Commit 30460e1e authored by Carlos Maiolino's avatar Carlos Maiolino Committed by Al Viro
Browse files

fs: Enable bmap() function to properly return errors 



By now, bmap() will either return the physical block number related to
the requested file offset or 0 in case of error or the requested offset
maps into a hole.
This patch makes the needed changes to enable bmap() to proper return
errors, using the return value as an error return, and now, a pointer
must be passed to bmap() to be filled with the mapped physical block.

It will change the behavior of bmap() on return:

- negative value in case of error
- zero on success or map fell into a hole

In case of a hole, the *block will be zero too

Since this is a prep patch, by now, the only error return is -EINVAL if
->bmap doesn't exist.

Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarCarlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent c79f46a2

drivers/md/md-bitmap.c

+10 −6
Original line number Diff line number Diff line
@@ -364,7 +364,7 @@ static int read_page(struct file *file, unsigned long index, 
	int ret = 0;

	struct inode *inode = file_inode(file);

	struct buffer_head *bh;

	sector_t block;

	sector_t block, blk_cur;



	pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,

		 (unsigned long long)index << PAGE_SHIFT);
@@ -375,17 +375,21 @@ static int read_page(struct file *file, unsigned long index, 
		goto out;

	}

	attach_page_buffers(page, bh);

	block = index << (PAGE_SHIFT - inode->i_blkbits);

	blk_cur = index << (PAGE_SHIFT - inode->i_blkbits);

	while (bh) {

		block = blk_cur;



		if (count == 0)

			bh->b_blocknr = 0;

		else {

			bh->b_blocknr = bmap(inode, block);

			if (bh->b_blocknr == 0) {

				/* Cannot use this file! */

			ret = bmap(inode, &block);

			if (ret || !block) {

				ret = -EINVAL;

				bh->b_blocknr = 0;

				goto out;

			}



			bh->b_blocknr = block;

			bh->b_bdev = inode->i_sb->s_bdev;

			if (count < (1<<inode->i_blkbits))

				count = 0;
@@ -399,7 +403,7 @@ static int read_page(struct file *file, unsigned long index, 
			set_buffer_mapped(bh);

			submit_bh(REQ_OP_READ, 0, bh);

		}

		block++;

		blk_cur++;

		bh = bh->b_this_page;

	}

	page->index = index;

fs/f2fs/data.c

+11 −5
Original line number Diff line number Diff line
@@ -3170,12 +3170,16 @@ static int check_swap_activate(struct file *swap_file, unsigned int max) 
	while ((probe_block + blocks_per_page) <= last_block && page_no < max) {

		unsigned block_in_page;

		sector_t first_block;

		sector_t block = 0;

		int	 err = 0;



		cond_resched();



		first_block = bmap(inode, probe_block);

		if (first_block == 0)

		block = probe_block;

		err = bmap(inode, &block);

		if (err || !block)

			goto bad_bmap;

		first_block = block;



		/*

		 * It must be PAGE_SIZE aligned on-disk
@@ -3187,11 +3191,13 @@ static int check_swap_activate(struct file *swap_file, unsigned int max) 


		for (block_in_page = 1; block_in_page < blocks_per_page;

					block_in_page++) {

			sector_t block;



			block = bmap(inode, probe_block + block_in_page);

			if (block == 0)

			block = probe_block + block_in_page;

			err = bmap(inode, &block);



			if (err || !block)

				goto bad_bmap;



			if (block != first_block + block_in_page) {

				/* Discontiguity */

				probe_block++;

fs/inode.c

+19 −13
Original line number Diff line number Diff line
@@ -1598,25 +1598,31 @@ retry: 
}

EXPORT_SYMBOL(iput);



#ifdef CONFIG_BLOCK

/**

 *	bmap	- find a block number in a file

 *	@inode: inode of file

 *	@block: block to find

 *	@inode:  inode owning the block number being requested

 *	@block: pointer containing the block to find

 *

 *	Returns the block number on the device holding the inode that

 *	is the disk block number for the block of the file requested.

 *	That is, asked for block 4 of inode 1 the function will return the

 *	disk block relative to the disk start that holds that block of the

 *	file.

 *	Replaces the value in *block with the block number on the device holding

 *	corresponding to the requested block number in the file.

 *	That is, asked for block 4 of inode 1 the function will replace the

 *	4 in *block, with disk block relative to the disk start that holds that

 *	block of the file.

 *

 *	Returns -EINVAL in case of error, 0 otherwise. If mapping falls into a

 *	hole, returns 0 and *block is also set to 0.

 */

sector_t bmap(struct inode *inode, sector_t block)

int bmap(struct inode *inode, sector_t *block)

{

	sector_t res = 0;

	if (inode->i_mapping->a_ops->bmap)

		res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block);

	return res;

	if (!inode->i_mapping->a_ops->bmap)

		return -EINVAL;



	*block = inode->i_mapping->a_ops->bmap(inode->i_mapping, *block);

	return 0;

}

EXPORT_SYMBOL(bmap);

#endif



/*

 * With relative atime, only update atime if the previous atime is

fs/jbd2/journal.c

+15 −7
Original line number Diff line number Diff line
@@ -795,18 +795,23 @@ int jbd2_journal_bmap(journal_t *journal, unsigned long blocknr, 
{

	int err = 0;

	unsigned long long ret;

	sector_t block = 0;



	if (journal->j_inode) {

		ret = bmap(journal->j_inode, blocknr);

		if (ret)

			*retp = ret;

		else {

		block = blocknr;

		ret = bmap(journal->j_inode, &block);



		if (ret || !block) {

			printk(KERN_ALERT "%s: journal block not found "

					"at offset %lu on %s\n",

			       __func__, blocknr, journal->j_devname);

			err = -EIO;

			__journal_abort_soft(journal, err);



		} else {

			*retp = block;

		}



	} else {

		*retp = blocknr; /* +journal->j_blk_offset */

	}
@@ -1244,11 +1249,14 @@ journal_t *jbd2_journal_init_dev(struct block_device *bdev, 
journal_t *jbd2_journal_init_inode(struct inode *inode)

{

	journal_t *journal;

	sector_t blocknr;

	char *p;

	unsigned long long blocknr;

	int err = 0;



	blocknr = 0;

	err = bmap(inode, &blocknr);



	blocknr = bmap(inode, 0);

	if (!blocknr) {

	if (err || !blocknr) {

		pr_err("%s: Cannot locate journal superblock\n",

			__func__);

		return NULL;

include/linux/fs.h

+8 −1
Original line number Diff line number Diff line
@@ -2865,9 +2865,16 @@ static inline ssize_t generic_write_sync(struct kiocb *iocb, ssize_t count) 


extern void emergency_sync(void);

extern void emergency_remount(void);



#ifdef CONFIG_BLOCK

extern sector_t bmap(struct inode *, sector_t);

extern int bmap(struct inode *inode, sector_t *block);

#else

static inline int bmap(struct inode *inode,  sector_t *block)

{

	return -EINVAL;

}

#endif



extern int notify_change(struct dentry *, struct iattr *, struct inode **);

extern int inode_permission(struct inode *, int);

extern int generic_permission(struct inode *, int);

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