices */
+ ret = erofs_init_devices(sb, dsb);
out:
kunmap(page);
put_page(page);
Opt_cache_strategy,
Opt_dax,
Opt_dax_enum,
+ Opt_device,
Opt_err
};
erofs_param_cache_strategy),
fsparam_flag("dax", Opt_dax),
fsparam_enum("dax", Opt_dax_enum, erofs_dax_param_enums),
+ fsparam_string("device", Opt_device),
{}
};
static int erofs_fc_parse_param(struct fs_context *fc,
struct fs_parameter *param)
{
- struct erofs_fs_context *ctx __maybe_unused = fc->fs_private;
+ struct erofs_fs_context *ctx = fc->fs_private;
struct fs_parse_result result;
- int opt;
+ struct erofs_device_info *dif;
+ int opt, ret;
opt = fs_parse(fc, erofs_fs_parameters, param, &result);
if (opt < 0)
if (!erofs_fc_set_dax_mode(fc, result.uint_32))
return -EINVAL;
break;
+ case Opt_device:
+ dif = kzalloc(sizeof(*dif), GFP_KERNEL);
+ if (!dif)
+ return -ENOMEM;
+ dif->path = kstrdup(param->string, GFP_KERNEL);
+ if (!dif->path) {
+ kfree(dif);
+ return -ENOMEM;
+ }
+ down_write(&ctx->devs->rwsem);
+ ret = idr_alloc(&ctx->devs->tree, dif, 0, 0, GFP_KERNEL);
+ up_write(&ctx->devs->rwsem);
+ if (ret < 0) {
+ kfree(dif->path);
+ kfree(dif);
+ return ret;
+ }
+ ++ctx->devs->extra_devices;
+ break;
default:
return -ENOPARAM;
}
sb->s_fs_info = sbi;
sbi->opt = ctx->opt;
sbi->dax_dev = fs_dax_get_by_bdev(sb->s_bdev);
+ sbi->devs = ctx->devs;
+ ctx->devs = NULL;
+
err = erofs_read_superblock(sb);
if (err)
return err;
return 0;
}
+static int erofs_release_device_info(int id, void *ptr, void *data)
+{
+ struct erofs_device_info *dif = ptr;
+
+ fs_put_dax(dif->dax_dev);
+ if (dif->bdev)
+ blkdev_put(dif->bdev, FMODE_READ | FMODE_EXCL);
+ kfree(dif->path);
+ kfree(dif);
+ return 0;
+}
+
+static void erofs_free_dev_context(struct erofs_dev_context *devs)
+{
+ if (!devs)
+ return;
+ idr_for_each(&devs->tree, &erofs_release_device_info, NULL);
+ idr_destroy(&devs->tree);
+ kfree(devs);
+}
+
static void erofs_fc_free(struct fs_context *fc)
{
- kfree(fc->fs_private);
+ struct erofs_fs_context *ctx = fc->fs_private;
+
+ erofs_free_dev_context(ctx->devs);
+ kfree(ctx);
}
static const struct fs_context_operations erofs_context_ops = {
static int erofs_init_fs_context(struct fs_context *fc)
{
- fc->fs_private = kzalloc(sizeof(struct erofs_fs_context), GFP_KERNEL);
- if (!fc->fs_private)
- return -ENOMEM;
+ struct erofs_fs_context *ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
- /* set default mount options */
- erofs_default_options(fc->fs_private);
+ if (!ctx)
+ return -ENOMEM;
+ ctx->devs = kzalloc(sizeof(struct erofs_dev_context), GFP_KERNEL);
+ if (!ctx->devs) {
+ kfree(ctx);
+ return -ENOMEM;
+ }
+ fc->fs_private = ctx;
+ idr_init(&ctx->devs->tree);
+ init_rwsem(&ctx->devs->rwsem);
+ erofs_default_options(ctx);
fc->ops = &erofs_context_ops;
return 0;
}
sbi = EROFS_SB(sb);
if (!sbi)
return;
+
+ erofs_free_dev_context(sbi->devs);
fs_put_dax(sbi->dax_dev);
kfree(sbi);
sb->s_fs_info = NULL;
buf->f_type = sb->s_magic;
buf->f_bsize = EROFS_BLKSIZ;
- buf->f_blocks = sbi->blocks;
+ buf->f_blocks = sbi->total_blocks;
buf->f_bfree = buf->f_bavail = 0;
buf->f_files = ULLONG_MAX;
struct z_erofs_decompressqueue *q[NR_JOBQUEUES];
void *bi_private;
z_erofs_next_pcluster_t owned_head = f->clt.owned_head;
- /* since bio will be NULL, no need to initialize last_index */
+ /* bio is NULL initially, so no need to initialize last_{index,bdev} */
pgoff_t last_index;
+ struct block_device *last_bdev;
unsigned int nr_bios = 0;
struct bio *bio = NULL;
q[JQ_SUBMIT]->head = owned_head;
do {
+ struct erofs_map_dev mdev;
struct z_erofs_pcluster *pcl;
pgoff_t cur, end;
unsigned int i = 0;
pcl = container_of(owned_head, struct z_erofs_pcluster, next);
- cur = pcl->obj.index;
+ /* no device id here, thus it will always succeed */
+ mdev = (struct erofs_map_dev) {
+ .m_pa = blknr_to_addr(pcl->obj.index),
+ };
+ (void)erofs_map_dev(sb, &mdev);
+
+ cur = erofs_blknr(mdev.m_pa);
end = cur + pcl->pclusterpages;
/* close the main owned chain at first */
if (!page)
continue;
- if (bio && cur != last_index + 1) {
+ if (bio && (cur != last_index + 1 ||
+ last_bdev != mdev.m_bdev)) {
submit_bio_retry:
submit_bio(bio);
bio = NULL;
if (!bio) {
bio = bio_alloc(GFP_NOIO, BIO_MAX_VECS);
-
bio->bi_end_io = z_erofs_decompressqueue_endio;
- bio_set_dev(bio, sb->s_bdev);
+
+ bio_set_dev(bio, mdev.m_bdev);
+ last_bdev = mdev.m_bdev;
bio->bi_iter.bi_sector = (sector_t)cur <<
LOG_SECTORS_PER_BLOCK;
bio->bi_private = bi_private;
projects / platform / kernel / linux-starfive.git / commitdiff