From b8a7a3a6674725d7ca0ff6e322f6c1cab6e6a11d Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Thu, 24 Mar 2016 14:38:37 +0100 Subject: posix_acl: Inode acl caching fixes When get_acl() is called for an inode whose ACL is not cached yet, the get_acl inode operation is called to fetch the ACL from the filesystem. The inode operation is responsible for updating the cached acl with set_cached_acl(). This is done without locking at the VFS level, so another task can call set_cached_acl() or forget_cached_acl() before the get_acl inode operation gets to calling set_cached_acl(), and then get_acl's call to set_cached_acl() results in caching an outdate ACL. Prevent this from happening by setting the cached ACL pointer to a task-specific sentinel value before calling the get_acl inode operation. Move the responsibility for updating the cached ACL from the get_acl inode operations to get_acl(). There, only set the cached ACL if the sentinel value hasn't changed. The sentinel values are chosen to have odd values. Likewise, the value of ACL_NOT_CACHED is odd. In contrast, ACL object pointers always have an even value (ACLs are aligned in memory). This allows to distinguish uncached ACLs values from ACL objects. In addition, switch from guarding inode->i_acl and inode->i_default_acl upates by the inode->i_lock spinlock to using xchg() and cmpxchg(). Filesystems that do not want ACLs returned from their get_acl inode operations to be cached must call forget_cached_acl() to prevent the VFS from doing so. (Patch written by Al Viro and Andreas Gruenbacher.) Signed-off-by: Andreas Gruenbacher Signed-off-by: Al Viro --- fs/hfsplus/posix_acl.c | 3 --- 1 file changed, 3 deletions(-) (limited to 'fs/hfsplus') diff --git a/fs/hfsplus/posix_acl.c b/fs/hfsplus/posix_acl.c index afb33eda6d7d..ab7ea2506b4d 100644 --- a/fs/hfsplus/posix_acl.c +++ b/fs/hfsplus/posix_acl.c @@ -48,9 +48,6 @@ struct posix_acl *hfsplus_get_posix_acl(struct inode *inode, int type) hfsplus_destroy_attr_entry((hfsplus_attr_entry *)value); - if (!IS_ERR(acl)) - set_cached_acl(inode, type, acl); - return acl; } -- cgit v1.2.3 From b296821a7c42fa58baa17513b2b7b30ae66f3336 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 10 Apr 2016 20:48:24 -0400 Subject: xattr_handler: pass dentry and inode as separate arguments of ->get() ... and do not assume they are already attached to each other Signed-off-by: Al Viro --- fs/hfsplus/xattr.c | 10 +++++----- fs/hfsplus/xattr.h | 2 +- fs/hfsplus/xattr_security.c | 6 +++--- fs/hfsplus/xattr_trusted.c | 6 +++--- fs/hfsplus/xattr_user.c | 6 +++--- 5 files changed, 15 insertions(+), 15 deletions(-) (limited to 'fs/hfsplus') diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c index ab01530b4930..45dc4ae3791a 100644 --- a/fs/hfsplus/xattr.c +++ b/fs/hfsplus/xattr.c @@ -579,7 +579,7 @@ failed_getxattr_init: return res; } -ssize_t hfsplus_getxattr(struct dentry *dentry, const char *name, +ssize_t hfsplus_getxattr(struct inode *inode, const char *name, void *value, size_t size, const char *prefix, size_t prefixlen) { @@ -594,7 +594,7 @@ ssize_t hfsplus_getxattr(struct dentry *dentry, const char *name, strcpy(xattr_name, prefix); strcpy(xattr_name + prefixlen, name); - res = __hfsplus_getxattr(d_inode(dentry), xattr_name, value, size); + res = __hfsplus_getxattr(inode, xattr_name, value, size); kfree(xattr_name); return res; @@ -844,8 +844,8 @@ end_removexattr: } static int hfsplus_osx_getxattr(const struct xattr_handler *handler, - struct dentry *dentry, const char *name, - void *buffer, size_t size) + struct dentry *unused, struct inode *inode, + const char *name, void *buffer, size_t size) { /* * Don't allow retrieving properly prefixed attributes @@ -860,7 +860,7 @@ static int hfsplus_osx_getxattr(const struct xattr_handler *handler, * creates), so we pass the name through unmodified (after * ensuring it doesn't conflict with another namespace). */ - return __hfsplus_getxattr(d_inode(dentry), name, buffer, size); + return __hfsplus_getxattr(inode, name, buffer, size); } static int hfsplus_osx_setxattr(const struct xattr_handler *handler, diff --git a/fs/hfsplus/xattr.h b/fs/hfsplus/xattr.h index f9b0955b3d28..d04ba6f58df2 100644 --- a/fs/hfsplus/xattr.h +++ b/fs/hfsplus/xattr.h @@ -28,7 +28,7 @@ int hfsplus_setxattr(struct dentry *dentry, const char *name, ssize_t __hfsplus_getxattr(struct inode *inode, const char *name, void *value, size_t size); -ssize_t hfsplus_getxattr(struct dentry *dentry, const char *name, +ssize_t hfsplus_getxattr(struct inode *inode, const char *name, void *value, size_t size, const char *prefix, size_t prefixlen); diff --git a/fs/hfsplus/xattr_security.c b/fs/hfsplus/xattr_security.c index 72a68a3a0c99..ae2ca8c2e335 100644 --- a/fs/hfsplus/xattr_security.c +++ b/fs/hfsplus/xattr_security.c @@ -14,10 +14,10 @@ #include "acl.h" static int hfsplus_security_getxattr(const struct xattr_handler *handler, - struct dentry *dentry, const char *name, - void *buffer, size_t size) + struct dentry *unused, struct inode *inode, + const char *name, void *buffer, size_t size) { - return hfsplus_getxattr(dentry, name, buffer, size, + return hfsplus_getxattr(inode, name, buffer, size, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN); } diff --git a/fs/hfsplus/xattr_trusted.c b/fs/hfsplus/xattr_trusted.c index 95a7704c7abb..eae2947060aa 100644 --- a/fs/hfsplus/xattr_trusted.c +++ b/fs/hfsplus/xattr_trusted.c @@ -12,10 +12,10 @@ #include "xattr.h" static int hfsplus_trusted_getxattr(const struct xattr_handler *handler, - struct dentry *dentry, const char *name, - void *buffer, size_t size) + struct dentry *unused, struct inode *inode, + const char *name, void *buffer, size_t size) { - return hfsplus_getxattr(dentry, name, buffer, size, + return hfsplus_getxattr(inode, name, buffer, size, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); } diff --git a/fs/hfsplus/xattr_user.c b/fs/hfsplus/xattr_user.c index 6fc269baf959..3c9eec3e4c7b 100644 --- a/fs/hfsplus/xattr_user.c +++ b/fs/hfsplus/xattr_user.c @@ -12,11 +12,11 @@ #include "xattr.h" static int hfsplus_user_getxattr(const struct xattr_handler *handler, - struct dentry *dentry, const char *name, - void *buffer, size_t size) + struct dentry *unused, struct inode *inode, + const char *name, void *buffer, size_t size) { - return hfsplus_getxattr(dentry, name, buffer, size, + return hfsplus_getxattr(inode, name, buffer, size, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN); } -- cgit v1.2.3