From cac2f8b8d8b50ef32b3e34f6dcbbf08937e4f616 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 22 Sep 2022 17:17:00 +0200 Subject: fs: rename current get acl method The current way of setting and getting posix acls through the generic xattr interface is error prone and type unsafe. The vfs needs to interpret and fixup posix acls before storing or reporting it to userspace. Various hacks exist to make this work. The code is hard to understand and difficult to maintain in it's current form. Instead of making this work by hacking posix acls through xattr handlers we are building a dedicated posix acl api around the get and set inode operations. This removes a lot of hackiness and makes the codepaths easier to maintain. A lot of background can be found in [1]. The current inode operation for getting posix acls takes an inode argument but various filesystems (e.g., 9p, cifs, overlayfs) need access to the dentry. In contrast to the ->set_acl() inode operation we cannot simply extend ->get_acl() to take a dentry argument. The ->get_acl() inode operation is called from: acl_permission_check() -> check_acl() -> get_acl() which is part of generic_permission() which in turn is part of inode_permission(). Both generic_permission() and inode_permission() are called in the ->permission() handler of various filesystems (e.g., overlayfs). So simply passing a dentry argument to ->get_acl() would amount to also having to pass a dentry argument to ->permission(). We should avoid this unnecessary change. So instead of extending the existing inode operation rename it from ->get_acl() to ->get_inode_acl() and add a ->get_acl() method later that passes a dentry argument and which filesystems that need access to the dentry can implement instead of ->get_inode_acl(). Filesystems like cifs which allow setting and getting posix acls but not using them for permission checking during lookup can simply not implement ->get_inode_acl(). This is intended to be a non-functional change. Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1] Suggested-by/Inspired-by: Christoph Hellwig Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner (Microsoft) --- fs/9p/vfs_inode_dotl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/9p') diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c index 5cfa4b4f070f..0d1a7f2c579d 100644 --- a/fs/9p/vfs_inode_dotl.c +++ b/fs/9p/vfs_inode_dotl.c @@ -983,14 +983,14 @@ const struct inode_operations v9fs_dir_inode_operations_dotl = { .getattr = v9fs_vfs_getattr_dotl, .setattr = v9fs_vfs_setattr_dotl, .listxattr = v9fs_listxattr, - .get_acl = v9fs_iop_get_acl, + .get_inode_acl = v9fs_iop_get_acl, }; const struct inode_operations v9fs_file_inode_operations_dotl = { .getattr = v9fs_vfs_getattr_dotl, .setattr = v9fs_vfs_setattr_dotl, .listxattr = v9fs_listxattr, - .get_acl = v9fs_iop_get_acl, + .get_inode_acl = v9fs_iop_get_acl, }; const struct inode_operations v9fs_symlink_inode_operations_dotl = { -- cgit v1.2.3 From 6cd4d4e8b6e1495eb0cafa3a59d1fde137a98d22 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 22 Sep 2022 17:17:04 +0200 Subject: 9p: implement get acl method The current way of setting and getting posix acls through the generic xattr interface is error prone and type unsafe. The vfs needs to interpret and fixup posix acls before storing or reporting it to userspace. Various hacks exist to make this work. The code is hard to understand and difficult to maintain in it's current form. Instead of making this work by hacking posix acls through xattr handlers we are building a dedicated posix acl api around the get and set inode operations. This removes a lot of hackiness and makes the codepaths easier to maintain. A lot of background can be found in [1]. In order to build a type safe posix api around get and set acl we need all filesystem to implement get and set acl. So far 9p implemented a ->get_inode_acl() operation that didn't require access to the dentry in order to allow (limited) permission checking via posix acls in the vfs. Now that we have get and set acl inode operations that take a dentry argument we can give 9p get and set acl inode operations. This is mostly a refactoring of the codepaths currently used in 9p posix acl xattr handler. After we have fully implemented the posix acl api and switched the vfs over to it, the 9p specific posix acl xattr handler and associated code will be removed. Note, until the vfs has been switched to the new posix acl api this patch is a non-functional change. Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1] Signed-off-by: Christian Brauner (Microsoft) --- fs/9p/acl.c | 80 +++++++++++++++++++++++++++++++---------- fs/9p/acl.h | 5 ++- fs/9p/vfs_inode_dotl.c | 6 ++-- include/linux/posix_acl_xattr.h | 11 ++++++ 4 files changed, 80 insertions(+), 22 deletions(-) (limited to 'fs/9p') diff --git a/fs/9p/acl.c b/fs/9p/acl.c index 4dac4a0dc5f4..67f8b57c67e0 100644 --- a/fs/9p/acl.c +++ b/fs/9p/acl.c @@ -17,34 +17,64 @@ #include "v9fs_vfs.h" #include "fid.h" -static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, char *name) +static struct posix_acl *v9fs_fid_get_acl(struct p9_fid *fid, const char *name) { ssize_t size; void *value = NULL; struct posix_acl *acl = NULL; size = v9fs_fid_xattr_get(fid, name, NULL, 0); - if (size > 0) { - value = kzalloc(size, GFP_NOFS); - if (!value) - return ERR_PTR(-ENOMEM); - size = v9fs_fid_xattr_get(fid, name, value, size); - if (size > 0) { - acl = posix_acl_from_xattr(&init_user_ns, value, size); - if (IS_ERR(acl)) - goto err_out; - } - } else if (size == -ENODATA || size == 0 || - size == -ENOSYS || size == -EOPNOTSUPP) { - acl = NULL; - } else - acl = ERR_PTR(-EIO); - -err_out: + if (size < 0) + return ERR_PTR(size); + if (size == 0) + return ERR_PTR(-ENODATA); + + value = kzalloc(size, GFP_NOFS); + if (!value) + return ERR_PTR(-ENOMEM); + + size = v9fs_fid_xattr_get(fid, name, value, size); + if (size < 0) + acl = ERR_PTR(size); + else if (size == 0) + acl = ERR_PTR(-ENODATA); + else + acl = posix_acl_from_xattr(&init_user_ns, value, size); kfree(value); return acl; } +static struct posix_acl *v9fs_acl_get(struct dentry *dentry, const char *name) +{ + struct p9_fid *fid; + struct posix_acl *acl = NULL; + + fid = v9fs_fid_lookup(dentry); + if (IS_ERR(fid)) + return ERR_CAST(fid); + + acl = v9fs_fid_get_acl(fid, name); + p9_fid_put(fid); + return acl; +} + +static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, const char *name) +{ + int retval; + struct posix_acl *acl = NULL; + + acl = v9fs_fid_get_acl(fid, name); + if (!IS_ERR(acl)) + return acl; + + retval = PTR_ERR(acl); + if (retval == -ENODATA || retval == -ENOSYS || retval == -EOPNOTSUPP) + return NULL; + + /* map everything else to -EIO */ + return ERR_PTR(-EIO); +} + int v9fs_get_acl(struct inode *inode, struct p9_fid *fid) { int retval = 0; @@ -89,7 +119,7 @@ static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type) return acl; } -struct posix_acl *v9fs_iop_get_acl(struct inode *inode, int type, bool rcu) +struct posix_acl *v9fs_iop_get_inode_acl(struct inode *inode, int type, bool rcu) { struct v9fs_session_info *v9ses; @@ -109,6 +139,18 @@ struct posix_acl *v9fs_iop_get_acl(struct inode *inode, int type, bool rcu) } +struct posix_acl *v9fs_iop_get_acl(struct user_namespace *mnt_userns, + struct dentry *dentry, int type) +{ + struct v9fs_session_info *v9ses; + + v9ses = v9fs_dentry2v9ses(dentry); + /* We allow set/get/list of acl when access=client is not specified. */ + if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) + return v9fs_acl_get(dentry, posix_acl_xattr_name(type)); + return v9fs_get_cached_acl(d_inode(dentry), type); +} + static int v9fs_set_acl(struct p9_fid *fid, int type, struct posix_acl *acl) { int retval; diff --git a/fs/9p/acl.h b/fs/9p/acl.h index ce5175d463dd..359dab4da900 100644 --- a/fs/9p/acl.h +++ b/fs/9p/acl.h @@ -8,8 +8,10 @@ #ifdef CONFIG_9P_FS_POSIX_ACL int v9fs_get_acl(struct inode *inode, struct p9_fid *fid); -struct posix_acl *v9fs_iop_get_acl(struct inode *inode, int type, +struct posix_acl *v9fs_iop_get_inode_acl(struct inode *inode, int type, bool rcu); +struct posix_acl *v9fs_iop_get_acl(struct user_namespace *mnt_userns, + struct dentry *dentry, int type); int v9fs_acl_chmod(struct inode *inode, struct p9_fid *fid); int v9fs_set_create_acl(struct inode *inode, struct p9_fid *fid, struct posix_acl *dacl, struct posix_acl *acl); @@ -17,6 +19,7 @@ int v9fs_acl_mode(struct inode *dir, umode_t *modep, struct posix_acl **dpacl, struct posix_acl **pacl); void v9fs_put_acl(struct posix_acl *dacl, struct posix_acl *acl); #else +#define v9fs_iop_get_inode_acl NULL #define v9fs_iop_get_acl NULL static inline int v9fs_get_acl(struct inode *inode, struct p9_fid *fid) { diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c index 0d1a7f2c579d..a4211fcb9168 100644 --- a/fs/9p/vfs_inode_dotl.c +++ b/fs/9p/vfs_inode_dotl.c @@ -983,14 +983,16 @@ const struct inode_operations v9fs_dir_inode_operations_dotl = { .getattr = v9fs_vfs_getattr_dotl, .setattr = v9fs_vfs_setattr_dotl, .listxattr = v9fs_listxattr, - .get_inode_acl = v9fs_iop_get_acl, + .get_inode_acl = v9fs_iop_get_inode_acl, + .get_acl = v9fs_iop_get_acl, }; const struct inode_operations v9fs_file_inode_operations_dotl = { .getattr = v9fs_vfs_getattr_dotl, .setattr = v9fs_vfs_setattr_dotl, .listxattr = v9fs_listxattr, - .get_inode_acl = v9fs_iop_get_acl, + .get_inode_acl = v9fs_iop_get_inode_acl, + .get_acl = v9fs_iop_get_acl, }; const struct inode_operations v9fs_symlink_inode_operations_dotl = { diff --git a/include/linux/posix_acl_xattr.h b/include/linux/posix_acl_xattr.h index 8163dd48c430..ebfa11ac7046 100644 --- a/include/linux/posix_acl_xattr.h +++ b/include/linux/posix_acl_xattr.h @@ -60,6 +60,17 @@ int posix_acl_to_xattr(struct user_namespace *user_ns, struct posix_acl *vfs_set_acl_prepare(struct user_namespace *mnt_userns, struct user_namespace *fs_userns, const void *value, size_t size); +static inline const char *posix_acl_xattr_name(int type) +{ + switch (type) { + case ACL_TYPE_ACCESS: + return XATTR_NAME_POSIX_ACL_ACCESS; + case ACL_TYPE_DEFAULT: + return XATTR_NAME_POSIX_ACL_DEFAULT; + } + + return ""; +} extern const struct xattr_handler posix_acl_access_xattr_handler; extern const struct xattr_handler posix_acl_default_xattr_handler; -- cgit v1.2.3 From 079da629383ea960dfa0615e18d51d8bd121bd0c Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 22 Sep 2022 17:17:05 +0200 Subject: 9p: implement set acl method The current way of setting and getting posix acls through the generic xattr interface is error prone and type unsafe. The vfs needs to interpret and fixup posix acls before storing or reporting it to userspace. Various hacks exist to make this work. The code is hard to understand and difficult to maintain in it's current form. Instead of making this work by hacking posix acls through xattr handlers we are building a dedicated posix acl api around the get and set inode operations. This removes a lot of hackiness and makes the codepaths easier to maintain. A lot of background can be found in [1]. In order to build a type safe posix api around get and set acl we need all filesystem to implement get and set acl. So far 9p implemented a ->get_inode_acl() operation that didn't require access to the dentry in order to allow (limited) permission checking via posix acls in the vfs. Now that we have get and set acl inode operations that take a dentry argument we can give 9p get and set acl inode operations. This is mostly a light refactoring of the codepaths currently used in 9p posix acl xattr handler. After we have fully implemented the posix acl api and switched the vfs over to it, the 9p specific posix acl xattr handler and associated code will be removed. Note, until the vfs has been switched to the new posix acl api this patch is a non-functional change. Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1] Signed-off-by: Christian Brauner (Microsoft) --- fs/9p/acl.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++ fs/9p/acl.h | 3 ++ fs/9p/vfs_inode_dotl.c | 2 ++ 3 files changed, 99 insertions(+) (limited to 'fs/9p') diff --git a/fs/9p/acl.c b/fs/9p/acl.c index 67f8b57c67e0..135b26cee63a 100644 --- a/fs/9p/acl.c +++ b/fs/9p/acl.c @@ -151,6 +151,100 @@ struct posix_acl *v9fs_iop_get_acl(struct user_namespace *mnt_userns, return v9fs_get_cached_acl(d_inode(dentry), type); } +int v9fs_iop_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry, + struct posix_acl *acl, int type) +{ + int retval; + size_t size = 0; + void *value = NULL; + const char *acl_name; + struct v9fs_session_info *v9ses; + struct inode *inode = d_inode(dentry); + + if (acl) { + retval = posix_acl_valid(inode->i_sb->s_user_ns, acl); + if (retval) + goto err_out; + + size = posix_acl_xattr_size(acl->a_count); + + value = kzalloc(size, GFP_NOFS); + if (!value) { + retval = -ENOMEM; + goto err_out; + } + + retval = posix_acl_to_xattr(&init_user_ns, acl, value, size); + if (retval < 0) + goto err_out; + } + + /* + * set the attribute on the remote. Without even looking at the + * xattr value. We leave it to the server to validate + */ + acl_name = posix_acl_xattr_name(type); + v9ses = v9fs_dentry2v9ses(dentry); + if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) { + retval = v9fs_xattr_set(dentry, acl_name, value, size, 0); + goto err_out; + } + + if (S_ISLNK(inode->i_mode)) { + retval = -EOPNOTSUPP; + goto err_out; + } + + if (!inode_owner_or_capable(&init_user_ns, inode)) { + retval = -EPERM; + goto err_out; + } + + switch (type) { + case ACL_TYPE_ACCESS: + if (acl) { + struct iattr iattr = {}; + struct posix_acl *acl_mode = acl; + + retval = posix_acl_update_mode(&init_user_ns, inode, + &iattr.ia_mode, + &acl_mode); + if (retval) + goto err_out; + if (!acl_mode) { + /* + * ACL can be represented by the mode bits. + * So don't update ACL below. + */ + kfree(value); + value = NULL; + size = 0; + } + iattr.ia_valid = ATTR_MODE; + /* + * FIXME should we update ctime ? + * What is the following setxattr update the mode ? + */ + v9fs_vfs_setattr_dotl(&init_user_ns, dentry, &iattr); + } + break; + case ACL_TYPE_DEFAULT: + if (!S_ISDIR(inode->i_mode)) { + retval = acl ? -EINVAL : 0; + goto err_out; + } + break; + } + + retval = v9fs_xattr_set(dentry, acl_name, value, size, 0); + if (!retval) + set_cached_acl(inode, type, acl); + +err_out: + kfree(value); + return retval; +} + static int v9fs_set_acl(struct p9_fid *fid, int type, struct posix_acl *acl) { int retval; diff --git a/fs/9p/acl.h b/fs/9p/acl.h index 359dab4da900..4c60a2bce5de 100644 --- a/fs/9p/acl.h +++ b/fs/9p/acl.h @@ -12,6 +12,8 @@ struct posix_acl *v9fs_iop_get_inode_acl(struct inode *inode, int type, bool rcu); struct posix_acl *v9fs_iop_get_acl(struct user_namespace *mnt_userns, struct dentry *dentry, int type); +int v9fs_iop_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry, + struct posix_acl *acl, int type); int v9fs_acl_chmod(struct inode *inode, struct p9_fid *fid); int v9fs_set_create_acl(struct inode *inode, struct p9_fid *fid, struct posix_acl *dacl, struct posix_acl *acl); @@ -21,6 +23,7 @@ void v9fs_put_acl(struct posix_acl *dacl, struct posix_acl *acl); #else #define v9fs_iop_get_inode_acl NULL #define v9fs_iop_get_acl NULL +#define v9fs_iop_set_acl NULL static inline int v9fs_get_acl(struct inode *inode, struct p9_fid *fid) { return 0; diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c index a4211fcb9168..03c1743c4aff 100644 --- a/fs/9p/vfs_inode_dotl.c +++ b/fs/9p/vfs_inode_dotl.c @@ -985,6 +985,7 @@ const struct inode_operations v9fs_dir_inode_operations_dotl = { .listxattr = v9fs_listxattr, .get_inode_acl = v9fs_iop_get_inode_acl, .get_acl = v9fs_iop_get_acl, + .set_acl = v9fs_iop_set_acl, }; const struct inode_operations v9fs_file_inode_operations_dotl = { @@ -993,6 +994,7 @@ const struct inode_operations v9fs_file_inode_operations_dotl = { .listxattr = v9fs_listxattr, .get_inode_acl = v9fs_iop_get_inode_acl, .get_acl = v9fs_iop_get_acl, + .set_acl = v9fs_iop_set_acl, }; const struct inode_operations v9fs_symlink_inode_operations_dotl = { -- cgit v1.2.3 From 39a6497a9bbb760c3c26a1bef7a0ab0b9fdefd9f Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 22 Sep 2022 17:17:26 +0200 Subject: 9p: use stub posix acl handlers Now that 9p supports the get and set acl inode operations and the vfs has been switched to the new posi api, 9p can simply rely on the stub posix acl handlers. The custom xattr handlers and associated unused helpers can be removed. Signed-off-by: Christian Brauner (Microsoft) --- fs/9p/acl.c | 121 ---------------------------------------------------------- fs/9p/xattr.c | 7 ++-- fs/9p/xattr.h | 2 - 3 files changed, 4 insertions(+), 126 deletions(-) (limited to 'fs/9p') diff --git a/fs/9p/acl.c b/fs/9p/acl.c index 135b26cee63a..c397c51f80d9 100644 --- a/fs/9p/acl.c +++ b/fs/9p/acl.c @@ -343,124 +343,3 @@ int v9fs_acl_mode(struct inode *dir, umode_t *modep, *modep = mode; return 0; } - -static int v9fs_xattr_get_acl(const struct xattr_handler *handler, - struct dentry *dentry, struct inode *inode, - const char *name, void *buffer, size_t size) -{ - struct v9fs_session_info *v9ses; - struct posix_acl *acl; - int error; - - v9ses = v9fs_dentry2v9ses(dentry); - /* - * We allow set/get/list of acl when access=client is not specified - */ - if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) - return v9fs_xattr_get(dentry, handler->name, buffer, size); - - acl = v9fs_get_cached_acl(inode, handler->flags); - if (IS_ERR(acl)) - return PTR_ERR(acl); - if (acl == NULL) - return -ENODATA; - error = posix_acl_to_xattr(&init_user_ns, acl, buffer, size); - posix_acl_release(acl); - - return error; -} - -static int v9fs_xattr_set_acl(const struct xattr_handler *handler, - struct user_namespace *mnt_userns, - struct dentry *dentry, struct inode *inode, - const char *name, const void *value, - size_t size, int flags) -{ - int retval; - struct posix_acl *acl; - struct v9fs_session_info *v9ses; - - v9ses = v9fs_dentry2v9ses(dentry); - /* - * set the attribute on the remote. Without even looking at the - * xattr value. We leave it to the server to validate - */ - if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) - return v9fs_xattr_set(dentry, handler->name, value, size, - flags); - - if (S_ISLNK(inode->i_mode)) - return -EOPNOTSUPP; - if (!inode_owner_or_capable(&init_user_ns, inode)) - return -EPERM; - if (value) { - /* update the cached acl value */ - acl = posix_acl_from_xattr(&init_user_ns, value, size); - if (IS_ERR(acl)) - return PTR_ERR(acl); - else if (acl) { - retval = posix_acl_valid(inode->i_sb->s_user_ns, acl); - if (retval) - goto err_out; - } - } else - acl = NULL; - - switch (handler->flags) { - case ACL_TYPE_ACCESS: - if (acl) { - struct iattr iattr = { 0 }; - struct posix_acl *old_acl = acl; - - retval = posix_acl_update_mode(&init_user_ns, inode, - &iattr.ia_mode, &acl); - if (retval) - goto err_out; - if (!acl) { - /* - * ACL can be represented - * by the mode bits. So don't - * update ACL. - */ - posix_acl_release(old_acl); - value = NULL; - size = 0; - } - iattr.ia_valid = ATTR_MODE; - /* FIXME should we update ctime ? - * What is the following setxattr update the - * mode ? - */ - v9fs_vfs_setattr_dotl(&init_user_ns, dentry, &iattr); - } - break; - case ACL_TYPE_DEFAULT: - if (!S_ISDIR(inode->i_mode)) { - retval = acl ? -EINVAL : 0; - goto err_out; - } - break; - default: - BUG(); - } - retval = v9fs_xattr_set(dentry, handler->name, value, size, flags); - if (!retval) - set_cached_acl(inode, handler->flags, acl); -err_out: - posix_acl_release(acl); - return retval; -} - -const struct xattr_handler v9fs_xattr_acl_access_handler = { - .name = XATTR_NAME_POSIX_ACL_ACCESS, - .flags = ACL_TYPE_ACCESS, - .get = v9fs_xattr_get_acl, - .set = v9fs_xattr_set_acl, -}; - -const struct xattr_handler v9fs_xattr_acl_default_handler = { - .name = XATTR_NAME_POSIX_ACL_DEFAULT, - .flags = ACL_TYPE_DEFAULT, - .get = v9fs_xattr_get_acl, - .set = v9fs_xattr_set_acl, -}; diff --git a/fs/9p/xattr.c b/fs/9p/xattr.c index 1f9298a4bd42..ae6a93871338 100644 --- a/fs/9p/xattr.c +++ b/fs/9p/xattr.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include @@ -182,9 +183,9 @@ static struct xattr_handler v9fs_xattr_security_handler = { const struct xattr_handler *v9fs_xattr_handlers[] = { &v9fs_xattr_user_handler, &v9fs_xattr_trusted_handler, -#ifdef CONFIG_9P_FS_POSIX_ACL - &v9fs_xattr_acl_access_handler, - &v9fs_xattr_acl_default_handler, +#ifdef CONFIG_FS_POSIX_ACL + &posix_acl_access_xattr_handler, + &posix_acl_default_xattr_handler, #endif #ifdef CONFIG_9P_FS_SECURITY &v9fs_xattr_security_handler, diff --git a/fs/9p/xattr.h b/fs/9p/xattr.h index 3e11fc3331eb..b5636e544c8a 100644 --- a/fs/9p/xattr.h +++ b/fs/9p/xattr.h @@ -11,8 +11,6 @@ #include extern const struct xattr_handler *v9fs_xattr_handlers[]; -extern const struct xattr_handler v9fs_xattr_acl_access_handler; -extern const struct xattr_handler v9fs_xattr_acl_default_handler; ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name, void *buffer, size_t buffer_size); -- cgit v1.2.3