[PATCH 5/6] erofs-utils: build erofs_xattr_entry upon extra xattr name prefix

[Jingbo Xu <jefflexu@linux.alibaba.com>]

Build the xattr entry also considering the extra xattr name prefix.  The
user specified extra xattr name prefix takes precedence over the
predefined xattr name prefix.

Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
---
 include/erofs/internal.h |  3 +++
 lib/xattr.c              | 44 ++++++++++++++++++++++++++++++++++++++++
 mkfs/main.c              |  2 ++
 3 files changed, 49 insertions(+)

diff --git a/include/erofs/internal.h b/include/erofs/internal.h
index 641a795..f441429 100644
--- a/include/erofs/internal.h
+++ b/include/erofs/internal.h
@@ -102,6 +102,9 @@ struct erofs_sb_info {
 		u16 device_id_mask;		/* used for others */
 	};
 	erofs_nid_t packed_nid;
+
+	u32 ea_prefix_off;
+	u8 ea_prefix_count;
 };
 
 /* make sure that any user of the erofs headers has atleast 64bit off_t type */
diff --git a/lib/xattr.c b/lib/xattr.c
index ec40aad..f1db8bf 100644
--- a/lib/xattr.c
+++ b/lib/xattr.c
@@ -17,6 +17,7 @@
 #include "erofs/xattr.h"
 #include "erofs/cache.h"
 #include "erofs/io.h"
+#include "erofs/fragments.h"
 #include "liberofs_private.h"
 
 #define EA_HASHTABLE_BITS 16
@@ -138,7 +139,16 @@ static struct xattr_item *get_xattritem(u8 prefix, char *kvbuf,
 static bool match_prefix(const char *key, u8 *index, u16 *len)
 {
 	struct xattr_prefix *p;
+	struct ea_type_node *tnode;
 
+	list_for_each_entry(tnode, &ea_types, list) {
+		p = &tnode->type;
+		if (p->prefix && !strncmp(p->prefix, key, p->prefix_len)) {
+			*len = p->prefix_len;
+			*index = tnode->index;
+			return true;
+		}
+	}
 	for (p = xattr_types; p < xattr_types + ARRAY_SIZE(xattr_types); ++p) {
 		if (p->prefix && !strncmp(p->prefix, key, p->prefix_len)) {
 			*len = p->prefix_len;
@@ -587,6 +597,34 @@ static int comp_xattr_item(const void *a, const void *b)
 	return la > lb;
 }
 
+static int erofs_xattr_write_ea_prefix(void)
+{
+	struct ea_type_node *tnode;
+	struct xattr_prefix *p;
+#ifdef HAVE_FTELLO64
+	off64_t offset = ftello64(packedfile);
+#else
+	off_t offset = ftello(packedfile);
+#endif
+
+	if (offset < 0)
+		return -errno;
+	if (offset > UINT32_MAX)
+		return -EOVERFLOW;
+
+	sbi.ea_prefix_count = ea_types_count;
+	sbi.ea_prefix_off = (u32)offset;
+
+	list_for_each_entry(tnode, &ea_types, list) {
+		p = &tnode->type;
+		if (fwrite(&p->prefix_len, sizeof(u8), 1, packedfile) != 1)
+			return -EIO;
+		if (fwrite(p->prefix, p->prefix_len + 1, 1, packedfile) != 1)
+			return -EIO;
+	}
+	return 0;
+}
+
 int erofs_build_shared_xattrs_from_path(const char *path)
 {
 	int ret;
@@ -610,6 +648,12 @@ int erofs_build_shared_xattrs_from_path(const char *path)
 	if (ret)
 		return ret;
 
+	if (ea_types_count) {
+		ret = erofs_xattr_write_ea_prefix();
+		if (ret)
+			return ret;
+	}
+
 	if (!shared_xattrs_size)
 		goto out;
 
diff --git a/mkfs/main.c b/mkfs/main.c
index 50fd908..56b100c 100644
--- a/mkfs/main.c
+++ b/mkfs/main.c
@@ -574,6 +574,8 @@ int erofs_mkfs_update_super_block(struct erofs_buffer_head *bh,
 		.blocks = 0,
 		.meta_blkaddr  = sbi.meta_blkaddr,
 		.xattr_blkaddr = sbi.xattr_blkaddr,
+		.ea_prefix_count = sbi.ea_prefix_count,
+		.ea_prefix_off = cpu_to_le32(sbi.ea_prefix_off),
 		.feature_incompat = cpu_to_le32(sbi.feature_incompat),
 		.feature_compat = cpu_to_le32(sbi.feature_compat &
 					      ~EROFS_FEATURE_COMPAT_SB_CHKSUM),
-- 
2.19.1.6.gb485710b