gfs2: Turn trunc_dealloc into punch_hole

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@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
This commit is contained in:
Andreas Gruenbacher 2017-12-19 00:06:44 +01:00
parent 5cf26b1e88
commit 10d2cf94c2

View File

@ -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
@ -1243,38 +1236,48 @@ out:
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
* @mp: starting metapath
* @h: desired height to search
*
* Assumes the metapath is valid (with buffers) out to height h.
* Returns: true if a non-null pointer was found in the metapath buffer
* 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;
while (true) {
ptr = metapointer(h, mp);
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 (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] = 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 {
@ -1284,16 +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];
@ -1306,29 +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 (or 0 for truncate)
*
* 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.
* 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 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;
@ -1336,19 +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;
@ -1367,7 +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);
}
@ -1411,7 +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,
@ -1448,13 +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++;
}
@ -1474,6 +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);
}
@ -1490,7 +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;
@ -1587,7 +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);
@ -1719,7 +1780,7 @@ out:
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;
@ -1727,7 +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);
}
/**