staging: erofs: introduce xattr & acl support

This implements xattr and acl functionalities. Inline and shared xattrs are introduced for flexibility. Specifically, if the same xattr occurs for many times in a large number of inodes or the value of a xattr is so large that it isn't suitable to be inlined, a shared xattr kept in the xattr meta will be used instead. Signed-off-by: Miao Xie <[email protected]> Signed-off-by: Chao Yu <[email protected]> Signed-off-by: Gao Xiang <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
0day-ci · Jul 27, 2018 · b17500a · b17500a
1 parent fd68c6a
commit b17500a
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diff --git a/drivers/staging/erofs/Kconfig b/drivers/staging/erofs/Kconfig
@@ -26,6 +26,43 @@ config EROFS_FS_DEBUG
 
  For daily use, say N.
 
+config EROFS_FS_XATTR
+ bool "EROFS extended attributes"
+ depends on EROFS_FS
+ default y
+ help
+ Extended attributes are name:value pairs associated with inodes by
+ the kernel or by users (see the attr(5) manual page, or visit
+ <http://acl.bestbits.at/> for details).
+
+ If unsure, say N.
+
+config EROFS_FS_POSIX_ACL
+ bool "EROFS Access Control Lists"
+ depends on EROFS_FS_XATTR
+ select FS_POSIX_ACL
+ default y
+ help
+ Posix Access Control Lists (ACLs) support permissions for users and
+ groups beyond the owner/group/world scheme.
+
+ To learn more about Access Control Lists, visit the POSIX ACLs for
+ Linux website <http://acl.bestbits.at/>.
+
+ If you don't know what Access Control Lists are, say N.
+
+config EROFS_FS_SECURITY
+ bool "EROFS Security Labels"
+ depends on EROFS_FS_XATTR
+ help
+ Security labels provide an access control facility to support Linux
+ Security Models (LSMs) accepted by AppArmor, SELinux, Smack and TOMOYO
+ Linux. This option enables an extended attribute handler for file
+ security labels in the erofs filesystem, so that it requires enabling
+ the extended attribute support in advance.
+
+ If you are not using a security module, say N.
+
 config EROFS_FS_USE_VM_MAP_RAM
  bool "EROFS VM_MAP_RAM Support"
  depends on EROFS_FS

diff --git a/drivers/staging/erofs/Makefile b/drivers/staging/erofs/Makefile
@@ -8,4 +8,5 @@ obj-$(CONFIG_EROFS_FS) += erofs.o
 # staging requirement: to be self-contained in its own directory
 ccflags-y += -I$(src)/include
 erofs-objs := super.o inode.o data.o namei.o dir.o
+erofs-$(CONFIG_EROFS_FS_XATTR) += xattr.o
 
diff --git a/drivers/staging/erofs/inode.c b/drivers/staging/erofs/inode.c
@@ -10,7 +10,7 @@
  * License. See the file COPYING in the main directory of the Linux
  * distribution for more details.
  */
-#include "internal.h"
+#include "xattr.h"
 
 /* no locking */
 static int read_inode(struct inode *inode, void *data)
@@ -152,15 +152,26 @@ static int fill_inode(struct inode *inode, int isdir)
  if (!err) {
  /* setup the new inode */
  if (S_ISREG(inode->i_mode)) {
+#ifdef CONFIG_EROFS_FS_XATTR
+ if (vi->xattr_isize)
+ inode->i_op = &erofs_generic_xattr_iops;
+#endif
  inode->i_fop = &generic_ro_fops;
  } else if (S_ISDIR(inode->i_mode)) {
  inode->i_op =
+#ifdef CONFIG_EROFS_FS_XATTR
+ vi->xattr_isize ? &erofs_dir_xattr_iops :
+#endif
  &erofs_dir_iops;
  inode->i_fop = &erofs_dir_fops;
  } else if (S_ISLNK(inode->i_mode)) {
  /* by default, page_get_link is used for symlink */
  inode->i_op =
+#ifdef CONFIG_EROFS_FS_XATTR
+ &erofs_symlink_xattr_iops,
+#else
  &page_symlink_inode_operations;
+#endif
  inode_nohighmem(inode);
  } else {
  err = -EIO;
@@ -208,3 +219,23 @@ struct inode *erofs_iget(struct super_block *sb,
  return inode;
 }
 
+#ifdef CONFIG_EROFS_FS_XATTR
+const struct inode_operations erofs_generic_xattr_iops = {
+ .listxattr = erofs_listxattr,
+};
+#endif
+
+#ifdef CONFIG_EROFS_FS_XATTR
+const struct inode_operations erofs_symlink_xattr_iops = {
+ .get_link = page_get_link,
+ .listxattr = erofs_listxattr,
+};
+#endif
+
+#ifdef CONFIG_EROFS_FS_XATTR
+const struct inode_operations erofs_fast_symlink_xattr_iops = {
+ .get_link = simple_get_link,
+ .listxattr = erofs_listxattr,
+};
+#endif
+
diff --git a/drivers/staging/erofs/internal.h b/drivers/staging/erofs/internal.h
@@ -50,6 +50,9 @@ typedef u64 erofs_nid_t;
 struct erofs_sb_info {
  u32 blocks;
  u32 meta_blkaddr;
+#ifdef CONFIG_EROFS_FS_XATTR
+ u32 xattr_blkaddr;
+#endif
 
  /* inode slot unit size in bit shift */
  unsigned char islotbits;
@@ -72,6 +75,10 @@ struct erofs_sb_info {
 #define EROFS_SB(sb) ((struct erofs_sb_info *)(sb)->s_fs_info)
 #define EROFS_I_SB(inode) ((struct erofs_sb_info *)(inode)->i_sb->s_fs_info)
 
+/* Mount flags set via mount options or defaults */
+#define EROFS_MOUNT_XATTR_USER 0x00000010
+#define EROFS_MOUNT_POSIX_ACL 0x00000020
+
 #define clear_opt(sbi, option) ((sbi)->mount_opt &= ~EROFS_MOUNT_##option)
 #define set_opt(sbi, option) ((sbi)->mount_opt |= EROFS_MOUNT_##option)
 #define test_opt(sbi, option) ((sbi)->mount_opt & EROFS_MOUNT_##option)
@@ -237,17 +244,32 @@ int erofs_namei(struct inode *dir, struct qstr *name,
  erofs_nid_t *nid, unsigned *d_type);
 
 /* xattr.c */
+#ifdef CONFIG_EROFS_FS_XATTR
 extern const struct xattr_handler *erofs_xattr_handlers[];
+#endif
 
 /* symlink */
+#ifdef CONFIG_EROFS_FS_XATTR
+extern const struct inode_operations erofs_symlink_xattr_iops;
+extern const struct inode_operations erofs_fast_symlink_xattr_iops;
+#endif
+
 static inline void set_inode_fast_symlink(struct inode *inode)
 {
+#ifdef CONFIG_EROFS_FS_XATTR
+ inode->i_op = &erofs_fast_symlink_xattr_iops;
+#else
  inode->i_op = &simple_symlink_inode_operations;
+#endif
 }
 
 static inline bool is_inode_fast_symlink(struct inode *inode)
 {
+#ifdef CONFIG_EROFS_FS_XATTR
+ return inode->i_op == &erofs_fast_symlink_xattr_iops;
+#else
  return inode->i_op == &simple_symlink_inode_operations;
+#endif
 }
 
 static inline void *erofs_vmap(struct page **pages, unsigned int count)

diff --git a/drivers/staging/erofs/namei.c b/drivers/staging/erofs/namei.c
@@ -11,6 +11,7 @@
  * distribution for more details.
  */
 #include "internal.h"
+#include "xattr.h"
 
 /* based on the value of qn->len is accurate */
 static inline int dirnamecmp(struct qstr *qn,
@@ -239,5 +240,8 @@ const struct inode_operations erofs_dir_iops = {
 
 const struct inode_operations erofs_dir_xattr_iops = {
  .lookup = erofs_lookup,
+#ifdef CONFIG_EROFS_FS_XATTR
+ .listxattr = erofs_listxattr,
+#endif
 };
 
diff --git a/drivers/staging/erofs/super.c b/drivers/staging/erofs/super.c
@@ -14,6 +14,7 @@
 #include <linux/buffer_head.h>
 #include <linux/statfs.h>
 #include <linux/parser.h>
+#include <linux/seq_file.h>
 #include "internal.h"
 
 static struct kmem_cache *erofs_inode_cachep __read_mostly;
@@ -107,6 +108,9 @@ static int superblock_read(struct super_block *sb)
 
  sbi->blocks = le32_to_cpu(layout->blocks);
  sbi->meta_blkaddr = le32_to_cpu(layout->meta_blkaddr);
+#ifdef CONFIG_EROFS_FS_XATTR
+ sbi->xattr_blkaddr = le32_to_cpu(layout->xattr_blkaddr);
+#endif
  sbi->islotbits = ffs(sizeof(struct erofs_inode_v1)) - 1;
 
  sbi->root_nid = le16_to_cpu(layout->root_nid);
@@ -127,13 +131,28 @@ static int superblock_read(struct super_block *sb)
 
 static void default_options(struct erofs_sb_info *sbi)
 {
+#ifdef CONFIG_EROFS_FS_XATTR
+ set_opt(sbi, XATTR_USER);
+#endif
+
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+ set_opt(sbi, POSIX_ACL);
+#endif
 }
 
 enum {
+ Opt_user_xattr,
+ Opt_nouser_xattr,
+ Opt_acl,
+ Opt_noacl,
  Opt_err
 };
 
 static match_table_t erofs_tokens = {
+ {Opt_user_xattr, "user_xattr"},
+ {Opt_nouser_xattr, "nouser_xattr"},
+ {Opt_acl, "acl"},
+ {Opt_noacl, "noacl"},
  {Opt_err, NULL}
 };
 
@@ -155,6 +174,36 @@ static int parse_options(struct super_block *sb, char *options)
  token = match_token(p, erofs_tokens, args);
 
  switch (token) {
+#ifdef CONFIG_EROFS_FS_XATTR
+ case Opt_user_xattr:
+ set_opt(EROFS_SB(sb), XATTR_USER);
+ break;
+ case Opt_nouser_xattr:
+ clear_opt(EROFS_SB(sb), XATTR_USER);
+ break;
+#else
+ case Opt_user_xattr:
+ infoln("user_xattr options not supported");
+ break;
+ case Opt_nouser_xattr:
+ infoln("nouser_xattr options not supported");
+ break;
+#endif
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+ case Opt_acl:
+ set_opt(EROFS_SB(sb), POSIX_ACL);
+ break;
+ case Opt_noacl:
+ clear_opt(EROFS_SB(sb), POSIX_ACL);
+ break;
+#else
+ case Opt_acl:
+ infoln("acl options not supported");
+ break;
+ case Opt_noacl:
+ infoln("noacl options not supported");
+ break;
+#endif
  default:
  errln("Unrecognized mount option \"%s\" "
  "or missing value", p);
@@ -197,6 +246,10 @@ static int erofs_read_super(struct super_block *sb,
 
  sb->s_op = &erofs_sops;
 
+#ifdef CONFIG_EROFS_FS_XATTR
+ sb->s_xattr = erofs_xattr_handlers;
+#endif
+
  /* set erofs default mount options */
  default_options(sbi);
 
@@ -386,6 +439,20 @@ static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
 
 static int erofs_show_options(struct seq_file *seq, struct dentry *root)
 {
+ struct erofs_sb_info *sbi __maybe_unused = EROFS_SB(root->d_sb);
+
+#ifdef CONFIG_EROFS_FS_XATTR
+ if (test_opt(sbi, XATTR_USER))
+ seq_puts(seq, ",user_xattr");
+ else
+ seq_puts(seq, ",nouser_xattr");
+#endif
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+ if (test_opt(sbi, POSIX_ACL))
+ seq_puts(seq, ",acl");
+ else
+ seq_puts(seq, ",noacl");
+#endif
  return 0;
 }