erofs: add helpers to load long xattr name prefixes

Long xattr name prefixes will be scanned upon mounting and the in-memory
long xattr name prefix array will be initialized accordingly.

Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Acked-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20230407141710.113882-6-jefflexu@linux.alibaba.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 8b5168f..5a9c196 100644 (file)
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -117,6 +117,11 @@ struct erofs_fscache {
        char *name;
 };
 
+struct erofs_xattr_prefix_item {
+       struct erofs_xattr_long_prefix *prefix;
+       u8 infix_len;
+};
+
 struct erofs_sb_info {
        struct erofs_mount_opts opt;    /* options */
 #ifdef CONFIG_EROFS_FS_ZIP
@@ -145,6 +150,9 @@ struct erofs_sb_info {
        u32 meta_blkaddr;
 #ifdef CONFIG_EROFS_FS_XATTR
        u32 xattr_blkaddr;
+       u32 xattr_prefix_start;
+       u8 xattr_prefix_count;
+       struct erofs_xattr_prefix_item *xattr_prefixes;
 #endif
        u16 device_id_mask;     /* valid bits of device id to be used */
 
@@ -440,6 +448,8 @@ extern const struct iomap_ops z_erofs_iomap_report_ops;
 #define EROFS_REG_COOKIE_SHARE         0x0001
 #define EROFS_REG_COOKIE_NEED_NOEXIST  0x0002
 
+void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf,
+                         erofs_off_t *offset, int *lengthp);
 void erofs_unmap_metabuf(struct erofs_buf *buf);
 void erofs_put_metabuf(struct erofs_buf *buf);
 void *erofs_bread(struct erofs_buf *buf, erofs_blk_t blkaddr,

diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 2ab70e9..ddfb73b 100644 (file)
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -126,10 +126,9 @@ static bool check_layout_compatibility(struct super_block *sb,
        return true;
 }
 
-#ifdef CONFIG_EROFS_FS_ZIP
 /* read variable-sized metadata, offset will be aligned by 4-byte */
-static void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf,
-                                erofs_off_t *offset, int *lengthp)
+void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf,
+                         erofs_off_t *offset, int *lengthp)
 {
        u8 *buffer, *ptr;
        int len, i, cnt;
@@ -162,6 +161,7 @@ static void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf,
        return buffer;
 }
 
+#ifdef CONFIG_EROFS_FS_ZIP
 static int erofs_load_compr_cfgs(struct super_block *sb,
                                 struct erofs_super_block *dsb)
 {

diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
index d76b74e..684571e 100644 (file)
--- a/fs/erofs/xattr.c
+++ b/fs/erofs/xattr.c
@@ -610,6 +610,62 @@ ssize_t erofs_listxattr(struct dentry *dentry,
        return ret;
 }
 
+void erofs_xattr_prefixes_cleanup(struct super_block *sb)
+{
+       struct erofs_sb_info *sbi = EROFS_SB(sb);
+       int i;
+
+       if (sbi->xattr_prefixes) {
+               for (i = 0; i < sbi->xattr_prefix_count; i++)
+                       kfree(sbi->xattr_prefixes[i].prefix);
+               kfree(sbi->xattr_prefixes);
+               sbi->xattr_prefixes = NULL;
+       }
+}
+
+int erofs_xattr_prefixes_init(struct super_block *sb)
+{
+       struct erofs_sb_info *sbi = EROFS_SB(sb);
+       struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+       erofs_off_t pos = (erofs_off_t)sbi->xattr_prefix_start << 2;
+       struct erofs_xattr_prefix_item *pfs;
+       int ret = 0, i, len;
+
+       if (!sbi->xattr_prefix_count)
+               return 0;
+
+       pfs = kzalloc(sbi->xattr_prefix_count * sizeof(*pfs), GFP_KERNEL);
+       if (!pfs)
+               return -ENOMEM;
+
+       if (erofs_sb_has_fragments(sbi))
+               buf.inode = sbi->packed_inode;
+       else
+               erofs_init_metabuf(&buf, sb);
+
+       for (i = 0; i < sbi->xattr_prefix_count; i++) {
+               void *ptr = erofs_read_metadata(sb, &buf, &pos, &len);
+
+               if (IS_ERR(ptr)) {
+                       ret = PTR_ERR(ptr);
+                       break;
+               } else if (len < sizeof(*pfs->prefix) ||
+                          len > EROFS_NAME_LEN + sizeof(*pfs->prefix)) {
+                       kfree(ptr);
+                       ret = -EFSCORRUPTED;
+                       break;
+               }
+               pfs[i].prefix = ptr;
+               pfs[i].infix_len = len - sizeof(struct erofs_xattr_long_prefix);
+       }
+
+       erofs_put_metabuf(&buf);
+       sbi->xattr_prefixes = pfs;
+       if (ret)
+               erofs_xattr_prefixes_cleanup(sb);
+       return ret;
+}
+
 #ifdef CONFIG_EROFS_FS_POSIX_ACL
 struct posix_acl *erofs_get_acl(struct inode *inode, int type, bool rcu)
 {

diff --git a/fs/erofs/xattr.h b/fs/erofs/xattr.h
index a65158c..e126535 100644 (file)
--- a/fs/erofs/xattr.h
+++ b/fs/erofs/xattr.h
@@ -40,9 +40,13 @@ static inline const struct xattr_handler *erofs_xattr_handler(unsigned int idx)
 
 extern const struct xattr_handler *erofs_xattr_handlers[];
 
+int erofs_xattr_prefixes_init(struct super_block *sb);
+void erofs_xattr_prefixes_cleanup(struct super_block *sb);
 int erofs_getxattr(struct inode *, int, const char *, void *, size_t);
 ssize_t erofs_listxattr(struct dentry *, char *, size_t);
 #else
+static inline int erofs_xattr_prefixes_init(struct super_block *sb) { return 0; }
+static inline void erofs_xattr_prefixes_cleanup(struct super_block *sb) {}
 static inline int erofs_getxattr(struct inode *inode, int index,
                                 const char *name, void *buffer,
                                 size_t buffer_size)