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Merge tag 'vfs-6.10.iomap' of git://git.kernel.org/pub/scm/linux/kern…
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…el/git/vfs/vfs

Pull vfs iomap updates from Christian Brauner:
 "This contains a few cleanups to the iomap code. Nothing particularly
  stands out"

* tag 'vfs-6.10.iomap' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  iomap: do some small logical cleanup in buffered write
  iomap: make iomap_write_end() return a boolean
  iomap: use a new variable to handle the written bytes in iomap_write_iter()
  iomap: don't increase i_size if it's not a write operation
  iomap: drop the write failure handles when unsharing and zeroing
  iomap: convert iomap_writepages to writeack_iter
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Linus Torvalds committed May 13, 2024
2 parents 8815da9 + e1f453d commit c117a43
Showing 1 changed file with 65 additions and 54 deletions.
119 changes: 65 additions & 54 deletions fs/iomap/buffered-io.c
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Original file line number Diff line number Diff line change
Expand Up @@ -824,12 +824,11 @@ static int iomap_write_begin(struct iomap_iter *iter, loff_t pos,

out_unlock:
__iomap_put_folio(iter, pos, 0, folio);
iomap_write_failed(iter->inode, pos, len);

return status;
}

static size_t __iomap_write_end(struct inode *inode, loff_t pos, size_t len,
static bool __iomap_write_end(struct inode *inode, loff_t pos, size_t len,
size_t copied, struct folio *folio)
{
flush_dcache_folio(folio);
Expand All @@ -846,14 +845,14 @@ static size_t __iomap_write_end(struct inode *inode, loff_t pos, size_t len,
* redo the whole thing.
*/
if (unlikely(copied < len && !folio_test_uptodate(folio)))
return 0;
return false;
iomap_set_range_uptodate(folio, offset_in_folio(folio, pos), len);
iomap_set_range_dirty(folio, offset_in_folio(folio, pos), copied);
filemap_dirty_folio(inode->i_mapping, folio);
return copied;
return true;
}

static size_t iomap_write_end_inline(const struct iomap_iter *iter,
static void iomap_write_end_inline(const struct iomap_iter *iter,
struct folio *folio, loff_t pos, size_t copied)
{
const struct iomap *iomap = &iter->iomap;
Expand All @@ -868,59 +867,51 @@ static size_t iomap_write_end_inline(const struct iomap_iter *iter,
kunmap_local(addr);

mark_inode_dirty(iter->inode);
return copied;
}

/* Returns the number of bytes copied. May be 0. Cannot be an errno. */
static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len,
/*
* Returns true if all copied bytes have been written to the pagecache,
* otherwise return false.
*/
static bool iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len,
size_t copied, struct folio *folio)
{
const struct iomap *srcmap = iomap_iter_srcmap(iter);
loff_t old_size = iter->inode->i_size;
size_t ret;

if (srcmap->type == IOMAP_INLINE) {
ret = iomap_write_end_inline(iter, folio, pos, copied);
} else if (srcmap->flags & IOMAP_F_BUFFER_HEAD) {
ret = block_write_end(NULL, iter->inode->i_mapping, pos, len,
copied, &folio->page, NULL);
} else {
ret = __iomap_write_end(iter->inode, pos, len, copied, folio);
iomap_write_end_inline(iter, folio, pos, copied);
return true;
}

/*
* Update the in-memory inode size after copying the data into the page
* cache. It's up to the file system to write the updated size to disk,
* preferably after I/O completion so that no stale data is exposed.
*/
if (pos + ret > old_size) {
i_size_write(iter->inode, pos + ret);
iter->iomap.flags |= IOMAP_F_SIZE_CHANGED;
if (srcmap->flags & IOMAP_F_BUFFER_HEAD) {
size_t bh_written;

bh_written = block_write_end(NULL, iter->inode->i_mapping, pos,
len, copied, &folio->page, NULL);
WARN_ON_ONCE(bh_written != copied && bh_written != 0);
return bh_written == copied;
}
__iomap_put_folio(iter, pos, ret, folio);

if (old_size < pos)
pagecache_isize_extended(iter->inode, old_size, pos);
if (ret < len)
iomap_write_failed(iter->inode, pos + ret, len - ret);
return ret;
return __iomap_write_end(iter->inode, pos, len, copied, folio);
}

static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
{
loff_t length = iomap_length(iter);
size_t chunk = PAGE_SIZE << MAX_PAGECACHE_ORDER;
loff_t pos = iter->pos;
ssize_t written = 0;
ssize_t total_written = 0;
long status = 0;
struct address_space *mapping = iter->inode->i_mapping;
unsigned int bdp_flags = (iter->flags & IOMAP_NOWAIT) ? BDP_ASYNC : 0;

do {
struct folio *folio;
loff_t old_size;
size_t offset; /* Offset into folio */
size_t bytes; /* Bytes to write to folio */
size_t copied; /* Bytes copied from user */
size_t written; /* Bytes have been written */

bytes = iov_iter_count(i);
retry:
Expand Down Expand Up @@ -950,8 +941,10 @@ static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
}

status = iomap_write_begin(iter, pos, bytes, &folio);
if (unlikely(status))
if (unlikely(status)) {
iomap_write_failed(iter->inode, pos, bytes);
break;
}
if (iter->iomap.flags & IOMAP_F_STALE)
break;

Expand All @@ -963,37 +956,55 @@ static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
flush_dcache_folio(folio);

copied = copy_folio_from_iter_atomic(folio, offset, bytes, i);
status = iomap_write_end(iter, pos, bytes, copied, folio);
written = iomap_write_end(iter, pos, bytes, copied, folio) ?
copied : 0;

/*
* Update the in-memory inode size after copying the data into
* the page cache. It's up to the file system to write the
* updated size to disk, preferably after I/O completion so that
* no stale data is exposed. Only once that's done can we
* unlock and release the folio.
*/
old_size = iter->inode->i_size;
if (pos + written > old_size) {
i_size_write(iter->inode, pos + written);
iter->iomap.flags |= IOMAP_F_SIZE_CHANGED;
}
__iomap_put_folio(iter, pos, written, folio);

if (unlikely(copied != status))
iov_iter_revert(i, copied - status);
if (old_size < pos)
pagecache_isize_extended(iter->inode, old_size, pos);

cond_resched();
if (unlikely(status == 0)) {
if (unlikely(written == 0)) {
/*
* A short copy made iomap_write_end() reject the
* thing entirely. Might be memory poisoning
* halfway through, might be a race with munmap,
* might be severe memory pressure.
*/
iomap_write_failed(iter->inode, pos, bytes);
iov_iter_revert(i, copied);

if (chunk > PAGE_SIZE)
chunk /= 2;
if (copied) {
bytes = copied;
goto retry;
}
} else {
pos += status;
written += status;
length -= status;
pos += written;
total_written += written;
length -= written;
}
} while (iov_iter_count(i) && length);

if (status == -EAGAIN) {
iov_iter_revert(i, written);
iov_iter_revert(i, total_written);
return -EAGAIN;
}
return written ? written : status;
return total_written ? total_written : status;
}

ssize_t
Expand Down Expand Up @@ -1322,6 +1333,7 @@ static loff_t iomap_unshare_iter(struct iomap_iter *iter)
int status;
size_t offset;
size_t bytes = min_t(u64, SIZE_MAX, length);
bool ret;

status = iomap_write_begin(iter, pos, bytes, &folio);
if (unlikely(status))
Expand All @@ -1333,8 +1345,9 @@ static loff_t iomap_unshare_iter(struct iomap_iter *iter)
if (bytes > folio_size(folio) - offset)
bytes = folio_size(folio) - offset;

bytes = iomap_write_end(iter, pos, bytes, bytes, folio);
if (WARN_ON_ONCE(bytes == 0))
ret = iomap_write_end(iter, pos, bytes, bytes, folio);
__iomap_put_folio(iter, pos, bytes, folio);
if (WARN_ON_ONCE(!ret))
return -EIO;

cond_resched();
Expand Down Expand Up @@ -1383,6 +1396,7 @@ static loff_t iomap_zero_iter(struct iomap_iter *iter, bool *did_zero)
int status;
size_t offset;
size_t bytes = min_t(u64, SIZE_MAX, length);
bool ret;

status = iomap_write_begin(iter, pos, bytes, &folio);
if (status)
Expand All @@ -1397,8 +1411,9 @@ static loff_t iomap_zero_iter(struct iomap_iter *iter, bool *did_zero)
folio_zero_range(folio, offset, bytes);
folio_mark_accessed(folio);

bytes = iomap_write_end(iter, pos, bytes, bytes, folio);
if (WARN_ON_ONCE(bytes == 0))
ret = iomap_write_end(iter, pos, bytes, bytes, folio);
__iomap_put_folio(iter, pos, bytes, folio);
if (WARN_ON_ONCE(!ret))
return -EIO;

pos += bytes;
Expand Down Expand Up @@ -1958,18 +1973,13 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc,
return error;
}

static int iomap_do_writepage(struct folio *folio,
struct writeback_control *wbc, void *data)
{
return iomap_writepage_map(data, wbc, folio);
}

int
iomap_writepages(struct address_space *mapping, struct writeback_control *wbc,
struct iomap_writepage_ctx *wpc,
const struct iomap_writeback_ops *ops)
{
int ret;
struct folio *folio = NULL;
int error;

/*
* Writeback from reclaim context should never happen except in the case
Expand All @@ -1980,8 +1990,9 @@ iomap_writepages(struct address_space *mapping, struct writeback_control *wbc,
return -EIO;

wpc->ops = ops;
ret = write_cache_pages(mapping, wbc, iomap_do_writepage, wpc);
return iomap_submit_ioend(wpc, ret);
while ((folio = writeback_iter(mapping, wbc, folio, &error)))
error = iomap_writepage_map(wpc, wbc, folio);
return iomap_submit_ioend(wpc, error);
}
EXPORT_SYMBOL_GPL(iomap_writepages);

Expand Down

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