Based on the original Hongbo's version [1], it enables storing the
SHA-256 digest of each inode as an extended attribute, in preparation
for the upcoming page cache sharing feature.
Example usage:
$ mkfs.erofs --xattr-inode-digest=system.erofs.fingerprint [-zlz4hc]
foo.erofs foo/
[1] https://lore.kernel.org/r/[email protected]
Co-developed-by: Hongbo Li <[email protected]>
Signed-off-by: Gao Xiang <[email protected]>
Tested-by: Hongbo Li <[email protected]>
---
v2:
https://lore.kernel.org/r/[email protected]
v3:
- Support the hidden xattr namespace, so that user programs cannot
access inode fingerprints via normal mounts in any case.
include/erofs/internal.h | 2 +
include/erofs/xattr.h | 2 +
include/erofs_fs.h | 4 +-
lib/inode.c | 46 +++++++++-
lib/super.c | 13 ++-
lib/xattr.c | 19 +++-
mkfs/main.c | 187 ++++++++++++++++++++++-----------------
7 files changed, 182 insertions(+), 91 deletions(-)
diff --git a/include/erofs/internal.h b/include/erofs/internal.h
index 26bf612..ef019a5 100644
--- a/include/erofs/internal.h
+++ b/include/erofs/internal.h
@@ -130,6 +130,7 @@ struct erofs_sb_info {
u32 xattr_prefix_start;
u8 xattr_prefix_count;
+ u8 ishare_xattr_prefix_id;
struct erofs_xattr_prefix_item *xattr_prefixes;
struct erofs_vfile bdev;
@@ -190,6 +191,7 @@ EROFS_FEATURE_FUNCS(metabox, incompat, INCOMPAT_METABOX)
EROFS_FEATURE_FUNCS(sb_chksum, compat, COMPAT_SB_CHKSUM)
EROFS_FEATURE_FUNCS(xattr_filter, compat, COMPAT_XATTR_FILTER)
EROFS_FEATURE_FUNCS(plain_xattr_pfx, compat, COMPAT_PLAIN_XATTR_PFX)
+EROFS_FEATURE_FUNCS(ishare_xattrs, compat, COMPAT_ISHARE_XATTRS)
#define EROFS_I_EA_INITED_BIT 0
#define EROFS_I_Z_INITED_BIT 1
diff --git a/include/erofs/xattr.h b/include/erofs/xattr.h
index 941bed7..9654636 100644
--- a/include/erofs/xattr.h
+++ b/include/erofs/xattr.h
@@ -33,6 +33,8 @@ char *erofs_export_xattr_ibody(struct erofs_inode *inode);
int erofs_load_shared_xattrs_from_path(struct erofs_sb_info *sbi, const char
*path,
long inlinexattr_tolerance);
int erofs_xattr_insert_name_prefix(const char *prefix);
+int erofs_xattr_set_ishare_prefix(struct erofs_sb_info *sbi,
+ const char *prefix);
void erofs_xattr_cleanup_name_prefixes(void);
int erofs_xattr_flush_name_prefixes(struct erofs_importer *im, bool plain);
int erofs_xattr_prefixes_init(struct erofs_sb_info *sbi);
diff --git a/include/erofs_fs.h b/include/erofs_fs.h
index 887f37f..8b0d155 100644
--- a/include/erofs_fs.h
+++ b/include/erofs_fs.h
@@ -17,6 +17,7 @@
#define EROFS_FEATURE_COMPAT_MTIME 0x00000002
#define EROFS_FEATURE_COMPAT_XATTR_FILTER 0x00000004
#define EROFS_FEATURE_COMPAT_PLAIN_XATTR_PFX 0x00000010
+#define EROFS_FEATURE_COMPAT_ISHARE_XATTRS 0x00000020
/*
* Any bits that aren't in EROFS_ALL_FEATURE_INCOMPAT should
@@ -82,7 +83,8 @@ struct erofs_super_block {
__le32 xattr_prefix_start; /* start of long xattr prefixes */
__le64 packed_nid; /* nid of the special packed inode */
__u8 xattr_filter_reserved; /* reserved for xattr name filter */
- __u8 reserved[3];
+ __u8 ishare_xattr_prefix_id;
+ __u8 reserved[2];
__le32 build_time; /* seconds added to epoch for mkfs time */
__le64 rootnid_8b; /* (48BIT on) nid of root directory */
__le64 reserved2;
diff --git a/lib/inode.c b/lib/inode.c
index 299ec46..e3ee79a 100644
--- a/lib/inode.c
+++ b/lib/inode.c
@@ -31,6 +31,7 @@
#include "liberofs_metabox.h"
#include "liberofs_private.h"
#include "liberofs_rebuild.h"
+#include "sha256.h"
static inline bool erofs_is_special_identifier(const char *path)
{
@@ -1954,6 +1955,37 @@ static int erofs_prepare_dir_inode(const struct
erofs_mkfs_btctx *ctx,
return 0;
}
+static int erofs_set_inode_fingerprint(struct erofs_inode *inode, int fd,
+ erofs_off_t pos)
+{
+ u8 ishare_xattr_prefix_id = inode->sbi->ishare_xattr_prefix_id;
+ erofs_off_t remaining = inode->i_size;
+ struct erofs_vfile vf = { .fd = fd };
+ struct sha256_state md;
+ u8 out[32 + sizeof("sha256:") - 1];
+ int ret;
+
+ if (!ishare_xattr_prefix_id)
+ return 0;
+ erofs_sha256_init(&md);
+ do {
+ u8 buf[32768];
+
+ ret = erofs_io_pread(&vf, buf,
+ min_t(u64, remaining, sizeof(buf)), pos);
+ if (ret < 0)
+ return ret;
+ if (ret > 0)
+ erofs_sha256_process(&md, buf, ret);
+ remaining -= ret;
+ pos += ret;
+ } while (remaining);
+ erofs_sha256_done(&md, out + sizeof("sha256:") - 1);
+ memcpy(out, "sha256:", sizeof("sha256:") - 1);
+ return erofs_setxattr(inode, ishare_xattr_prefix_id, "",
+ out, sizeof(out));
+}
+
static int erofs_mkfs_begin_nondirectory(const struct erofs_mkfs_btctx *btctx,
struct erofs_inode *inode)
{
@@ -1973,11 +2005,18 @@ static int erofs_mkfs_begin_nondirectory(const struct
erofs_mkfs_btctx *btctx,
ctx.fd = open(inode->i_srcpath, O_RDONLY | O_BINARY);
if (ctx.fd < 0)
return -errno;
- __erofs_fallthrough;
- default:
break;
+ default:
+ goto out;
}
- if (ctx.fd >= 0 && cfg.c_compr_opts[0].alg &&
+
+ if (S_ISREG(inode->i_mode) && inode->i_size) {
+ ret = erofs_set_inode_fingerprint(inode, ctx.fd, ctx.fpos);
+ if (ret < 0)
+ return ret;
+ }
+
+ if (cfg.c_compr_opts[0].alg &&
erofs_file_is_compressible(im, inode)) {
ctx.ictx = erofs_prepare_compressed_file(im, inode);
if (IS_ERR(ctx.ictx))
@@ -1989,6 +2028,7 @@ static int erofs_mkfs_begin_nondirectory(const struct
erofs_mkfs_btctx *btctx,
return ret;
}
}
+out:
return erofs_mkfs_go(btctx, EROFS_MKFS_JOB_NDIR, &ctx, sizeof(ctx));
}
diff --git a/lib/super.c b/lib/super.c
index a203f96..0180087 100644
--- a/lib/super.c
+++ b/lib/super.c
@@ -146,7 +146,15 @@ int erofs_read_superblock(struct erofs_sb_info *sbi)
sbi->build_time = le32_to_cpu(dsb->build_time);
memcpy(&sbi->uuid, dsb->uuid, sizeof(dsb->uuid));
-
+ if (erofs_sb_has_ishare_xattrs(sbi)) {
+ if (dsb->ishare_xattr_prefix_id >= sbi->xattr_prefix_count) {
+ erofs_err("invalid ishare xattr prefix id %d",
+ dsb->ishare_xattr_prefix_id);
+ return -EFSCORRUPTED;
+ }
+ sbi->ishare_xattr_prefix_id =
+ dsb->ishare_xattr_prefix_id | EROFS_XATTR_LONG_PREFIX;
+ }
ret = z_erofs_parse_cfgs(sbi, dsb);
if (ret)
return ret;
@@ -160,7 +168,6 @@ int erofs_read_superblock(struct erofs_sb_info *sbi)
free(sbi->devs);
sbi->devs = NULL;
}
-
sbi->sb_valid = !ret;
return ret;
}
@@ -206,6 +213,8 @@ int erofs_writesb(struct erofs_sb_info *sbi)
.extra_devices = cpu_to_le16(sbi->extra_devices),
.devt_slotoff = cpu_to_le16(sbi->devt_slotoff),
.packed_nid = cpu_to_le64(sbi->packed_nid),
+ .ishare_xattr_prefix_id = sbi->ishare_xattr_prefix_id &
+ EROFS_XATTR_LONG_PREFIX_MASK,
};
char *buf;
int ret;
diff --git a/lib/xattr.c b/lib/xattr.c
index 9b0f2ca..d8c7bff 100644
--- a/lib/xattr.c
+++ b/lib/xattr.c
@@ -1483,8 +1483,9 @@ int erofs_xattr_insert_name_prefix(const char *prefix)
if (!erofs_xattr_prefix_matches(prefix, &tnode->base_index,
&tnode->base_len)) {
- free(tnode);
- return -ENODATA;
+ /* Use internal hidden xattrs */
+ tnode->base_index = 0;
+ tnode->base_len = 0;
