[PATCH v3] xfs: fix the symbolic link assert in xfs_ifree

[PATCH v3] xfs: fix the symbolic link assert in xfs_ifree

[Mark Tinguely]

[-- Attachment #1: v3-xfs-fix-assert-in-xfs_ifree.patch --]
[-- Type: text/plain, Size: 4213 bytes --]

Adding an extended attribute to a symbolic link can force that
link to an remote extent. xfs_inactive() incorrectly assumes
that any symbolic link small enough to be in the inode core
is incore, resulting in the remote extent to not be removed.
xfs_ifree() will assert on presence of this leaked remote extent.

Signed-off-by: Mark Tinguely <tinguely@sgi.com>
---
 fs/xfs/xfs_symlink.c  |   49 +++++++++++++++++++++++++++++++++++++++++++++++--
 fs/xfs/xfs_symlink.h  |    2 +-
 fs/xfs/xfs_trace.h    |    2 ++
 fs/xfs/xfs_vnodeops.c |   15 +++------------
 4 files changed, 53 insertions(+), 15 deletions(-)

Index: b/fs/xfs/xfs_symlink.c
===================================================================
--- a/fs/xfs/xfs_symlink.c
+++ b/fs/xfs/xfs_symlink.c
@@ -585,7 +585,7 @@ xfs_symlink(
 /*
  * Free a symlink that has blocks associated with it.
  */
-int
+STATIC int
 xfs_inactive_symlink_rmt(
 	xfs_inode_t	*ip,
 	xfs_trans_t	**tpp)
@@ -606,7 +606,7 @@ xfs_inactive_symlink_rmt(
 
 	tp = *tpp;
 	mp = ip->i_mount;
-	ASSERT(ip->i_d.di_size > XFS_IFORK_DSIZE(ip));
+	ASSERT(ip->i_df.if_flags & XFS_IFEXTENTS);
 	/*
 	 * We're freeing a symlink that has some
 	 * blocks allocated to it.  Free the
@@ -720,3 +720,48 @@ xfs_inactive_symlink_rmt(
  error0:
 	return error;
 }
+
+/*
+ * xfs_inactive_symlink - free a symlink
+ */
+int
+xfs_inactive_symlink(
+	struct xfs_inode	*ip,
+	struct xfs_trans	**tp)
+{
+	struct xfs_mount *mp = ip->i_mount;
+	xfs_fsize_t	pathlen;
+
+	trace_xfs_readlink(ip);
+
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
+
+	if (XFS_FORCED_SHUTDOWN(mp))
+		return XFS_ERROR(EIO);
+
+	/*
+	 * Zero length symlinks _can_ exist.
+	 */
+	pathlen = ip->i_d.di_size;
+	if (!pathlen)
+		return 0;
+
+	if (pathlen < 0 || pathlen > MAXPATHLEN) {
+		xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",
+			 __func__, (unsigned long long) ip->i_ino,
+			 (long long) pathlen);
+		ASSERT(0);
+		return XFS_ERROR(EFSCORRUPTED);
+	}
+
+	if (ip->i_df.if_flags & XFS_IFINLINE) {
+		if (ip->i_df.if_bytes > 0)
+			xfs_idata_realloc(ip, -(ip->i_df.if_bytes),
+					  XFS_DATA_FORK);
+		ASSERT(ip->i_df.if_bytes == 0);
+		return 0;
+	}
+
+	/* remove the remote symlink */
+	return(xfs_inactive_symlink_rmt(ip, tp));
+}
Index: b/fs/xfs/xfs_symlink.h
===================================================================
--- a/fs/xfs/xfs_symlink.h
+++ b/fs/xfs/xfs_symlink.h
@@ -60,7 +60,7 @@ extern const struct xfs_buf_ops xfs_syml
 int xfs_symlink(struct xfs_inode *dp, struct xfs_name *link_name,
 		const char *target_path, umode_t mode, struct xfs_inode **ipp);
 int xfs_readlink(struct xfs_inode *ip, char *link);
-int xfs_inactive_symlink_rmt(struct xfs_inode *ip, struct xfs_trans **tpp);
+int xfs_inactive_symlink(struct xfs_inode *ip, struct xfs_trans **tpp);
 
 #endif /* __KERNEL__ */
 #endif /* __XFS_SYMLINK_H */
Index: b/fs/xfs/xfs_trace.h
===================================================================
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -594,6 +594,8 @@ DEFINE_INODE_EVENT(xfs_inode_set_eofbloc
 DEFINE_INODE_EVENT(xfs_inode_clear_eofblocks_tag);
 DEFINE_INODE_EVENT(xfs_inode_free_eofblocks_invalid);
 
+DEFINE_INODE_EVENT(xfs_symlink_inactive);
+
 DECLARE_EVENT_CLASS(xfs_iref_class,
 	TP_PROTO(struct xfs_inode *ip, unsigned long caller_ip),
 	TP_ARGS(ip, caller_ip),
Index: b/fs/xfs/xfs_vnodeops.c
===================================================================
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -322,18 +322,9 @@ xfs_inactive(
 	xfs_trans_ijoin(tp, ip, 0);
 
 	if (S_ISLNK(ip->i_d.di_mode)) {
-		/*
-		 * Zero length symlinks _can_ exist.
-		 */
-		if (ip->i_d.di_size > XFS_IFORK_DSIZE(ip)) {
-			error = xfs_inactive_symlink_rmt(ip, &tp);
-			if (error)
-				goto out_cancel;
-		} else if (ip->i_df.if_bytes > 0) {
-			xfs_idata_realloc(ip, -(ip->i_df.if_bytes),
-					  XFS_DATA_FORK);
-			ASSERT(ip->i_df.if_bytes == 0);
-		}
+		error = xfs_inactive_symlink(ip, &tp);
+		if (error)
+			goto out_cancel;
 	} else if (truncate) {
 		ip->i_d.di_size = 0;
 		xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);


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Re: [PATCH v3] xfs: fix the symbolic link assert in xfs_ifree

[Mark Tinguely]

On 06/13/13 12:04, Mark Tinguely wrote:
> race_xfs_readlink(ip);
> +

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Re: [PATCH v3] xfs: fix the symbolic link assert in xfs_ifree

[Mark Tinguely]

On 06/13/13 12:50, Mark Tinguely wrote:
> On 06/13/13 12:04, Mark Tinguely wrote:
>> race_xfs_readlink(ip);
>> +
>

Augh, one of those days - oops I got the wrong trace in this version of 
the patch... should be trace_xfs_symlink_inactive(ip) added in xfs_trace.h

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Re: [PATCH v3] xfs: fix the symbolic link assert in xfs_ifree

[Dave Chinner]

On Thu, Jun 13, 2013 at 12:04:49PM -0500, Mark Tinguely wrote:
> Adding an extended attribute to a symbolic link can force that
> link to an remote extent. xfs_inactive() incorrectly assumes
> that any symbolic link small enough to be in the inode core
> is incore, resulting in the remote extent to not be removed.
> xfs_ifree() will assert on presence of this leaked remote extent.
> 
> Signed-off-by: Mark Tinguely <tinguely@sgi.com>
.....
> +/*
> + * xfs_inactive_symlink - free a symlink
> + */
> +int
> +xfs_inactive_symlink(
> +	struct xfs_inode	*ip,
> +	struct xfs_trans	**tp)
> +{
> +	struct xfs_mount *mp = ip->i_mount;
> +	xfs_fsize_t	pathlen;

int will do here - it can't be more than MAXPATHLEN = 1024, and this
gets rid of the casts in the error print.

> +
> +	trace_xfs_readlink(ip);

trace_xfs_inactive_symlink, as you mentioned ;)

> +
> +	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
> +
> +	if (XFS_FORCED_SHUTDOWN(mp))
> +		return XFS_ERROR(EIO);
> +
> +	/*
> +	 * Zero length symlinks _can_ exist.
> +	 */
> +	pathlen = ip->i_d.di_size;
> +	if (!pathlen)
> +		return 0;
> +
> +	if (pathlen < 0 || pathlen > MAXPATHLEN) {
> +		xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",
> +			 __func__, (unsigned long long) ip->i_ino,
                                                       ^ whitespace
> +			 (long long) pathlen);

Can we change this to a hex-based inode number (much easier to read)
and the pathlen cast can go away if you use an int. i.e.:

		xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)",
			 __func__, (unsigned long long)ip->i_ino, pathlen);


> +		ASSERT(0);
> +		return XFS_ERROR(EFSCORRUPTED);
> +	}
> +
> +	if (ip->i_df.if_flags & XFS_IFINLINE) {
> +		if (ip->i_df.if_bytes > 0)
> +			xfs_idata_realloc(ip, -(ip->i_df.if_bytes),
> +					  XFS_DATA_FORK);
> +		ASSERT(ip->i_df.if_bytes == 0);
> +		return 0;
> +	}
> +
> +	/* remove the remote symlink */
> +	return(xfs_inactive_symlink_rmt(ip, tp));

And no () around xfs_inactive_symlink_rmt().

> +}
> Index: b/fs/xfs/xfs_symlink.h
> ===================================================================
> --- a/fs/xfs/xfs_symlink.h
> +++ b/fs/xfs/xfs_symlink.h
> @@ -60,7 +60,7 @@ extern const struct xfs_buf_ops xfs_syml
>  int xfs_symlink(struct xfs_inode *dp, struct xfs_name *link_name,
>  		const char *target_path, umode_t mode, struct xfs_inode **ipp);
>  int xfs_readlink(struct xfs_inode *ip, char *link);
> -int xfs_inactive_symlink_rmt(struct xfs_inode *ip, struct xfs_trans **tpp);
> +int xfs_inactive_symlink(struct xfs_inode *ip, struct xfs_trans **tpp);
>  
>  #endif /* __KERNEL__ */
>  #endif /* __XFS_SYMLINK_H */
> Index: b/fs/xfs/xfs_trace.h
> ===================================================================
> --- a/fs/xfs/xfs_trace.h
> +++ b/fs/xfs/xfs_trace.h
> @@ -594,6 +594,8 @@ DEFINE_INODE_EVENT(xfs_inode_set_eofbloc
>  DEFINE_INODE_EVENT(xfs_inode_clear_eofblocks_tag);
>  DEFINE_INODE_EVENT(xfs_inode_free_eofblocks_invalid);
>  
> +DEFINE_INODE_EVENT(xfs_symlink_inactive);
> +

No need for the extra whitespace, just put it hard up against the
other DEFINE_INODE_EVENT()s. Might be better to put it directly
after the readlink trace definition.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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Re: [PATCH v3] xfs: fix the symbolic link assert in xfs_ifree

[Mark Tinguely]

On 06/13/13 21:17, Dave Chinner wrote:
> On Thu, Jun 13, 2013 at 12:04:49PM -0500, Mark Tinguely wrote:
>> Adding an extended attribute to a symbolic link can force that
>> link to an remote extent. xfs_inactive() incorrectly assumes
>> that any symbolic link small enough to be in the inode core
>> is incore, resulting in the remote extent to not be removed.
>> xfs_ifree() will assert on presence of this leaked remote extent.
>>
>> Signed-off-by: Mark Tinguely<tinguely@sgi.com>
> .....
>> +/*
>> + * xfs_inactive_symlink - free a symlink
>> + */
>> +int
>> +xfs_inactive_symlink(
>> +	struct xfs_inode	*ip,
>> +	struct xfs_trans	**tp)
>> +{
>> +	struct xfs_mount *mp = ip->i_mount;
>> +	xfs_fsize_t	pathlen;
>
> int will do here - it can't be more than MAXPATHLEN = 1024, and this
> gets rid of the casts in the error print.
>
>> +
>> +	trace_xfs_readlink(ip);
>
> trace_xfs_inactive_symlink, as you mentioned ;)

sigh, and I reverted the inactive and symlink in the trace below. sigh 
again.

>
>> +
>> +	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
>> +
>> +	if (XFS_FORCED_SHUTDOWN(mp))
>> +		return XFS_ERROR(EIO);
>> +
>> +	/*
>> +	 * Zero length symlinks _can_ exist.
>> +	 */
>> +	pathlen = ip->i_d.di_size;
>> +	if (!pathlen)
>> +		return 0;
>> +
>> +	if (pathlen<  0 || pathlen>  MAXPATHLEN) {
>> +		xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",
>> +			 __func__, (unsigned long long) ip->i_ino,
>                                                         ^ whitespace
>> +			 (long long) pathlen);
>
> Can we change this to a hex-based inode number (much easier to read)
> and the pathlen cast can go away if you use an int. i.e.:
>
> 		xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)",
> 			 __func__, (unsigned long long)ip->i_ino, pathlen);
>
>

Both of the items above were stole directly from xfs_readlink().
Thought they should be consistent(ly wrong :) ).


>> +		ASSERT(0);
>> +		return XFS_ERROR(EFSCORRUPTED);
>> +	}
>> +
>> +	if (ip->i_df.if_flags&  XFS_IFINLINE) {
>> +		if (ip->i_df.if_bytes>  0)
>> +			xfs_idata_realloc(ip, -(ip->i_df.if_bytes),
>> +					  XFS_DATA_FORK);
>> +		ASSERT(ip->i_df.if_bytes == 0);
>> +		return 0;
>> +	}
>> +
>> +	/* remove the remote symlink */
>> +	return(xfs_inactive_symlink_rmt(ip, tp));
>
> And no () around xfs_inactive_symlink_rmt().

>
>> +}
>> Index: b/fs/xfs/xfs_symlink.h
>> ===================================================================
>> --- a/fs/xfs/xfs_symlink.h
>> +++ b/fs/xfs/xfs_symlink.h
>> @@ -60,7 +60,7 @@ extern const struct xfs_buf_ops xfs_syml
>>   int xfs_symlink(struct xfs_inode *dp, struct xfs_name *link_name,
>>   		const char *target_path, umode_t mode, struct xfs_inode **ipp);
>>   int xfs_readlink(struct xfs_inode *ip, char *link);
>> -int xfs_inactive_symlink_rmt(struct xfs_inode *ip, struct xfs_trans **tpp);
>> +int xfs_inactive_symlink(struct xfs_inode *ip, struct xfs_trans **tpp);
>>
>>   #endif /* __KERNEL__ */
>>   #endif /* __XFS_SYMLINK_H */
>> Index: b/fs/xfs/xfs_trace.h
>> ===================================================================
>> --- a/fs/xfs/xfs_trace.h
>> +++ b/fs/xfs/xfs_trace.h
>> @@ -594,6 +594,8 @@ DEFINE_INODE_EVENT(xfs_inode_set_eofbloc
>>   DEFINE_INODE_EVENT(xfs_inode_clear_eofblocks_tag);
>>   DEFINE_INODE_EVENT(xfs_inode_free_eofblocks_invalid);
>>
>> +DEFINE_INODE_EVENT(xfs_symlink_inactive);
>> +
>
> No need for the extra whitespace, just put it hard up against the
> other DEFINE_INODE_EVENT()s. Might be better to put it directly
> after the readlink trace definition.
>
> Cheers,
>
> Dave.

Thanks.

--Mark.

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