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authorLinus Torvalds <torvalds@linux-foundation.org>2023-09-23 09:56:40 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2023-09-23 09:56:40 -0700
commit59c376d636387a9b896c8da1d1bb68bb0bda67c0 (patch)
tree875ef35172a5fb93be3bbbdfc708c6c53966fc5c
parentd90b0276af8f25a0b8ae081a30d1b2a61263393b (diff)
parenta5f31a5028d1e88e97c3b6cdc3e3bf2da085e232 (diff)
downloadlwn-59c376d636387a9b896c8da1d1bb68bb0bda67c0.tar.gz
lwn-59c376d636387a9b896c8da1d1bb68bb0bda67c0.zip
Merge tag 'iomap-6.6-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull iomap fixes from Darrick Wong: - Return EIO on bad inputs to iomap_to_bh instead of BUGging, to deal less poorly with block device io racing with block device resizing - Fix a stale page data exposure bug introduced in 6.6-rc1 when unsharing a file range that is not in the page cache * tag 'iomap-6.6-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: iomap: convert iomap_unshare_iter to use large folios iomap: don't skip reading in !uptodate folios when unsharing a range iomap: handle error conditions more gracefully in iomap_to_bh
-rw-r--r--fs/buffer.c25
-rw-r--r--fs/iomap/buffered-io.c30
2 files changed, 32 insertions, 23 deletions
diff --git a/fs/buffer.c b/fs/buffer.c
index 2379564e5aea..a6785cd07081 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2011,7 +2011,7 @@ void folio_zero_new_buffers(struct folio *folio, size_t from, size_t to)
}
EXPORT_SYMBOL(folio_zero_new_buffers);
-static void
+static int
iomap_to_bh(struct inode *inode, sector_t block, struct buffer_head *bh,
const struct iomap *iomap)
{
@@ -2025,7 +2025,8 @@ iomap_to_bh(struct inode *inode, sector_t block, struct buffer_head *bh,
* current block, then do not map the buffer and let the caller
* handle it.
*/
- BUG_ON(offset >= iomap->offset + iomap->length);
+ if (offset >= iomap->offset + iomap->length)
+ return -EIO;
switch (iomap->type) {
case IOMAP_HOLE:
@@ -2037,7 +2038,7 @@ iomap_to_bh(struct inode *inode, sector_t block, struct buffer_head *bh,
if (!buffer_uptodate(bh) ||
(offset >= i_size_read(inode)))
set_buffer_new(bh);
- break;
+ return 0;
case IOMAP_DELALLOC:
if (!buffer_uptodate(bh) ||
(offset >= i_size_read(inode)))
@@ -2045,7 +2046,7 @@ iomap_to_bh(struct inode *inode, sector_t block, struct buffer_head *bh,
set_buffer_uptodate(bh);
set_buffer_mapped(bh);
set_buffer_delay(bh);
- break;
+ return 0;
case IOMAP_UNWRITTEN:
/*
* For unwritten regions, we always need to ensure that regions
@@ -2062,7 +2063,10 @@ iomap_to_bh(struct inode *inode, sector_t block, struct buffer_head *bh,
bh->b_blocknr = (iomap->addr + offset - iomap->offset) >>
inode->i_blkbits;
set_buffer_mapped(bh);
- break;
+ return 0;
+ default:
+ WARN_ON_ONCE(1);
+ return -EIO;
}
}
@@ -2103,13 +2107,12 @@ int __block_write_begin_int(struct folio *folio, loff_t pos, unsigned len,
clear_buffer_new(bh);
if (!buffer_mapped(bh)) {
WARN_ON(bh->b_size != blocksize);
- if (get_block) {
+ if (get_block)
err = get_block(inode, block, bh, 1);
- if (err)
- break;
- } else {
- iomap_to_bh(inode, block, bh, iomap);
- }
+ else
+ err = iomap_to_bh(inode, block, bh, iomap);
+ if (err)
+ break;
if (buffer_new(bh)) {
clean_bdev_bh_alias(bh);
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index ae8673ce08b1..644479ccefbd 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -640,11 +640,13 @@ static int __iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
size_t poff, plen;
/*
- * If the write completely overlaps the current folio, then
+ * If the write or zeroing completely overlaps the current folio, then
* entire folio will be dirtied so there is no need for
* per-block state tracking structures to be attached to this folio.
+ * For the unshare case, we must read in the ondisk contents because we
+ * are not changing pagecache contents.
*/
- if (pos <= folio_pos(folio) &&
+ if (!(iter->flags & IOMAP_UNSHARE) && pos <= folio_pos(folio) &&
pos + len >= folio_pos(folio) + folio_size(folio))
return 0;
@@ -1261,7 +1263,6 @@ static loff_t iomap_unshare_iter(struct iomap_iter *iter)
const struct iomap *srcmap = iomap_iter_srcmap(iter);
loff_t pos = iter->pos;
loff_t length = iomap_length(iter);
- long status = 0;
loff_t written = 0;
/* don't bother with blocks that are not shared to start with */
@@ -1272,28 +1273,33 @@ static loff_t iomap_unshare_iter(struct iomap_iter *iter)
return length;
do {
- unsigned long offset = offset_in_page(pos);
- unsigned long bytes = min_t(loff_t, PAGE_SIZE - offset, length);
struct folio *folio;
+ int status;
+ size_t offset;
+ size_t bytes = min_t(u64, SIZE_MAX, length);
status = iomap_write_begin(iter, pos, bytes, &folio);
if (unlikely(status))
return status;
- if (iter->iomap.flags & IOMAP_F_STALE)
+ if (iomap->flags & IOMAP_F_STALE)
break;
- status = iomap_write_end(iter, pos, bytes, bytes, folio);
- if (WARN_ON_ONCE(status == 0))
+ offset = offset_in_folio(folio, pos);
+ 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))
return -EIO;
cond_resched();
- pos += status;
- written += status;
- length -= status;
+ pos += bytes;
+ written += bytes;
+ length -= bytes;
balance_dirty_pages_ratelimited(iter->inode->i_mapping);
- } while (length);
+ } while (length > 0);
return written;
}