[PATCH] fs/ext*,f2fs,jffs2,reiserfs: give comments for acl size and count calculation

[Chen Gang <gang.chen@xxxxxxxxxxx>]

  give comments (by Theodore Ts'o)

    ACL_USER_OBJ ACL_USER*[1] ACL_GROUP_OBJ ACL_GROUP*[1] ACL_MASK[2] ACL_OTHER

    [1] Where * is the regexp sense of "0 or more times"
    [2] Only if there is at least one ACL_USER or ACL_GROUP tag;
        otherwise skip ACL_MASK.

  use macro instead of hard code number (by Chen Gang)

Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Chen Gang <gang.chen@xxxxxxxxxxx>
---
 fs/ext2/acl.h             |   10 +++++-----
 fs/ext3/acl.h             |   10 +++++-----
 fs/ext4/acl.h             |   10 +++++-----
 fs/f2fs/acl.c             |   12 +++++++-----
 fs/jffs2/acl.c            |   15 +++++++++------
 fs/reiserfs/acl.h         |   10 +++++-----
 include/linux/posix_acl.h |    9 +++++++++
 7 files changed, 45 insertions(+), 31 deletions(-)

diff --git a/fs/ext2/acl.h b/fs/ext2/acl.h
index 503bfb0..9af79d0 100644
--- a/fs/ext2/acl.h
+++ b/fs/ext2/acl.h
@@ -25,13 +25,13 @@ typedef struct {
 
 static inline size_t ext2_acl_size(int count)
 {
-	if (count <= 4) {
+	if (count <= ACL_MAX_SHORT_ENTRY) {
 		return sizeof(ext2_acl_header) +
 		       count * sizeof(ext2_acl_entry_short);
 	} else {
 		return sizeof(ext2_acl_header) +
-		       4 * sizeof(ext2_acl_entry_short) +
-		       (count - 4) * sizeof(ext2_acl_entry);
+		       ACL_MAX_SHORT_ENTRY * sizeof(ext2_acl_entry_short) +
+		       (count - ACL_MAX_SHORT_ENTRY) * sizeof(ext2_acl_entry);
 	}
 }
 
@@ -39,7 +39,7 @@ static inline int ext2_acl_count(size_t size)
 {
 	ssize_t s;
 	size -= sizeof(ext2_acl_header);
-	s = size - 4 * sizeof(ext2_acl_entry_short);
+	s = size - ACL_MAX_SHORT_ENTRY * sizeof(ext2_acl_entry_short);
 	if (s < 0) {
 		if (size % sizeof(ext2_acl_entry_short))
 			return -1;
@@ -47,7 +47,7 @@ static inline int ext2_acl_count(size_t size)
 	} else {
 		if (s % sizeof(ext2_acl_entry))
 			return -1;
-		return s / sizeof(ext2_acl_entry) + 4;
+		return s / sizeof(ext2_acl_entry) + ACL_MAX_SHORT_ENTRY;
 	}
 }
 
diff --git a/fs/ext3/acl.h b/fs/ext3/acl.h
index dbc921e..b1cf2c0 100644
--- a/fs/ext3/acl.h
+++ b/fs/ext3/acl.h
@@ -25,13 +25,13 @@ typedef struct {
 
 static inline size_t ext3_acl_size(int count)
 {
-	if (count <= 4) {
+	if (count <= ACL_MAX_SHORT_ENTRY) {
 		return sizeof(ext3_acl_header) +
 		       count * sizeof(ext3_acl_entry_short);
 	} else {
 		return sizeof(ext3_acl_header) +
-		       4 * sizeof(ext3_acl_entry_short) +
-		       (count - 4) * sizeof(ext3_acl_entry);
+		       ACL_MAX_SHORT_ENTRY * sizeof(ext3_acl_entry_short) +
+		       (count - ACL_MAX_SHORT_ENTRY) * sizeof(ext3_acl_entry);
 	}
 }
 
@@ -39,7 +39,7 @@ static inline int ext3_acl_count(size_t size)
 {
 	ssize_t s;
 	size -= sizeof(ext3_acl_header);
-	s = size - 4 * sizeof(ext3_acl_entry_short);
+	s = size - ACL_MAX_SHORT_ENTRY * sizeof(ext3_acl_entry_short);
 	if (s < 0) {
 		if (size % sizeof(ext3_acl_entry_short))
 			return -1;
@@ -47,7 +47,7 @@ static inline int ext3_acl_count(size_t size)
 	} else {
 		if (s % sizeof(ext3_acl_entry))
 			return -1;
-		return s / sizeof(ext3_acl_entry) + 4;
+		return s / sizeof(ext3_acl_entry) + ACL_MAX_SHORT_ENTRY;
 	}
 }
 
diff --git a/fs/ext4/acl.h b/fs/ext4/acl.h
index 18cb39e..66d1fa3 100644
--- a/fs/ext4/acl.h
+++ b/fs/ext4/acl.h
@@ -25,13 +25,13 @@ typedef struct {
 
 static inline size_t ext4_acl_size(int count)
 {
-	if (count <= 4) {
+	if (count <= ACL_MAX_SHORT_ENTRY) {
 		return sizeof(ext4_acl_header) +
 		       count * sizeof(ext4_acl_entry_short);
 	} else {
 		return sizeof(ext4_acl_header) +
-		       4 * sizeof(ext4_acl_entry_short) +
-		       (count - 4) * sizeof(ext4_acl_entry);
+		       ACL_MAX_SHORT_ENTRY * sizeof(ext4_acl_entry_short) +
+		       (count - ACL_MAX_SHORT_ENTRY) * sizeof(ext4_acl_entry);
 	}
 }
 
@@ -39,7 +39,7 @@ static inline int ext4_acl_count(size_t size)
 {
 	ssize_t s;
 	size -= sizeof(ext4_acl_header);
-	s = size - 4 * sizeof(ext4_acl_entry_short);
+	s = size - ACL_MAX_SHORT_ENTRY * sizeof(ext4_acl_entry_short);
 	if (s < 0) {
 		if (size % sizeof(ext4_acl_entry_short))
 			return -1;
@@ -47,7 +47,7 @@ static inline int ext4_acl_count(size_t size)
 	} else {
 		if (s % sizeof(ext4_acl_entry))
 			return -1;
-		return s / sizeof(ext4_acl_entry) + 4;
+		return s / sizeof(ext4_acl_entry) + ACL_MAX_SHORT_ENTRY;
 	}
 }
 
diff --git a/fs/f2fs/acl.c b/fs/f2fs/acl.c
index fed74d1..42e0070 100644
--- a/fs/f2fs/acl.c
+++ b/fs/f2fs/acl.c
@@ -22,13 +22,15 @@
 
 static inline size_t f2fs_acl_size(int count)
 {
-	if (count <= 4) {
+	if (count <= ACL_MAX_SHORT_ENTRY) {
 		return sizeof(struct f2fs_acl_header) +
 			count * sizeof(struct f2fs_acl_entry_short);
 	} else {
 		return sizeof(struct f2fs_acl_header) +
-			4 * sizeof(struct f2fs_acl_entry_short) +
-			(count - 4) * sizeof(struct f2fs_acl_entry);
+			ACL_MAX_SHORT_ENTRY
+			 * sizeof(struct f2fs_acl_entry_short) +
+			(count - ACL_MAX_SHORT_ENTRY)
+			 * sizeof(struct f2fs_acl_entry);
 	}
 }
 
@@ -36,7 +38,7 @@ static inline int f2fs_acl_count(size_t size)
 {
 	ssize_t s;
 	size -= sizeof(struct f2fs_acl_header);
-	s = size - 4 * sizeof(struct f2fs_acl_entry_short);
+	s = size - ACL_MAX_SHORT_ENTRY * sizeof(struct f2fs_acl_entry_short);
 	if (s < 0) {
 		if (size % sizeof(struct f2fs_acl_entry_short))
 			return -1;
@@ -44,7 +46,7 @@ static inline int f2fs_acl_count(size_t size)
 	} else {
 		if (s % sizeof(struct f2fs_acl_entry))
 			return -1;
-		return s / sizeof(struct f2fs_acl_entry) + 4;
+		return s / sizeof(struct f2fs_acl_entry) + ACL_MAX_SHORT_ENTRY;
 	}
 }
 
diff --git a/fs/jffs2/acl.c b/fs/jffs2/acl.c
index 223283c..48ef4b8 100644
--- a/fs/jffs2/acl.c
+++ b/fs/jffs2/acl.c
@@ -25,13 +25,15 @@
 
 static size_t jffs2_acl_size(int count)
 {
-	if (count <= 4) {
+	if (count <= ACL_MAX_SHORT_ENTRY) {
 		return sizeof(struct jffs2_acl_header)
 		       + count * sizeof(struct jffs2_acl_entry_short);
 	} else {
 		return sizeof(struct jffs2_acl_header)
-		       + 4 * sizeof(struct jffs2_acl_entry_short)
-		       + (count - 4) * sizeof(struct jffs2_acl_entry);
+		       + ACL_MAX_SHORT_ENTRY
+				 * sizeof(struct jffs2_acl_entry_short)
+		       + (count - ACL_MAX_SHORT_ENTRY)
+				 * sizeof(struct jffs2_acl_entry);
 	}
 }
 
@@ -40,15 +42,16 @@ static int jffs2_acl_count(size_t size)
 	size_t s;
 
 	size -= sizeof(struct jffs2_acl_header);
-	if (size < 4 * sizeof(struct jffs2_acl_entry_short)) {
+	if (size < ACL_MAX_SHORT_ENTRY * sizeof(struct jffs2_acl_entry_short)) {
 		if (size % sizeof(struct jffs2_acl_entry_short))
 			return -1;
 		return size / sizeof(struct jffs2_acl_entry_short);
 	} else {
-		s = size - 4 * sizeof(struct jffs2_acl_entry_short);
+		s = size - ACL_MAX_SHORT_ENTRY
+				 * sizeof(struct jffs2_acl_entry_short);
 		if (s % sizeof(struct jffs2_acl_entry))
 			return -1;
-		return s / sizeof(struct jffs2_acl_entry) + 4;
+		return s / sizeof(struct jffs2_acl_entry) + ACL_MAX_SHORT_ENTRY;
 	}
 }
 
diff --git a/fs/reiserfs/acl.h b/fs/reiserfs/acl.h
index f096b80..cb967a3 100644
--- a/fs/reiserfs/acl.h
+++ b/fs/reiserfs/acl.h
@@ -20,13 +20,13 @@ typedef struct {
 
 static inline size_t reiserfs_acl_size(int count)
 {
-	if (count <= 4) {
+	if (count <= ACL_MAX_SHORT_ENTRY) {
 		return sizeof(reiserfs_acl_header) +
 		    count * sizeof(reiserfs_acl_entry_short);
 	} else {
 		return sizeof(reiserfs_acl_header) +
-		    4 * sizeof(reiserfs_acl_entry_short) +
-		    (count - 4) * sizeof(reiserfs_acl_entry);
+		    ACL_MAX_SHORT_ENTRY * sizeof(reiserfs_acl_entry_short) +
+		    (count - ACL_MAX_SHORT_ENTRY) * sizeof(reiserfs_acl_entry);
 	}
 }
 
@@ -34,7 +34,7 @@ static inline int reiserfs_acl_count(size_t size)
 {
 	ssize_t s;
 	size -= sizeof(reiserfs_acl_header);
-	s = size - 4 * sizeof(reiserfs_acl_entry_short);
+	s = size - ACL_MAX_SHORT_ENTRY * sizeof(reiserfs_acl_entry_short);
 	if (s < 0) {
 		if (size % sizeof(reiserfs_acl_entry_short))
 			return -1;
@@ -42,7 +42,7 @@ static inline int reiserfs_acl_count(size_t size)
 	} else {
 		if (s % sizeof(reiserfs_acl_entry))
 			return -1;
-		return s / sizeof(reiserfs_acl_entry) + 4;
+		return s / sizeof(reiserfs_acl_entry) + ACL_MAX_SHORT_ENTRY;
 	}
 }
 
diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h
index 7931efe..d75d2f6 100644
--- a/include/linux/posix_acl.h
+++ b/include/linux/posix_acl.h
@@ -26,6 +26,15 @@
 #define ACL_MASK		(0x10)
 #define ACL_OTHER		(0x20)
 
+/*
+ * ACL_USER_OBJ ACL_USER*[1] ACL_GROUP_OBJ ACL_GROUP*[1] ACL_MASK[2] ACL_OTHER
+ *
+ * [1] Where * is the regexp sense of "0 or more times"
+ * [2] Only if there is at least one ACL_USER or ACL_GROUP tag;
+ *     otherwise skip ACL_MASK.
+ */
+#define ACL_MAX_SHORT_ENTRY     (4)
+
 /* permissions in the e_perm field */
 #define ACL_READ		(0x04)
 #define ACL_WRITE		(0x02)
-- 
1.7.10.4
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