The patch titled
Subject: buffer: return bool from grow_dev_folio()
has been added to the -mm mm-unstable branch. Its filename is
buffer-return-bool-from-grow_dev_folio.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/buffer-return-bool-from-grow_dev_folio.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: buffer: return bool from grow_dev_folio()
Date: Thu, 9 Nov 2023 21:06:02 +0000
Patch series "More buffer_head cleanups", v2.
The first patch is a left-over from last cycle. The rest fix "obvious"
block size > PAGE_SIZE problems. I haven't tested with a large block size
setup (but I have done an ext4 xfstests run).
This patch (of 7):
Rename grow_dev_page() to grow_dev_folio() and make it return a bool.
Document what that bool means; it's more subtle than it first appears.
Also rename the 'failed' label to 'unlock' beacuse it's not exactly
'failed'. It just hasn't succeeded.
Link: https://lkml.kernel.org/r/20231109210608.2252323-2-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxx>
Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Cc: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
Cc: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/buffer.c | 50 +++++++++++++++++++++++++-------------------------
1 file changed, 25 insertions(+), 25 deletions(-)
--- a/fs/buffer.c~buffer-return-bool-from-grow_dev_folio
+++ a/fs/buffer.c
@@ -1024,40 +1024,43 @@ static sector_t folio_init_buffers(struc
}
/*
- * Create the page-cache page that contains the requested block.
+ * Create the page-cache folio that contains the requested block.
*
* This is used purely for blockdev mappings.
+ *
+ * Returns false if we have a 'permanent' failure. Returns true if
+ * we succeeded, or the caller should retry.
*/
-static int
-grow_dev_page(struct block_device *bdev, sector_t block,
- pgoff_t index, int size, int sizebits, gfp_t gfp)
+static bool grow_dev_folio(struct block_device *bdev, sector_t block,
+ pgoff_t index, unsigned size, int sizebits, gfp_t gfp)
{
struct inode *inode = bdev->bd_inode;
struct folio *folio;
struct buffer_head *bh;
- sector_t end_block;
- int ret = 0;
+ sector_t end_block = 0;
folio = __filemap_get_folio(inode->i_mapping, index,
FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp);
if (IS_ERR(folio))
- return PTR_ERR(folio);
+ return false;
bh = folio_buffers(folio);
if (bh) {
if (bh->b_size == size) {
end_block = folio_init_buffers(folio, bdev,
(sector_t)index << sizebits, size);
- goto done;
+ goto unlock;
}
+
+ /* Caller should retry if this call fails */
+ end_block = ~0ULL;
if (!try_to_free_buffers(folio))
- goto failed;
+ goto unlock;
}
- ret = -ENOMEM;
bh = folio_alloc_buffers(folio, size, gfp | __GFP_ACCOUNT);
if (!bh)
- goto failed;
+ goto unlock;
/*
* Link the folio to the buffers and initialise them. Take the
@@ -1069,20 +1072,19 @@ grow_dev_page(struct block_device *bdev,
end_block = folio_init_buffers(folio, bdev,
(sector_t)index << sizebits, size);
spin_unlock(&inode->i_mapping->private_lock);
-done:
- ret = (block < end_block) ? 1 : -ENXIO;
-failed:
+unlock:
folio_unlock(folio);
folio_put(folio);
- return ret;
+ return block < end_block;
}
/*
- * Create buffers for the specified block device block's page. If
- * that page was dirty, the buffers are set dirty also.
+ * Create buffers for the specified block device block's folio. If
+ * that folio was dirty, the buffers are set dirty also. Returns false
+ * if we've hit a permanent error.
*/
-static int
-grow_buffers(struct block_device *bdev, sector_t block, int size, gfp_t gfp)
+static bool grow_buffers(struct block_device *bdev, sector_t block,
+ unsigned size, gfp_t gfp)
{
pgoff_t index;
int sizebits;
@@ -1099,11 +1101,11 @@ grow_buffers(struct block_device *bdev,
"device %pg\n",
__func__, (unsigned long long)block,
bdev);
- return -EIO;
+ return false;
}
- /* Create a page with the proper size buffers.. */
- return grow_dev_page(bdev, block, index, size, sizebits, gfp);
+ /* Create a folio with the proper size buffers */
+ return grow_dev_folio(bdev, block, index, size, sizebits, gfp);
}
static struct buffer_head *
@@ -1124,14 +1126,12 @@ __getblk_slow(struct block_device *bdev,
for (;;) {
struct buffer_head *bh;
- int ret;
bh = __find_get_block(bdev, block, size);
if (bh)
return bh;
- ret = grow_buffers(bdev, block, size, gfp);
- if (ret < 0)
+ if (!grow_buffers(bdev, block, size, gfp))
return NULL;
}
}
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
mm-add-folio_zero_tail-and-use-it-in-ext4.patch
mm-add-folio_fill_tail-and-use-it-in-iomap.patch
gfs2-convert-stuffed_readpage-to-stuffed_read_folio.patch
mm-remove-test_set_page_writeback.patch
afs-do-not-test-the-return-value-of-folio_start_writeback.patch
smb-do-not-test-the-return-value-of-folio_start_writeback.patch
mm-return-void-from-folio_start_writeback-and-related-functions.patch
mm-make-mapping_evict_folio-the-preferred-way-to-evict-clean-folios.patch
mm-convert-__do_fault-to-use-a-folio.patch
mm-use-mapping_evict_folio-in-truncate_error_page.patch
mm-convert-soft_offline_in_use_page-to-use-a-folio.patch
mm-convert-isolate_page-to-mf_isolate_folio.patch
mm-remove-invalidate_inode_page.patch
buffer-return-bool-from-grow_dev_folio.patch
buffer-calculate-block-number-inside-folio_init_buffers.patch
buffer-fix-grow_buffers-for-block-size-page_size.patch
buffer-cast-block-to-loff_t-before-shifting-it.patch
buffer-fix-various-functions-for-block-size-page_size.patch
buffer-handle-large-folios-in-__block_write_begin_int.patch
buffer-fix-more-functions-for-block-size-page_size.patch
