Patchwork ext3: set i_extra_isize of 11th inode

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Submitter Masayoshi MIZUMA
Date Aug. 20, 2010, 2:20 a.m.
Message ID <20100820112011.E6FA.61FB500B@jp.fujitsu.com>
Download mbox | patch
Permalink /patch/62247/
State Not Applicable
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Comments

Masayoshi MIZUMA - Aug. 20, 2010, 2:20 a.m.
Hi,

In ext3 filesystem, if following conditions 1., 2., 3. and 4. is satisfied,
getfattr can't search the extended attribute (EA) after remount.

Condition:
    1. the inode size is over 128 byte
    2. "lost+found" whose inode number is 11 was removed 
    3. the 11th inode is used for a file.
    4. the EA locates in-inode

This happens because of following logic:
    i_extra_isize is set to over 0 by ext3_new_inode() when we create
    a file whose inode number is 11 after removing "lost+found". 
    Therefore setfattr creates the EA in-inode.
    After remount, i_extra_isize of 11th inode is set to 0 by ext3_iget()
    when we lookup the file, so getfattr tries to search the EA out-inode.
    However, the EA locates in-inode, so getfattr can't search the EA.

How to reproduce:
    1. mkfs.ext3 -I 256 /dev/sdXX
    2. mount -o acl,user_xattr  /dev/sdXX /TEST
    3. rm -rf /TEST/*
    4. touch /TEST/file (whose inode number is 11)
    5. cd /TEST; setfattr -n user.foo0 -v bar0 file
    6. cd /TEST; getfattr -d file
       -> can see foo0/bar0
    7. umount  /dev/sdXX
    8. mount -o acl,user_xattr /dev/sdXX /TEST
    9. cd /TEST; getfattr -d file
       -> can't see foo0/bar0

Though the 11th inode is used for "lost+found" normally, the other
file can also use it. Therefore, i_extra_isize of 11th inode should be set
to the suitable value by ext3_iget().

Signed-off-by: Masayoshi MIZUMA <m.mizuma@jp.fujitsu.com>
---
 fs/ext3/inode.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)
Andreas Dilger - Aug. 20, 2010, 7:42 a.m.
On 2010-08-19, at 20:20, Masayoshi MIZUMA wrote:
> In ext3 filesystem, if following conditions 1., 2., 3. and 4. is satisfied,
> getfattr can't search the extended attribute (EA) after remount.
> 
> This happens because of following logic:
>    i_extra_isize is set to over 0 by ext3_new_inode() when we create
>    a file whose inode number is 11 after removing "lost+found". 
>    Therefore setfattr creates the EA in-inode.
>    After remount, i_extra_isize of 11th inode is set to 0 by ext3_iget()
>    when we lookup the file, so getfattr tries to search the EA out-inode.
>    However, the EA locates in-inode, so getfattr can't search the EA.

This was a workaround for a bug in mke2fs a couple of years ago, and is probably no longer needed.

> @@ -2881,8 +2881,7 @@ struct inode *ext3_iget(struct super_block *sb, unsigned long ino)
> 		atomic_set(&ei->i_datasync_tid, tid);
> 	}
> 
> -	if (inode->i_ino >= EXT3_FIRST_INO(inode->i_sb) + 1 &&
> -	    EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE) {
> +	if (EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE) {
> 		/*
> 		 * When mke2fs creates big inodes it does not zero out
> 		 * the unused bytes above EXT3_GOOD_OLD_INODE_SIZE,

This should also remove the above comment, which is no longer relevant.


Cheers, Andreas





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Masayoshi MIZUMA - Aug. 23, 2010, 12:16 a.m.
On Fri, 20 Aug 2010 01:42:25 -0600
Andreas Dilger <adilger@dilger.ca> wrote:

> On 2010-08-19, at 20:20, Masayoshi MIZUMA wrote:
> > In ext3 filesystem, if following conditions 1., 2., 3. and 4. is satisfied,
> > getfattr can't search the extended attribute (EA) after remount.
> > 
> > This happens because of following logic:
> >    i_extra_isize is set to over 0 by ext3_new_inode() when we create
> >    a file whose inode number is 11 after removing "lost+found". 
> >    Therefore setfattr creates the EA in-inode.
> >    After remount, i_extra_isize of 11th inode is set to 0 by ext3_iget()
> >    when we lookup the file, so getfattr tries to search the EA out-inode.
> >    However, the EA locates in-inode, so getfattr can't search the EA.
> 
> This was a workaround for a bug in mke2fs a couple of years ago, and is probably no longer needed.
I understand it. Thanks.

> 
> > @@ -2881,8 +2881,7 @@ struct inode *ext3_iget(struct super_block *sb, unsigned long ino)
> > 		atomic_set(&ei->i_datasync_tid, tid);
> > 	}
> > 
> > -	if (inode->i_ino >= EXT3_FIRST_INO(inode->i_sb) + 1 &&
> > -	    EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE) {
> > +	if (EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE) {
> > 		/*
> > 		 * When mke2fs creates big inodes it does not zero out
> > 		 * the unused bytes above EXT3_GOOD_OLD_INODE_SIZE,
> 
> This should also remove the above comment, which is no longer relevant.
OK. I will resend the patch which is removed the above comment.

Thanks,
Masayoshi

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Patch

diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c
index 735f019..85e8574 100644
--- a/fs/ext3/inode.c
+++ b/fs/ext3/inode.c
@@ -2881,8 +2881,7 @@  struct inode *ext3_iget(struct super_block *sb, unsigned long ino)
 		atomic_set(&ei->i_datasync_tid, tid);
 	}
 
-	if (inode->i_ino >= EXT3_FIRST_INO(inode->i_sb) + 1 &&
-	    EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE) {
+	if (EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE) {
 		/*
 		 * When mke2fs creates big inodes it does not zero out
 		 * the unused bytes above EXT3_GOOD_OLD_INODE_SIZE,