From: Arnd Bergmann <arnd@arndb.de>
To: Theodore Ts'o <tytso@mit.edu>,
Andreas Dilger <adilger.kernel@dilger.ca>,
Jan Kara <jack@suse.com>
Cc: y2038@lists.linaro.org, linux-ext4@vger.kernel.org,
Arnd Bergmann <arnd@arndb.de>,
stable@vger.kernel.org, Tyson Nottingham <tgnottingham@gmail.com>,
Riccardo Schirone <sirmy15@gmail.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH 1/6] ext4: sysfs: print ext4_super_block fields as little-endian
Date: Wed, 20 Jun 2018 17:32:58 +0200 [thread overview]
Message-ID: <20180620153322.54221-1-arnd@arndb.de> (raw)
While working on extended rand for last_error/first_error timestamps,
I noticed that the endianess is wrong, we access the little-endian
fields in struct ext4_super_block as native-endian when we print them.
This adds a special case in ext4_attr_show() and ext4_attr_store()
to byteswap the superblock fields if needed.
In older kernels, this code was part of super.c, it got moved to sysfs.c
in linux-4.4.
Cc: stable@vger.kernel.org
Fixes: 52c198c6820f ("ext4: add sysfs entry showing whether the fs contains errors")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
fs/ext4/sysfs.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c
index f34da0bb8f17..b970a200f20c 100644
--- a/fs/ext4/sysfs.c
+++ b/fs/ext4/sysfs.c
@@ -274,8 +274,12 @@ static ssize_t ext4_attr_show(struct kobject *kobj,
case attr_pointer_ui:
if (!ptr)
return 0;
- return snprintf(buf, PAGE_SIZE, "%u\n",
- *((unsigned int *) ptr));
+ if (a->attr_ptr == ptr_ext4_super_block_offset)
+ return snprintf(buf, PAGE_SIZE, "%u\n",
+ le32_to_cpup(ptr));
+ else
+ return snprintf(buf, PAGE_SIZE, "%u\n",
+ *((unsigned int *) ptr));
case attr_pointer_atomic:
if (!ptr)
return 0;
@@ -308,7 +312,10 @@ static ssize_t ext4_attr_store(struct kobject *kobj,
ret = kstrtoul(skip_spaces(buf), 0, &t);
if (ret)
return ret;
- *((unsigned int *) ptr) = t;
+ if (a->attr_ptr == ptr_ext4_super_block_offset)
+ *((__le32 *) ptr) = cpu_to_le32(t);
+ else
+ *((unsigned int *) ptr) = t;
return len;
case attr_inode_readahead:
return inode_readahead_blks_store(sbi, buf, len);
--
2.9.0
next reply other threads:[~2018-06-20 15:34 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-20 15:32 Arnd Bergmann [this message]
2018-06-20 15:32 ` [PATCH 2/6] ext4: use 64-bit timestamps for mmp_time Arnd Bergmann
2018-06-21 17:20 ` Andreas Dilger
2018-06-22 7:38 ` Jan Kara
2018-06-20 15:33 ` [PATCH 3/6] ext4: use ktime_get_real_seconds for i_dtime Arnd Bergmann
2018-06-21 17:27 ` Andreas Dilger
2018-06-21 20:07 ` Arnd Bergmann
2018-06-20 15:33 ` [PATCH 4/6] ext4: use timespec64 for all inode times Arnd Bergmann
2018-06-21 17:29 ` Andreas Dilger
2018-06-22 7:37 ` Jan Kara
2018-06-22 8:15 ` Arnd Bergmann
2018-06-20 15:33 ` [PATCH 5/6] jbd2: replace current_kernel_time64 with ktime equivalent Arnd Bergmann
2018-06-21 17:32 ` Andreas Dilger
2018-06-22 7:41 ` Jan Kara
2018-06-20 15:33 ` [PATCH 6/6] [RFC] ext4: super: extend timestamps to 40 bits Arnd Bergmann
2018-06-21 17:46 ` Andreas Dilger
2018-06-21 20:17 ` Arnd Bergmann
2018-06-21 17:49 ` [PATCH 1/6] ext4: sysfs: print ext4_super_block fields as little-endian Andreas Dilger
2018-06-21 20:07 ` Arnd Bergmann
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