Re: [PATCH 1/5] xfs: cleanup uuid handling

[Christoph Hellwig <hch@infradead.org>]

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On Wed, Mar 18, 2009 at 05:41:20AM -0400, Christoph Hellwig wrote:
> The uuid table handling should not be part of a semi-generic uuid library
> but in the XFS code using it, so move those bits to xfs_mount.c and
> refactor the whole glob to give a proper abstraction.
> 
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> 
> Index: xfs/fs/xfs/support/uuid.c
> ===================================================================
> --- xfs.orig/fs/xfs/support/uuid.c	2009-02-15 19:40:08.564944522 +0100
> +++ xfs/fs/xfs/support/uuid.c	2009-02-24 21:50:49.051029140 +0100
> @@ -17,10 +17,6 @@
>   */
>  #include <xfs.h>
>  
> -static DEFINE_MUTEX(uuid_monitor);
> -static int	uuid_table_size;
> -static uuid_t	*uuid_table;
> -
>  /* IRIX interpretation of an uuid_t */
>  typedef struct {
>  	__be32	uu_timelow;
> @@ -46,12 +42,6 @@ uuid_getnodeuniq(uuid_t *uuid, int fsid 
>  	fsid[1] = be32_to_cpu(uup->uu_timelow);
>  }
>  
> -void
> -uuid_create_nil(uuid_t *uuid)
> -{
> -	memset(uuid, 0, sizeof(*uuid));
> -}
> -
>  int
>  uuid_is_nil(uuid_t *uuid)
>  {
> @@ -71,64 +61,3 @@ uuid_equal(uuid_t *uuid1, uuid_t *uuid2)
>  {
>  	return memcmp(uuid1, uuid2, sizeof(uuid_t)) ? 0 : 1;
>  }
> -
> -/*
> - * Given a 128-bit uuid, return a 64-bit value by adding the top and bottom
> - * 64-bit words.  NOTE: This function can not be changed EVER.  Although
> - * brain-dead, some applications depend on this 64-bit value remaining
> - * persistent.  Specifically, DMI vendors store the value as a persistent
> - * filehandle.
> - */
> -__uint64_t
> -uuid_hash64(uuid_t *uuid)
> -{
> -	__uint64_t	*sp = (__uint64_t *)uuid;
> -
> -	return sp[0] + sp[1];
> -}
> -
> -int
> -uuid_table_insert(uuid_t *uuid)
> -{
> -	int	i, hole;
> -
> -	mutex_lock(&uuid_monitor);
> -	for (i = 0, hole = -1; i < uuid_table_size; i++) {
> -		if (uuid_is_nil(&uuid_table[i])) {
> -			hole = i;
> -			continue;
> -		}
> -		if (uuid_equal(uuid, &uuid_table[i])) {
> -			mutex_unlock(&uuid_monitor);
> -			return 0;
> -		}
> -	}
> -	if (hole < 0) {
> -		uuid_table = kmem_realloc(uuid_table,
> -			(uuid_table_size + 1) * sizeof(*uuid_table),
> -			uuid_table_size  * sizeof(*uuid_table),
> -			KM_SLEEP);
> -		hole = uuid_table_size++;
> -	}
> -	uuid_table[hole] = *uuid;
> -	mutex_unlock(&uuid_monitor);
> -	return 1;
> -}
> -
> -void
> -uuid_table_remove(uuid_t *uuid)
> -{
> -	int	i;
> -
> -	mutex_lock(&uuid_monitor);
> -	for (i = 0; i < uuid_table_size; i++) {
> -		if (uuid_is_nil(&uuid_table[i]))
> -			continue;
> -		if (!uuid_equal(uuid, &uuid_table[i]))
> -			continue;
> -		uuid_create_nil(&uuid_table[i]);
> -		break;
> -	}
> -	ASSERT(i < uuid_table_size);
> -	mutex_unlock(&uuid_monitor);
> -}
> Index: xfs/fs/xfs/support/uuid.h
> ===================================================================
> --- xfs.orig/fs/xfs/support/uuid.h	2009-02-15 19:40:08.569944670 +0100
> +++ xfs/fs/xfs/support/uuid.h	2009-02-24 21:50:37.206029255 +0100
> @@ -22,12 +22,8 @@ typedef struct {
>  	unsigned char	__u_bits[16];
>  } uuid_t;
>  
> -extern void uuid_create_nil(uuid_t *uuid);
>  extern int uuid_is_nil(uuid_t *uuid);
>  extern int uuid_equal(uuid_t *uuid1, uuid_t *uuid2);
>  extern void uuid_getnodeuniq(uuid_t *uuid, int fsid [2]);
> -extern __uint64_t uuid_hash64(uuid_t *uuid);
> -extern int uuid_table_insert(uuid_t *uuid);
> -extern void uuid_table_remove(uuid_t *uuid);
>  
>  #endif	/* __XFS_SUPPORT_UUID_H__ */
> Index: xfs/fs/xfs/xfs_mount.c
> ===================================================================
> --- xfs.orig/fs/xfs/xfs_mount.c	2009-02-24 15:32:35.871518446 +0100
> +++ xfs/fs/xfs/xfs_mount.c	2009-02-24 21:51:03.558027729 +0100
> @@ -45,7 +45,6 @@
>  #include "xfs_fsops.h"
>  #include "xfs_utils.h"
>  
> -STATIC int	xfs_uuid_mount(xfs_mount_t *);
>  STATIC void	xfs_unmountfs_wait(xfs_mount_t *);
>  
>  
> @@ -121,6 +120,84 @@ static const struct {
>      { sizeof(xfs_sb_t),			 0 }
>  };
>  
> +static DEFINE_MUTEX(xfs_uuid_table_mutex);
> +static int xfs_uuid_table_size;
> +static uuid_t *xfs_uuid_table;
> +
> +/*
> + * See if the UUID is unique among mounted XFS filesystems.
> + * Mount fails if UUID is nil or a FS with the same UUID is already mounted.
> + */
> +STATIC int
> +xfs_uuid_mount(
> +	struct xfs_mount	*mp)
> +{
> +	uuid_t			*uuid = &mp->m_sb.sb_uuid;
> +	int			hole, i;
> +
> +	if (mp->m_flags & XFS_MOUNT_NOUUID)
> +		return 0;
> +
> +	if (uuid_is_nil(uuid)) {
> +		cmn_err(CE_WARN,
> +			"XFS: Filesystem %s has nil UUID - can't mount",
> +			mp->m_fsname);
> +		return XFS_ERROR(EINVAL);
> +	}
> +
> +	mutex_lock(&xfs_uuid_table_mutex);
> +	for (i = 0, hole = -1; i < xfs_uuid_table_size; i++) {
> +		if (uuid_is_nil(&xfs_uuid_table[i])) {
> +			hole = i;
> +			continue;
> +		}
> +		if (uuid_equal(uuid, &xfs_uuid_table[i]))
> +			goto out_duplicate;
> +	}
> +
> +	if (hole < 0) {
> +		xfs_uuid_table = kmem_realloc(xfs_uuid_table,
> +			(xfs_uuid_table_size + 1) * sizeof(*xfs_uuid_table),
> +			xfs_uuid_table_size  * sizeof(*xfs_uuid_table),
> +			KM_SLEEP);
> +		hole = xfs_uuid_table_size++;
> +	}
> +	xfs_uuid_table[hole] = *uuid;
> +	mutex_unlock(&xfs_uuid_table_mutex);
> +
> +	return 0;
> +
> + out_duplicate:
> +	mutex_unlock(&xfs_uuid_table_mutex);
> +	cmn_err(CE_WARN, "XFS: Filesystem %s has duplicate UUID - can't mount",
> +			 mp->m_fsname);
> +	return XFS_ERROR(EINVAL);
> +}
> +
> +STATIC void
> +xfs_uuid_unmount(
> +	struct xfs_mount	*mp)
> +{
> +	uuid_t			*uuid = &mp->m_sb.sb_uuid;
> +	int			i;
> +
> +	if (mp->m_flags & XFS_MOUNT_NOUUID)
> +		return;
> +
> +	mutex_lock(&xfs_uuid_table_mutex);
> +	for (i = 0; i < xfs_uuid_table_size; i++) {
> +		if (uuid_is_nil(&xfs_uuid_table[i]))
> +			continue;
> +		if (!uuid_equal(uuid, &xfs_uuid_table[i]))
> +			continue;
> +		memset(&xfs_uuid_table[i], 0, sizeof(uuid_t));
> +		break;
> +	}
> +	ASSERT(i < xfs_uuid_table_size);
> +	mutex_unlock(&xfs_uuid_table_mutex);
> +}
> +
> +
>  /*
>   * Free up the resources associated with a mount structure.  Assume that
>   * the structure was initially zeroed, so we can tell which fields got
> @@ -1016,18 +1093,9 @@ xfs_mountfs(
>  
>  	mp->m_maxioffset = xfs_max_file_offset(sbp->sb_blocklog);
>  
> -	/*
> -	 * XFS uses the uuid from the superblock as the unique
> -	 * identifier for fsid.  We can not use the uuid from the volume
> -	 * since a single partition filesystem is identical to a single
> -	 * partition volume/filesystem.
> -	 */
> -	if (!(mp->m_flags & XFS_MOUNT_NOUUID)) {
> -		if (xfs_uuid_mount(mp)) {
> -			error = XFS_ERROR(EINVAL);
> -			goto out;
> -		}
> -	}
> +	error = xfs_uuid_mount(mp);
> +	if (error)
> +		goto out;
>  
>  	/*
>  	 * Set the minimum read and write sizes
> @@ -1275,8 +1343,7 @@ xfs_mountfs(
>   out_free_perag:
>  	xfs_free_perag(mp);
>   out_remove_uuid:
> -	if (!(mp->m_flags & XFS_MOUNT_NOUUID))
> -		uuid_table_remove(&mp->m_sb.sb_uuid);
> +	xfs_uuid_unmount(mp);
>   out:
>  	return error;
>  }
> @@ -1351,9 +1418,7 @@ xfs_unmountfs(
>  	xfs_unmountfs_wait(mp); 		/* wait for async bufs */
>  	xfs_log_unmount_write(mp);
>  	xfs_log_unmount(mp);
> -
> -	if ((mp->m_flags & XFS_MOUNT_NOUUID) == 0)
> -		uuid_table_remove(&mp->m_sb.sb_uuid);
> +	xfs_uuid_unmount(mp);
>  
>  #if defined(DEBUG)
>  	xfs_errortag_clearall(mp, 0);
> @@ -1855,29 +1920,6 @@ xfs_freesb(
>  }
>  
>  /*
> - * See if the UUID is unique among mounted XFS filesystems.
> - * Mount fails if UUID is nil or a FS with the same UUID is already mounted.
> - */
> -STATIC int
> -xfs_uuid_mount(
> -	xfs_mount_t	*mp)
> -{
> -	if (uuid_is_nil(&mp->m_sb.sb_uuid)) {
> -		cmn_err(CE_WARN,
> -			"XFS: Filesystem %s has nil UUID - can't mount",
> -			mp->m_fsname);
> -		return -1;
> -	}
> -	if (!uuid_table_insert(&mp->m_sb.sb_uuid)) {
> -		cmn_err(CE_WARN,
> -			"XFS: Filesystem %s has duplicate UUID - can't mount",
> -			mp->m_fsname);
> -		return -1;
> -	}
> -	return 0;
> -}
> -
> -/*
>   * Used to log changes to the superblock unit and width fields which could
>   * be altered by the mount options, as well as any potential sb_features2
>   * fixup. Only the first superblock is updated.
> 
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