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Commit 123a28d8 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 

Pull ext2 fix from Jan Kara:
 "Fix for DAX on ext2"

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  ext2: Add locking for DAX faults
parents 373ee21e 5726b27b

fs/ext2/ext2.h

+11 −0
Original line number Diff line number Diff line
@@ -684,6 +684,9 @@ struct ext2_inode_info { 
	struct rw_semaphore xattr_sem;

#endif

	rwlock_t i_meta_lock;

#ifdef CONFIG_FS_DAX

	struct rw_semaphore dax_sem;

#endif



	/*

	 * truncate_mutex is for serialising ext2_truncate() against
@@ -699,6 +702,14 @@ struct ext2_inode_info { 
#endif

};



#ifdef CONFIG_FS_DAX

#define dax_sem_down_write(ext2_inode)	down_write(&(ext2_inode)->dax_sem)

#define dax_sem_up_write(ext2_inode)	up_write(&(ext2_inode)->dax_sem)

#else

#define dax_sem_down_write(ext2_inode)

#define dax_sem_up_write(ext2_inode)

#endif



/*

 * Inode dynamic state flags

 */

fs/ext2/file.c

+80 −4
Original line number Diff line number Diff line
@@ -27,27 +27,103 @@ 
#include "acl.h"



#ifdef CONFIG_FS_DAX

/*

 * The lock ordering for ext2 DAX fault paths is:

 *

 * mmap_sem (MM)

 *   sb_start_pagefault (vfs, freeze)

 *     ext2_inode_info->dax_sem

 *       address_space->i_mmap_rwsem or page_lock (mutually exclusive in DAX)

 *         ext2_inode_info->truncate_mutex

 *

 * The default page_lock and i_size verification done by non-DAX fault paths

 * is sufficient because ext2 doesn't support hole punching.

 */

static int ext2_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)

{

	return dax_fault(vma, vmf, ext2_get_block, NULL);

	struct inode *inode = file_inode(vma->vm_file);

	struct ext2_inode_info *ei = EXT2_I(inode);

	int ret;



	if (vmf->flags & FAULT_FLAG_WRITE) {

		sb_start_pagefault(inode->i_sb);

		file_update_time(vma->vm_file);

	}

	down_read(&ei->dax_sem);



	ret = __dax_fault(vma, vmf, ext2_get_block, NULL);



	up_read(&ei->dax_sem);

	if (vmf->flags & FAULT_FLAG_WRITE)

		sb_end_pagefault(inode->i_sb);

	return ret;

}



static int ext2_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,

						pmd_t *pmd, unsigned int flags)

{

	return dax_pmd_fault(vma, addr, pmd, flags, ext2_get_block, NULL);

	struct inode *inode = file_inode(vma->vm_file);

	struct ext2_inode_info *ei = EXT2_I(inode);

	int ret;



	if (flags & FAULT_FLAG_WRITE) {

		sb_start_pagefault(inode->i_sb);

		file_update_time(vma->vm_file);

	}

	down_read(&ei->dax_sem);



	ret = __dax_pmd_fault(vma, addr, pmd, flags, ext2_get_block, NULL);



	up_read(&ei->dax_sem);

	if (flags & FAULT_FLAG_WRITE)

		sb_end_pagefault(inode->i_sb);

	return ret;

}



static int ext2_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)

{

	return dax_mkwrite(vma, vmf, ext2_get_block, NULL);

	struct inode *inode = file_inode(vma->vm_file);

	struct ext2_inode_info *ei = EXT2_I(inode);

	int ret;



	sb_start_pagefault(inode->i_sb);

	file_update_time(vma->vm_file);

	down_read(&ei->dax_sem);



	ret = __dax_mkwrite(vma, vmf, ext2_get_block, NULL);



	up_read(&ei->dax_sem);

	sb_end_pagefault(inode->i_sb);

	return ret;

}



static int ext2_dax_pfn_mkwrite(struct vm_area_struct *vma,

		struct vm_fault *vmf)

{

	struct inode *inode = file_inode(vma->vm_file);

	struct ext2_inode_info *ei = EXT2_I(inode);

	int ret = VM_FAULT_NOPAGE;

	loff_t size;



	sb_start_pagefault(inode->i_sb);

	file_update_time(vma->vm_file);

	down_read(&ei->dax_sem);



	/* check that the faulting page hasn't raced with truncate */

	size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;

	if (vmf->pgoff >= size)

		ret = VM_FAULT_SIGBUS;



	up_read(&ei->dax_sem);

	sb_end_pagefault(inode->i_sb);

	return ret;

}



static const struct vm_operations_struct ext2_dax_vm_ops = {

	.fault		= ext2_dax_fault,

	.pmd_fault	= ext2_dax_pmd_fault,

	.page_mkwrite	= ext2_dax_mkwrite,

	.pfn_mkwrite	= dax_pfn_mkwrite,

	.pfn_mkwrite	= ext2_dax_pfn_mkwrite,

};



static int ext2_file_mmap(struct file *file, struct vm_area_struct *vma)

fs/ext2/inode.c

+10 −0
Original line number Diff line number Diff line
@@ -1085,6 +1085,7 @@ static void ext2_free_branches(struct inode *inode, __le32 *p, __le32 *q, int de 
		ext2_free_data(inode, p, q);

}



/* dax_sem must be held when calling this function */

static void __ext2_truncate_blocks(struct inode *inode, loff_t offset)

{

	__le32 *i_data = EXT2_I(inode)->i_data;
@@ -1100,6 +1101,10 @@ static void __ext2_truncate_blocks(struct inode *inode, loff_t offset) 
	blocksize = inode->i_sb->s_blocksize;

	iblock = (offset + blocksize-1) >> EXT2_BLOCK_SIZE_BITS(inode->i_sb);



#ifdef CONFIG_FS_DAX

	WARN_ON(!rwsem_is_locked(&ei->dax_sem));

#endif



	n = ext2_block_to_path(inode, iblock, offsets, NULL);

	if (n == 0)

		return;
@@ -1185,7 +1190,10 @@ static void ext2_truncate_blocks(struct inode *inode, loff_t offset) 
		return;

	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))

		return;



	dax_sem_down_write(EXT2_I(inode));

	__ext2_truncate_blocks(inode, offset);

	dax_sem_up_write(EXT2_I(inode));

}



static int ext2_setsize(struct inode *inode, loff_t newsize)
@@ -1213,8 +1221,10 @@ static int ext2_setsize(struct inode *inode, loff_t newsize) 
	if (error)

		return error;



	dax_sem_down_write(EXT2_I(inode));

	truncate_setsize(inode, newsize);

	__ext2_truncate_blocks(inode, newsize);

	dax_sem_up_write(EXT2_I(inode));



	inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;

	if (inode_needs_sync(inode)) {

fs/ext2/super.c

+3 −0
Original line number Diff line number Diff line
@@ -192,6 +192,9 @@ static void init_once(void *foo) 
	init_rwsem(&ei->xattr_sem);

#endif

	mutex_init(&ei->truncate_mutex);

#ifdef CONFIG_FS_DAX

	init_rwsem(&ei->dax_sem);

#endif

	inode_init_once(&ei->vfs_inode);

}