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Re: [PATCH 09/18] f2fs: use generic posix ACL infrastructure

To: Jaegeuk Kim <jaegeuk.kim@xxxxxxxxxxx>
Subject: Re: [PATCH 09/18] f2fs: use generic posix ACL infrastructure
From: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Date: Sun, 8 Dec 2013 01:14:43 -0800
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>, viro@xxxxxxxxxxxxxxxxxx, linux-fsdevel@xxxxxxxxxxxxxxx, linux-btrfs@xxxxxxxxxxxxxxx, linux-ext4@xxxxxxxxxxxxxxx, linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx, linux-mtd@xxxxxxxxxxxxxxxxxxx, Mark Fasheh <mfasheh@xxxxxxxx>, Joel Becker <jlbec@xxxxxxxxxxxx>, reiserfs-devel@xxxxxxxxxxxxxxx, xfs@xxxxxxxxxxx, jfs-discussion@xxxxxxxxxxxxxxxxxxxxx, cluster-devel@xxxxxxxxxx, linux-nfs@xxxxxxxxxxxxxxx
Delivered-to: xfs@xxxxxxxxxxx
In-reply-to: <1386293854.2101.8.camel@kjgkr>
References: <20131201115903.910559036@xxxxxxxxxxxxxxxxxxxxxx> <20131201120655.205206019@xxxxxxxxxxxxxxxxxxxxxx> <1386293854.2101.8.camel@kjgkr>
User-agent: Mutt/1.5.21 (2010-09-15)
On Fri, Dec 06, 2013 at 10:37:34AM +0900, Jaegeuk Kim wrote:
> f2fs caches a new mode bit for a while to make the consistency between
> xattr's acl mode and the inode mode.

Can you explain what exactly you're trying to do there?  I've been
trying to unwrap what's going on and can't really see the point:

 - i_acl_mode and FI_ACL_MODE get set in __setattr_copy, but right
   after that call, still under i_mutex and before marking the inode
   dirty f2fs_acl_chmod makes use of it, and it gets cleared right
   after. Is there any race that could happen with a locked inode
   not marked dirty yet on f2fs?  We could pass a mode argument
   to posix_acl_create, but I'd prefer to avoid that if we can.
 - on the set_acl side it gets set in __f2fs_set_acl, and then
   i_mode is update in __f2fs_setxattr which could easily done with
   a stack variable.

RFC patch below:


diff --git a/fs/f2fs/acl.c b/fs/f2fs/acl.c
index 4f52fe0f..6647545 100644
--- a/fs/f2fs/acl.c
+++ b/fs/f2fs/acl.c
@@ -17,9 +17,6 @@
 #include "xattr.h"
 #include "acl.h"
 
-#define get_inode_mode(i)      ((is_inode_flag_set(F2FS_I(i), FI_ACL_MODE)) ? \
-                                       (F2FS_I(i)->i_acl_mode) : ((i)->i_mode))
-
 static inline size_t f2fs_acl_size(int count)
 {
        if (count <= 4) {
@@ -209,11 +206,11 @@ static int __f2fs_set_acl(struct inode *inode, int type,
                        struct posix_acl *acl, struct page *ipage)
 {
        struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
-       struct f2fs_inode_info *fi = F2FS_I(inode);
        int name_index;
        void *value = NULL;
        size_t size = 0;
        int error;
+       umode_t mode = 0;
 
        if (!test_opt(sbi, POSIX_ACL))
                return 0;
@@ -224,10 +221,10 @@ static int __f2fs_set_acl(struct inode *inode, int type,
        case ACL_TYPE_ACCESS:
                name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
                if (acl) {
-                       error = posix_acl_equiv_mode(acl, &inode->i_mode);
+                       mode = inode->i_mode;
+                       error = posix_acl_equiv_mode(acl, &mode);
                        if (error < 0)
                                return error;
-                       set_acl_inode(fi, inode->i_mode);
                        if (error == 0)
                                acl = NULL;
                }
@@ -245,19 +242,15 @@ static int __f2fs_set_acl(struct inode *inode, int type,
 
        if (acl) {
                value = f2fs_acl_to_disk(acl, &size);
-               if (IS_ERR(value)) {
-                       cond_clear_inode_flag(fi, FI_ACL_MODE);
+               if (IS_ERR(value))
                        return (int)PTR_ERR(value);
-               }
        }
 
-       error = f2fs_setxattr(inode, name_index, "", value, size, ipage);
+       error = f2fs_setxattr(inode, name_index, "", value, size, ipage, mode);
 
        kfree(value);
        if (!error)
                set_cached_acl(inode, type, acl);
-
-       cond_clear_inode_flag(fi, FI_ACL_MODE);
        return error;
 }
 
@@ -289,28 +282,3 @@ int f2fs_init_acl(struct inode *inode, struct inode *dir, 
struct page *ipage)
 
        return error;
 }
-
-int f2fs_acl_chmod(struct inode *inode)
-{
-       struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
-       struct posix_acl *acl;
-       int error;
-       umode_t mode = get_inode_mode(inode);
-
-       if (!test_opt(sbi, POSIX_ACL))
-               return 0;
-       if (S_ISLNK(mode))
-               return -EOPNOTSUPP;
-
-       acl = f2fs_get_acl(inode, ACL_TYPE_ACCESS);
-       if (IS_ERR(acl) || !acl)
-               return PTR_ERR(acl);
-
-       error = __posix_acl_chmod(&acl, GFP_KERNEL, mode);
-       if (error)
-               return error;
-
-       error = __f2fs_set_acl(inode, ACL_TYPE_ACCESS, acl, NULL);
-       posix_acl_release(acl);
-       return error;
-}
diff --git a/fs/f2fs/acl.h b/fs/f2fs/acl.h
index 2af31fe..e086465 100644
--- a/fs/f2fs/acl.h
+++ b/fs/f2fs/acl.h
@@ -38,18 +38,12 @@ struct f2fs_acl_header {
 
 extern struct posix_acl *f2fs_get_acl(struct inode *, int);
 extern int f2fs_set_acl(struct inode *inode, struct posix_acl *acl, int type);
-extern int f2fs_acl_chmod(struct inode *);
 extern int f2fs_init_acl(struct inode *, struct inode *, struct page *);
 #else
 #define f2fs_check_acl NULL
 #define f2fs_get_acl   NULL
 #define f2fs_set_acl   NULL
 
-static inline int f2fs_acl_chmod(struct inode *inode)
-{
-       return 0;
-}
-
 static inline int f2fs_init_acl(struct inode *inode, struct inode *dir,
                                                        struct page *page)
 {
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 89dc750..1e774e6 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -181,7 +181,6 @@ struct f2fs_inode_info {
        unsigned char i_advise;         /* use to give file attribute hints */
        unsigned int i_current_depth;   /* use only in directory structure */
        unsigned int i_pino;            /* parent inode number */
-       umode_t i_acl_mode;             /* keep file acl mode temporarily */
 
        /* Use below internally in f2fs*/
        unsigned long flags;            /* use to pass per-file flags */
@@ -872,7 +871,6 @@ enum {
        FI_NEW_INODE,           /* indicate newly allocated inode */
        FI_DIRTY_INODE,         /* indicate inode is dirty or not */
        FI_INC_LINK,            /* need to increment i_nlink */
-       FI_ACL_MODE,            /* indicate acl mode */
        FI_NO_ALLOC,            /* should not allocate any blocks */
        FI_UPDATE_DIR,          /* should update inode block for consistency */
        FI_DELAY_IPUT,          /* used for the recovery */
@@ -894,21 +892,6 @@ static inline void clear_inode_flag(struct f2fs_inode_info 
*fi, int flag)
        clear_bit(flag, &fi->flags);
 }
 
-static inline void set_acl_inode(struct f2fs_inode_info *fi, umode_t mode)
-{
-       fi->i_acl_mode = mode;
-       set_inode_flag(fi, FI_ACL_MODE);
-}
-
-static inline int cond_clear_inode_flag(struct f2fs_inode_info *fi, int flag)
-{
-       if (is_inode_flag_set(fi, FI_ACL_MODE)) {
-               clear_inode_flag(fi, FI_ACL_MODE);
-               return 1;
-       }
-       return 0;
-}
-
 static inline void get_inline_info(struct f2fs_inode_info *fi,
                                        struct f2fs_inode *ri)
 {
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 13eff60..80ef669 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -339,41 +339,9 @@ int f2fs_getattr(struct vfsmount *mnt,
        return 0;
 }
 
-#ifdef CONFIG_F2FS_FS_POSIX_ACL
-static void __setattr_copy(struct inode *inode, const struct iattr *attr)
-{
-       struct f2fs_inode_info *fi = F2FS_I(inode);
-       unsigned int ia_valid = attr->ia_valid;
-
-       if (ia_valid & ATTR_UID)
-               inode->i_uid = attr->ia_uid;
-       if (ia_valid & ATTR_GID)
-               inode->i_gid = attr->ia_gid;
-       if (ia_valid & ATTR_ATIME)
-               inode->i_atime = timespec_trunc(attr->ia_atime,
-                                               inode->i_sb->s_time_gran);
-       if (ia_valid & ATTR_MTIME)
-               inode->i_mtime = timespec_trunc(attr->ia_mtime,
-                                               inode->i_sb->s_time_gran);
-       if (ia_valid & ATTR_CTIME)
-               inode->i_ctime = timespec_trunc(attr->ia_ctime,
-                                               inode->i_sb->s_time_gran);
-       if (ia_valid & ATTR_MODE) {
-               umode_t mode = attr->ia_mode;
-
-               if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
-                       mode &= ~S_ISGID;
-               set_acl_inode(fi, mode);
-       }
-}
-#else
-#define __setattr_copy setattr_copy
-#endif
-
 int f2fs_setattr(struct dentry *dentry, struct iattr *attr)
 {
        struct inode *inode = dentry->d_inode;
-       struct f2fs_inode_info *fi = F2FS_I(inode);
        int err;
 
        err = inode_change_ok(inode, attr);
@@ -387,15 +355,9 @@ int f2fs_setattr(struct dentry *dentry, struct iattr *attr)
                f2fs_balance_fs(F2FS_SB(inode->i_sb));
        }
 
-       __setattr_copy(inode, attr);
-
-       if (attr->ia_valid & ATTR_MODE) {
-               err = f2fs_acl_chmod(inode);
-               if (err || is_inode_flag_set(fi, FI_ACL_MODE)) {
-                       inode->i_mode = fi->i_acl_mode;
-                       clear_inode_flag(fi, FI_ACL_MODE);
-               }
-       }
+       setattr_copy(inode, attr);
+       if (attr->ia_valid & ATTR_MODE)
+               err = posix_acl_chmod(inode);
 
        mark_inode_dirty(inode);
        return err;
diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
index e2b9299..8820857 100644
--- a/fs/f2fs/xattr.c
+++ b/fs/f2fs/xattr.c
@@ -108,7 +108,7 @@ static int f2fs_xattr_generic_set(struct dentry *dentry, 
const char *name,
        if (strcmp(name, "") == 0)
                return -EINVAL;
 
-       return f2fs_setxattr(dentry->d_inode, type, name, value, size, NULL);
+       return f2fs_setxattr(dentry->d_inode, type, name, value, size, NULL, 0);
 }
 
 static size_t f2fs_xattr_advise_list(struct dentry *dentry, char *list,
@@ -157,7 +157,7 @@ static int f2fs_xattr_advise_set(struct dentry *dentry, 
const char *name,
 #ifdef CONFIG_F2FS_FS_SECURITY
 static int __f2fs_setxattr(struct inode *inode, int name_index,
                        const char *name, const void *value, size_t value_len,
-                       struct page *ipage);
+                       struct page *ipage, umode_t mode);
 static int f2fs_initxattrs(struct inode *inode, const struct xattr 
*xattr_array,
                void *page)
 {
@@ -167,7 +167,7 @@ static int f2fs_initxattrs(struct inode *inode, const 
struct xattr *xattr_array,
        for (xattr = xattr_array; xattr->name != NULL; xattr++) {
                err = __f2fs_setxattr(inode, F2FS_XATTR_INDEX_SECURITY,
                                xattr->name, xattr->value,
-                               xattr->value_len, (struct page *)page);
+                               xattr->value_len, (struct page *)page, 0);
                if (err < 0)
                        break;
        }
@@ -475,9 +475,8 @@ cleanup:
 
 static int __f2fs_setxattr(struct inode *inode, int name_index,
                        const char *name, const void *value, size_t value_len,
-                       struct page *ipage)
+                       struct page *ipage, umode_t mode)
 {
-       struct f2fs_inode_info *fi = F2FS_I(inode);
        struct f2fs_xattr_entry *here, *last;
        void *base_addr;
        int found, newsize;
@@ -566,10 +565,9 @@ static int __f2fs_setxattr(struct inode *inode, int 
name_index,
        if (error)
                goto exit;
 
-       if (is_inode_flag_set(fi, FI_ACL_MODE)) {
-               inode->i_mode = fi->i_acl_mode;
+       if (mode) {
+               inode->i_mode = mode;
                inode->i_ctime = CURRENT_TIME;
-               clear_inode_flag(fi, FI_ACL_MODE);
        }
 
        if (ipage)
@@ -582,7 +580,8 @@ exit:
 }
 
 int f2fs_setxattr(struct inode *inode, int name_index, const char *name,
-                       const void *value, size_t value_len, struct page *ipage)
+                       const void *value, size_t value_len, struct page *ipage,
+                       umode_t mode)
 {
        struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
        int err;
@@ -590,7 +589,8 @@ int f2fs_setxattr(struct inode *inode, int name_index, 
const char *name,
        f2fs_balance_fs(sbi);
 
        f2fs_lock_op(sbi);
-       err = __f2fs_setxattr(inode, name_index, name, value, value_len, ipage);
+       err = __f2fs_setxattr(inode, name_index, name, value, value_len, ipage,
+                             mode);
        f2fs_unlock_op(sbi);
 
        return err;
diff --git a/fs/f2fs/xattr.h b/fs/f2fs/xattr.h
index b21d9eb..c73588a 100644
--- a/fs/f2fs/xattr.h
+++ b/fs/f2fs/xattr.h
@@ -114,14 +114,15 @@ extern const struct xattr_handler 
f2fs_xattr_security_handler;
 extern const struct xattr_handler *f2fs_xattr_handlers[];
 
 extern int f2fs_setxattr(struct inode *, int, const char *,
-                               const void *, size_t, struct page *);
+                               const void *, size_t, struct page *, umode_t);
 extern int f2fs_getxattr(struct inode *, int, const char *, void *, size_t);
 extern ssize_t f2fs_listxattr(struct dentry *, char *, size_t);
 #else
 
 #define f2fs_xattr_handlers    NULL
 static inline int f2fs_setxattr(struct inode *inode, int name_index,
-               const char *name, const void *value, size_t value_len)
+               const char *name, const void *value, size_t value_len,
+               umode_t mode)
 {
        return -EOPNOTSUPP;
 }

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