Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 430657b6 authored by Ross Zwisler's avatar Ross Zwisler Committed by Theodore Ts'o
Browse files

ext4: handle layout changes to pinned DAX mappings 



Follow the lead of xfs_break_dax_layouts() and add synchronization between
operations in ext4 which remove blocks from an inode (hole punch, truncate
down, etc.) and pages which are pinned due to DAX DMA operations.

Signed-off-by: default avatarRoss Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Reviewed-by: default avatarLukas Czerner <lczerner@redhat.com>
parent cdbf8897

fs/ext4/ext4.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -2459,6 +2459,7 @@ extern int ext4_get_inode_loc(struct inode *, struct ext4_iloc *); 
extern int ext4_inode_attach_jinode(struct inode *inode);

extern int ext4_inode_attach_jinode(struct inode *inode);

extern int ext4_can_truncate(struct inode *inode);

extern int ext4_can_truncate(struct inode *inode);

extern int ext4_truncate(struct inode *);

extern int ext4_truncate(struct inode *);

extern int ext4_break_layouts(struct inode *);

extern int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length);

extern int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length);

extern int ext4_truncate_restart_trans(handle_t *, struct inode *, int nblocks);

extern int ext4_truncate_restart_trans(handle_t *, struct inode *, int nblocks);

extern void ext4_set_inode_flags(struct inode *);

extern void ext4_set_inode_flags(struct inode *);

fs/ext4/extents.c

+17 −0
Original line number Original line Diff line number Diff line
@@ -4826,6 +4826,13 @@ static long ext4_zero_range(struct file *file, loff_t offset, 
		 * released from page cache.

		 * released from page cache.

		 */

		 */

		down_write(&EXT4_I(inode)->i_mmap_sem);

		down_write(&EXT4_I(inode)->i_mmap_sem);



		ret = ext4_break_layouts(inode);

		if (ret) {

			up_write(&EXT4_I(inode)->i_mmap_sem);

			goto out_mutex;

		}



		ret = ext4_update_disksize_before_punch(inode, offset, len);

		ret = ext4_update_disksize_before_punch(inode, offset, len);

		if (ret) {

		if (ret) {

			up_write(&EXT4_I(inode)->i_mmap_sem);

			up_write(&EXT4_I(inode)->i_mmap_sem);
@@ -5499,6 +5506,11 @@ int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len) 
	 * page cache.

	 * page cache.

	 */

	 */

	down_write(&EXT4_I(inode)->i_mmap_sem);

	down_write(&EXT4_I(inode)->i_mmap_sem);



	ret = ext4_break_layouts(inode);

	if (ret)

		goto out_mmap;



	/*

	/*

	 * Need to round down offset to be aligned with page size boundary

	 * Need to round down offset to be aligned with page size boundary

	 * for page size > block size.

	 * for page size > block size.
@@ -5647,6 +5659,11 @@ int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len) 
	 * page cache.

	 * page cache.

	 */

	 */

	down_write(&EXT4_I(inode)->i_mmap_sem);

	down_write(&EXT4_I(inode)->i_mmap_sem);



	ret = ext4_break_layouts(inode);

	if (ret)

		goto out_mmap;



	/*

	/*

	 * Need to round down to align start offset to page size boundary

	 * Need to round down to align start offset to page size boundary

	 * for page size > block size.

	 * for page size > block size.

fs/ext4/inode.c

+46 −0
Original line number Original line Diff line number Diff line
@@ -4191,6 +4191,39 @@ int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset, 
	return 0;

	return 0;

}

}





static void ext4_wait_dax_page(struct ext4_inode_info *ei, bool *did_unlock)

{

	*did_unlock = true;

	up_write(&ei->i_mmap_sem);

	schedule();

	down_write(&ei->i_mmap_sem);

}



int ext4_break_layouts(struct inode *inode)

{

	struct ext4_inode_info *ei = EXT4_I(inode);

	struct page *page;

	bool retry;

	int error;



	if (WARN_ON_ONCE(!rwsem_is_locked(&ei->i_mmap_sem)))

		return -EINVAL;



	do {

		retry = false;

		page = dax_layout_busy_page(inode->i_mapping);

		if (!page)

			return 0;



		error = ___wait_var_event(&page->_refcount,

				atomic_read(&page->_refcount) == 1,

				TASK_INTERRUPTIBLE, 0, 0,

				ext4_wait_dax_page(ei, &retry));

	} while (error == 0 && retry);



	return error;

}



/*

/*

 * ext4_punch_hole: punches a hole in a file by releasing the blocks

 * ext4_punch_hole: punches a hole in a file by releasing the blocks

 * associated with the given offset and length

 * associated with the given offset and length
@@ -4264,6 +4297,11 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length) 
	 * page cache.

	 * page cache.

	 */

	 */

	down_write(&EXT4_I(inode)->i_mmap_sem);

	down_write(&EXT4_I(inode)->i_mmap_sem);



	ret = ext4_break_layouts(inode);

	if (ret)

		goto out_dio;



	first_block_offset = round_up(offset, sb->s_blocksize);

	first_block_offset = round_up(offset, sb->s_blocksize);

	last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;

	last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
@@ -5553,6 +5591,14 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr) 
				ext4_wait_for_tail_page_commit(inode);

				ext4_wait_for_tail_page_commit(inode);

		}

		}

		down_write(&EXT4_I(inode)->i_mmap_sem);

		down_write(&EXT4_I(inode)->i_mmap_sem);



		rc = ext4_break_layouts(inode);

		if (rc) {

			up_write(&EXT4_I(inode)->i_mmap_sem);

			error = rc;

			goto err_out;

		}



		/*

		/*

		 * Truncate pagecache after we've waited for commit

		 * Truncate pagecache after we've waited for commit

		 * in data=journal mode to make pages freeable.

		 * in data=journal mode to make pages freeable.

fs/ext4/truncate.h

+4 −0
Original line number Original line Diff line number Diff line
@@ -11,6 +11,10 @@ 
 */

 */

static inline void ext4_truncate_failed_write(struct inode *inode)

static inline void ext4_truncate_failed_write(struct inode *inode)

{

{

	/*

	 * We don't need to call ext4_break_layouts() because the blocks we

	 * are truncating were never visible to userspace.

	 */

	down_write(&EXT4_I(inode)->i_mmap_sem);

	down_write(&EXT4_I(inode)->i_mmap_sem);

	truncate_inode_pages(inode->i_mapping, inode->i_size);

	truncate_inode_pages(inode->i_mapping, inode->i_size);

	ext4_truncate(inode);

	ext4_truncate(inode);