archives/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-03-08 03:44:45 +01:00
Code Issues Projects Releases Packages Wiki Activity Actions

iomap: set accurate iter->pos when reading folio ranges

Browse source 
Advance iter to the correct position before calling an IO helper to read
in a folio range. This allows the helper to reliably use iter->pos to
determine the starting offset for reading.

This will simplify the interface for reading in folio ranges when iomap
read/readahead supports caller-provided callbacks.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Joanne Koong 2025-09-25 17:26:03 -07:00 • committed by Christian Brauner
parent d43558ae67
commit fb7a10ac47
No known key found for this signature in database
GPG key ID: 91C61BC06578DCA2
1 changed files with 13 additions and 8 deletions
Download patch file Download diff file Expand all files Collapse all files

21
fs/iomap/buffered-io.c
View file

@ -375,10 +375,11 @@ static void iomap_bio_submit_read(struct iomap_read_folio_ctx *ctx)
}
static void iomap_bio_read_folio_range(const struct iomap_iter *iter,
struct iomap_read_folio_ctx *ctx, loff_t pos, size_t plen)
struct iomap_read_folio_ctx *ctx, size_t plen)
{
struct folio *folio = ctx->cur_folio;
const struct iomap *iomap = &iter->iomap;
loff_t pos = iter->pos;
size_t poff = offset_in_folio(folio, pos);
loff_t length = iomap_length(iter);
sector_t sector;
@ -506,7 +507,7 @@ static int iomap_read_folio_iter(struct iomap_iter *iter,
loff_t length = iomap_length(iter);
struct folio *folio = ctx->cur_folio;
size_t poff, plen;
loff_t count;
loff_t pos_diff;
int ret;
if (iomap->type == IOMAP_INLINE) {
@ -524,12 +525,16 @@ static int iomap_read_folio_iter(struct iomap_iter *iter,
iomap_adjust_read_range(iter->inode, folio, &pos, length, &poff,
&plen);
count = pos - iter->pos + plen;
if (WARN_ON_ONCE(count > length))
pos_diff = pos - iter->pos;
if (WARN_ON_ONCE(pos_diff + plen > length))
return -EIO;
ret = iomap_iter_advance(iter, pos_diff);
if (ret)
return ret;
if (plen == 0)
return iomap_iter_advance(iter, count);
return 0;
/* zero post-eof blocks as the page may be mapped */
if (iomap_block_needs_zeroing(iter, pos)) {
@ -539,13 +544,13 @@ static int iomap_read_folio_iter(struct iomap_iter *iter,
if (!*bytes_pending)
iomap_read_init(folio);
*bytes_pending += plen;
iomap_bio_read_folio_range(iter, ctx, pos, plen);
iomap_bio_read_folio_range(iter, ctx, plen);
}
ret = iomap_iter_advance(iter, count);
ret = iomap_iter_advance(iter, plen);
if (ret)
return ret;
length -= count;
length -= pos_diff + plen;
pos = iter->pos;
}
return 0;