lkml.org 
[lkml]   [2018]   [Sep]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.18 043/123] ext4: sysfs: print ext4_super_block fields as little-endian
    Date
    4.18-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Arnd Bergmann <arnd@arndb.de>

    commit a4d2aadca184ece182418950d45ba4ffc7b652d2 upstream.

    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")
    Reviewed-by: Andreas Dilger <adilger@dilger.ca>
    Signed-off-by: Arnd Bergmann <arnd@arndb.de>
    Signed-off-by: Theodore Ts'o <tytso@mit.edu>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    fs/ext4/sysfs.c | 13 ++++++++++---
    1 file changed, 10 insertions(+), 3 deletions(-)

    --- a/fs/ext4/sysfs.c
    +++ b/fs/ext4/sysfs.c
    @@ -274,8 +274,12 @@ static ssize_t ext4_attr_show(struct kob
    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 ko
    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);

    \
     
     \ /
      Last update: 2018-09-03 19:34    [W:4.195 / U:0.260 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site