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bcachefs: refactor fiemap processing into extent helper and struct

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The bulk of the loop in bch2_fiemap() involves processing the
current extent key from the iter, including following indirections
and trimming the extent size and such. This patch makes a few
changes to reduce the size of the loop and facilitate future changes
to support delalloc extents.

Define a new bch_fiemap_extent structure to wrap the bkey buffer
that holds the extent key to report to userspace along with
associated fiemap flags. Update bch2_fill_extent() to take the
bch_fiemap_extent as a param instead of the individual fields.
Finally, lift the bulk of the extent processing into a
bch2_fiemap_extent() helper that takes the current key and formats
the bch_fiemap_extent appropriately for the fill function.

No functional changes intended by this patch.

Signed-off-by: Brian Foster <bfoster@redhat.com>
This commit is contained in:
Brian Foster
2024-01-15 14:27:49 -05:00
committed by Kent Overstreet
parent d020a9fb11
commit 2d55a63709
1 changed files with 53 additions and 34 deletions
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87
fs/bcachefs/fs.c
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@@ -1262,10 +1262,18 @@ static int bch2_tmpfile(struct mnt_idmap *idmap,
return finish_open_simple(file, 0);
}
struct bch_fiemap_extent {
struct bkey_buf kbuf;
unsigned flags;
};
static int bch2_fill_extent(struct bch_fs *c,
struct fiemap_extent_info *info,
struct bkey_s_c k, unsigned flags)
struct bch_fiemap_extent *fe)
{
struct bkey_s_c k = bkey_i_to_s_c(fe->kbuf.k);
unsigned flags = fe->flags;
if (bkey_extent_is_direct_data(k.k)) {
struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
const union bch_extent_entry *entry;
@@ -1318,6 +1326,36 @@ static int bch2_fill_extent(struct bch_fs *c,
}
}
static int bch2_fiemap_extent(struct btree_trans *trans,
struct btree_iter *iter, struct bkey_s_c k,
struct bch_fiemap_extent *cur)
{
s64 offset_into_extent = iter->pos.offset - bkey_start_offset(k.k);
unsigned sectors = k.k->size - offset_into_extent;
bch2_bkey_buf_reassemble(&cur->kbuf, trans->c, k);
enum btree_id data_btree = BTREE_ID_extents;
int ret = bch2_read_indirect_extent(trans, &data_btree, &offset_into_extent,
&cur->kbuf);
if (ret)
return ret;
k = bkey_i_to_s_c(cur->kbuf.k);
sectors = min_t(unsigned, sectors, k.k->size - offset_into_extent);
bch2_cut_front(POS(k.k->p.inode,
bkey_start_offset(k.k) + offset_into_extent),
cur->kbuf.k);
bch2_key_resize(&cur->kbuf.k->k, sectors);
cur->kbuf.k->k.p = iter->pos;
cur->kbuf.k->k.p.offset += cur->kbuf.k->k.size;
cur->flags = 0;
return 0;
}
static int bch2_fiemap(struct inode *vinode, struct fiemap_extent_info *info,
u64 start, u64 len)
{
@@ -1326,7 +1364,7 @@ static int bch2_fiemap(struct inode *vinode, struct fiemap_extent_info *info,
struct btree_trans *trans;
struct btree_iter iter;
struct bkey_s_c k;
struct bkey_buf cur, prev;
struct bch_fiemap_extent cur, prev;
bool have_extent = false;
int ret = 0;
@@ -1340,15 +1378,14 @@ static int bch2_fiemap(struct inode *vinode, struct fiemap_extent_info *info,
start >>= 9;
bch2_bkey_buf_init(&cur);
bch2_bkey_buf_init(&prev);
bch2_bkey_buf_init(&cur.kbuf);
bch2_bkey_buf_init(&prev.kbuf);
trans = bch2_trans_get(c);
bch2_trans_iter_init(trans, &iter, BTREE_ID_extents,
POS(ei->v.i_ino, start), 0);
while (!ret || bch2_err_matches(ret, BCH_ERR_transaction_restart)) {
enum btree_id data_btree = BTREE_ID_extents;
bch2_trans_begin(trans);
@@ -1373,39 +1410,21 @@ static int bch2_fiemap(struct inode *vinode, struct fiemap_extent_info *info,
continue;
}
s64 offset_into_extent = iter.pos.offset - bkey_start_offset(k.k);
unsigned sectors = k.k->size - offset_into_extent;
bch2_bkey_buf_reassemble(&cur, c, k);
ret = bch2_read_indirect_extent(trans, &data_btree,
&offset_into_extent, &cur);
ret = bch2_fiemap_extent(trans, &iter, k, &cur);
if (ret)
continue;
k = bkey_i_to_s_c(cur.k);
bch2_bkey_buf_realloc(&prev, c, k.k->u64s);
sectors = min_t(unsigned, sectors, k.k->size - offset_into_extent);
start = iter.pos.offset + sectors;
bch2_cut_front(POS(k.k->p.inode,
bkey_start_offset(k.k) +
offset_into_extent),
cur.k);
bch2_key_resize(&cur.k->k, sectors);
cur.k->k.p = iter.pos;
cur.k->k.p.offset += cur.k->k.size;
break;
bch2_bkey_buf_realloc(&prev.kbuf, c, cur.kbuf.k->k.u64s);
start = cur.kbuf.k->k.p.offset;
if (have_extent) {
bch2_trans_unlock(trans);
ret = bch2_fill_extent(c, info,
bkey_i_to_s_c(prev.k), 0);
ret = bch2_fill_extent(c, info, &prev);
if (ret)
break;
}
bkey_copy(prev.k, cur.k);
bkey_copy(prev.kbuf.k, cur.kbuf.k);
prev.flags = cur.flags;
have_extent = true;
bch2_btree_iter_set_pos(trans, &iter, POS(iter.pos.inode, start));
@@ -1414,13 +1433,13 @@ static int bch2_fiemap(struct inode *vinode, struct fiemap_extent_info *info,
if (!ret && have_extent) {
bch2_trans_unlock(trans);
ret = bch2_fill_extent(c, info, bkey_i_to_s_c(prev.k),
FIEMAP_EXTENT_LAST);
prev.flags |= FIEMAP_EXTENT_LAST;
ret = bch2_fill_extent(c, info, &prev);
}
bch2_trans_put(trans);
bch2_bkey_buf_exit(&cur, c);
bch2_bkey_buf_exit(&prev, c);
bch2_bkey_buf_exit(&cur.kbuf, c);
bch2_bkey_buf_exit(&prev.kbuf, c);
return ret < 0 ? ret : 0;
}