[Cluster-devel] [PATCH 11/12] gfs2: Turn trunc_dealloc into punch_hole
Andreas Gruenbacher
agruenba at redhat.com
Fri Dec 22 14:35:06 UTC 2017
Add an upper bound to the range of blocks to deallocate blocks to
function trunc_dealloc so that this function can be used for truncating
a file as well as for punching a hole into a file.
Signed-off-by: Andreas Gruenbacher <agruenba at redhat.com>
---
fs/gfs2/bmap.c | 176 +++++++++++++++++++++++++++++++++++++++------------------
1 file changed, 120 insertions(+), 56 deletions(-)
diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index 984e27715a2e..da7e04b9973e 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -461,13 +461,6 @@ enum alloc_state {
/* ALLOC_UNSTUFF = 3, TBD and rather complicated */
};
-static inline unsigned int hptrs(struct gfs2_sbd *sdp, const unsigned int hgt)
-{
- if (hgt)
- return sdp->sd_inptrs;
- return sdp->sd_diptrs;
-}
-
/**
* gfs2_bmap_alloc - Build a metadata tree of the requested height
* @inode: The GFS2 inode
@@ -1240,6 +1233,13 @@ static int sweep_bh_for_rgrps(struct gfs2_inode *ip, struct gfs2_holder *rd_gh,
return ret;
}
+static bool mp_eq_to_hgt(struct metapath *mp, __u16 *list, unsigned int h)
+{
+ if (memcmp(mp->mp_list, list, h * sizeof(mp->mp_list[0])))
+ return false;
+ return true;
+}
+
/**
* find_nonnull_ptr - find a non-null pointer given a metapath and height
* assumes the metapath is valid (with buffers) out to height h
@@ -1250,28 +1250,34 @@ static int sweep_bh_for_rgrps(struct gfs2_inode *ip, struct gfs2_holder *rd_gh,
* false if all remaining pointers are NULL in the buffer
*/
static bool find_nonnull_ptr(struct gfs2_sbd *sdp, struct metapath *mp,
- unsigned int h)
+ unsigned int h,
+ __u16 *end_list, unsigned int end_aligned)
{
- __be64 *ptr;
- unsigned int ptrs = hptrs(sdp, h) - 1;
+ struct buffer_head *bh = mp->mp_bh[h];
+ __be64 *first, *ptr, *end;
+
+ first = metaptr1(h, mp);
+ ptr = first + mp->mp_list[h];
+ end = (__be64 *)(bh->b_data + bh->b_size);
+ if (end_list && mp_eq_to_hgt(mp, end_list, h)) {
+ bool keep_end = h < end_aligned;
+ end = first + end_list[h] + keep_end;
+ }
- while (true) {
- ptr = metapointer(h, mp);
+ while (ptr < end) {
if (*ptr) { /* if we have a non-null pointer */
/* Now zero the metapath after the current height. */
+ mp->mp_list[h] = ptr - first;
+
h++;
if (h < GFS2_MAX_META_HEIGHT)
- memset(&mp->mp_list[h], 0,
- (GFS2_MAX_META_HEIGHT - h) *
- sizeof(mp->mp_list[0]));
+ mp->mp_list[h + 1] = 0;
return true;
}
- if (mp->mp_list[h] < ptrs)
- mp->mp_list[h]++;
- else
- return false; /* no more pointers in this buffer */
+ ptr++;
}
+ return false;
}
enum dealloc_states {
@@ -1281,16 +1287,10 @@ enum dealloc_states {
DEALLOC_DONE = 3, /* process complete */
};
-static bool mp_eq_to_hgt(struct metapath *mp, __u16 *list, unsigned int h)
-{
- if (memcmp(mp->mp_list, list, h * sizeof(mp->mp_list[0])))
- return false;
- return true;
-}
-
static inline void
metapointer_range(struct metapath *mp, int height,
__u16 *start_list, unsigned int start_aligned,
+ __u16 *end_list, unsigned int end_aligned,
__be64 **start, __be64 **end)
{
struct buffer_head *bh = mp->mp_bh[height];
@@ -1303,29 +1303,55 @@ metapointer_range(struct metapath *mp, int height,
*start = first + start_list[height] + keep_start;
}
*end = (__be64 *)(bh->b_data + bh->b_size);
+ if (end_list && mp_eq_to_hgt(mp, end_list, height)) {
+ bool keep_end = height < end_aligned;
+ *end = first + end_list[height] + keep_end;
+ }
+}
+
+static inline bool walk_done(struct gfs2_sbd *sdp,
+ struct metapath *mp, int height,
+ __u16 *end_list, unsigned int end_aligned)
+{
+ __u16 end;
+
+ if (end_list) {
+ bool keep_end = height < end_aligned;
+ if (!mp_eq_to_hgt(mp, end_list, height))
+ return false;
+ end = end_list[height] + keep_end;
+ } else
+ end = (height > 0) ? sdp->sd_inptrs : sdp->sd_diptrs;
+ return mp->mp_list[height] >= end;
}
/**
- * trunc_dealloc - truncate a file down to a desired size
+ * punch_hole - deallocate blocks in a file
* @ip: inode to truncate
- * @newsize: The desired size of the file
+ * @offset: the start of the hole
+ * @length: the size of the hole
+ *
+ * Punch a hole into a file or truncate a file at a given position. This
+ * function operates in whole blocks (@offset and @length are rounded
+ * accordingly); partially filled blocks must be cleared otherwise.
*
- * This function truncates a file to newsize. It works from the
- * bottom up, and from the right to the left. In other words, it strips off
- * the highest layer (data) before stripping any of the metadata. Doing it
- * this way is best in case the operation is interrupted by power failure, etc.
- * The dinode is rewritten in every transaction to guarantee integrity.
+ * This function works from the bottom up, and from the right to the left. In
+ * other words, it strips off the highest layer (data) before stripping any of
+ * the metadata. Doing it this way is best in case the operation is interrupted
+ * by power failure, etc. The dinode is rewritten in every transaction to
+ * guarantee integrity.
*/
-static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize)
+static int punch_hole(struct gfs2_inode *ip, u64 offset, u64 length)
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
- struct metapath mp;
+ struct metapath mp = {};
struct buffer_head *dibh, *bh;
struct gfs2_holder rd_gh;
unsigned int bsize_shift = sdp->sd_sb.sb_bsize_shift;
- u64 lblock = (newsize + (1 << bsize_shift) - 1) >> bsize_shift;
- __u16 start_list[GFS2_MAX_META_HEIGHT]; /* new beginning of truncation */
- unsigned int start_aligned;
+ u64 lblock = (offset + (1 << bsize_shift) - 1) >> bsize_shift;
+ __u16 start_list[GFS2_MAX_META_HEIGHT];
+ __u16 __end_list[GFS2_MAX_META_HEIGHT], *end_list = NULL;
+ unsigned int start_aligned, end_aligned;
unsigned int strip_h = ip->i_height - 1;
u32 btotal = 0;
int ret, state;
@@ -1333,19 +1359,49 @@ static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize)
u64 prev_bnr = 0;
__be64 *start, *end;
- memset(&mp, 0, sizeof(mp));
- find_metapath(sdp, lblock, &mp, ip->i_height);
+ /*
+ * The start position of the hole is defined by lblock, start_list, and
+ * start_aligned. The end position of the hole is defined by lend,
+ * end_list, and end_aligned.
+ *
+ * start_aligned and end_aligned define down to which height the start
+ * and end positions are aligned to the metadata tree (i.e., the
+ * position is a multiple of the metadata granularity at the height
+ * above). This determines at which heights additional meta pointers
+ * needs to be preserved for the remaining data.
+ */
+
+ if (length) {
+ u64 maxsize = sdp->sd_heightsize[ip->i_height];
+ u64 end_offset = offset + length;
+ u64 lend;
+
+ /*
+ * Clip the end at the maximum file size for the given height:
+ * that's how far the metadata goes; files bigger than that
+ * will have additional layers of indirection.
+ */
+ if (end_offset > maxsize)
+ end_offset = maxsize;
+ lend = end_offset >> bsize_shift;
+
+ if (lblock >= lend)
+ return 0;
+ find_metapath(sdp, lend, &mp, ip->i_height);
+ end_list = __end_list;
+ memcpy(end_list, mp.mp_list, sizeof(mp.mp_list));
+
+ for (mp_h = ip->i_height - 1; mp_h > 0; mp_h--) {
+ if (end_list[mp_h])
+ break;
+ }
+ end_aligned = mp_h;
+ }
+
+ find_metapath(sdp, lblock, &mp, ip->i_height);
memcpy(start_list, mp.mp_list, sizeof(start_list));
- /*
- * Set start_aligned to the metadata height up to which the truncate
- * point is aligned to the metadata tree (i.e., the truncate point is a
- * multiple of the granularity at the height above). This determines
- * at which heights an additional meta pointer needs to be preserved:
- * an additional meta pointer is needed at a given height if
- * height < start_aligned.
- */
for (mp_h = ip->i_height - 1; mp_h > 0; mp_h--) {
if (start_list[mp_h])
break;
@@ -1364,7 +1420,7 @@ static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize)
/* issue read-ahead on metadata */
for (mp_h = 0; mp_h < mp.mp_aheight - 1; mp_h++) {
metapointer_range(&mp, mp_h, start_list, start_aligned,
- &start, &end);
+ end_list, end_aligned, &start, &end);
gfs2_metapath_ra(ip->i_gl, start, end);
}
@@ -1408,7 +1464,14 @@ static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize)
goto out;
}
+ /*
+ * Below, passing end_aligned as 0 gives us the
+ * metapointer range excluding the end point: the end
+ * point is the first metapath we must not deallocate!
+ */
+
metapointer_range(&mp, mp_h, start_list, start_aligned,
+ end_list, 0 /* end_aligned */,
&start, &end);
ret = sweep_bh_for_rgrps(ip, &rd_gh, mp.mp_bh[mp_h],
start, end,
@@ -1445,13 +1508,13 @@ static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize)
}
mp.mp_list[mp_h] = 0;
mp_h--; /* search one metadata height down */
- if (mp.mp_list[mp_h] >= hptrs(sdp, mp_h) - 1)
- break; /* loop around in the same state */
mp.mp_list[mp_h]++;
+ if (walk_done(sdp, &mp, mp_h, end_list, end_aligned))
+ break;
/* Here we've found a part of the metapath that is not
* allocated. We need to search at that height for the
* next non-null pointer. */
- if (find_nonnull_ptr(sdp, &mp, mp_h)) {
+ if (find_nonnull_ptr(sdp, &mp, mp_h, end_list, end_aligned)) {
state = DEALLOC_FILL_MP;
mp_h++;
}
@@ -1471,6 +1534,7 @@ static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize)
for (; ret > 1; ret--) {
metapointer_range(&mp, mp.mp_aheight - ret,
start_list, start_aligned,
+ end_list, end_aligned,
&start, &end);
gfs2_metapath_ra(ip->i_gl, start, end);
}
@@ -1487,7 +1551,7 @@ static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize)
/* If we find a non-null block pointer, crawl a bit
higher up in the metapath and try again, otherwise
we need to look lower for a new starting point. */
- if (find_nonnull_ptr(sdp, &mp, mp_h))
+ if (find_nonnull_ptr(sdp, &mp, mp_h, end_list, end_aligned))
mp_h++;
else
state = DEALLOC_MP_LOWER;
@@ -1584,7 +1648,7 @@ static int do_shrink(struct inode *inode, u64 newsize)
if (gfs2_is_stuffed(ip))
return 0;
- error = trunc_dealloc(ip, newsize);
+ error = punch_hole(ip, newsize, 0);
if (error == 0)
error = trunc_end(ip);
@@ -1716,7 +1780,7 @@ int gfs2_setattr_size(struct inode *inode, u64 newsize)
int gfs2_truncatei_resume(struct gfs2_inode *ip)
{
int error;
- error = trunc_dealloc(ip, i_size_read(&ip->i_inode));
+ error = punch_hole(ip, i_size_read(&ip->i_inode), 0);
if (!error)
error = trunc_end(ip);
return error;
@@ -1724,7 +1788,7 @@ int gfs2_truncatei_resume(struct gfs2_inode *ip)
int gfs2_file_dealloc(struct gfs2_inode *ip)
{
- return trunc_dealloc(ip, 0);
+ return punch_hole(ip, 0, 0);
}
/**
--
2.14.3
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