GFS2: Clean up journal extent mapping
This patch fixes a long standing issue in mapping the journal
extents. Most journals will consist of only a single extent,
and although the cache took account of that by merging extents,
it did not actually map large extents, but instead was doing a
block by block mapping. Since the journal was only being mapped
on mount, this was not normally noticeable.
With the updated code, it is now possible to use the same extent
mapping system during journal recovery (which will be added in a
later patch). This will allow checking of the integrity of the
journal before any reply of the journal content is attempted. For
this reason the code is moving to bmap.c, since it will be used
more widely in due course.
An exercise left for the reader is to compare the new function
gfs2_map_journal_extents() with gfs2_write_alloc_required()
Additionally, should there be a failure, the error reporting is
also updated to show more detail about what went wrong.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/gfs2/bmap.h b/fs/gfs2/bmap.h
index 42fea03..81ded5e 100644
--- a/fs/gfs2/bmap.h
+++ b/fs/gfs2/bmap.h
@@ -55,5 +55,7 @@
extern int gfs2_file_dealloc(struct gfs2_inode *ip);
extern int gfs2_write_alloc_required(struct gfs2_inode *ip, u64 offset,
unsigned int len);
+extern int gfs2_map_journal_extents(struct gfs2_sbd *sdp, struct gfs2_jdesc *jd);
+extern void gfs2_free_journal_extents(struct gfs2_jdesc *jd);
#endif /* __BMAP_DOT_H__ */