From 1db175428ee374489448361213e9c3b749d14900 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Fri, 21 Oct 2016 11:33:49 +0200 Subject: [PATCH] ext4: Simplify DAX fault path Now that dax_iomap_fault() calls ->iomap_begin() without entry lock, we can use transaction starting in ext4_iomap_begin() and thus simplify ext4_dax_fault(). It also provides us proper retries in case of ENOSPC. Signed-off-by: Jan Kara Signed-off-by: Dan Williams --- fs/ext4/file.c | 48 ++++++++++-------------------------------------- 1 file changed, 10 insertions(+), 38 deletions(-) diff --git a/fs/ext4/file.c b/fs/ext4/file.c index b5f184493c57..d663d3d7c81c 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -258,7 +258,6 @@ out: static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf) { int result; - handle_t *handle = NULL; struct inode *inode = file_inode(vma->vm_file); struct super_block *sb = inode->i_sb; bool write = vmf->flags & FAULT_FLAG_WRITE; @@ -266,24 +265,12 @@ static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf) if (write) { sb_start_pagefault(sb); file_update_time(vma->vm_file); - down_read(&EXT4_I(inode)->i_mmap_sem); - handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE, - EXT4_DATA_TRANS_BLOCKS(sb)); - } else - down_read(&EXT4_I(inode)->i_mmap_sem); - - if (IS_ERR(handle)) - result = VM_FAULT_SIGBUS; - else - result = dax_iomap_fault(vma, vmf, &ext4_iomap_ops); - - if (write) { - if (!IS_ERR(handle)) - ext4_journal_stop(handle); - up_read(&EXT4_I(inode)->i_mmap_sem); + } + down_read(&EXT4_I(inode)->i_mmap_sem); + result = dax_iomap_fault(vma, vmf, &ext4_iomap_ops); + up_read(&EXT4_I(inode)->i_mmap_sem); + if (write) sb_end_pagefault(sb); - } else - up_read(&EXT4_I(inode)->i_mmap_sem); return result; } @@ -292,7 +279,6 @@ static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr, pmd_t *pmd, unsigned int flags) { int result; - handle_t *handle = NULL; struct inode *inode = file_inode(vma->vm_file); struct super_block *sb = inode->i_sb; bool write = flags & FAULT_FLAG_WRITE; @@ -300,27 +286,13 @@ static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr, if (write) { sb_start_pagefault(sb); file_update_time(vma->vm_file); - down_read(&EXT4_I(inode)->i_mmap_sem); - handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE, - ext4_chunk_trans_blocks(inode, - PMD_SIZE / PAGE_SIZE)); - } else - down_read(&EXT4_I(inode)->i_mmap_sem); - - if (IS_ERR(handle)) - result = VM_FAULT_SIGBUS; - else { - result = dax_iomap_pmd_fault(vma, addr, pmd, flags, - &ext4_iomap_ops); } - - if (write) { - if (!IS_ERR(handle)) - ext4_journal_stop(handle); - up_read(&EXT4_I(inode)->i_mmap_sem); + down_read(&EXT4_I(inode)->i_mmap_sem); + result = dax_iomap_pmd_fault(vma, addr, pmd, flags, + &ext4_iomap_ops); + up_read(&EXT4_I(inode)->i_mmap_sem); + if (write) sb_end_pagefault(sb); - } else - up_read(&EXT4_I(inode)->i_mmap_sem); return result; } -- 2.30.2