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From: Brian Foster <bfoster@redhat.com>
To: xfs@oss.sgi.com
Subject: [PATCH 02/10] xfs: reserve v5 superblock read-only compat. feature bit for finobt
Date: Wed,  9 Oct 2013 14:06:50 -0400	[thread overview]
Message-ID: <1381342018-35829-3-git-send-email-bfoster@redhat.com> (raw)
In-Reply-To: <1381342018-35829-1-git-send-email-bfoster@redhat.com>

Reserve a v5 read-only compatibility feature bit for the finobt and
create the xfs_sb_version_hasfinobt() helper to determine whether
an fs has the feature enabled.

The finobt does not change existing on-disk structures, but must
remain consistent with the ialloc btree. Modifications from older
kernels would violate that constrant. Therefore, we restrict older
kernels to read-only mounts of finobt-enabled filesystems.

Note that this does not yet enable the ability to rw mount a finobt
fs (by setting the feature bit in the XFS_SB_FEAT_RO_COMPAT_ALL
mask).

Signed-off-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/xfs_sb.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/xfs/xfs_sb.h b/fs/xfs/xfs_sb.h
index 6835b44..0013bac 100644
--- a/fs/xfs/xfs_sb.h
+++ b/fs/xfs/xfs_sb.h
@@ -585,6 +585,7 @@ xfs_sb_has_compat_feature(
 	return (sbp->sb_features_compat & feature) != 0;
 }
 
+#define XFS_SB_FEAT_RO_COMPAT_FINOBT   (1 << 0)		/* free inode btree */
 #define XFS_SB_FEAT_RO_COMPAT_ALL 0
 #define XFS_SB_FEAT_RO_COMPAT_UNKNOWN	~XFS_SB_FEAT_RO_COMPAT_ALL
 static inline bool
@@ -639,6 +640,12 @@ static inline int xfs_sb_version_hasftype(struct xfs_sb *sbp)
 		 (sbp->sb_features2 & XFS_SB_VERSION2_FTYPE));
 }
 
+static inline int xfs_sb_version_hasfinobt(xfs_sb_t *sbp)
+{
+	return (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5) &&
+		(sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_FINOBT);
+}
+
 /*
  * end of superblock version macros
  */
-- 
1.8.1.4

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  parent reply	other threads:[~2013-10-09 18:07 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-09 18:06 [PATCH 00/10] xfs: introduce the free inode btree Brian Foster
2013-10-09 18:06 ` [PATCH 01/10] xfs: refactor xfs_ialloc_btree.c to support multiple inobt numbers Brian Foster
2013-10-09 18:06 ` Brian Foster [this message]
2013-10-09 18:06 ` [PATCH 03/10] xfs: support the XFS_BTNUM_FINOBT free inode btree type Brian Foster
2013-10-09 18:06 ` [PATCH 04/10] xfs: update inode allocation/free transaction reservations for finobt Brian Foster
2013-10-09 18:06 ` [PATCH 05/10] xfs: insert newly allocated inode chunks into the finobt Brian Foster
2013-10-09 18:06 ` [PATCH 06/10] xfs: use and update the finobt on inode allocation Brian Foster
2013-10-09 18:06 ` [PATCH 07/10] xfs: refactor xfs_difree() inobt bits into xfs_difree_inobt() helper Brian Foster
2013-10-09 18:06 ` [PATCH 08/10] xfs: update the finobt on inode free Brian Foster
2013-10-09 18:06 ` [PATCH 09/10] xfs: add finobt support to growfs Brian Foster
2013-10-09 18:06 ` [PATCH 10/10] xfs: enable the finobt feature on v5 superblocks Brian Foster
     [not found] ` <5261633E.8050504@gmail.com>
     [not found]   ` <526168BA.2000002@redhat.com>
2013-10-18 17:03     ` [PATCH 00/10] xfs: introduce the free inode btree Brian Foster

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