fs/buffer: introduce sleeping flavors for pagecache lookups

Add __find_get_block_nonatomic() and sb_find_get_block_nonatomic()
calls for which users will be converted where safe. These versions
will take the folio lock instead of the mapping's private_lock.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Link: https://kdevops.org/ext4/v6.15-rc2.html
Link: https://lore.kernel.org/all/aAAEvcrmREWa1SKF@bombadil.infradead.org/
Link: https://lore.kernel.org/20250418015921.132400-3-dave@stgolabs.net
Tested-by: kdevops@lists.linux.dev
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/buffer.c b/fs/buffer.c
index f8fcffdbe5d9058fd5076a83c042a3bf43b5d4c2..5b1d74c818e9753f9b51e7e8bdf0925fba20f753 100644 (file)
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1414,6 +1414,15 @@ __find_get_block(struct block_device *bdev, sector_t block, unsigned size)
 }
 EXPORT_SYMBOL(__find_get_block);
 
+/* same as __find_get_block() but allows sleeping contexts */
+struct buffer_head *
+__find_get_block_nonatomic(struct block_device *bdev, sector_t block,
+                          unsigned size)
+{
+       return find_get_block_common(bdev, block, size, false);
+}
+EXPORT_SYMBOL(__find_get_block_nonatomic);
+
 /**
  * bdev_getblk - Get a buffer_head in a block device's buffer cache.
  * @bdev: The block device.

diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index f0a4ad7839b62f35eeed3f17eb523515c9c78987..c791aa9a08daa0d6a124f9aeb4954edf38f1d501 100644 (file)
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -222,6 +222,8 @@ void __wait_on_buffer(struct buffer_head *);
 wait_queue_head_t *bh_waitq_head(struct buffer_head *bh);
 struct buffer_head *__find_get_block(struct block_device *bdev, sector_t block,
                        unsigned size);
+struct buffer_head *__find_get_block_nonatomic(struct block_device *bdev,
+                       sector_t block, unsigned size);
 struct buffer_head *bdev_getblk(struct block_device *bdev, sector_t block,
                unsigned size, gfp_t gfp);
 void __brelse(struct buffer_head *);
@@ -397,6 +399,12 @@ sb_find_get_block(struct super_block *sb, sector_t block)
        return __find_get_block(sb->s_bdev, block, sb->s_blocksize);
 }
 
+static inline struct buffer_head *
+sb_find_get_block_nonatomic(struct super_block *sb, sector_t block)
+{
+       return __find_get_block_nonatomic(sb->s_bdev, block, sb->s_blocksize);
+}
+
 static inline void
 map_bh(struct buffer_head *bh, struct super_block *sb, sector_t block)
 {