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GFS2: Make height info part of metapath
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This patch eliminates height parameters from function gfs2_bmap_alloc.
Function find_metapath determines the metapath's "find height", also
known as the desired height. Function lookup_metapath determines the
metapath's "actual height", previously known as starting height or
sheight. Function gfs2_bmap_alloc now gets both height values from
the metapath. This simplification was done as a step toward switching
the block_map functions to using iomap. The bh_map responsibilities
are also removed from function gfs2_bmap_alloc for the same reason.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Bob Peterson authored and Andreas Gruenbacher committed Oct 31, 2017
1 parent 0c9a66e commit 5f8bd44
Showing 1 changed file with 62 additions and 47 deletions.
109 changes: 62 additions & 47 deletions fs/gfs2/bmap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,8 @@
struct metapath {
struct buffer_head *mp_bh[GFS2_MAX_META_HEIGHT];
__u16 mp_list[GFS2_MAX_META_HEIGHT];
int mp_fheight; /* find_metapath height */
int mp_aheight; /* actual height (lookup height) */
};

/**
Expand Down Expand Up @@ -235,9 +237,9 @@ static void find_metapath(const struct gfs2_sbd *sdp, u64 block,
{
unsigned int i;

mp->mp_fheight = height;
for (i = height; i--;)
mp->mp_list[i] = do_div(block, sdp->sd_inptrs);

}

static inline unsigned int metapath_branch_start(const struct metapath *mp)
Expand Down Expand Up @@ -345,10 +347,13 @@ static int lookup_metapath(struct gfs2_inode *ip, struct metapath *mp)
for (x = 0; x < end_of_metadata; x++) {
ret = lookup_mp_height(ip, mp, x);
if (ret)
return ret;
goto out;
}

return ip->i_height;
ret = ip->i_height;
out:
mp->mp_aheight = ret;
return ret;
}

/**
Expand Down Expand Up @@ -480,10 +485,11 @@ static inline unsigned int hptrs(struct gfs2_sbd *sdp, const unsigned int hgt)
* @inode: The GFS2 inode
* @lblock: The logical starting block of the extent
* @bh_map: This is used to return the mapping details
* @mp: The metapath
* @sheight: The starting height (i.e. whats already mapped)
* @height: The height to build to
* @zero_new: True if newly allocated blocks should be zeroed
* @mp: The metapath, with proper height information calculated
* @maxlen: The max number of data blocks to alloc
* @dblock: Pointer to return the resulting new block
* @dblks: Pointer to return the number of blocks allocated
*
* In this routine we may have to alloc:
* i) Indirect blocks to grow the metadata tree height
Expand All @@ -500,62 +506,63 @@ static inline unsigned int hptrs(struct gfs2_sbd *sdp, const unsigned int hgt)
*/

static int gfs2_bmap_alloc(struct inode *inode, const sector_t lblock,
struct buffer_head *bh_map, struct metapath *mp,
const unsigned int sheight,
const unsigned int height,
const size_t maxlen)
bool zero_new, struct metapath *mp,
const size_t maxlen, sector_t *dblock,
unsigned *dblks)
{
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
struct super_block *sb = sdp->sd_vfs;
struct buffer_head *dibh = mp->mp_bh[0];
u64 bn, dblock = 0;
u64 bn;
unsigned n, i, blks, alloced = 0, iblks = 0, branch_start = 0;
unsigned dblks = 0;
unsigned ptrs_per_blk;
const unsigned end_of_metadata = height - 1;
const unsigned end_of_metadata = mp->mp_fheight - 1;
int ret;
int eob = 0;
enum alloc_state state;
__be64 *ptr;
__be64 zero_bn = 0;

BUG_ON(sheight < 1);
BUG_ON(mp->mp_aheight < 1);
BUG_ON(dibh == NULL);

*dblock = 0;
*dblks = 0;
gfs2_trans_add_meta(ip->i_gl, dibh);

if (height == sheight) {
if (mp->mp_fheight == mp->mp_aheight) {
struct buffer_head *bh;
/* Bottom indirect block exists, find unalloced extent size */
ptr = metapointer(end_of_metadata, mp);
bh = mp->mp_bh[end_of_metadata];
dblks = gfs2_extent_length(bh->b_data, bh->b_size, ptr, maxlen,
&eob);
BUG_ON(dblks < 1);
*dblks = gfs2_extent_length(bh->b_data, bh->b_size, ptr,
maxlen, &eob);
BUG_ON(*dblks < 1);
state = ALLOC_DATA;
} else {
/* Need to allocate indirect blocks */
ptrs_per_blk = height > 1 ? sdp->sd_inptrs : sdp->sd_diptrs;
dblks = min(maxlen, (size_t)(ptrs_per_blk -
mp->mp_list[end_of_metadata]));
if (height == ip->i_height) {
ptrs_per_blk = mp->mp_fheight > 1 ? sdp->sd_inptrs :
sdp->sd_diptrs;
*dblks = min(maxlen, (size_t)(ptrs_per_blk -
mp->mp_list[end_of_metadata]));
if (mp->mp_fheight == ip->i_height) {
/* Writing into existing tree, extend tree down */
iblks = height - sheight;
iblks = mp->mp_fheight - mp->mp_aheight;
state = ALLOC_GROW_DEPTH;
} else {
/* Building up tree height */
state = ALLOC_GROW_HEIGHT;
iblks = height - ip->i_height;
iblks = mp->mp_fheight - ip->i_height;
branch_start = metapath_branch_start(mp);
iblks += (height - branch_start);
iblks += (mp->mp_fheight - branch_start);
}
}

/* start of the second part of the function (state machine) */

blks = dblks + iblks;
i = sheight;
blks = *dblks + iblks;
i = mp->mp_aheight;
do {
int error;
n = blks - alloced;
Expand All @@ -573,9 +580,10 @@ static int gfs2_bmap_alloc(struct inode *inode, const sector_t lblock,
sizeof(struct gfs2_dinode));
zero_bn = *ptr;
}
for (; i - 1 < height - ip->i_height && n > 0; i++, n--)
for (; i - 1 < mp->mp_fheight - ip->i_height && n > 0;
i++, n--)
gfs2_indirect_init(mp, ip->i_gl, i, 0, bn++);
if (i - 1 == height - ip->i_height) {
if (i - 1 == mp->mp_fheight - ip->i_height) {
i--;
gfs2_buffer_copy_tail(mp->mp_bh[i],
sizeof(struct gfs2_meta_header),
Expand All @@ -587,7 +595,7 @@ static int gfs2_bmap_alloc(struct inode *inode, const sector_t lblock,
sizeof(struct gfs2_meta_header));
*ptr = zero_bn;
state = ALLOC_GROW_DEPTH;
for(i = branch_start; i < height; i++) {
for(i = branch_start; i < mp->mp_fheight; i++) {
if (mp->mp_bh[i] == NULL)
break;
brelse(mp->mp_bh[i]);
Expand All @@ -599,44 +607,40 @@ static int gfs2_bmap_alloc(struct inode *inode, const sector_t lblock,
break;
/* Branching from existing tree */
case ALLOC_GROW_DEPTH:
if (i > 1 && i < height)
if (i > 1 && i < mp->mp_fheight)
gfs2_trans_add_meta(ip->i_gl, mp->mp_bh[i-1]);
for (; i < height && n > 0; i++, n--)
for (; i < mp->mp_fheight && n > 0; i++, n--)
gfs2_indirect_init(mp, ip->i_gl, i,
mp->mp_list[i-1], bn++);
if (i == height)
if (i == mp->mp_fheight)
state = ALLOC_DATA;
if (n == 0)
break;
/* Tree complete, adding data blocks */
case ALLOC_DATA:
BUG_ON(n > dblks);
BUG_ON(n > *dblks);
BUG_ON(mp->mp_bh[end_of_metadata] == NULL);
gfs2_trans_add_meta(ip->i_gl, mp->mp_bh[end_of_metadata]);
dblks = n;
*dblks = n;
ptr = metapointer(end_of_metadata, mp);
dblock = bn;
*dblock = bn;
while (n-- > 0)
*ptr++ = cpu_to_be64(bn++);
if (buffer_zeronew(bh_map)) {
ret = sb_issue_zeroout(sb, dblock, dblks,
if (zero_new) {
ret = sb_issue_zeroout(sb, *dblock, *dblks,
GFP_NOFS);
if (ret) {
fs_err(sdp,
"Failed to zero data buffers\n");
clear_buffer_zeronew(bh_map);
}
}
break;
}
} while ((state != ALLOC_DATA) || !dblock);
} while ((state != ALLOC_DATA) || !(*dblock));

ip->i_height = height;
ip->i_height = mp->mp_fheight;
gfs2_add_inode_blocks(&ip->i_inode, alloced);
gfs2_dinode_out(ip, mp->mp_bh[0]->b_data);
map_bh(bh_map, inode->i_sb, dblock);
bh_map->b_size = dblks << inode->i_blkbits;
set_buffer_new(bh_map);
return 0;
}

Expand Down Expand Up @@ -670,6 +674,9 @@ int gfs2_block_map(struct inode *inode, sector_t lblock,
unsigned int len;
struct buffer_head *bh;
u8 height;
bool zero_new = false;
sector_t dblock = 0;
unsigned dblks;

BUG_ON(maxlen == 0);

Expand Down Expand Up @@ -699,13 +706,13 @@ int gfs2_block_map(struct inode *inode, sector_t lblock,
while (size > arr[height])
height++;
find_metapath(sdp, lblock, &mp, height);
ret = 1;
mp.mp_aheight = 1;
if (height > ip->i_height || gfs2_is_stuffed(ip))
goto do_alloc;
ret = lookup_metapath(ip, &mp);
if (ret < 0)
goto out;
if (ret != ip->i_height)
if (mp.mp_aheight != ip->i_height)
goto do_alloc;
ptr = metapointer(ip->i_height - 1, &mp);
if (*ptr == 0)
Expand All @@ -732,7 +739,15 @@ int gfs2_block_map(struct inode *inode, sector_t lblock,
}

/* At this point ret is the tree depth of already allocated blocks */
ret = gfs2_bmap_alloc(inode, lblock, bh_map, &mp, ret, height, maxlen);
if (buffer_zeronew(bh_map))
zero_new = true;
ret = gfs2_bmap_alloc(inode, lblock, zero_new, &mp, maxlen, &dblock,
&dblks);
if (ret == 0) {
map_bh(bh_map, inode->i_sb, dblock);
bh_map->b_size = dblks << inode->i_blkbits;
set_buffer_new(bh_map);
}
goto out;
}

Expand Down

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