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Date: Mon, 7 Jan 2013 20:20:16 +0100
From: Jan Kara <jack@...e.cz>
To: Chen Gang <gang.chen@...anux.com>
Cc: jack@...e.cz, akpm@...ux-foundation.org, adilger.kernel@...ger.ca,
Theodore Ts'o <tytso@....edu>, jaegeuk.kim@...sung.com,
dwmw2@...radead.org, torvalds@...ux-foundation.org,
linux-ext4@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net,
linux-mtd@...ts.infradead.org, reiserfs-devel@...r.kernel.org
Subject: Re: [PATCH v3] fs/ext*,f2fs,jffs2,reiserfs: give comments for acl
size and count calculation
On Fri 04-01-13 11:26:53, Chen Gang wrote:
>
> 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.
Note that I actually updated the entry [2] to be more precise in my
suggested comment. I wrote:
[2] If ACL_USER or ACL_GROUP is present, then ACL_MASK must be present.
Please use this formulation because the old version suggests ACL_MASK
cannot be present if neither ACL_USER nor ACL_GROUP are present and that's
not true. Otherwise your patch looks fine. Thanks!
Honza
>
> give comments (by Jan Kara)
> posix_acl_valid() makes sure that if there are <= 4 ACL entries, then
> all of them are short. Otherwise exactly 4 entries are short ones and
> other have full length. See comment before that function for exact ACL
> format.
>
> use macro instead of hard code number (by Chen Gang)
>
> Signed-off-by: Theodore Ts'o <tytso@....edu>
> Signed-off-by: Jan Kara <jack@...e.cz>
> Signed-off-by: Chen Gang <gang.chen@...anux.com>
> ---
> 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/posix_acl.c | 8 ++++++++
> fs/reiserfs/acl.h | 10 +++++-----
> include/linux/posix_acl.h | 8 ++++++++
> 8 files changed, 52 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/posix_acl.c b/fs/posix_acl.c
> index 8bd2135..8cfdebe 100644
> --- a/fs/posix_acl.c
> +++ b/fs/posix_acl.c
> @@ -72,6 +72,14 @@ posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
>
> /*
> * Check if an acl is valid. Returns 0 if it is, or -E... otherwise.
> + *
> + * make sure ACL format is the following:
> + *
> + * 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.
> */
> int
> posix_acl_valid(const struct posix_acl *acl)
> 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..2c5609c 100644
> --- a/include/linux/posix_acl.h
> +++ b/include/linux/posix_acl.h
> @@ -26,6 +26,14 @@
> #define ACL_MASK (0x10)
> #define ACL_OTHER (0x20)
>
> +/*
> + * posix_acl_valid() makes sure that if there are <= 4 ACL entries, then
> + * all of them are short. Otherwise exactly 4 entries are short ones and
> + * other have full length. See comment before that function for exact ACL
> + * format.
> + */
> +#define ACL_MAX_SHORT_ENTRY 4
> +
> /* permissions in the e_perm field */
> #define ACL_READ (0x04)
> #define ACL_WRITE (0x02)
> --
> 1.7.10.4
--
Jan Kara <jack@...e.cz>
SUSE Labs, CR
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