[Cluster-devel] [PATCH 08/17] GFS2: Implement iomap for block_map
Bob Peterson
rpeterso at redhat.com
Mon Nov 13 14:35:53 UTC 2017
This patch implements iomap for block mapping, and switches the
block_map function to use it under the covers.
The additional IOMAP_F_BOUNDARY iomap flag indicates when iomap has
reached a "metadata boundary" and fetching the next mapping is likely to
incur an additional I/O. This flag is used for setting the bh buffer
boundary flag.
Signed-off-by: Bob Peterson <rpeterso at redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba at redhat.com>
---
fs/gfs2/bmap.c | 273 +++++++++++++++++++++++++++++++++++++-------------
fs/gfs2/bmap.h | 4 +
fs/gfs2/trace_gfs2.h | 65 ++++++++++++
include/linux/iomap.h | 3 +-
4 files changed, 276 insertions(+), 69 deletions(-)
diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index 03badc8417d7..d5f0d96169c5 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -13,6 +13,7 @@
#include <linux/blkdev.h>
#include <linux/gfs2_ondisk.h>
#include <linux/crc32.h>
+#include <linux/iomap.h>
#include "gfs2.h"
#include "incore.h"
@@ -505,10 +506,8 @@ static inline unsigned int hptrs(struct gfs2_sbd *sdp, const unsigned int hgt)
* Returns: errno on error
*/
-static int gfs2_bmap_alloc(struct inode *inode, const sector_t lblock,
- bool zero_new, struct metapath *mp,
- const size_t maxlen, sector_t *dblock,
- unsigned *dblks)
+static int gfs2_iomap_alloc(struct inode *inode, struct iomap *iomap,
+ unsigned flags, struct metapath *mp)
{
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
@@ -516,36 +515,37 @@ static int gfs2_bmap_alloc(struct inode *inode, const sector_t lblock,
struct buffer_head *dibh = mp->mp_bh[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 = mp->mp_fheight - 1;
int ret;
- int eob = 0;
enum alloc_state state;
__be64 *ptr;
__be64 zero_bn = 0;
+ size_t maxlen = iomap->length >> inode->i_blkbits;
BUG_ON(mp->mp_aheight < 1);
BUG_ON(dibh == NULL);
- *dblock = 0;
- *dblks = 0;
gfs2_trans_add_meta(ip->i_gl, dibh);
if (mp->mp_fheight == mp->mp_aheight) {
struct buffer_head *bh;
+ int eob;
+
/* 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 = mp->mp_fheight > 1 ? sdp->sd_inptrs :
sdp->sd_diptrs;
- *dblks = min(maxlen, (size_t)(ptrs_per_blk -
- mp->mp_list[end_of_metadata]));
+ 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 = mp->mp_fheight - mp->mp_aheight;
@@ -561,7 +561,7 @@ static int gfs2_bmap_alloc(struct inode *inode, const sector_t lblock,
/* start of the second part of the function (state machine) */
- blks = *dblks + iblks;
+ blks = dblks + iblks;
i = mp->mp_aheight;
do {
int error;
@@ -618,26 +618,29 @@ static int gfs2_bmap_alloc(struct inode *inode, const sector_t lblock,
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;
+ iomap->addr = bn << inode->i_blkbits;
+ iomap->flags |= IOMAP_F_NEW;
while (n-- > 0)
*ptr++ = cpu_to_be64(bn++);
- if (zero_new) {
- ret = sb_issue_zeroout(sb, *dblock, *dblks,
- GFP_NOFS);
+ if (flags & IOMAP_ZERO) {
+ ret = sb_issue_zeroout(sb, iomap->addr >> inode->i_blkbits,
+ dblks, GFP_NOFS);
if (ret) {
fs_err(sdp,
"Failed to zero data buffers\n");
+ flags &= ~IOMAP_ZERO;
}
}
break;
}
- } while ((state != ALLOC_DATA) || !(*dblock));
+ } while (iomap->addr == IOMAP_NULL_ADDR);
+ iomap->length = (u64)dblks << inode->i_blkbits;
ip->i_height = mp->mp_fheight;
gfs2_add_inode_blocks(&ip->i_inode, alloced);
gfs2_dinode_out(ip, mp->mp_bh[0]->b_data);
@@ -645,47 +648,123 @@ static int gfs2_bmap_alloc(struct inode *inode, const sector_t lblock,
}
/**
- * gfs2_block_map - Map a block from an inode to a disk block
+ * hole_size - figure out the size of a hole
* @inode: The inode
- * @lblock: The logical block number
- * @bh_map: The bh to be mapped
- * @create: True if its ok to alloc blocks to satify the request
+ * @lblock: The logical starting block number
+ * @mp: The metapath
*
- * Sets buffer_mapped() if successful, sets buffer_boundary() if a
- * read of metadata will be required before the next block can be
- * mapped. Sets buffer_new() if new blocks were allocated.
+ * Returns: The hole size in bytes
*
- * Returns: errno
*/
+static u64 hole_size(struct inode *inode, sector_t lblock, struct metapath *mp)
+{
+ struct gfs2_inode *ip = GFS2_I(inode);
+ struct gfs2_sbd *sdp = GFS2_SB(inode);
+ struct metapath mp_eof;
+ u64 factor = 1;
+ int hgt;
+ u64 holesz = 0;
+ const __be64 *first, *end, *ptr;
+ const struct buffer_head *bh;
+ u64 lblock_stop = (i_size_read(inode) - 1) >> inode->i_blkbits;
+ int zeroptrs;
+ bool done = false;
+
+ /* Get another metapath, to the very last byte */
+ find_metapath(sdp, lblock_stop, &mp_eof, ip->i_height);
+ for (hgt = ip->i_height - 1; hgt >= 0 && !done; hgt--) {
+ bh = mp->mp_bh[hgt];
+ if (bh) {
+ zeroptrs = 0;
+ first = metapointer(hgt, mp);
+ end = (const __be64 *)(bh->b_data + bh->b_size);
+
+ for (ptr = first; ptr < end; ptr++) {
+ if (*ptr) {
+ done = true;
+ break;
+ } else {
+ zeroptrs++;
+ }
+ }
+ } else {
+ zeroptrs = sdp->sd_inptrs;
+ }
+ if (factor * zeroptrs >= lblock_stop - lblock + 1) {
+ holesz = lblock_stop - lblock + 1;
+ break;
+ }
+ holesz += factor * zeroptrs;
-int gfs2_block_map(struct inode *inode, sector_t lblock,
- struct buffer_head *bh_map, int create)
+ factor *= sdp->sd_inptrs;
+ if (hgt && (mp->mp_list[hgt - 1] < mp_eof.mp_list[hgt - 1]))
+ (mp->mp_list[hgt - 1])++;
+ }
+ return holesz << inode->i_blkbits;
+}
+
+static void gfs2_stuffed_iomap(struct inode *inode, struct iomap *iomap)
+{
+ struct gfs2_inode *ip = GFS2_I(inode);
+
+ iomap->addr = (ip->i_no_addr << inode->i_blkbits) +
+ sizeof(struct gfs2_dinode);
+ iomap->offset = 0;
+ iomap->length = i_size_read(inode);
+ iomap->type = IOMAP_MAPPED;
+ iomap->flags = IOMAP_F_DATA_INLINE;
+}
+
+/**
+ * gfs2_iomap_begin - Map blocks from an inode to disk blocks
+ * @inode: The inode
+ * @pos: Starting position in bytes
+ * @length: Length to map, in bytes
+ * @flags: iomap flags
+ * @iomap: The iomap structure
+ *
+ * Returns: errno
+ */
+int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
+ unsigned flags, struct iomap *iomap)
{
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
+ struct metapath mp = { .mp_aheight = 1, };
unsigned int factor = sdp->sd_sb.sb_bsize;
- const size_t maxlen = bh_map->b_size >> inode->i_blkbits;
const u64 *arr = sdp->sd_heightsize;
__be64 *ptr;
- u64 size;
- struct metapath mp;
+ sector_t lblock;
+ sector_t lend;
int ret;
int eob;
unsigned int len;
struct buffer_head *bh;
u8 height;
- bool zero_new = false;
- sector_t dblock = 0;
- unsigned dblks;
- BUG_ON(maxlen == 0);
+ trace_gfs2_iomap_start(ip, pos, length, flags);
+ if (!length) {
+ ret = -EINVAL;
+ goto out;
+ }
- memset(&mp, 0, sizeof(mp));
- bmap_lock(ip, create);
- clear_buffer_mapped(bh_map);
- clear_buffer_new(bh_map);
- clear_buffer_boundary(bh_map);
- trace_gfs2_bmap(ip, bh_map, lblock, create, 1);
+ if ((flags & IOMAP_REPORT) && gfs2_is_stuffed(ip)) {
+ gfs2_stuffed_iomap(inode, iomap);
+ if (pos >= iomap->length)
+ return -ENOENT;
+ ret = 0;
+ goto out;
+ }
+
+ lblock = pos >> inode->i_blkbits;
+ lend = (pos + length + sdp->sd_sb.sb_bsize - 1) >> inode->i_blkbits;
+
+ iomap->offset = lblock << inode->i_blkbits;
+ iomap->addr = IOMAP_NULL_ADDR;
+ iomap->type = IOMAP_HOLE;
+ iomap->length = (u64)(lend - lblock) << inode->i_blkbits;
+ iomap->flags = IOMAP_F_MERGED;
+ bmap_lock(ip, 0);
/*
* Directory data blocks have a struct gfs2_meta_header header, so the
@@ -699,56 +778,114 @@ int gfs2_block_map(struct inode *inode, sector_t lblock,
ret = gfs2_meta_inode_buffer(ip, &mp.mp_bh[0]);
if (ret)
- goto out;
+ goto out_release;
height = ip->i_height;
- size = (lblock + 1) * factor;
- while (size > arr[height])
+ while ((lblock + 1) * factor > arr[height])
height++;
find_metapath(sdp, lblock, &mp, height);
- 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;
+ goto out_release;
+
if (mp.mp_aheight != ip->i_height)
goto do_alloc;
+
ptr = metapointer(ip->i_height - 1, &mp);
if (*ptr == 0)
goto do_alloc;
- map_bh(bh_map, inode->i_sb, be64_to_cpu(*ptr));
+
+ iomap->type = IOMAP_MAPPED;
+ iomap->addr = be64_to_cpu(*ptr) << inode->i_blkbits;
+
bh = mp.mp_bh[ip->i_height - 1];
- len = gfs2_extent_length(bh->b_data, bh->b_size, ptr, maxlen, &eob);
- bh_map->b_size = (len << inode->i_blkbits);
+ len = gfs2_extent_length(bh->b_data, bh->b_size, ptr, lend - lblock, &eob);
if (eob)
- set_buffer_boundary(bh_map);
+ iomap->flags |= IOMAP_F_BOUNDARY;
+ iomap->length = (u64)len << inode->i_blkbits;
+
ret = 0;
-out:
+
+out_release:
release_metapath(&mp);
- trace_gfs2_bmap(ip, bh_map, lblock, create, ret);
- bmap_unlock(ip, create);
+ bmap_unlock(ip, 0);
+out:
+ trace_gfs2_iomap_end(ip, iomap, ret);
return ret;
do_alloc:
- /* All allocations are done here, firstly check create flag */
- if (!create) {
- BUG_ON(gfs2_is_stuffed(ip));
+ if (!(flags & IOMAP_WRITE)) {
+ if (pos >= i_size_read(inode)) {
+ ret = -ENOENT;
+ goto out_release;
+ }
ret = 0;
- goto out;
+ iomap->length = hole_size(inode, lblock, &mp);
+ goto out_release;
}
- /* At this point ret is the tree depth of already allocated blocks */
+ ret = gfs2_iomap_alloc(inode, iomap, flags, &mp);
+ goto out_release;
+}
+
+/**
+ * gfs2_block_map - Map a block from an inode to a disk block
+ * @inode: The inode
+ * @lblock: The logical block number
+ * @bh_map: The bh to be mapped
+ * @create: True if its ok to alloc blocks to satify the request
+ *
+ * Sets buffer_mapped() if successful, sets buffer_boundary() if a
+ * read of metadata will be required before the next block can be
+ * mapped. Sets buffer_new() if new blocks were allocated.
+ *
+ * Returns: errno
+ */
+
+int gfs2_block_map(struct inode *inode, sector_t lblock,
+ struct buffer_head *bh_map, int create)
+{
+ struct gfs2_inode *ip = GFS2_I(inode);
+ struct iomap iomap;
+ int ret, flags = 0;
+
+ clear_buffer_mapped(bh_map);
+ clear_buffer_new(bh_map);
+ clear_buffer_boundary(bh_map);
+ trace_gfs2_bmap(ip, bh_map, lblock, create, 1);
+
+ if (create)
+ flags |= IOMAP_WRITE;
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);
+ flags |= IOMAP_ZERO;
+ ret = gfs2_iomap_begin(inode, (loff_t)lblock << inode->i_blkbits,
+ bh_map->b_size, flags, &iomap);
+ if (ret) {
+ if (!create && ret == -ENOENT) {
+ /* Return unmapped buffer beyond the end of file. */
+ ret = 0;
+ }
+ goto out;
+ }
+
+ if (iomap.length > bh_map->b_size) {
+ iomap.length = bh_map->b_size;
+ iomap.flags &= ~IOMAP_F_BOUNDARY;
}
- goto out;
+ if (iomap.addr != IOMAP_NULL_ADDR)
+ map_bh(bh_map, inode->i_sb, iomap.addr >> inode->i_blkbits);
+ bh_map->b_size = iomap.length;
+ if (iomap.flags & IOMAP_F_BOUNDARY)
+ set_buffer_boundary(bh_map);
+ if (iomap.flags & IOMAP_F_NEW)
+ set_buffer_new(bh_map);
+
+out:
+ trace_gfs2_bmap(ip, bh_map, lblock, create, ret);
+ return ret;
}
/*
diff --git a/fs/gfs2/bmap.h b/fs/gfs2/bmap.h
index 81ded5e2aaa2..443cc182cf18 100644
--- a/fs/gfs2/bmap.h
+++ b/fs/gfs2/bmap.h
@@ -10,6 +10,8 @@
#ifndef __BMAP_DOT_H__
#define __BMAP_DOT_H__
+#include <linux/iomap.h>
+
#include "inode.h"
struct inode;
@@ -47,6 +49,8 @@ static inline void gfs2_write_calc_reserv(const struct gfs2_inode *ip,
extern int gfs2_unstuff_dinode(struct gfs2_inode *ip, struct page *page);
extern int gfs2_block_map(struct inode *inode, sector_t lblock,
struct buffer_head *bh, int create);
+extern int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
+ unsigned flags, struct iomap *iomap);
extern int gfs2_extent_map(struct inode *inode, u64 lblock, int *new,
u64 *dblock, unsigned *extlen);
extern int gfs2_setattr_size(struct inode *inode, u64 size);
diff --git a/fs/gfs2/trace_gfs2.h b/fs/gfs2/trace_gfs2.h
index 49ac55da4e33..3c91ae3cf0b2 100644
--- a/fs/gfs2/trace_gfs2.h
+++ b/fs/gfs2/trace_gfs2.h
@@ -12,6 +12,7 @@
#include <linux/gfs2_ondisk.h>
#include <linux/writeback.h>
#include <linux/ktime.h>
+#include <linux/iomap.h>
#include "incore.h"
#include "glock.h"
#include "rgrp.h"
@@ -469,6 +470,70 @@ TRACE_EVENT(gfs2_bmap,
__entry->errno)
);
+TRACE_EVENT(gfs2_iomap_start,
+
+ TP_PROTO(const struct gfs2_inode *ip, loff_t pos, ssize_t length,
+ u16 flags),
+
+ TP_ARGS(ip, pos, length, flags),
+
+ TP_STRUCT__entry(
+ __field( dev_t, dev )
+ __field( u64, inum )
+ __field( loff_t, pos )
+ __field( ssize_t, length )
+ __field( u16, flags )
+ ),
+
+ TP_fast_assign(
+ __entry->dev = ip->i_gl->gl_name.ln_sbd->sd_vfs->s_dev;
+ __entry->inum = ip->i_no_addr;
+ __entry->pos = pos;
+ __entry->length = length;
+ __entry->flags = flags;
+ ),
+
+ TP_printk("%u,%u bmap %llu iomap start %llu/%lu flags:%08x",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ (unsigned long long)__entry->inum,
+ (unsigned long long)__entry->pos,
+ (unsigned long)__entry->length, (u16)__entry->flags)
+);
+
+TRACE_EVENT(gfs2_iomap_end,
+
+ TP_PROTO(const struct gfs2_inode *ip, struct iomap *iomap, int ret),
+
+ TP_ARGS(ip, iomap, ret),
+
+ TP_STRUCT__entry(
+ __field( dev_t, dev )
+ __field( u64, inum )
+ __field( loff_t, offset )
+ __field( ssize_t, length )
+ __field( u16, flags )
+ __field( u16, type )
+ __field( int, ret )
+ ),
+
+ TP_fast_assign(
+ __entry->dev = ip->i_gl->gl_name.ln_sbd->sd_vfs->s_dev;
+ __entry->inum = ip->i_no_addr;
+ __entry->offset = iomap->offset;
+ __entry->length = iomap->length;
+ __entry->flags = iomap->flags;
+ __entry->type = iomap->type;
+ __entry->ret = ret;
+ ),
+
+ TP_printk("%u,%u bmap %llu iomap end %llu/%lu ty:%d flags:%08x rc:%d",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ (unsigned long long)__entry->inum,
+ (unsigned long long)__entry->offset,
+ (unsigned long)__entry->length, (u16)__entry->type,
+ (u16)__entry->flags, __entry->ret)
+);
+
/* Keep track of blocks as they are allocated/freed */
TRACE_EVENT(gfs2_block_alloc,
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 2b0790dbd6ea..a61be86710b5 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -21,7 +21,8 @@ struct vm_fault;
/*
* Flags for all iomap mappings:
*/
-#define IOMAP_F_NEW 0x01 /* blocks have been newly allocated */
+#define IOMAP_F_NEW 0x01 /* blocks have been newly allocated */
+#define IOMAP_F_BOUNDARY 0x02 /* mapping ends at metadata boundary */
/*
* Flags that only need to be reported for IOMAP_REPORT requests:
--
2.13.6
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