summaryrefslogtreecommitdiffstats
path: root/fs/gfs2/bmap.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/gfs2/bmap.c')
-rw-r--r--fs/gfs2/bmap.c210
1 files changed, 153 insertions, 57 deletions
diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index fcf2f7d166de..69f846418ad5 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -278,6 +278,21 @@ static inline __be64 *metapointer(unsigned int height, const struct metapath *mp
return p + mp->mp_list[height];
}
+static inline const __be64 *metaend(unsigned int height, const struct metapath *mp)
+{
+ const struct buffer_head *bh = mp->mp_bh[height];
+ return (const __be64 *)(bh->b_data + bh->b_size);
+}
+
+static void clone_metapath(struct metapath *clone, struct metapath *mp)
+{
+ unsigned int hgt;
+
+ *clone = *mp;
+ for (hgt = 0; hgt < mp->mp_aheight; hgt++)
+ get_bh(clone->mp_bh[hgt]);
+}
+
static void gfs2_metapath_ra(struct gfs2_glock *gl, __be64 *start, __be64 *end)
{
const __be64 *t;
@@ -419,6 +434,142 @@ static inline unsigned int gfs2_extent_length(void *start, unsigned int len, __b
return (ptr - first);
}
+typedef const __be64 *(*gfs2_metadata_walker)(
+ struct metapath *mp,
+ const __be64 *start, const __be64 *end,
+ u64 factor, void *data);
+
+#define WALK_STOP ((__be64 *)0)
+#define WALK_NEXT ((__be64 *)1)
+
+static int gfs2_walk_metadata(struct inode *inode, sector_t lblock,
+ u64 len, struct metapath *mp, gfs2_metadata_walker walker,
+ void *data)
+{
+ struct metapath clone;
+ struct gfs2_inode *ip = GFS2_I(inode);
+ struct gfs2_sbd *sdp = GFS2_SB(inode);
+ const __be64 *start, *end, *ptr;
+ u64 factor = 1;
+ unsigned int hgt;
+ int ret = 0;
+
+ for (hgt = ip->i_height - 1; hgt >= mp->mp_aheight; hgt--)
+ factor *= sdp->sd_inptrs;
+
+ for (;;) {
+ u64 step;
+
+ /* Walk indirect block. */
+ start = metapointer(hgt, mp);
+ end = metaend(hgt, mp);
+
+ step = (end - start) * factor;
+ if (step > len)
+ end = start + DIV_ROUND_UP_ULL(len, factor);
+
+ ptr = walker(mp, start, end, factor, data);
+ if (ptr == WALK_STOP)
+ break;
+ if (step >= len)
+ break;
+ len -= step;
+ if (ptr != WALK_NEXT) {
+ BUG_ON(!*ptr);
+ mp->mp_list[hgt] += ptr - start;
+ goto fill_up_metapath;
+ }
+
+lower_metapath:
+ /* Decrease height of metapath. */
+ if (mp != &clone) {
+ clone_metapath(&clone, mp);
+ mp = &clone;
+ }
+ brelse(mp->mp_bh[hgt]);
+ mp->mp_bh[hgt] = NULL;
+ if (!hgt)
+ break;
+ hgt--;
+ factor *= sdp->sd_inptrs;
+
+ /* Advance in metadata tree. */
+ (mp->mp_list[hgt])++;
+ start = metapointer(hgt, mp);
+ end = metaend(hgt, mp);
+ if (start >= end) {
+ mp->mp_list[hgt] = 0;
+ if (!hgt)
+ break;
+ goto lower_metapath;
+ }
+
+fill_up_metapath:
+ /* Increase height of metapath. */
+ if (mp != &clone) {
+ clone_metapath(&clone, mp);
+ mp = &clone;
+ }
+ ret = fillup_metapath(ip, mp, ip->i_height - 1);
+ if (ret < 0)
+ break;
+ hgt += ret;
+ for (; ret; ret--)
+ do_div(factor, sdp->sd_inptrs);
+ mp->mp_aheight = hgt + 1;
+ }
+ if (mp == &clone)
+ release_metapath(mp);
+ return ret;
+}
+
+struct gfs2_hole_walker_args {
+ u64 blocks;
+};
+
+static const __be64 *gfs2_hole_walker(struct metapath *mp,
+ const __be64 *start, const __be64 *end,
+ u64 factor, void *data)
+{
+ struct gfs2_hole_walker_args *args = data;
+ const __be64 *ptr;
+
+ for (ptr = start; ptr < end; ptr++) {
+ if (*ptr) {
+ args->blocks += (ptr - start) * factor;
+ if (mp->mp_aheight == mp->mp_fheight)
+ return WALK_STOP;
+ return ptr; /* increase height */
+ }
+ }
+ args->blocks += (end - start) * factor;
+ return WALK_NEXT;
+}
+
+/**
+ * gfs2_hole_size - figure out the size of a hole
+ * @inode: The inode
+ * @lblock: The logical starting block number
+ * @len: How far to look (in blocks)
+ * @mp: The metapath at lblock
+ * @iomap: The iomap to store the hole size in
+ *
+ * This function modifies @mp.
+ *
+ * Returns: errno on error
+ */
+static int gfs2_hole_size(struct inode *inode, sector_t lblock, u64 len,
+ struct metapath *mp, struct iomap *iomap)
+{
+ struct gfs2_hole_walker_args args = { };
+ int ret = 0;
+
+ ret = gfs2_walk_metadata(inode, lblock, len, mp, gfs2_hole_walker, &args);
+ if (!ret)
+ iomap->length = args.blocks << inode->i_blkbits;
+ return ret;
+}
+
static inline void bmap_lock(struct gfs2_inode *ip, int create)
{
if (create)
@@ -615,62 +766,6 @@ static int gfs2_iomap_alloc(struct inode *inode, struct iomap *iomap,
return 0;
}
-/**
- * hole_size - figure out the size of a hole
- * @inode: 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;
- 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;
-
- 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);
@@ -726,6 +821,7 @@ int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
lblock = pos >> inode->i_blkbits;
lend = (pos + length + sdp->sd_sb.sb_bsize - 1) >> inode->i_blkbits;
+ len = lend - lblock;
iomap->offset = lblock << inode->i_blkbits;
iomap->addr = IOMAP_NULL_ADDR;
@@ -780,7 +876,7 @@ do_alloc:
if (pos >= size)
ret = -ENOENT;
else if (height <= ip->i_height)
- iomap->length = hole_size(inode, lblock, &mp);
+ ret = gfs2_hole_size(inode, lblock, len, &mp, iomap);
else
iomap->length = size - pos;
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-03 19:03:20 +0000