[PATCH 4.15 026/128] gfs2: Clean up {lookup,fillup}_metapath

Greg Kroah-Hartman
2018-03-16T15:22:47Z

From: Andreas Gruenbacher <agruenba@redhat.com>

commit e8b43fe0c1e035a135be7ca3791d465fcb1b501e upstream.

Split out the entire lookup loop from lookup_metapath and
fillup_metapath. Make both functions return the actual height in
mp->mp_aheight, and return 0 on success. Handle lookup errors properly
in trunc_dealloc.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/gfs2/bmap.c | 74 +++++++++++++++++++++++----------------------------------
1 file changed, 30 insertions(+), 44 deletions(-)

--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -305,21 +305,22 @@ static void gfs2_metapath_ra(struct gfs2
}
}

-/**
- * lookup_mp_height - helper function for lookup_metapath
- * @ip: the inode
- * @mp: the metapath
- * @h: the height which needs looking up
- */
-static int lookup_mp_height(struct gfs2_inode *ip, struct metapath *mp, int h)
+static int __fillup_metapath(struct gfs2_inode *ip, struct metapath *mp,
+ unsigned int x, unsigned int h)
{
- __be64 *ptr = metapointer(h, mp);
- u64 dblock = be64_to_cpu(*ptr);
-
- if (!dblock)
- return h + 1;
+ for (; x < h; x++) {
+ __be64 *ptr = metapointer(x, mp);
+ u64 dblock = be64_to_cpu(*ptr);
+ int ret;

- return gfs2_meta_indirect_buffer(ip, h + 1, dblock, &mp->mp_bh[h + 1]);
+ if (!dblock)
+ break;
+ ret = gfs2_meta_indirect_buffer(ip, x + 1, dblock, &mp->mp_bh[x + 1]);
+ if (ret)
+ return ret;
+ }
+ mp->mp_aheight = x + 1;
+ return 0;
}

/**
@@ -336,25 +337,12 @@ static int lookup_mp_height(struct gfs2_
* at which it found the unallocated block. Blocks which are found are
* added to the mp->mp_bh[] list.
*
- * Returns: error or height of metadata tree
+ * Returns: error
*/

static int lookup_metapath(struct gfs2_inode *ip, struct metapath *mp)
{
- unsigned int end_of_metadata = ip->i_height - 1;
- unsigned int x;
- int ret;
-
- for (x = 0; x < end_of_metadata; x++) {
- ret = lookup_mp_height(ip, mp, x);
- if (ret)
- goto out;
- }
-
- ret = ip->i_height;
-out:
- mp->mp_aheight = ret;
- return ret;
+ return __fillup_metapath(ip, mp, 0, ip->i_height - 1);
}

/**
@@ -365,25 +353,21 @@ out:
*
* Similar to lookup_metapath, but does lookups for a range of heights
*
- * Returns: error or height of metadata tree
+ * Returns: error
*/

static int fillup_metapath(struct gfs2_inode *ip, struct metapath *mp, int h)
{
- unsigned int start_h = h - 1;
- int ret;
+ unsigned int x = 0;

if (h) {
/* find the first buffer we need to look up. */
- while (start_h > 0 && mp->mp_bh[start_h] == NULL)
- start_h--;
- for (; start_h < h; start_h++) {
- ret = lookup_mp_height(ip, mp, start_h);
- if (ret)
- return ret;
+ for (x = h - 1; x > 0; x--) {
+ if (mp->mp_bh[x])
+ break;
}
}
- return ip->i_height;
+ return __fillup_metapath(ip, mp, x, h);
}

static inline void release_metapath(struct metapath *mp)
@@ -790,7 +774,7 @@ int gfs2_iomap_begin(struct inode *inode
goto do_alloc;

ret = lookup_metapath(ip, &mp);
- if (ret < 0)
+ if (ret)
goto out_release;

if (mp.mp_aheight != ip->i_height)
@@ -1339,7 +1323,9 @@ static int trunc_dealloc(struct gfs2_ino

mp.mp_bh[0] = dibh;
ret = lookup_metapath(ip, &mp);
- if (ret == ip->i_height)
+ if (ret)
+ goto out_metapath;
+ if (mp.mp_aheight == ip->i_height)
state = DEALLOC_MP_FULL; /* We have a complete metapath */
else
state = DEALLOC_FILL_MP; /* deal with partial metapath */
@@ -1435,16 +1421,16 @@ static int trunc_dealloc(struct gfs2_ino
case DEALLOC_FILL_MP:
/* Fill the buffers out to the current height. */
ret = fillup_metapath(ip, &mp, mp_h);
- if (ret < 0)
+ if (ret)
goto out;

/* If buffers found for the entire strip height */
- if ((ret == ip->i_height) && (mp_h == strip_h)) {
+ if (mp.mp_aheight - 1 == strip_h) {
state = DEALLOC_MP_FULL;
break;
}
- if (ret < ip->i_height) /* We have a partial height */
- mp_h = ret - 1;
+ if (mp.mp_aheight < ip->i_height) /* We have a partial height */
+ mp_h = mp.mp_aheight - 1;

/* If we find a non-null block pointer, crawl a bit
higher up in the metapath and try again, otherwise