Commit 8394a6ab authored by zhangyi (F)'s avatar zhangyi (F) Committed by Theodore Ts'o
Browse files

ext4: introduce ext4_sb_bread_unmovable() to replace sb_bread_unmovable() 



Now we only use sb_bread_unmovable() to read superblock and descriptor
block at mount time, so there is no opportunity that we need to clear
buffer verified bit and also handle buffer write_io error bit. But for
the sake of unification, let's introduce ext4_sb_bread_unmovable() to
replace all sb_bread_unmovable(). After this patch, we stop using read
helpers in fs/buffer.c.

Signed-off-by: default avatarzhangyi (F) <yi.zhang@huawei.com>
Link: https://lore.kernel.org/r/20200924073337.861472-8-yi.zhang@huawei.com


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 0a846f49

fs/ext4/ext4.h

+2 −0
Original line number Diff line number Diff line
@@ -2823,6 +2823,8 @@ extern int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count); 
/* super.c */

extern struct buffer_head *ext4_sb_bread(struct super_block *sb,

					 sector_t block, int op_flags);

extern struct buffer_head *ext4_sb_bread_unmovable(struct super_block *sb,

						   sector_t block);

extern void ext4_read_bh_nowait(struct buffer_head *bh, int op_flags,

				bh_end_io_t *end_io);

extern int ext4_read_bh(struct buffer_head *bh, int op_flags,

fs/ext4/super.c

+29 −9
Original line number Diff line number Diff line
@@ -204,18 +204,19 @@ int ext4_read_bh_lock(struct buffer_head *bh, int op_flags, bool wait) 
}



/*

 * This works like sb_bread() except it uses ERR_PTR for error

 * This works like __bread_gfp() except it uses ERR_PTR for error

 * returns.  Currently with sb_bread it's impossible to distinguish

 * between ENOMEM and EIO situations (since both result in a NULL

 * return.

 */

struct buffer_head *

ext4_sb_bread(struct super_block *sb, sector_t block, int op_flags)

static struct buffer_head *__ext4_sb_bread_gfp(struct super_block *sb,

					       sector_t block, int op_flags,

					       gfp_t gfp)

{

	struct buffer_head *bh;

	int ret;



	bh = sb_getblk(sb, block);

	bh = sb_getblk_gfp(sb, block, gfp);

	if (bh == NULL)

		return ERR_PTR(-ENOMEM);

	if (ext4_buffer_uptodate(bh))
@@ -229,6 +230,18 @@ ext4_sb_bread(struct super_block *sb, sector_t block, int op_flags) 
	return bh;

}



struct buffer_head *ext4_sb_bread(struct super_block *sb, sector_t block,

				   int op_flags)

{

	return __ext4_sb_bread_gfp(sb, block, op_flags, __GFP_MOVABLE);

}



struct buffer_head *ext4_sb_bread_unmovable(struct super_block *sb,

					    sector_t block)

{

	return __ext4_sb_bread_gfp(sb, block, 0, 0);

}



void ext4_sb_breadahead_unmovable(struct super_block *sb, sector_t block)

{

	struct buffer_head *bh = sb_getblk_gfp(sb, block, 0);
@@ -3954,8 +3967,11 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) 
		logical_sb_block = sb_block;

	}



	if (!(bh = sb_bread_unmovable(sb, logical_sb_block))) {

	bh = ext4_sb_bread_unmovable(sb, logical_sb_block);

	if (IS_ERR(bh)) {

		ext4_msg(sb, KERN_ERR, "unable to read superblock");

		ret = PTR_ERR(bh);

		bh = NULL;

		goto out_fail;

	}

	/*
@@ -4351,10 +4367,12 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) 
		brelse(bh);

		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;

		offset = do_div(logical_sb_block, blocksize);

		bh = sb_bread_unmovable(sb, logical_sb_block);

		if (!bh) {

		bh = ext4_sb_bread_unmovable(sb, logical_sb_block);

		if (IS_ERR(bh)) {

			ext4_msg(sb, KERN_ERR,

			       "Can't read superblock on 2nd try");

			ret = PTR_ERR(bh);

			bh = NULL;

			goto failed_mount;

		}

		es = (struct ext4_super_block *)(bh->b_data + offset);
@@ -4573,11 +4591,13 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) 
		struct buffer_head *bh;



		block = descriptor_loc(sb, logical_sb_block, i);

		bh = sb_bread_unmovable(sb, block);

		if (!bh) {

		bh = ext4_sb_bread_unmovable(sb, block);

		if (IS_ERR(bh)) {

			ext4_msg(sb, KERN_ERR,

			       "can't read group descriptor %d", i);

			db_count = i;

			ret = PTR_ERR(bh);

			bh = NULL;

			goto failed_mount2;

		}

		rcu_read_lock();

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