This patch adds a generic iomap_get_t interface to GFS2 for
block mapping.
Signed-off-by: Bob Peterson <rpeterso@xxxxxxxxxx>
---
fs/gfs2/bmap.c | 151 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/gfs2/bmap.h | 2 +
2 files changed, 153 insertions(+)
diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index 61296ec..5636257 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"
@@ -587,6 +588,156 @@ static int gfs2_bmap_alloc(struct inode *inode, const sector_t lblock,
}
/**
+ * hole_size - figure out the size of a hole
+ * @ip: The inode
+ * @lblock: The logical starting block number
+ * @mp: The metapath
+ *
+ * Returns: The hole size in bytes
+ *
+ */
+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;
+ unsigned int end_of_metadata = ip->i_height - 1;
+ u64 factor = 1;
+ int hgt = end_of_metadata;
+ u64 holesz = 0, holestep;
+ const __be64 *first, *end, *ptr;
+ const struct buffer_head *bh;
+ u64 isize = i_size_read(inode);
+ int zeroptrs;
+ bool done = false;
+
+ /* Get another metapath, to the very last byte */
+ find_metapath(sdp, (isize - 1) >> inode->i_blkbits, &mp_eof,
+ ip->i_height);
+ for (hgt = end_of_metadata; 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;
+ }
+ holestep = min(factor * zeroptrs,
+ isize - (lblock + (zeroptrs * holesz)));
+ holesz += holestep;
+ if (lblock + holesz >= isize)
+ return holesz << inode->i_blkbits;
+
+ 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;
+}
+
+/**
+ * gfs2_get_iomap - Map blocks from an inode to disk blocks
+ * @mapping: The address space
+ * @pos: Starting position in bytes
+ * @length: Length to map, in bytes
+ * @iomap: The iomap structure
+ *
+ * Returns: errno
+ */
+
+int gfs2_get_iomap(struct address_space *mapping, loff_t pos, ssize_t length,
+ struct iomap *iomap)
+{
+ struct inode *inode = mapping->host;
+ struct gfs2_inode *ip = GFS2_I(inode);
+ struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
+ unsigned int bsize = sdp->sd_sb.sb_bsize;
+ const u64 *arr = sdp->sd_heightsize;
+ __be64 *ptr;
+ sector_t lblock = pos >> sdp->sd_sb.sb_bsize_shift;
+ u64 size;
+ struct metapath mp;
+ int ret, eob;
+ unsigned int len;
+ struct buffer_head *bh;
+ u8 height;
+ loff_t isize = i_size_read(inode);
+
+ if (length == 0)
+ return -EINVAL;
+
+ iomap->offset = pos;
+ iomap->blkno = 0;
+ iomap->type = IOMAP_HOLE;
+ iomap->length = length;
+
+ if (pos >= isize)
+ return 0;
+
+ memset(mp.mp_bh, 0, sizeof(mp.mp_bh));
+ bmap_lock(ip, 0);
+ if (gfs2_is_dir(ip)) {
+ bsize = sdp->sd_jbsize;
+ arr = sdp->sd_jheightsize;
+ }
+
+ ret = gfs2_meta_inode_buffer(ip, &mp.mp_bh[0]);
+ if (ret)
+ goto out_release;
+
+ height = ip->i_height;
+ size = (lblock + 1) * bsize;
+ while (size > arr[height])
+ height++;
+ find_metapath(sdp, lblock, &mp, height);
+ if (height > ip->i_height || gfs2_is_stuffed(ip)) {
+ ret = -EINVAL;
+ goto out_release;
+ }
+ ret = lookup_metapath(ip, &mp);
+ if (ret < 0)
+ goto out_release;
+
+ if (ret != ip->i_height) {
+ iomap->length = hole_size(inode, lblock, &mp);
+ goto out_meta_hole;
+ }
+
+ ptr = metapointer(ip->i_height - 1, &mp);
+ iomap->blkno = be64_to_cpu(*ptr);
+ if (*ptr)
+ iomap->type = IOMAP_MAPPED;
+ else
+ iomap->type = IOMAP_HOLE;
+
+ bh = mp.mp_bh[ip->i_height - 1];
+ len = gfs2_extent_length(bh->b_data, bh->b_size, ptr,
+ length >> inode->i_blkbits, &eob);
+ iomap->length = len << sdp->sd_sb.sb_bsize_shift;
+ /* If we go past eof, round up to the nearest block */
+ if (iomap->offset + iomap->length >= isize)
+ iomap->length = (((isize - iomap->offset) + (bsize - 1)) &
+ ~(bsize - 1));
+
+out_meta_hole:
+ ret = 0;
+out_release:
+ release_metapath(&mp);
+ bmap_unlock(ip, 0);
+ return ret;
+}
+
+/**
* gfs2_block_map - Map a block from an inode to a disk block
* @inode: The inode
* @lblock: The logical block number
diff --git a/fs/gfs2/bmap.h b/fs/gfs2/bmap.h
index 81ded5e..815a527 100644
--- a/fs/gfs2/bmap.h
+++ b/fs/gfs2/bmap.h
@@ -47,6 +47,8 @@ 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_get_iomap(struct address_space *mapping, loff_t pos,
+ ssize_t length, 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);
--
2.5.0
--
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