On Wed 14-12-16 12:55:23, Dave Jiang wrote:
> The callers into dax needs to clear __GFP_FS since they are responsible
> for acquiring locks / transactions that block __GFP_FS allocation. They
> will restore the lag when dax function return.
^^^ flags ^^^ returns.
Otherwise the patch looks good to me. Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
>
> Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
> ---
> fs/dax.c | 1 +
> fs/ext2/file.c | 9 ++++++++-
> fs/ext4/file.c | 10 +++++++++-
> fs/xfs/xfs_file.c | 14 +++++++++++++-
> 4 files changed, 31 insertions(+), 3 deletions(-)
>
> diff --git a/fs/dax.c b/fs/dax.c
> index d3fe880..6395bc6 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -1380,6 +1380,7 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
> vmf.pgoff = pgoff;
> vmf.flags = flags;
> vmf.gfp_mask = mapping_gfp_mask(mapping) | __GFP_IO;
> + vmf.gfp_mask &= ~__GFP_FS;
>
> switch (iomap.type) {
> case IOMAP_MAPPED:
> diff --git a/fs/ext2/file.c b/fs/ext2/file.c
> index b0f2415..8422d5f 100644
> --- a/fs/ext2/file.c
> +++ b/fs/ext2/file.c
> @@ -92,16 +92,19 @@ static int ext2_dax_fault(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;
> + gfp_t old_gfp = vmf->gfp_mask;
>
> if (vmf->flags & FAULT_FLAG_WRITE) {
> sb_start_pagefault(inode->i_sb);
> file_update_time(vma->vm_file);
> }
> + vmf->gfp_mask &= ~__GFP_FS;
> down_read(&ei->dax_sem);
>
> ret = dax_iomap_fault(vma, vmf, &ext2_iomap_ops);
>
> up_read(&ei->dax_sem);
> + vmf->gfp_mask = old_gfp;
> if (vmf->flags & FAULT_FLAG_WRITE)
> sb_end_pagefault(inode->i_sb);
> return ret;
> @@ -114,6 +117,7 @@ static int ext2_dax_pfn_mkwrite(struct vm_area_struct *vma,
> struct ext2_inode_info *ei = EXT2_I(inode);
> loff_t size;
> int ret;
> + gfp_t old_gfp = vmf->gfp_mask;
>
> sb_start_pagefault(inode->i_sb);
> file_update_time(vma->vm_file);
> @@ -123,8 +127,11 @@ static int ext2_dax_pfn_mkwrite(struct vm_area_struct *vma,
> size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
> if (vmf->pgoff >= size)
> ret = VM_FAULT_SIGBUS;
> - else
> + else {
> + vmf->gfp_mask &= ~__GFP_FS;
> ret = dax_pfn_mkwrite(vma, vmf);
> + vmf->gfp_mask = old_gfp;
> + }
>
> up_read(&ei->dax_sem);
> sb_end_pagefault(inode->i_sb);
> diff --git a/fs/ext4/file.c b/fs/ext4/file.c
> index d663d3d..a3f2bf0 100644
> --- a/fs/ext4/file.c
> +++ b/fs/ext4/file.c
> @@ -261,14 +261,17 @@ static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
> struct inode *inode = file_inode(vma->vm_file);
> struct super_block *sb = inode->i_sb;
> bool write = vmf->flags & FAULT_FLAG_WRITE;
> + gfp_t old_gfp = vmf->gfp_mask;
>
> if (write) {
> sb_start_pagefault(sb);
> file_update_time(vma->vm_file);
> }
> + vmf->gfp_mask &= ~__GFP_FS;
> 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);
> + vmf->gfp_mask = old_gfp;
> if (write)
> sb_end_pagefault(sb);
>
> @@ -320,8 +323,13 @@ static int ext4_dax_pfn_mkwrite(struct vm_area_struct *vma,
> size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
> if (vmf->pgoff >= size)
> ret = VM_FAULT_SIGBUS;
> - else
> + else {
> + gfp_t old_gfp = vmf->gfp_mask;
> +
> + vmf->gfp_mask &= ~__GFP_FS;
> ret = dax_pfn_mkwrite(vma, vmf);
> + vmf->gfp_mask = old_gfp;
> + }
> up_read(&EXT4_I(inode)->i_mmap_sem);
> sb_end_pagefault(sb);
>
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index d818c16..52202b4 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -1474,7 +1474,11 @@ xfs_filemap_page_mkwrite(
> xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
>
> if (IS_DAX(inode)) {
> + gfp_t old_gfp = vmf->gfp_mask;
> +
> + vmf->gfp_mask &= ~__GFP_FS;
> ret = dax_iomap_fault(vma, vmf, &xfs_iomap_ops);
> + vmf->gfp_mask = old_gfp;
> } else {
> ret = iomap_page_mkwrite(vma, vmf, &xfs_iomap_ops);
> ret = block_page_mkwrite_return(ret);
> @@ -1502,13 +1506,16 @@ xfs_filemap_fault(
>
> xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
> if (IS_DAX(inode)) {
> + gfp_t old_gfp = vmf->gfp_mask;
> /*
> * we do not want to trigger unwritten extent conversion on read
> * faults - that is unnecessary overhead and would also require
> * changes to xfs_get_blocks_direct() to map unwritten extent
> * ioend for conversion on read-only mappings.
> */
> + vmf->gfp_mask &= ~__GFP_FS;
> ret = dax_iomap_fault(vma, vmf, &xfs_iomap_ops);
> + vmf->gfp_mask = old_gfp;
> } else
> ret = filemap_fault(vma, vmf);
> xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
> @@ -1581,8 +1588,13 @@ xfs_filemap_pfn_mkwrite(
> size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
> if (vmf->pgoff >= size)
> ret = VM_FAULT_SIGBUS;
> - else if (IS_DAX(inode))
> + else if (IS_DAX(inode)) {
> + gfp_t old_gfp = vmf->gfp_mask;
> +
> + vmf->gfp_mask &= ~__GFP_FS;
> ret = dax_pfn_mkwrite(vma, vmf);
> + vmf->gfp_mask = old_gfp;
> + }
> xfs_iunlock(ip, XFS_MMAPLOCK_SHARED);
> sb_end_pagefault(inode->i_sb);
> return ret;
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
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