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xfs: consolidate the various page fault handlers 

Add a new __xfs_filemap_fault helper that implements all four page fault
callouts, and make these methods themselves small stubs that set the
correct write_fault flag, and exit early for the non-DAX case for the
hugepage related ones.

Also remove the extra size checking in the pfn_fault path, which is now
handled in the core DAX code.

Life would be so much simpler if we only had one method for all this.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
This commit is contained in:
Christoph Hellwig 2017-08-29 10:08:41 -07:00 committed by Darrick J. Wong
parent e7647fb491
commit d522d569d6
2 changed files with 71 additions and 76 deletions
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118
fs/xfs/xfs_file.c
View File

@ -1011,97 +1011,69 @@ xfs_file_llseek(
* page_lock (MM)
* i_lock (XFS - extent map serialisation)
*/
/*
* mmap()d file has taken write protection fault and is being made writable. We
* can set the page state up correctly for a writable page, which means we can
* do correct delalloc accounting (ENOSPC checking!) and unwritten extent
* mapping.
*/
STATIC int
xfs_filemap_page_mkwrite(
struct vm_fault *vmf)
{
struct inode *inode = file_inode(vmf->vma->vm_file);
int ret;
trace_xfs_filemap_page_mkwrite(XFS_I(inode));
sb_start_pagefault(inode->i_sb);
file_update_time(vmf->vma->vm_file);
xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
if (IS_DAX(inode)) {
ret = dax_iomap_fault(vmf, PE_SIZE_PTE, &xfs_iomap_ops);
} else {
ret = iomap_page_mkwrite(vmf, &xfs_iomap_ops);
}
xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
sb_end_pagefault(inode->i_sb);
return ret;
}
STATIC int
xfs_filemap_fault(
struct vm_fault *vmf)
{
struct inode *inode = file_inode(vmf->vma->vm_file);
int ret;
trace_xfs_filemap_fault(XFS_I(inode));
/* DAX can shortcut the normal fault path on write faults! */
if ((vmf->flags & FAULT_FLAG_WRITE) && IS_DAX(inode))
return xfs_filemap_page_mkwrite(vmf);
xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
if (IS_DAX(inode))
ret = dax_iomap_fault(vmf, PE_SIZE_PTE, &xfs_iomap_ops);
else
ret = filemap_fault(vmf);
xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
return ret;
}
/*
* Similar to xfs_filemap_fault(), the DAX fault path can call into here on
* both read and write faults. Hence we need to handle both cases. There is no
* ->huge_mkwrite callout for huge pages, so we have a single function here to
* handle both cases here. @flags carries the information on the type of fault
* occuring.
*/
STATIC int
xfs_filemap_huge_fault(
static int
__xfs_filemap_fault(
struct vm_fault *vmf,
enum page_entry_size pe_size)
enum page_entry_size pe_size,
bool write_fault)
{
struct inode *inode = file_inode(vmf->vma->vm_file);
struct xfs_inode *ip = XFS_I(inode);
int ret;
if (!IS_DAX(inode))
return VM_FAULT_FALLBACK;
trace_xfs_filemap_fault(ip, pe_size, write_fault);
trace_xfs_filemap_huge_fault(ip);
if (vmf->flags & FAULT_FLAG_WRITE) {
if (write_fault) {
sb_start_pagefault(inode->i_sb);
file_update_time(vmf->vma->vm_file);
}
xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
ret = dax_iomap_fault(vmf, pe_size, &xfs_iomap_ops);
if (IS_DAX(inode)) {
ret = dax_iomap_fault(vmf, pe_size, &xfs_iomap_ops);
} else {
if (write_fault)
ret = iomap_page_mkwrite(vmf, &xfs_iomap_ops);
else
ret = filemap_fault(vmf);
}
xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
if (vmf->flags & FAULT_FLAG_WRITE)
if (write_fault)
sb_end_pagefault(inode->i_sb);
return ret;
}
static int
xfs_filemap_fault(
struct vm_fault *vmf)
{
/* DAX can shortcut the normal fault path on write faults! */
return __xfs_filemap_fault(vmf, PE_SIZE_PTE,
IS_DAX(file_inode(vmf->vma->vm_file)) &&
(vmf->flags & FAULT_FLAG_WRITE));
}
static int
xfs_filemap_huge_fault(
struct vm_fault *vmf,
enum page_entry_size pe_size)
{
if (!IS_DAX(file_inode(vmf->vma->vm_file)))
return VM_FAULT_FALLBACK;
/* DAX can shortcut the normal fault path on write faults! */
return __xfs_filemap_fault(vmf, pe_size,
(vmf->flags & FAULT_FLAG_WRITE));
}
static int
xfs_filemap_page_mkwrite(
struct vm_fault *vmf)
{
return __xfs_filemap_fault(vmf, PE_SIZE_PTE, true);
}
/*
* pfn_mkwrite was originally inteneded to ensure we capture time stamp
* updates on write faults. In reality, it's need to serialise against

29
fs/xfs/xfs_trace.h
View File

@ -688,11 +688,34 @@ DEFINE_INODE_EVENT(xfs_inode_set_cowblocks_tag);
DEFINE_INODE_EVENT(xfs_inode_clear_cowblocks_tag);
DEFINE_INODE_EVENT(xfs_inode_free_cowblocks_invalid);
DEFINE_INODE_EVENT(xfs_filemap_fault);
DEFINE_INODE_EVENT(xfs_filemap_huge_fault);
DEFINE_INODE_EVENT(xfs_filemap_page_mkwrite);
DEFINE_INODE_EVENT(xfs_filemap_pfn_mkwrite);
TRACE_EVENT(xfs_filemap_fault,
TP_PROTO(struct xfs_inode *ip, enum page_entry_size pe_size,
bool write_fault),
TP_ARGS(ip, pe_size, write_fault),
TP_STRUCT__entry(
__field(dev_t, dev)
__field(xfs_ino_t, ino)
__field(enum page_entry_size, pe_size)
__field(bool, write_fault)
),
TP_fast_assign(
__entry->dev = VFS_I(ip)->i_sb->s_dev;
__entry->ino = ip->i_ino;
__entry->pe_size = pe_size;
__entry->write_fault = write_fault;
),
TP_printk("dev %d:%d ino 0x%llx %s write_fault %d",
MAJOR(__entry->dev), MINOR(__entry->dev),
__entry->ino,
__print_symbolic(__entry->pe_size,
{ PE_SIZE_PTE, "PTE" },
{ PE_SIZE_PMD, "PMD" },
{ PE_SIZE_PUD, "PUD" }),
__entry->write_fault)
)
DECLARE_EVENT_CLASS(xfs_iref_class,
TP_PROTO(struct xfs_inode *ip, unsigned long caller_ip),
TP_ARGS(ip, caller_ip),