linux-ext4 - Re: [PATCH 02/24] debugfs: Only print the first 60 bytes from i

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Date:	Sat, 19 Jul 2014 10:49:35 -0600
From:	Andreas Dilger <adilger@...ger.ca>
To:	"Darrick J. Wong" <darrick.wong@...cle.com>
Cc:	"tytso@....edu" <tytso@....edu>,
	"linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>
Subject: Re: [PATCH 02/24] debugfs: Only print the first 60 bytes from i_block on a fast symlink

Wouldn't it be better to decode and print the whole symlink from the inline data?  Depending on the use of debugfs, printing only the first 60 bytes may cause people/scripts to think the link is corrupted. 

Cheers, Andreas

> On Jul 18, 2014, at 16:52, "Darrick J. Wong" <darrick.wong@...cle.com> wrote:
> 
> If we have an inline_data fast symlink, i_size can be larger than the
> size of i_block.  In this case, debugfs prints off the end of the
> buffer, so fix that.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com>
> ---
> debugfs/debugfs.c            |   15 ++++++++++-----
> tests/d_special_files/expect |    2 +-
> 2 files changed, 11 insertions(+), 6 deletions(-)
> 
> 
> diff --git a/debugfs/debugfs.c b/debugfs/debugfs.c
> index 51f386b..5eecabe 100644
> --- a/debugfs/debugfs.c
> +++ b/debugfs/debugfs.c
> @@ -783,11 +783,16 @@ void internal_dump_inode(FILE *out, const char *prefix,
>    }
> 
>    if (LINUX_S_ISLNK(inode->i_mode) &&
> -        ext2fs_inode_data_blocks(current_fs,inode) == 0 &&
> -        !(inode->i_flags & EXT4_INLINE_DATA_FL))
> -        fprintf(out, "%sFast_link_dest: %.*s\n", prefix,
> -            (int) inode->i_size, (char *)inode->i_block);
> -    else if (LINUX_S_ISBLK(inode->i_mode) || LINUX_S_ISCHR(inode->i_mode)) {
> +        ext2fs_inode_data_blocks(current_fs, inode) == 0 &&
> +        !(inode->i_flags & EXT4_INLINE_DATA_FL)) {
> +        int sz = EXT2_I_SIZE(inode);
> +
> +        if (sz > sizeof(inode->i_block))
> +            sz = sizeof(inode->i_block);
> +        fprintf(out, "%sFast link dest: \"%.*s\"\n", prefix, sz,
> +            (char *)inode->i_block);
> +    } else if (LINUX_S_ISBLK(inode->i_mode) ||
> +           LINUX_S_ISCHR(inode->i_mode)) {
>        int major, minor;
>        const char *devnote;
> 
> diff --git a/tests/d_special_files/expect b/tests/d_special_files/expect
> index 2b2dbfa..f729b0f 100644
> --- a/tests/d_special_files/expect
> +++ b/tests/d_special_files/expect
> @@ -11,7 +11,7 @@ Fragment:  Address: 0    Number: 0    Size: 0
> ctime: 0x50f560e0 -- Tue Jan 15 14:00:00 2013
> atime: 0x50f560e0 -- Tue Jan 15 14:00:00 2013
> mtime: 0x50f560e0 -- Tue Jan 15 14:00:00 2013
> -Fast_link_dest: bar
> +Fast link dest: "bar"
> Exit status is 0
> debugfs -R ''stat foo2'' -w test.img
> Inode: 13   Type: symlink    Mode:  0777   Flags: 0x0
> 
> --
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