* [PATCH v9 01/22] axonram: Fix bug in direct_access
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 02/22] Change direct_access calling convention Matthew Wilcox
` (20 subsequent siblings)
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Matthew Wilcox, willy
The 'pfn' returned by axonram was completely bogus, and has been since
2008.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
arch/powerpc/sysdev/axonram.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/sysdev/axonram.c b/arch/powerpc/sysdev/axonram.c
index 47b6b9f..830edc8 100644
--- a/arch/powerpc/sysdev/axonram.c
+++ b/arch/powerpc/sysdev/axonram.c
@@ -156,7 +156,7 @@ axon_ram_direct_access(struct block_device *device, sector_t sector,
}
*kaddr = (void *)(bank->ph_addr + offset);
- *pfn = virt_to_phys(kaddr) >> PAGE_SHIFT;
+ *pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT;
return 0;
}
--
2.0.1
--
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 02/22] Change direct_access calling convention
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 01/22] axonram: Fix bug in direct_access Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 03/22] Fix XIP fault vs truncate race Matthew Wilcox
` (19 subsequent siblings)
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Matthew Wilcox, willy
In order to support accesses to larger chunks of memory, pass in a
'size' parameter (counted in bytes), and return the amount available at
that address.
Add a new helper function, bdev_direct_access(), to handle common
functionality including partition handling, checking for the sector
being page-aligned, and checking the length of the request does not
pass the end of the partition.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
Documentation/filesystems/xip.txt | 15 +++++++++------
arch/powerpc/sysdev/axonram.c | 17 ++++-------------
drivers/block/brd.c | 12 +++++-------
drivers/s390/block/dcssblk.c | 21 +++++++++------------
fs/block_dev.c | 34 ++++++++++++++++++++++++++++++++++
fs/ext2/xip.c | 31 +++++++++++++------------------
include/linux/blkdev.h | 6 ++++--
7 files changed, 78 insertions(+), 58 deletions(-)
diff --git a/Documentation/filesystems/xip.txt b/Documentation/filesystems/xip.txt
index 0466ee5..b62eabf 100644
--- a/Documentation/filesystems/xip.txt
+++ b/Documentation/filesystems/xip.txt
@@ -28,12 +28,15 @@ Implementation
Execute-in-place is implemented in three steps: block device operation,
address space operation, and file operations.
-A block device operation named direct_access is used to retrieve a
-reference (pointer) to a block on-disk. The reference is supposed to be
-cpu-addressable, physical address and remain valid until the release operation
-is performed. A struct block_device reference is used to address the device,
-and a sector_t argument is used to identify the individual block. As an
-alternative, memory technology devices can be used for this.
+A block device operation named direct_access is used to translate the
+block device sector number to a page frame number (pfn) that identifies
+the physical page for the memory. It also returns a kernel virtual
+address that can be used to access the memory.
+
+The direct_access method takes a 'size' parameter that indicates the
+number of bytes being requested. The function should return the number
+of bytes that it can provide, although it must not exceed the number of
+bytes requested. It may also return a negative errno if an error occurs.
The block device operation is optional, these block devices support it as of
today:
diff --git a/arch/powerpc/sysdev/axonram.c b/arch/powerpc/sysdev/axonram.c
index 830edc8..741293f 100644
--- a/arch/powerpc/sysdev/axonram.c
+++ b/arch/powerpc/sysdev/axonram.c
@@ -139,26 +139,17 @@ axon_ram_make_request(struct request_queue *queue, struct bio *bio)
* axon_ram_direct_access - direct_access() method for block device
* @device, @sector, @data: see block_device_operations method
*/
-static int
+static long
axon_ram_direct_access(struct block_device *device, sector_t sector,
- void **kaddr, unsigned long *pfn)
+ void **kaddr, unsigned long *pfn, long size)
{
struct axon_ram_bank *bank = device->bd_disk->private_data;
- loff_t offset;
-
- offset = sector;
- if (device->bd_part != NULL)
- offset += device->bd_part->start_sect;
- offset <<= AXON_RAM_SECTOR_SHIFT;
- if (offset >= bank->size) {
- dev_err(&bank->device->dev, "Access outside of address space\n");
- return -ERANGE;
- }
+ loff_t offset = (loff_t)sector << AXON_RAM_SECTOR_SHIFT;
*kaddr = (void *)(bank->ph_addr + offset);
*pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT;
- return 0;
+ return min_t(long, size, bank->size - offset);
}
static const struct block_device_operations axon_ram_devops = {
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index c7d138e..a10a0a9 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -370,25 +370,23 @@ static int brd_rw_page(struct block_device *bdev, sector_t sector,
}
#ifdef CONFIG_BLK_DEV_XIP
-static int brd_direct_access(struct block_device *bdev, sector_t sector,
- void **kaddr, unsigned long *pfn)
+static long brd_direct_access(struct block_device *bdev, sector_t sector,
+ void **kaddr, unsigned long *pfn, long size)
{
struct brd_device *brd = bdev->bd_disk->private_data;
struct page *page;
if (!brd)
return -ENODEV;
- if (sector & (PAGE_SECTORS-1))
- return -EINVAL;
- if (sector + PAGE_SECTORS > get_capacity(bdev->bd_disk))
- return -ERANGE;
page = brd_insert_page(brd, sector);
if (!page)
return -ENOSPC;
*kaddr = page_address(page);
*pfn = page_to_pfn(page);
- return 0;
+ /* Could optimistically check to see if the next page in the
+ * file is mapped to the next page of physical RAM */
+ return min_t(long, PAGE_SIZE, size);
}
#endif
diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
index 0f47175..2ee5556 100644
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@ -28,8 +28,8 @@
static int dcssblk_open(struct block_device *bdev, fmode_t mode);
static void dcssblk_release(struct gendisk *disk, fmode_t mode);
static void dcssblk_make_request(struct request_queue *q, struct bio *bio);
-static int dcssblk_direct_access(struct block_device *bdev, sector_t secnum,
- void **kaddr, unsigned long *pfn);
+static long dcssblk_direct_access(struct block_device *bdev, sector_t secnum,
+ void **kaddr, unsigned long *pfn, long size);
static char dcssblk_segments[DCSSBLK_PARM_LEN] = "\0";
@@ -866,25 +866,22 @@ fail:
bio_io_error(bio);
}
-static int
+static long
dcssblk_direct_access (struct block_device *bdev, sector_t secnum,
- void **kaddr, unsigned long *pfn)
+ void **kaddr, unsigned long *pfn, long size)
{
struct dcssblk_dev_info *dev_info;
- unsigned long pgoff;
+ unsigned long offset, dev_sz;
dev_info = bdev->bd_disk->private_data;
if (!dev_info)
return -ENODEV;
- if (secnum % (PAGE_SIZE/512))
- return -EINVAL;
- pgoff = secnum / (PAGE_SIZE / 512);
- if ((pgoff+1)*PAGE_SIZE-1 > dev_info->end - dev_info->start)
- return -ERANGE;
- *kaddr = (void *) (dev_info->start+pgoff*PAGE_SIZE);
+ dev_sz = dev_info->end - dev_info->start;
+ offset = secnum * 512;
+ *kaddr = (void *) (dev_info->start + offset);
*pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT;
- return 0;
+ return min_t(long, size, dev_sz - offset);
}
static void
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 6d72746..93ebdd53 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -427,6 +427,40 @@ int bdev_write_page(struct block_device *bdev, sector_t sector,
}
EXPORT_SYMBOL_GPL(bdev_write_page);
+/**
+ * bdev_direct_access() - Get the address for directly-accessibly memory
+ * @bdev: The device containing the memory
+ * @sector: The offset within the device
+ * @addr: Where to put the address of the memory
+ * @pfn: The Page Frame Number for the memory
+ * @size: The number of bytes requested
+ *
+ * If a block device is made up of directly addressable memory, this function
+ * will tell the caller the PFN and the address of the memory. The address
+ * may be directly dereferenced within the kernel without the need to call
+ * ioremap(), kmap() or similar. THe PFN is suitable for inserting into
+ * page tables.
+ *
+ * Return: negative errno if an error occurs, otherwise the number of bytes
+ * accessible at this address.
+ */
+long bdev_direct_access(struct block_device *bdev, sector_t sector,
+ void **addr, unsigned long *pfn, long size)
+{
+ const struct block_device_operations *ops = bdev->bd_disk->fops;
+ if (!ops->direct_access)
+ return -EOPNOTSUPP;
+ if ((sector + DIV_ROUND_UP(size, 512)) >
+ part_nr_sects_read(bdev->bd_part))
+ return -ERANGE;
+ sector += get_start_sect(bdev);
+ if (sector % (PAGE_SIZE / 512))
+ return -EINVAL;
+ size = ops->direct_access(bdev, sector, addr, pfn, size);
+ return size ? size : -ERANGE;
+}
+EXPORT_SYMBOL_GPL(bdev_direct_access);
+
/*
* pseudo-fs
*/
diff --git a/fs/ext2/xip.c b/fs/ext2/xip.c
index e98171a..bbc5fec 100644
--- a/fs/ext2/xip.c
+++ b/fs/ext2/xip.c
@@ -13,18 +13,12 @@
#include "ext2.h"
#include "xip.h"
-static inline int
-__inode_direct_access(struct inode *inode, sector_t block,
- void **kaddr, unsigned long *pfn)
+static inline long __inode_direct_access(struct inode *inode, sector_t block,
+ void **kaddr, unsigned long *pfn, long size)
{
struct block_device *bdev = inode->i_sb->s_bdev;
- const struct block_device_operations *ops = bdev->bd_disk->fops;
- sector_t sector;
-
- sector = block * (PAGE_SIZE / 512); /* ext2 block to bdev sector */
-
- BUG_ON(!ops->direct_access);
- return ops->direct_access(bdev, sector, kaddr, pfn);
+ sector_t sector = block * (PAGE_SIZE / 512);
+ return bdev_direct_access(bdev, sector, kaddr, pfn, size);
}
static inline int
@@ -53,12 +47,13 @@ ext2_clear_xip_target(struct inode *inode, sector_t block)
{
void *kaddr;
unsigned long pfn;
- int rc;
+ long size;
- rc = __inode_direct_access(inode, block, &kaddr, &pfn);
- if (!rc)
- clear_page(kaddr);
- return rc;
+ size = __inode_direct_access(inode, block, &kaddr, &pfn, PAGE_SIZE);
+ if (size < 0)
+ return size;
+ clear_page(kaddr);
+ return 0;
}
void ext2_xip_verify_sb(struct super_block *sb)
@@ -77,7 +72,7 @@ void ext2_xip_verify_sb(struct super_block *sb)
int ext2_get_xip_mem(struct address_space *mapping, pgoff_t pgoff, int create,
void **kmem, unsigned long *pfn)
{
- int rc;
+ long rc;
sector_t block;
/* first, retrieve the sector number */
@@ -86,6 +81,6 @@ int ext2_get_xip_mem(struct address_space *mapping, pgoff_t pgoff, int create,
return rc;
/* retrieve address of the target data */
- rc = __inode_direct_access(mapping->host, block, kmem, pfn);
- return rc;
+ rc = __inode_direct_access(mapping->host, block, kmem, pfn, PAGE_SIZE);
+ return (rc < 0) ? rc : 0;
}
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 8699bcf..bc5ea9e 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1613,8 +1613,8 @@ struct block_device_operations {
int (*rw_page)(struct block_device *, sector_t, struct page *, int rw);
int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
- int (*direct_access) (struct block_device *, sector_t,
- void **, unsigned long *);
+ long (*direct_access) (struct block_device *, sector_t,
+ void **, unsigned long *pfn, long size);
unsigned int (*check_events) (struct gendisk *disk,
unsigned int clearing);
/* ->media_changed() is DEPRECATED, use ->check_events() instead */
@@ -1632,6 +1632,8 @@ extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
extern int bdev_read_page(struct block_device *, sector_t, struct page *);
extern int bdev_write_page(struct block_device *, sector_t, struct page *,
struct writeback_control *);
+extern long bdev_direct_access(struct block_device *, sector_t, void **addr,
+ unsigned long *pfn, long size);
#else /* CONFIG_BLOCK */
struct block_device;
--
2.0.1
--
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 03/22] Fix XIP fault vs truncate race
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 01/22] axonram: Fix bug in direct_access Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 02/22] Change direct_access calling convention Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 04/22] Allow page fault handlers to perform the COW Matthew Wilcox
` (18 subsequent siblings)
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Matthew Wilcox, willy
Pagecache faults recheck i_size after taking the page lock to ensure that
the fault didn't race against a truncate. We don't have a page to lock
in the XIP case, so use the i_mmap_mutex instead. It is locked in the
truncate path in unmap_mapping_range() after updating i_size. So while
we hold it in the fault path, we are guaranteed that either i_size has
already been updated in the truncate path, or that the truncate will
subsequently call zap_page_range_single() and so remove the mapping we
have just inserted.
There is a window of time in which i_size has been reduced and the
thread has a mapping to a page which will be removed from the file,
but this is harmless as the page will not be allocated to a different
purpose before the thread's access to it is revoked.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
mm/filemap_xip.c | 24 ++++++++++++++++++++++--
1 file changed, 22 insertions(+), 2 deletions(-)
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index d8d9fe3..c8d23e9 100644
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -260,8 +260,17 @@ again:
__xip_unmap(mapping, vmf->pgoff);
found:
+ /* We must recheck i_size under i_mmap_mutex */
+ mutex_lock(&mapping->i_mmap_mutex);
+ size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
+ PAGE_CACHE_SHIFT;
+ if (unlikely(vmf->pgoff >= size)) {
+ mutex_unlock(&mapping->i_mmap_mutex);
+ return VM_FAULT_SIGBUS;
+ }
err = vm_insert_mixed(vma, (unsigned long)vmf->virtual_address,
xip_pfn);
+ mutex_unlock(&mapping->i_mmap_mutex);
if (err == -ENOMEM)
return VM_FAULT_OOM;
/*
@@ -285,16 +294,27 @@ found:
}
if (error != -ENODATA)
goto out;
+
+ /* We must recheck i_size under i_mmap_mutex */
+ mutex_lock(&mapping->i_mmap_mutex);
+ size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
+ PAGE_CACHE_SHIFT;
+ if (unlikely(vmf->pgoff >= size)) {
+ ret = VM_FAULT_SIGBUS;
+ goto unlock;
+ }
/* not shared and writable, use xip_sparse_page() */
page = xip_sparse_page();
if (!page)
- goto out;
+ goto unlock;
err = vm_insert_page(vma, (unsigned long)vmf->virtual_address,
page);
if (err == -ENOMEM)
- goto out;
+ goto unlock;
ret = VM_FAULT_NOPAGE;
+unlock:
+ mutex_unlock(&mapping->i_mmap_mutex);
out:
write_seqcount_end(&xip_sparse_seq);
mutex_unlock(&xip_sparse_mutex);
--
2.0.1
--
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 04/22] Allow page fault handlers to perform the COW
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
` (2 preceding siblings ...)
2014-08-01 13:27 ` [PATCH v9 03/22] Fix XIP fault vs truncate race Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 05/22] Introduce IS_DAX(inode) Matthew Wilcox
` (17 subsequent siblings)
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Matthew Wilcox, willy
Currently COW of an XIP file is done by first bringing in a read-only
mapping, then retrying the fault and copying the page. It is much more
efficient to tell the fault handler that a COW is being attempted (by
passing in the pre-allocated page in the vm_fault structure), and allow
the handler to perform the COW operation itself.
The handler cannot insert the page itself if there is already a read-only
mapping at that address, so allow the handler to return VM_FAULT_LOCKED
and set the fault_page to be NULL. This indicates to the MM code that
the i_mmap_mutex is held instead of the page lock.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
---
include/linux/mm.h | 1 +
mm/memory.c | 33 ++++++++++++++++++++++++---------
2 files changed, 25 insertions(+), 9 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e03dd29..e04f531 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -208,6 +208,7 @@ struct vm_fault {
pgoff_t pgoff; /* Logical page offset based on vma */
void __user *virtual_address; /* Faulting virtual address */
+ struct page *cow_page; /* Handler may choose to COW */
struct page *page; /* ->fault handlers should return a
* page here, unless VM_FAULT_NOPAGE
* is set (which is also implied by
diff --git a/mm/memory.c b/mm/memory.c
index 8b44f76..f37a044 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2003,6 +2003,7 @@ static int do_page_mkwrite(struct vm_area_struct *vma, struct page *page,
vmf.pgoff = page->index;
vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
vmf.page = page;
+ vmf.cow_page = NULL;
ret = vma->vm_ops->page_mkwrite(vma, &vmf);
if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
@@ -2689,7 +2690,8 @@ oom:
}
static int __do_fault(struct vm_area_struct *vma, unsigned long address,
- pgoff_t pgoff, unsigned int flags, struct page **page)
+ pgoff_t pgoff, unsigned int flags,
+ struct page *cow_page, struct page **page)
{
struct vm_fault vmf;
int ret;
@@ -2698,10 +2700,13 @@ static int __do_fault(struct vm_area_struct *vma, unsigned long address,
vmf.pgoff = pgoff;
vmf.flags = flags;
vmf.page = NULL;
+ vmf.cow_page = cow_page;
ret = vma->vm_ops->fault(vma, &vmf);
if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
return ret;
+ if (!vmf.page)
+ goto out;
if (unlikely(PageHWPoison(vmf.page))) {
if (ret & VM_FAULT_LOCKED)
@@ -2715,6 +2720,7 @@ static int __do_fault(struct vm_area_struct *vma, unsigned long address,
else
VM_BUG_ON_PAGE(!PageLocked(vmf.page), vmf.page);
+ out:
*page = vmf.page;
return ret;
}
@@ -2894,7 +2900,7 @@ static int do_read_fault(struct mm_struct *mm, struct vm_area_struct *vma,
pte_unmap_unlock(pte, ptl);
}
- ret = __do_fault(vma, address, pgoff, flags, &fault_page);
+ ret = __do_fault(vma, address, pgoff, flags, NULL, &fault_page);
if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
return ret;
@@ -2933,24 +2939,33 @@ static int do_cow_fault(struct mm_struct *mm, struct vm_area_struct *vma,
return VM_FAULT_OOM;
}
- ret = __do_fault(vma, address, pgoff, flags, &fault_page);
+ ret = __do_fault(vma, address, pgoff, flags, new_page, &fault_page);
if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
goto uncharge_out;
- copy_user_highpage(new_page, fault_page, address, vma);
+ if (fault_page)
+ copy_user_highpage(new_page, fault_page, address, vma);
__SetPageUptodate(new_page);
pte = pte_offset_map_lock(mm, pmd, address, &ptl);
if (unlikely(!pte_same(*pte, orig_pte))) {
pte_unmap_unlock(pte, ptl);
- unlock_page(fault_page);
- page_cache_release(fault_page);
+ if (fault_page) {
+ unlock_page(fault_page);
+ page_cache_release(fault_page);
+ } else {
+ mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
+ }
goto uncharge_out;
}
do_set_pte(vma, address, new_page, pte, true, true);
pte_unmap_unlock(pte, ptl);
- unlock_page(fault_page);
- page_cache_release(fault_page);
+ if (fault_page) {
+ unlock_page(fault_page);
+ page_cache_release(fault_page);
+ } else {
+ mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
+ }
return ret;
uncharge_out:
mem_cgroup_uncharge_page(new_page);
@@ -2969,7 +2984,7 @@ static int do_shared_fault(struct mm_struct *mm, struct vm_area_struct *vma,
int dirtied = 0;
int ret, tmp;
- ret = __do_fault(vma, address, pgoff, flags, &fault_page);
+ ret = __do_fault(vma, address, pgoff, flags, NULL, &fault_page);
if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
return ret;
--
2.0.1
--
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see: http://www.linux-mm.org/ .
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 05/22] Introduce IS_DAX(inode)
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
` (3 preceding siblings ...)
2014-08-01 13:27 ` [PATCH v9 04/22] Allow page fault handlers to perform the COW Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 06/22] Add copy_to_iter(), copy_from_iter() and iov_iter_zero() Matthew Wilcox
` (16 subsequent siblings)
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Matthew Wilcox, willy
Use an inode flag to tag inodes which should avoid using the page cache.
Convert ext2 to use it instead of mapping_is_xip().
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
fs/ext2/inode.c | 9 ++++++---
fs/ext2/xip.h | 2 --
include/linux/fs.h | 6 ++++++
3 files changed, 12 insertions(+), 5 deletions(-)
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 36d35c3..0cb0448 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -731,7 +731,7 @@ static int ext2_get_blocks(struct inode *inode,
goto cleanup;
}
- if (ext2_use_xip(inode->i_sb)) {
+ if (IS_DAX(inode)) {
/*
* we need to clear the block
*/
@@ -1201,7 +1201,7 @@ static int ext2_setsize(struct inode *inode, loff_t newsize)
inode_dio_wait(inode);
- if (mapping_is_xip(inode->i_mapping))
+ if (IS_DAX(inode))
error = xip_truncate_page(inode->i_mapping, newsize);
else if (test_opt(inode->i_sb, NOBH))
error = nobh_truncate_page(inode->i_mapping,
@@ -1273,7 +1273,8 @@ void ext2_set_inode_flags(struct inode *inode)
{
unsigned int flags = EXT2_I(inode)->i_flags;
- inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
+ inode->i_flags &= ~(S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME |
+ S_DIRSYNC | S_DAX);
if (flags & EXT2_SYNC_FL)
inode->i_flags |= S_SYNC;
if (flags & EXT2_APPEND_FL)
@@ -1284,6 +1285,8 @@ void ext2_set_inode_flags(struct inode *inode)
inode->i_flags |= S_NOATIME;
if (flags & EXT2_DIRSYNC_FL)
inode->i_flags |= S_DIRSYNC;
+ if (test_opt(inode->i_sb, XIP))
+ inode->i_flags |= S_DAX;
}
/* Propagate flags from i_flags to EXT2_I(inode)->i_flags */
diff --git a/fs/ext2/xip.h b/fs/ext2/xip.h
index 18b34d2..29be737 100644
--- a/fs/ext2/xip.h
+++ b/fs/ext2/xip.h
@@ -16,9 +16,7 @@ static inline int ext2_use_xip (struct super_block *sb)
}
int ext2_get_xip_mem(struct address_space *, pgoff_t, int,
void **, unsigned long *);
-#define mapping_is_xip(map) unlikely(map->a_ops->get_xip_mem)
#else
-#define mapping_is_xip(map) 0
#define ext2_xip_verify_sb(sb) do { } while (0)
#define ext2_use_xip(sb) 0
#define ext2_clear_xip_target(inode, chain) 0
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e11d60c..a94e5d7 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1579,6 +1579,7 @@ struct super_operations {
#define S_IMA 1024 /* Inode has an associated IMA struct */
#define S_AUTOMOUNT 2048 /* Automount/referral quasi-directory */
#define S_NOSEC 4096 /* no suid or xattr security attributes */
+#define S_DAX 8192 /* Direct Access, avoiding the page cache */
/*
* Note that nosuid etc flags are inode-specific: setting some file-system
@@ -1616,6 +1617,11 @@ struct super_operations {
#define IS_IMA(inode) ((inode)->i_flags & S_IMA)
#define IS_AUTOMOUNT(inode) ((inode)->i_flags & S_AUTOMOUNT)
#define IS_NOSEC(inode) ((inode)->i_flags & S_NOSEC)
+#ifdef CONFIG_FS_XIP
+#define IS_DAX(inode) ((inode)->i_flags & S_DAX)
+#else
+#define IS_DAX(inode) 0
+#endif
/*
* Inode state bits. Protected by inode->i_lock
--
2.0.1
--
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 06/22] Add copy_to_iter(), copy_from_iter() and iov_iter_zero()
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
` (4 preceding siblings ...)
2014-08-01 13:27 ` [PATCH v9 05/22] Introduce IS_DAX(inode) Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 07/22] Replace XIP read and write with DAX I/O Matthew Wilcox
` (15 subsequent siblings)
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Matthew Wilcox
From: Matthew Wilcox <willy@linux.intel.com>
For DAX, we want to be able to copy between iovecs and kernel addresses
that don't necessarily have a struct page. This is a fairly simple
rearrangement for bvec iters to kmap the pages outside and pass them in,
but for user iovecs it gets more complicated because we might try various
different ways to kmap the memory. Duplicating the existing logic works
out best in this case.
We need to be able to write zeroes to an iovec for reads from unwritten
ranges in a file. This is performed by the new iov_iter_zero() function,
again patterned after the existing code that handles iovec iterators.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
---
include/linux/uio.h | 3 +
mm/iov_iter.c | 237 ++++++++++++++++++++++++++++++++++++++++++++++++----
2 files changed, 226 insertions(+), 14 deletions(-)
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 09a7cff..86fb3e9 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -80,6 +80,9 @@ size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i);
size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i);
+size_t copy_to_iter(void *addr, size_t bytes, struct iov_iter *i);
+size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
+size_t iov_iter_zero(size_t bytes, struct iov_iter *);
unsigned long iov_iter_alignment(const struct iov_iter *i);
void iov_iter_init(struct iov_iter *i, int direction, const struct iovec *iov,
unsigned long nr_segs, size_t count);
diff --git a/mm/iov_iter.c b/mm/iov_iter.c
index 7b5dbd1..e95ed80 100644
--- a/mm/iov_iter.c
+++ b/mm/iov_iter.c
@@ -4,6 +4,96 @@
#include <linux/slab.h>
#include <linux/vmalloc.h>
+static size_t copy_to_iter_iovec(void *from, size_t bytes, struct iov_iter *i)
+{
+ size_t skip, copy, left, wanted;
+ const struct iovec *iov;
+ char __user *buf;
+
+ if (unlikely(bytes > i->count))
+ bytes = i->count;
+
+ if (unlikely(!bytes))
+ return 0;
+
+ wanted = bytes;
+ iov = i->iov;
+ skip = i->iov_offset;
+ buf = iov->iov_base + skip;
+ copy = min(bytes, iov->iov_len - skip);
+
+ left = __copy_to_user(buf, from, copy);
+ copy -= left;
+ skip += copy;
+ from += copy;
+ bytes -= copy;
+ while (unlikely(!left && bytes)) {
+ iov++;
+ buf = iov->iov_base;
+ copy = min(bytes, iov->iov_len);
+ left = __copy_to_user(buf, from, copy);
+ copy -= left;
+ skip = copy;
+ from += copy;
+ bytes -= copy;
+ }
+
+ if (skip == iov->iov_len) {
+ iov++;
+ skip = 0;
+ }
+ i->count -= wanted - bytes;
+ i->nr_segs -= iov - i->iov;
+ i->iov = iov;
+ i->iov_offset = skip;
+ return wanted - bytes;
+}
+
+static size_t copy_from_iter_iovec(void *to, size_t bytes, struct iov_iter *i)
+{
+ size_t skip, copy, left, wanted;
+ const struct iovec *iov;
+ char __user *buf;
+
+ if (unlikely(bytes > i->count))
+ bytes = i->count;
+
+ if (unlikely(!bytes))
+ return 0;
+
+ wanted = bytes;
+ iov = i->iov;
+ skip = i->iov_offset;
+ buf = iov->iov_base + skip;
+ copy = min(bytes, iov->iov_len - skip);
+
+ left = __copy_from_user(to, buf, copy);
+ copy -= left;
+ skip += copy;
+ to += copy;
+ bytes -= copy;
+ while (unlikely(!left && bytes)) {
+ iov++;
+ buf = iov->iov_base;
+ copy = min(bytes, iov->iov_len);
+ left = __copy_from_user(to, buf, copy);
+ copy -= left;
+ skip = copy;
+ to += copy;
+ bytes -= copy;
+ }
+
+ if (skip == iov->iov_len) {
+ iov++;
+ skip = 0;
+ }
+ i->count -= wanted - bytes;
+ i->nr_segs -= iov - i->iov;
+ i->iov = iov;
+ i->iov_offset = skip;
+ return wanted - bytes;
+}
+
static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i)
{
@@ -166,6 +256,50 @@ done:
return wanted - bytes;
}
+static size_t zero_iovec(size_t bytes, struct iov_iter *i)
+{
+ size_t skip, copy, left, wanted;
+ const struct iovec *iov;
+ char __user *buf;
+
+ if (unlikely(bytes > i->count))
+ bytes = i->count;
+
+ if (unlikely(!bytes))
+ return 0;
+
+ wanted = bytes;
+ iov = i->iov;
+ skip = i->iov_offset;
+ buf = iov->iov_base + skip;
+ copy = min(bytes, iov->iov_len - skip);
+
+ left = __clear_user(buf, copy);
+ copy -= left;
+ skip += copy;
+ bytes -= copy;
+
+ while (unlikely(!left && bytes)) {
+ iov++;
+ buf = iov->iov_base;
+ copy = min(bytes, iov->iov_len);
+ left = __clear_user(buf, copy);
+ copy -= left;
+ skip = copy;
+ bytes -= copy;
+ }
+
+ if (skip == iov->iov_len) {
+ iov++;
+ skip = 0;
+ }
+ i->count -= wanted - bytes;
+ i->nr_segs -= iov - i->iov;
+ i->iov = iov;
+ i->iov_offset = skip;
+ return wanted - bytes;
+}
+
static size_t __iovec_copy_from_user_inatomic(char *vaddr,
const struct iovec *iov, size_t base, size_t bytes)
{
@@ -412,12 +546,17 @@ static void memcpy_to_page(struct page *page, size_t offset, char *from, size_t
kunmap_atomic(to);
}
-static size_t copy_page_to_iter_bvec(struct page *page, size_t offset, size_t bytes,
- struct iov_iter *i)
+static void memzero_page(struct page *page, size_t offset, size_t len)
+{
+ char *addr = kmap_atomic(page);
+ memset(addr + offset, 0, len);
+ kunmap_atomic(addr);
+}
+
+static size_t copy_to_iter_bvec(void *from, size_t bytes, struct iov_iter *i)
{
size_t skip, copy, wanted;
const struct bio_vec *bvec;
- void *kaddr, *from;
if (unlikely(bytes > i->count))
bytes = i->count;
@@ -430,8 +569,6 @@ static size_t copy_page_to_iter_bvec(struct page *page, size_t offset, size_t by
skip = i->iov_offset;
copy = min_t(size_t, bytes, bvec->bv_len - skip);
- kaddr = kmap_atomic(page);
- from = kaddr + offset;
memcpy_to_page(bvec->bv_page, skip + bvec->bv_offset, from, copy);
skip += copy;
from += copy;
@@ -444,7 +581,6 @@ static size_t copy_page_to_iter_bvec(struct page *page, size_t offset, size_t by
from += copy;
bytes -= copy;
}
- kunmap_atomic(kaddr);
if (skip == bvec->bv_len) {
bvec++;
skip = 0;
@@ -456,12 +592,10 @@ static size_t copy_page_to_iter_bvec(struct page *page, size_t offset, size_t by
return wanted - bytes;
}
-static size_t copy_page_from_iter_bvec(struct page *page, size_t offset, size_t bytes,
- struct iov_iter *i)
+static size_t copy_from_iter_bvec(void *to, size_t bytes, struct iov_iter *i)
{
size_t skip, copy, wanted;
const struct bio_vec *bvec;
- void *kaddr, *to;
if (unlikely(bytes > i->count))
bytes = i->count;
@@ -473,10 +607,6 @@ static size_t copy_page_from_iter_bvec(struct page *page, size_t offset, size_t
bvec = i->bvec;
skip = i->iov_offset;
- kaddr = kmap_atomic(page);
-
- to = kaddr + offset;
-
copy = min(bytes, bvec->bv_len - skip);
memcpy_from_page(to, bvec->bv_page, bvec->bv_offset + skip, copy);
@@ -493,7 +623,6 @@ static size_t copy_page_from_iter_bvec(struct page *page, size_t offset, size_t
to += copy;
bytes -= copy;
}
- kunmap_atomic(kaddr);
if (skip == bvec->bv_len) {
bvec++;
skip = 0;
@@ -505,6 +634,61 @@ static size_t copy_page_from_iter_bvec(struct page *page, size_t offset, size_t
return wanted;
}
+static size_t copy_page_to_iter_bvec(struct page *page, size_t offset,
+ size_t bytes, struct iov_iter *i)
+{
+ void *kaddr = kmap_atomic(page);
+ size_t wanted = copy_to_iter_bvec(kaddr + offset, bytes, i);
+ kunmap_atomic(kaddr);
+ return wanted;
+}
+
+static size_t copy_page_from_iter_bvec(struct page *page, size_t offset,
+ size_t bytes, struct iov_iter *i)
+{
+ void *kaddr = kmap_atomic(page);
+ size_t wanted = copy_from_iter_bvec(kaddr + offset, bytes, i);
+ kunmap_atomic(kaddr);
+ return wanted;
+}
+
+static size_t zero_bvec(size_t bytes, struct iov_iter *i)
+{
+ size_t skip, copy, wanted;
+ const struct bio_vec *bvec;
+
+ if (unlikely(bytes > i->count))
+ bytes = i->count;
+
+ if (unlikely(!bytes))
+ return 0;
+
+ wanted = bytes;
+ bvec = i->bvec;
+ skip = i->iov_offset;
+ copy = min_t(size_t, bytes, bvec->bv_len - skip);
+
+ memzero_page(bvec->bv_page, skip + bvec->bv_offset, copy);
+ skip += copy;
+ bytes -= copy;
+ while (bytes) {
+ bvec++;
+ copy = min(bytes, (size_t)bvec->bv_len);
+ memzero_page(bvec->bv_page, bvec->bv_offset, copy);
+ skip = copy;
+ bytes -= copy;
+ }
+ if (skip == bvec->bv_len) {
+ bvec++;
+ skip = 0;
+ }
+ i->count -= wanted - bytes;
+ i->nr_segs -= bvec - i->bvec;
+ i->bvec = bvec;
+ i->iov_offset = skip;
+ return wanted - bytes;
+}
+
static size_t copy_from_user_bvec(struct page *page,
struct iov_iter *i, unsigned long offset, size_t bytes)
{
@@ -669,6 +853,31 @@ size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
}
EXPORT_SYMBOL(copy_page_from_iter);
+size_t copy_to_iter(void *addr, size_t bytes, struct iov_iter *i)
+{
+ if (i->type & ITER_BVEC)
+ return copy_to_iter_bvec(addr, bytes, i);
+ else
+ return copy_to_iter_iovec(addr, bytes, i);
+}
+
+size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
+{
+ if (i->type & ITER_BVEC)
+ return copy_from_iter_bvec(addr, bytes, i);
+ else
+ return copy_from_iter_iovec(addr, bytes, i);
+}
+
+size_t iov_iter_zero(size_t bytes, struct iov_iter *i)
+{
+ if (i->type & ITER_BVEC) {
+ return zero_bvec(bytes, i);
+ } else {
+ return zero_iovec(bytes, i);
+ }
+}
+
size_t iov_iter_copy_from_user_atomic(struct page *page,
struct iov_iter *i, unsigned long offset, size_t bytes)
{
--
2.0.1
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 07/22] Replace XIP read and write with DAX I/O
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
` (5 preceding siblings ...)
2014-08-01 13:27 ` [PATCH v9 06/22] Add copy_to_iter(), copy_from_iter() and iov_iter_zero() Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 08/22] Replace ext2_clear_xip_target with dax_clear_blocks Matthew Wilcox
` (14 subsequent siblings)
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Matthew Wilcox, willy
Use the generic AIO infrastructure instead of custom read and write
methods. In addition to giving us support for AIO, this adds the missing
locking between read() and truncate().
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
fs/Makefile | 1 +
fs/dax.c | 195 ++++++++++++++++++++++++++++++++++++++++++++
fs/ext2/file.c | 6 +-
fs/ext2/inode.c | 8 +-
include/linux/fs.h | 18 ++++-
mm/filemap.c | 6 +-
mm/filemap_xip.c | 234 -----------------------------------------------------
7 files changed, 223 insertions(+), 245 deletions(-)
create mode 100644 fs/dax.c
diff --git a/fs/Makefile b/fs/Makefile
index 4030cbf..03f65091 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -28,6 +28,7 @@ obj-$(CONFIG_SIGNALFD) += signalfd.o
obj-$(CONFIG_TIMERFD) += timerfd.o
obj-$(CONFIG_EVENTFD) += eventfd.o
obj-$(CONFIG_AIO) += aio.o
+obj-$(CONFIG_FS_XIP) += dax.o
obj-$(CONFIG_FILE_LOCKING) += locks.o
obj-$(CONFIG_COMPAT) += compat.o compat_ioctl.o
obj-$(CONFIG_BINFMT_AOUT) += binfmt_aout.o
diff --git a/fs/dax.c b/fs/dax.c
new file mode 100644
index 0000000..108c68e
--- /dev/null
+++ b/fs/dax.c
@@ -0,0 +1,195 @@
+/*
+ * fs/dax.c - Direct Access filesystem code
+ * Copyright (c) 2013-2014 Intel Corporation
+ * Author: Matthew Wilcox <matthew.r.wilcox@intel.com>
+ * Author: Ross Zwisler <ross.zwisler@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/atomic.h>
+#include <linux/blkdev.h>
+#include <linux/buffer_head.h>
+#include <linux/fs.h>
+#include <linux/genhd.h>
+#include <linux/mutex.h>
+#include <linux/uio.h>
+
+static long dax_get_addr(struct buffer_head *bh, void **addr, unsigned blkbits)
+{
+ unsigned long pfn;
+ sector_t sector = bh->b_blocknr << (blkbits - 9);
+ return bdev_direct_access(bh->b_bdev, sector, addr, &pfn, bh->b_size);
+}
+
+static void dax_new_buf(void *addr, unsigned size, unsigned first, loff_t pos,
+ loff_t end)
+{
+ loff_t final = end - pos + first; /* The final byte of the buffer */
+
+ if (first > 0)
+ memset(addr, 0, first);
+ if (final < size)
+ memset(addr + final, 0, size - final);
+}
+
+static bool buffer_written(struct buffer_head *bh)
+{
+ return buffer_mapped(bh) && !buffer_unwritten(bh);
+}
+
+/*
+ * When ext4 encounters a hole, it returns without modifying the buffer_head
+ * which means that we can't trust b_size. To cope with this, we set b_state
+ * to 0 before calling get_block and, if any bit is set, we know we can trust
+ * b_size. Unfortunate, really, since ext4 knows precisely how long a hole is
+ * and would save us time calling get_block repeatedly.
+ */
+static bool buffer_size_valid(struct buffer_head *bh)
+{
+ return bh->b_state != 0;
+}
+
+static ssize_t dax_io(int rw, struct inode *inode, struct iov_iter *iter,
+ loff_t start, loff_t end, get_block_t get_block,
+ struct buffer_head *bh)
+{
+ ssize_t retval = 0;
+ loff_t pos = start;
+ loff_t max = start;
+ loff_t bh_max = start;
+ void *addr;
+ bool hole = false;
+
+ if (rw != WRITE)
+ end = min(end, i_size_read(inode));
+
+ while (pos < end) {
+ unsigned len;
+ if (pos == max) {
+ unsigned blkbits = inode->i_blkbits;
+ sector_t block = pos >> blkbits;
+ unsigned first = pos - (block << blkbits);
+ long size;
+
+ if (pos == bh_max) {
+ bh->b_size = PAGE_ALIGN(end - pos);
+ bh->b_state = 0;
+ retval = get_block(inode, block, bh,
+ rw == WRITE);
+ if (retval)
+ break;
+ if (!buffer_size_valid(bh))
+ bh->b_size = 1 << blkbits;
+ bh_max = pos - first + bh->b_size;
+ } else {
+ unsigned done = bh->b_size -
+ (bh_max - (pos - first));
+ bh->b_blocknr += done >> blkbits;
+ bh->b_size -= done;
+ }
+ if (rw == WRITE) {
+ if (!buffer_mapped(bh)) {
+ retval = -EIO;
+ /* FIXME: fall back to buffered I/O */
+ break;
+ }
+ hole = false;
+ } else {
+ hole = !buffer_written(bh);
+ }
+
+ if (hole) {
+ addr = NULL;
+ size = bh->b_size - first;
+ } else {
+ retval = dax_get_addr(bh, &addr, blkbits);
+ if (retval < 0)
+ break;
+ if (buffer_unwritten(bh) || buffer_new(bh))
+ dax_new_buf(addr, retval, first, pos,
+ end);
+ addr += first;
+ size = retval - first;
+ }
+ max = min(pos + size, end);
+ }
+
+ if (rw == WRITE)
+ len = copy_from_iter(addr, max - pos, iter);
+ else if (!hole)
+ len = copy_to_iter(addr, max - pos, iter);
+ else
+ len = iov_iter_zero(max - pos, iter);
+
+ if (!len)
+ break;
+
+ pos += len;
+ addr += len;
+ }
+
+ return (pos == start) ? retval : pos - start;
+}
+
+/**
+ * dax_do_io - Perform I/O to a DAX file
+ * @rw: READ to read or WRITE to write
+ * @iocb: The control block for this I/O
+ * @inode: The file which the I/O is directed at
+ * @iter: The addresses to do I/O from or to
+ * @pos: The file offset where the I/O starts
+ * @get_block: The filesystem method used to translate file offsets to blocks
+ * @end_io: A filesystem callback for I/O completion
+ * @flags: See below
+ *
+ * This function uses the same locking scheme as do_blockdev_direct_IO:
+ * If @flags has DIO_LOCKING set, we assume that the i_mutex is held by the
+ * caller for writes. For reads, we take and release the i_mutex ourselves.
+ * If DIO_LOCKING is not set, the filesystem takes care of its own locking.
+ * As with do_blockdev_direct_IO(), we increment i_dio_count while the I/O
+ * is in progress.
+ */
+ssize_t dax_do_io(int rw, struct kiocb *iocb, struct inode *inode,
+ struct iov_iter *iter, loff_t pos,
+ get_block_t get_block, dio_iodone_t end_io, int flags)
+{
+ struct buffer_head bh;
+ ssize_t retval = -EINVAL;
+ loff_t end = pos + iov_iter_count(iter);
+
+ memset(&bh, 0, sizeof(bh));
+
+ if ((flags & DIO_LOCKING) && (rw == READ)) {
+ struct address_space *mapping = inode->i_mapping;
+ mutex_lock(&inode->i_mutex);
+ retval = filemap_write_and_wait_range(mapping, pos, end - 1);
+ if (retval) {
+ mutex_unlock(&inode->i_mutex);
+ goto out;
+ }
+ }
+
+ /* Protects against truncate */
+ atomic_inc(&inode->i_dio_count);
+
+ retval = dax_io(rw, inode, iter, pos, end, get_block, &bh);
+
+ if ((flags & DIO_LOCKING) && (rw == READ))
+ mutex_unlock(&inode->i_mutex);
+
+ if ((retval > 0) && end_io)
+ end_io(iocb, pos, retval, bh.b_private);
+
+ inode_dio_done(inode);
+ out:
+ return retval;
+}
+EXPORT_SYMBOL_GPL(dax_do_io);
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
index 7c87b22..a247123 100644
--- a/fs/ext2/file.c
+++ b/fs/ext2/file.c
@@ -81,8 +81,10 @@ const struct file_operations ext2_file_operations = {
#ifdef CONFIG_EXT2_FS_XIP
const struct file_operations ext2_xip_file_operations = {
.llseek = generic_file_llseek,
- .read = xip_file_read,
- .write = xip_file_write,
+ .read = new_sync_read,
+ .write = new_sync_write,
+ .read_iter = generic_file_read_iter,
+ .write_iter = generic_file_write_iter,
.unlocked_ioctl = ext2_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = ext2_compat_ioctl,
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 0cb0448..3ccd5fd 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -859,7 +859,12 @@ ext2_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
size_t count = iov_iter_count(iter);
ssize_t ret;
- ret = blockdev_direct_IO(rw, iocb, inode, iter, offset, ext2_get_block);
+ if (IS_DAX(inode))
+ ret = dax_do_io(rw, iocb, inode, iter, offset, ext2_get_block,
+ NULL, DIO_LOCKING);
+ else
+ ret = blockdev_direct_IO(rw, iocb, inode, iter, offset,
+ ext2_get_block);
if (ret < 0 && (rw & WRITE))
ext2_write_failed(mapping, offset + count);
return ret;
@@ -888,6 +893,7 @@ const struct address_space_operations ext2_aops = {
const struct address_space_operations ext2_aops_xip = {
.bmap = ext2_bmap,
.get_xip_mem = ext2_get_xip_mem,
+ .direct_IO = ext2_direct_IO,
};
const struct address_space_operations ext2_nobh_aops = {
diff --git a/include/linux/fs.h b/include/linux/fs.h
index a94e5d7..87a135a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2463,17 +2463,22 @@ extern int generic_file_open(struct inode * inode, struct file * filp);
extern int nonseekable_open(struct inode * inode, struct file * filp);
#ifdef CONFIG_FS_XIP
-extern ssize_t xip_file_read(struct file *filp, char __user *buf, size_t len,
- loff_t *ppos);
extern int xip_file_mmap(struct file * file, struct vm_area_struct * vma);
-extern ssize_t xip_file_write(struct file *filp, const char __user *buf,
- size_t len, loff_t *ppos);
extern int xip_truncate_page(struct address_space *mapping, loff_t from);
+ssize_t dax_do_io(int rw, struct kiocb *, struct inode *, struct iov_iter *,
+ loff_t, get_block_t, dio_iodone_t, int flags);
#else
static inline int xip_truncate_page(struct address_space *mapping, loff_t from)
{
return 0;
}
+
+static inline ssize_t dax_do_io(int rw, struct kiocb *iocb, struct inode *inode,
+ const struct iovec *iov, loff_t pos, unsigned nr_segs,
+ get_block_t get_block, dio_iodone_t end_io, int flags)
+{
+ return -ENOTTY;
+}
#endif
#ifdef CONFIG_BLOCK
@@ -2630,6 +2635,11 @@ extern int generic_show_options(struct seq_file *m, struct dentry *root);
extern void save_mount_options(struct super_block *sb, char *options);
extern void replace_mount_options(struct super_block *sb, char *options);
+static inline bool io_is_direct(struct file *filp)
+{
+ return (filp->f_flags & O_DIRECT) || IS_DAX(file_inode(filp));
+}
+
static inline ino_t parent_ino(struct dentry *dentry)
{
ino_t res;
diff --git a/mm/filemap.c b/mm/filemap.c
index 900edfa..bc588fa 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1684,8 +1684,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
loff_t *ppos = &iocb->ki_pos;
loff_t pos = *ppos;
- /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */
- if (file->f_flags & O_DIRECT) {
+ if (io_is_direct(file)) {
struct address_space *mapping = file->f_mapping;
struct inode *inode = mapping->host;
size_t count = iov_iter_count(iter);
@@ -2561,8 +2560,7 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
if (err)
goto out;
- /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */
- if (unlikely(file->f_flags & O_DIRECT)) {
+ if (io_is_direct(file)) {
loff_t endbyte;
written = generic_file_direct_write(iocb, from, pos);
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index c8d23e9..f7c37a1 100644
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -42,119 +42,6 @@ static struct page *xip_sparse_page(void)
}
/*
- * This is a file read routine for execute in place files, and uses
- * the mapping->a_ops->get_xip_mem() function for the actual low-level
- * stuff.
- *
- * Note the struct file* is not used at all. It may be NULL.
- */
-static ssize_t
-do_xip_mapping_read(struct address_space *mapping,
- struct file_ra_state *_ra,
- struct file *filp,
- char __user *buf,
- size_t len,
- loff_t *ppos)
-{
- struct inode *inode = mapping->host;
- pgoff_t index, end_index;
- unsigned long offset;
- loff_t isize, pos;
- size_t copied = 0, error = 0;
-
- BUG_ON(!mapping->a_ops->get_xip_mem);
-
- pos = *ppos;
- index = pos >> PAGE_CACHE_SHIFT;
- offset = pos & ~PAGE_CACHE_MASK;
-
- isize = i_size_read(inode);
- if (!isize)
- goto out;
-
- end_index = (isize - 1) >> PAGE_CACHE_SHIFT;
- do {
- unsigned long nr, left;
- void *xip_mem;
- unsigned long xip_pfn;
- int zero = 0;
-
- /* nr is the maximum number of bytes to copy from this page */
- nr = PAGE_CACHE_SIZE;
- if (index >= end_index) {
- if (index > end_index)
- goto out;
- nr = ((isize - 1) & ~PAGE_CACHE_MASK) + 1;
- if (nr <= offset) {
- goto out;
- }
- }
- nr = nr - offset;
- if (nr > len - copied)
- nr = len - copied;
-
- error = mapping->a_ops->get_xip_mem(mapping, index, 0,
- &xip_mem, &xip_pfn);
- if (unlikely(error)) {
- if (error == -ENODATA) {
- /* sparse */
- zero = 1;
- } else
- goto out;
- }
-
- /* If users can be writing to this page using arbitrary
- * virtual addresses, take care about potential aliasing
- * before reading the page on the kernel side.
- */
- if (mapping_writably_mapped(mapping))
- /* address based flush */ ;
-
- /*
- * Ok, we have the mem, so now we can copy it to user space...
- *
- * The actor routine returns how many bytes were actually used..
- * NOTE! This may not be the same as how much of a user buffer
- * we filled up (we may be padding etc), so we can only update
- * "pos" here (the actor routine has to update the user buffer
- * pointers and the remaining count).
- */
- if (!zero)
- left = __copy_to_user(buf+copied, xip_mem+offset, nr);
- else
- left = __clear_user(buf + copied, nr);
-
- if (left) {
- error = -EFAULT;
- goto out;
- }
-
- copied += (nr - left);
- offset += (nr - left);
- index += offset >> PAGE_CACHE_SHIFT;
- offset &= ~PAGE_CACHE_MASK;
- } while (copied < len);
-
-out:
- *ppos = pos + copied;
- if (filp)
- file_accessed(filp);
-
- return (copied ? copied : error);
-}
-
-ssize_t
-xip_file_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
-{
- if (!access_ok(VERIFY_WRITE, buf, len))
- return -EFAULT;
-
- return do_xip_mapping_read(filp->f_mapping, &filp->f_ra, filp,
- buf, len, ppos);
-}
-EXPORT_SYMBOL_GPL(xip_file_read);
-
-/*
* __xip_unmap is invoked from xip_unmap and
* xip_write
*
@@ -340,127 +227,6 @@ int xip_file_mmap(struct file * file, struct vm_area_struct * vma)
}
EXPORT_SYMBOL_GPL(xip_file_mmap);
-static ssize_t
-__xip_file_write(struct file *filp, const char __user *buf,
- size_t count, loff_t pos, loff_t *ppos)
-{
- struct address_space * mapping = filp->f_mapping;
- const struct address_space_operations *a_ops = mapping->a_ops;
- struct inode *inode = mapping->host;
- long status = 0;
- size_t bytes;
- ssize_t written = 0;
-
- BUG_ON(!mapping->a_ops->get_xip_mem);
-
- do {
- unsigned long index;
- unsigned long offset;
- size_t copied;
- void *xip_mem;
- unsigned long xip_pfn;
-
- offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
- index = pos >> PAGE_CACHE_SHIFT;
- bytes = PAGE_CACHE_SIZE - offset;
- if (bytes > count)
- bytes = count;
-
- status = a_ops->get_xip_mem(mapping, index, 0,
- &xip_mem, &xip_pfn);
- if (status == -ENODATA) {
- /* we allocate a new page unmap it */
- mutex_lock(&xip_sparse_mutex);
- status = a_ops->get_xip_mem(mapping, index, 1,
- &xip_mem, &xip_pfn);
- mutex_unlock(&xip_sparse_mutex);
- if (!status)
- /* unmap page at pgoff from all other vmas */
- __xip_unmap(mapping, index);
- }
-
- if (status)
- break;
-
- copied = bytes -
- __copy_from_user_nocache(xip_mem + offset, buf, bytes);
-
- if (likely(copied > 0)) {
- status = copied;
-
- if (status >= 0) {
- written += status;
- count -= status;
- pos += status;
- buf += status;
- }
- }
- if (unlikely(copied != bytes))
- if (status >= 0)
- status = -EFAULT;
- if (status < 0)
- break;
- } while (count);
- *ppos = pos;
- /*
- * No need to use i_size_read() here, the i_size
- * cannot change under us because we hold i_mutex.
- */
- if (pos > inode->i_size) {
- i_size_write(inode, pos);
- mark_inode_dirty(inode);
- }
-
- return written ? written : status;
-}
-
-ssize_t
-xip_file_write(struct file *filp, const char __user *buf, size_t len,
- loff_t *ppos)
-{
- struct address_space *mapping = filp->f_mapping;
- struct inode *inode = mapping->host;
- size_t count;
- loff_t pos;
- ssize_t ret;
-
- mutex_lock(&inode->i_mutex);
-
- if (!access_ok(VERIFY_READ, buf, len)) {
- ret=-EFAULT;
- goto out_up;
- }
-
- pos = *ppos;
- count = len;
-
- /* We can write back this queue in page reclaim */
- current->backing_dev_info = mapping->backing_dev_info;
-
- ret = generic_write_checks(filp, &pos, &count, S_ISBLK(inode->i_mode));
- if (ret)
- goto out_backing;
- if (count == 0)
- goto out_backing;
-
- ret = file_remove_suid(filp);
- if (ret)
- goto out_backing;
-
- ret = file_update_time(filp);
- if (ret)
- goto out_backing;
-
- ret = __xip_file_write (filp, buf, count, pos, ppos);
-
- out_backing:
- current->backing_dev_info = NULL;
- out_up:
- mutex_unlock(&inode->i_mutex);
- return ret;
-}
-EXPORT_SYMBOL_GPL(xip_file_write);
-
/*
* truncate a page used for execute in place
* functionality is analog to block_truncate_page but does use get_xip_mem
--
2.0.1
--
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 08/22] Replace ext2_clear_xip_target with dax_clear_blocks
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
` (6 preceding siblings ...)
2014-08-01 13:27 ` [PATCH v9 07/22] Replace XIP read and write with DAX I/O Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 09/22] Replace the XIP page fault handler with the DAX page fault handler Matthew Wilcox
` (13 subsequent siblings)
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Matthew Wilcox, willy
This is practically generic code; other filesystems will want to call
it from other places, but there's nothing ext2-specific about it.
Make it a little more generic by allowing it to take a count of the number
of bytes to zero rather than fixing it to a single page. Thanks to Dave
Hansen for suggesting that I need to call cond_resched() if zeroing more
than one page.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
---
fs/dax.c | 35 +++++++++++++++++++++++++++++++++++
fs/ext2/inode.c | 8 +++++---
fs/ext2/xip.c | 14 --------------
fs/ext2/xip.h | 3 ---
include/linux/fs.h | 6 ++++++
5 files changed, 46 insertions(+), 20 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index 108c68e..02e226f 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -20,8 +20,43 @@
#include <linux/fs.h>
#include <linux/genhd.h>
#include <linux/mutex.h>
+#include <linux/sched.h>
#include <linux/uio.h>
+int dax_clear_blocks(struct inode *inode, sector_t block, long size)
+{
+ struct block_device *bdev = inode->i_sb->s_bdev;
+ sector_t sector = block << (inode->i_blkbits - 9);
+
+ might_sleep();
+ do {
+ void *addr;
+ unsigned long pfn;
+ long count;
+
+ count = bdev_direct_access(bdev, sector, &addr, &pfn, size);
+ if (count < 0)
+ return count;
+ while (count > 0) {
+ unsigned pgsz = PAGE_SIZE - offset_in_page(addr);
+ if (pgsz > count)
+ pgsz = count;
+ if (pgsz < PAGE_SIZE)
+ memset(addr, 0, pgsz);
+ else
+ clear_page(addr);
+ addr += pgsz;
+ size -= pgsz;
+ count -= pgsz;
+ sector += pgsz / 512;
+ cond_resched();
+ }
+ } while (size);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dax_clear_blocks);
+
static long dax_get_addr(struct buffer_head *bh, void **addr, unsigned blkbits)
{
unsigned long pfn;
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 3ccd5fd..52978b8 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -733,10 +733,12 @@ static int ext2_get_blocks(struct inode *inode,
if (IS_DAX(inode)) {
/*
- * we need to clear the block
+ * block must be initialised before we put it in the tree
+ * so that it's not found by another thread before it's
+ * initialised
*/
- err = ext2_clear_xip_target (inode,
- le32_to_cpu(chain[depth-1].key));
+ err = dax_clear_blocks(inode, le32_to_cpu(chain[depth-1].key),
+ 1 << inode->i_blkbits);
if (err) {
mutex_unlock(&ei->truncate_mutex);
goto cleanup;
diff --git a/fs/ext2/xip.c b/fs/ext2/xip.c
index bbc5fec..8cfca3a 100644
--- a/fs/ext2/xip.c
+++ b/fs/ext2/xip.c
@@ -42,20 +42,6 @@ __ext2_get_block(struct inode *inode, pgoff_t pgoff, int create,
return rc;
}
-int
-ext2_clear_xip_target(struct inode *inode, sector_t block)
-{
- void *kaddr;
- unsigned long pfn;
- long size;
-
- size = __inode_direct_access(inode, block, &kaddr, &pfn, PAGE_SIZE);
- if (size < 0)
- return size;
- clear_page(kaddr);
- return 0;
-}
-
void ext2_xip_verify_sb(struct super_block *sb)
{
struct ext2_sb_info *sbi = EXT2_SB(sb);
diff --git a/fs/ext2/xip.h b/fs/ext2/xip.h
index 29be737..b2592f2 100644
--- a/fs/ext2/xip.h
+++ b/fs/ext2/xip.h
@@ -7,8 +7,6 @@
#ifdef CONFIG_EXT2_FS_XIP
extern void ext2_xip_verify_sb (struct super_block *);
-extern int ext2_clear_xip_target (struct inode *, sector_t);
-
static inline int ext2_use_xip (struct super_block *sb)
{
struct ext2_sb_info *sbi = EXT2_SB(sb);
@@ -19,6 +17,5 @@ int ext2_get_xip_mem(struct address_space *, pgoff_t, int,
#else
#define ext2_xip_verify_sb(sb) do { } while (0)
#define ext2_use_xip(sb) 0
-#define ext2_clear_xip_target(inode, chain) 0
#define ext2_get_xip_mem NULL
#endif
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 87a135a..e38138b 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2463,11 +2463,17 @@ extern int generic_file_open(struct inode * inode, struct file * filp);
extern int nonseekable_open(struct inode * inode, struct file * filp);
#ifdef CONFIG_FS_XIP
+int dax_clear_blocks(struct inode *, sector_t block, long size);
extern int xip_file_mmap(struct file * file, struct vm_area_struct * vma);
extern int xip_truncate_page(struct address_space *mapping, loff_t from);
ssize_t dax_do_io(int rw, struct kiocb *, struct inode *, struct iov_iter *,
loff_t, get_block_t, dio_iodone_t, int flags);
#else
+static inline int dax_clear_blocks(struct inode *i, sector_t blk, long sz)
+{
+ return 0;
+}
+
static inline int xip_truncate_page(struct address_space *mapping, loff_t from)
{
return 0;
--
2.0.1
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 09/22] Replace the XIP page fault handler with the DAX page fault handler
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
` (7 preceding siblings ...)
2014-08-01 13:27 ` [PATCH v9 08/22] Replace ext2_clear_xip_target with dax_clear_blocks Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 10/22] Replace xip_truncate_page with dax_truncate_page Matthew Wilcox
` (12 subsequent siblings)
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Matthew Wilcox, willy
Instead of calling aops->get_xip_mem from the fault handler, the
filesystem passes a get_block_t that is used to find the appropriate
blocks.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
fs/dax.c | 194 +++++++++++++++++++++++++++++++++++++++++++++++++
fs/ext2/file.c | 35 ++++++++-
include/linux/fs.h | 4 +-
mm/filemap_xip.c | 206 -----------------------------------------------------
4 files changed, 230 insertions(+), 209 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index 02e226f..97fd885 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -19,9 +19,13 @@
#include <linux/buffer_head.h>
#include <linux/fs.h>
#include <linux/genhd.h>
+#include <linux/highmem.h>
+#include <linux/memcontrol.h>
+#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/uio.h>
+#include <linux/vmstat.h>
int dax_clear_blocks(struct inode *inode, sector_t block, long size)
{
@@ -64,6 +68,14 @@ static long dax_get_addr(struct buffer_head *bh, void **addr, unsigned blkbits)
return bdev_direct_access(bh->b_bdev, sector, addr, &pfn, bh->b_size);
}
+static long dax_get_pfn(struct buffer_head *bh, unsigned long *pfn,
+ unsigned blkbits)
+{
+ void *addr;
+ sector_t sector = bh->b_blocknr << (blkbits - 9);
+ return bdev_direct_access(bh->b_bdev, sector, &addr, pfn, bh->b_size);
+}
+
static void dax_new_buf(void *addr, unsigned size, unsigned first, loff_t pos,
loff_t end)
{
@@ -228,3 +240,185 @@ ssize_t dax_do_io(int rw, struct kiocb *iocb, struct inode *inode,
return retval;
}
EXPORT_SYMBOL_GPL(dax_do_io);
+
+/*
+ * The user has performed a load from a hole in the file. Allocating
+ * a new page in the file would cause excessive storage usage for
+ * workloads with sparse files. We allocate a page cache page instead.
+ * We'll kick it out of the page cache if it's ever written to,
+ * otherwise it will simply fall out of the page cache under memory
+ * pressure without ever having been dirtied.
+ */
+static int dax_load_hole(struct address_space *mapping, struct page *page,
+ struct vm_fault *vmf)
+{
+ unsigned long size;
+ struct inode *inode = mapping->host;
+ if (!page)
+ page = find_or_create_page(mapping, vmf->pgoff,
+ GFP_KERNEL | __GFP_ZERO);
+ if (!page)
+ return VM_FAULT_OOM;
+ /* Recheck i_size under page lock to avoid truncate race */
+ size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ if (vmf->pgoff >= size) {
+ unlock_page(page);
+ page_cache_release(page);
+ return VM_FAULT_SIGBUS;
+ }
+
+ vmf->page = page;
+ return VM_FAULT_LOCKED;
+}
+
+static int copy_user_bh(struct page *to, struct buffer_head *bh,
+ unsigned blkbits, unsigned long vaddr)
+{
+ void *vfrom, *vto;
+ if (dax_get_addr(bh, &vfrom, blkbits) < 0)
+ return -EIO;
+ vto = kmap_atomic(to);
+ copy_user_page(vto, vfrom, vaddr, to);
+ kunmap_atomic(vto);
+ return 0;
+}
+
+static int do_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
+ get_block_t get_block)
+{
+ struct file *file = vma->vm_file;
+ struct inode *inode = file_inode(file);
+ struct address_space *mapping = file->f_mapping;
+ struct page *page;
+ struct buffer_head bh;
+ unsigned long vaddr = (unsigned long)vmf->virtual_address;
+ unsigned blkbits = inode->i_blkbits;
+ sector_t block;
+ pgoff_t size;
+ unsigned long pfn;
+ int error;
+ int major = 0;
+
+ size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ if (vmf->pgoff >= size)
+ return VM_FAULT_SIGBUS;
+
+ memset(&bh, 0, sizeof(bh));
+ block = (sector_t)vmf->pgoff << (PAGE_SHIFT - blkbits);
+ bh.b_size = PAGE_SIZE;
+
+ repeat:
+ page = find_get_page(mapping, vmf->pgoff);
+ if (page) {
+ if (!lock_page_or_retry(page, vma->vm_mm, vmf->flags)) {
+ page_cache_release(page);
+ return VM_FAULT_RETRY;
+ }
+ if (unlikely(page->mapping != mapping)) {
+ unlock_page(page);
+ page_cache_release(page);
+ goto repeat;
+ }
+ } else {
+ mutex_lock(&mapping->i_mmap_mutex);
+ }
+
+ /* Guard against a race with truncate */
+ size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ if (unlikely(vmf->pgoff >= size))
+ goto sigbus;
+
+ error = get_block(inode, block, &bh, 0);
+ if (error || bh.b_size < PAGE_SIZE)
+ goto sigbus;
+
+ if (!buffer_written(&bh) && !vmf->cow_page) {
+ if (vmf->flags & FAULT_FLAG_WRITE) {
+ error = get_block(inode, block, &bh, 1);
+ count_vm_event(PGMAJFAULT);
+ mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT);
+ major = VM_FAULT_MAJOR;
+ if (error || bh.b_size < PAGE_SIZE)
+ goto sigbus;
+ } else {
+ if (!page)
+ mutex_unlock(&mapping->i_mmap_mutex);
+ return dax_load_hole(mapping, page, vmf);
+ }
+ }
+
+ if (vmf->cow_page) {
+ struct page *new_page = vmf->cow_page;
+ if (buffer_written(&bh))
+ error = copy_user_bh(new_page, &bh, blkbits, vaddr);
+ else
+ clear_user_highpage(new_page, vaddr);
+ if (error)
+ goto sigbus;
+ vmf->page = page;
+ return VM_FAULT_LOCKED;
+ }
+
+ if (buffer_unwritten(&bh) || buffer_new(&bh))
+ dax_clear_blocks(inode, bh.b_blocknr, bh.b_size);
+
+ if (page) {
+ unmap_mapping_range(mapping, vmf->pgoff << PAGE_SHIFT,
+ PAGE_CACHE_SIZE, 0);
+ delete_from_page_cache(page);
+ unlock_page(page);
+ page_cache_release(page);
+ mutex_lock(&mapping->i_mmap_mutex);
+ }
+
+ error = dax_get_pfn(&bh, &pfn, blkbits);
+ if (error > 0)
+ error = vm_insert_mixed(vma, vaddr, pfn);
+
+ mutex_unlock(&mapping->i_mmap_mutex);
+
+ if (error == -ENOMEM)
+ return VM_FAULT_OOM;
+ if (error == -EIO)
+ return VM_FAULT_SIGBUS;
+ /* -EBUSY is fine, somebody else faulted on the same PTE */
+ if (error != -EBUSY)
+ BUG_ON(error);
+ return VM_FAULT_NOPAGE | major;
+
+ sigbus:
+ if (page) {
+ unlock_page(page);
+ page_cache_release(page);
+ } else {
+ mutex_unlock(&mapping->i_mmap_mutex);
+ }
+ return VM_FAULT_SIGBUS;
+}
+
+/**
+ * dax_fault - handle a page fault on a DAX file
+ * @vma: The virtual memory area where the fault occurred
+ * @vmf: The description of the fault
+ * @get_block: The filesystem method used to translate file offsets to blocks
+ *
+ * When a page fault occurs, filesystems may call this helper in their
+ * fault handler for DAX files.
+ */
+int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
+ get_block_t get_block)
+{
+ int result;
+ struct super_block *sb = file_inode(vma->vm_file)->i_sb;
+
+ if (vmf->flags & FAULT_FLAG_WRITE) {
+ sb_start_pagefault(sb);
+ file_update_time(vma->vm_file);
+ }
+ result = do_dax_fault(vma, vmf, get_block);
+ if (vmf->flags & FAULT_FLAG_WRITE)
+ sb_end_pagefault(sb);
+
+ return result;
+}
+EXPORT_SYMBOL_GPL(dax_fault);
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
index a247123..da8dc64 100644
--- a/fs/ext2/file.c
+++ b/fs/ext2/file.c
@@ -25,6 +25,37 @@
#include "xattr.h"
#include "acl.h"
+#ifdef CONFIG_EXT2_FS_XIP
+static int ext2_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ return dax_fault(vma, vmf, ext2_get_block);
+}
+
+static int ext2_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ return dax_mkwrite(vma, vmf, ext2_get_block);
+}
+
+static const struct vm_operations_struct ext2_dax_vm_ops = {
+ .fault = ext2_dax_fault,
+ .page_mkwrite = ext2_dax_mkwrite,
+ .remap_pages = generic_file_remap_pages,
+};
+
+static int ext2_file_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ if (!IS_DAX(file_inode(file)))
+ return generic_file_mmap(file, vma);
+
+ file_accessed(file);
+ vma->vm_ops = &ext2_dax_vm_ops;
+ vma->vm_flags |= VM_MIXEDMAP;
+ return 0;
+}
+#else
+#define ext2_file_mmap generic_file_mmap
+#endif
+
/*
* Called when filp is released. This happens when all file descriptors
* for a single struct file are closed. Note that different open() calls
@@ -70,7 +101,7 @@ const struct file_operations ext2_file_operations = {
#ifdef CONFIG_COMPAT
.compat_ioctl = ext2_compat_ioctl,
#endif
- .mmap = generic_file_mmap,
+ .mmap = ext2_file_mmap,
.open = dquot_file_open,
.release = ext2_release_file,
.fsync = ext2_fsync,
@@ -89,7 +120,7 @@ const struct file_operations ext2_xip_file_operations = {
#ifdef CONFIG_COMPAT
.compat_ioctl = ext2_compat_ioctl,
#endif
- .mmap = xip_file_mmap,
+ .mmap = ext2_file_mmap,
.open = dquot_file_open,
.release = ext2_release_file,
.fsync = ext2_fsync,
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e38138b..d628b50 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -49,6 +49,7 @@ struct swap_info_struct;
struct seq_file;
struct workqueue_struct;
struct iov_iter;
+struct vm_fault;
extern void __init inode_init(void);
extern void __init inode_init_early(void);
@@ -2464,10 +2465,11 @@ extern int nonseekable_open(struct inode * inode, struct file * filp);
#ifdef CONFIG_FS_XIP
int dax_clear_blocks(struct inode *, sector_t block, long size);
-extern int xip_file_mmap(struct file * file, struct vm_area_struct * vma);
extern int xip_truncate_page(struct address_space *mapping, loff_t from);
ssize_t dax_do_io(int rw, struct kiocb *, struct inode *, struct iov_iter *,
loff_t, get_block_t, dio_iodone_t, int flags);
+int dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t);
+#define dax_mkwrite(vma, vmf, gb) dax_fault(vma, vmf, gb)
#else
static inline int dax_clear_blocks(struct inode *i, sector_t blk, long sz)
{
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index f7c37a1..9dd45f3 100644
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -22,212 +22,6 @@
#include <asm/io.h>
/*
- * We do use our own empty page to avoid interference with other users
- * of ZERO_PAGE(), such as /dev/zero
- */
-static DEFINE_MUTEX(xip_sparse_mutex);
-static seqcount_t xip_sparse_seq = SEQCNT_ZERO(xip_sparse_seq);
-static struct page *__xip_sparse_page;
-
-/* called under xip_sparse_mutex */
-static struct page *xip_sparse_page(void)
-{
- if (!__xip_sparse_page) {
- struct page *page = alloc_page(GFP_HIGHUSER | __GFP_ZERO);
-
- if (page)
- __xip_sparse_page = page;
- }
- return __xip_sparse_page;
-}
-
-/*
- * __xip_unmap is invoked from xip_unmap and
- * xip_write
- *
- * This function walks all vmas of the address_space and unmaps the
- * __xip_sparse_page when found at pgoff.
- */
-static void
-__xip_unmap (struct address_space * mapping,
- unsigned long pgoff)
-{
- struct vm_area_struct *vma;
- struct mm_struct *mm;
- unsigned long address;
- pte_t *pte;
- pte_t pteval;
- spinlock_t *ptl;
- struct page *page;
- unsigned count;
- int locked = 0;
-
- count = read_seqcount_begin(&xip_sparse_seq);
-
- page = __xip_sparse_page;
- if (!page)
- return;
-
-retry:
- mutex_lock(&mapping->i_mmap_mutex);
- vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
- mm = vma->vm_mm;
- address = vma->vm_start +
- ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
- BUG_ON(address < vma->vm_start || address >= vma->vm_end);
- pte = page_check_address(page, mm, address, &ptl, 1);
- if (pte) {
- /* Nuke the page table entry. */
- flush_cache_page(vma, address, pte_pfn(*pte));
- pteval = ptep_clear_flush(vma, address, pte);
- page_remove_rmap(page);
- dec_mm_counter(mm, MM_FILEPAGES);
- BUG_ON(pte_dirty(pteval));
- pte_unmap_unlock(pte, ptl);
- /* must invalidate_page _before_ freeing the page */
- mmu_notifier_invalidate_page(mm, address);
- page_cache_release(page);
- }
- }
- mutex_unlock(&mapping->i_mmap_mutex);
-
- if (locked) {
- mutex_unlock(&xip_sparse_mutex);
- } else if (read_seqcount_retry(&xip_sparse_seq, count)) {
- mutex_lock(&xip_sparse_mutex);
- locked = 1;
- goto retry;
- }
-}
-
-/*
- * xip_fault() is invoked via the vma operations vector for a
- * mapped memory region to read in file data during a page fault.
- *
- * This function is derived from filemap_fault, but used for execute in place
- */
-static int xip_file_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
-{
- struct file *file = vma->vm_file;
- struct address_space *mapping = file->f_mapping;
- struct inode *inode = mapping->host;
- pgoff_t size;
- void *xip_mem;
- unsigned long xip_pfn;
- struct page *page;
- int error;
-
- /* XXX: are VM_FAULT_ codes OK? */
-again:
- size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
- if (vmf->pgoff >= size)
- return VM_FAULT_SIGBUS;
-
- error = mapping->a_ops->get_xip_mem(mapping, vmf->pgoff, 0,
- &xip_mem, &xip_pfn);
- if (likely(!error))
- goto found;
- if (error != -ENODATA)
- return VM_FAULT_OOM;
-
- /* sparse block */
- if ((vma->vm_flags & (VM_WRITE | VM_MAYWRITE)) &&
- (vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) &&
- (!(mapping->host->i_sb->s_flags & MS_RDONLY))) {
- int err;
-
- /* maybe shared writable, allocate new block */
- mutex_lock(&xip_sparse_mutex);
- error = mapping->a_ops->get_xip_mem(mapping, vmf->pgoff, 1,
- &xip_mem, &xip_pfn);
- mutex_unlock(&xip_sparse_mutex);
- if (error)
- return VM_FAULT_SIGBUS;
- /* unmap sparse mappings at pgoff from all other vmas */
- __xip_unmap(mapping, vmf->pgoff);
-
-found:
- /* We must recheck i_size under i_mmap_mutex */
- mutex_lock(&mapping->i_mmap_mutex);
- size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
- PAGE_CACHE_SHIFT;
- if (unlikely(vmf->pgoff >= size)) {
- mutex_unlock(&mapping->i_mmap_mutex);
- return VM_FAULT_SIGBUS;
- }
- err = vm_insert_mixed(vma, (unsigned long)vmf->virtual_address,
- xip_pfn);
- mutex_unlock(&mapping->i_mmap_mutex);
- if (err == -ENOMEM)
- return VM_FAULT_OOM;
- /*
- * err == -EBUSY is fine, we've raced against another thread
- * that faulted-in the same page
- */
- if (err != -EBUSY)
- BUG_ON(err);
- return VM_FAULT_NOPAGE;
- } else {
- int err, ret = VM_FAULT_OOM;
-
- mutex_lock(&xip_sparse_mutex);
- write_seqcount_begin(&xip_sparse_seq);
- error = mapping->a_ops->get_xip_mem(mapping, vmf->pgoff, 0,
- &xip_mem, &xip_pfn);
- if (unlikely(!error)) {
- write_seqcount_end(&xip_sparse_seq);
- mutex_unlock(&xip_sparse_mutex);
- goto again;
- }
- if (error != -ENODATA)
- goto out;
-
- /* We must recheck i_size under i_mmap_mutex */
- mutex_lock(&mapping->i_mmap_mutex);
- size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
- PAGE_CACHE_SHIFT;
- if (unlikely(vmf->pgoff >= size)) {
- ret = VM_FAULT_SIGBUS;
- goto unlock;
- }
- /* not shared and writable, use xip_sparse_page() */
- page = xip_sparse_page();
- if (!page)
- goto unlock;
- err = vm_insert_page(vma, (unsigned long)vmf->virtual_address,
- page);
- if (err == -ENOMEM)
- goto unlock;
-
- ret = VM_FAULT_NOPAGE;
-unlock:
- mutex_unlock(&mapping->i_mmap_mutex);
-out:
- write_seqcount_end(&xip_sparse_seq);
- mutex_unlock(&xip_sparse_mutex);
-
- return ret;
- }
-}
-
-static const struct vm_operations_struct xip_file_vm_ops = {
- .fault = xip_file_fault,
- .page_mkwrite = filemap_page_mkwrite,
- .remap_pages = generic_file_remap_pages,
-};
-
-int xip_file_mmap(struct file * file, struct vm_area_struct * vma)
-{
- BUG_ON(!file->f_mapping->a_ops->get_xip_mem);
-
- file_accessed(file);
- vma->vm_ops = &xip_file_vm_ops;
- vma->vm_flags |= VM_MIXEDMAP;
- return 0;
-}
-EXPORT_SYMBOL_GPL(xip_file_mmap);
-
-/*
* truncate a page used for execute in place
* functionality is analog to block_truncate_page but does use get_xip_mem
* to get the page instead of page cache
--
2.0.1
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 10/22] Replace xip_truncate_page with dax_truncate_page
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
` (8 preceding siblings ...)
2014-08-01 13:27 ` [PATCH v9 09/22] Replace the XIP page fault handler with the DAX page fault handler Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 11/22] Replace XIP documentation with DAX documentation Matthew Wilcox
` (11 subsequent siblings)
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Matthew Wilcox, willy
It takes a get_block parameter just like nobh_truncate_page() and
block_truncate_page()
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
---
fs/dax.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
fs/ext2/inode.c | 2 +-
include/linux/fs.h | 4 ++--
mm/filemap_xip.c | 40 ----------------------------------------
4 files changed, 47 insertions(+), 43 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index 97fd885..15654ce 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -422,3 +422,47 @@ int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
return result;
}
EXPORT_SYMBOL_GPL(dax_fault);
+
+/**
+ * dax_truncate_page - handle a partial page being truncated in a DAX file
+ * @inode: The file being truncated
+ * @from: The file offset that is being truncated to
+ * @get_block: The filesystem method used to translate file offsets to blocks
+ *
+ * Similar to block_truncate_page(), this function can be called by a
+ * filesystem when it is truncating an DAX file to handle the partial page.
+ *
+ * We work in terms of PAGE_CACHE_SIZE here for commonality with
+ * block_truncate_page(), but we could go down to PAGE_SIZE if the filesystem
+ * took care of disposing of the unnecessary blocks. Even if the filesystem
+ * block size is smaller than PAGE_SIZE, we have to zero the rest of the page
+ * since the file might be mmaped.
+ */
+int dax_truncate_page(struct inode *inode, loff_t from, get_block_t get_block)
+{
+ struct buffer_head bh;
+ pgoff_t index = from >> PAGE_CACHE_SHIFT;
+ unsigned offset = from & (PAGE_CACHE_SIZE-1);
+ unsigned length = PAGE_CACHE_ALIGN(from) - from;
+ int err;
+
+ /* Block boundary? Nothing to do */
+ if (!length)
+ return 0;
+
+ memset(&bh, 0, sizeof(bh));
+ bh.b_size = PAGE_CACHE_SIZE;
+ err = get_block(inode, index, &bh, 0);
+ if (err < 0)
+ return err;
+ if (buffer_written(&bh)) {
+ void *addr;
+ err = dax_get_addr(&bh, &addr, inode->i_blkbits);
+ if (err < 0)
+ return err;
+ memset(addr + offset, 0, length);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dax_truncate_page);
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 52978b8..5ac0a34 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -1210,7 +1210,7 @@ static int ext2_setsize(struct inode *inode, loff_t newsize)
inode_dio_wait(inode);
if (IS_DAX(inode))
- error = xip_truncate_page(inode->i_mapping, newsize);
+ error = dax_truncate_page(inode, newsize, ext2_get_block);
else if (test_opt(inode->i_sb, NOBH))
error = nobh_truncate_page(inode->i_mapping,
newsize, ext2_get_block);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index d628b50..0cdb57b 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2465,7 +2465,7 @@ extern int nonseekable_open(struct inode * inode, struct file * filp);
#ifdef CONFIG_FS_XIP
int dax_clear_blocks(struct inode *, sector_t block, long size);
-extern int xip_truncate_page(struct address_space *mapping, loff_t from);
+int dax_truncate_page(struct inode *, loff_t from, get_block_t);
ssize_t dax_do_io(int rw, struct kiocb *, struct inode *, struct iov_iter *,
loff_t, get_block_t, dio_iodone_t, int flags);
int dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t);
@@ -2476,7 +2476,7 @@ static inline int dax_clear_blocks(struct inode *i, sector_t blk, long sz)
return 0;
}
-static inline int xip_truncate_page(struct address_space *mapping, loff_t from)
+static inline int dax_truncate_page(struct inode *i, loff_t frm, get_block_t gb)
{
return 0;
}
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index 9dd45f3..6316578 100644
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -21,43 +21,3 @@
#include <asm/tlbflush.h>
#include <asm/io.h>
-/*
- * truncate a page used for execute in place
- * functionality is analog to block_truncate_page but does use get_xip_mem
- * to get the page instead of page cache
- */
-int
-xip_truncate_page(struct address_space *mapping, loff_t from)
-{
- pgoff_t index = from >> PAGE_CACHE_SHIFT;
- unsigned offset = from & (PAGE_CACHE_SIZE-1);
- unsigned blocksize;
- unsigned length;
- void *xip_mem;
- unsigned long xip_pfn;
- int err;
-
- BUG_ON(!mapping->a_ops->get_xip_mem);
-
- blocksize = 1 << mapping->host->i_blkbits;
- length = offset & (blocksize - 1);
-
- /* Block boundary? Nothing to do */
- if (!length)
- return 0;
-
- length = blocksize - length;
-
- err = mapping->a_ops->get_xip_mem(mapping, index, 0,
- &xip_mem, &xip_pfn);
- if (unlikely(err)) {
- if (err == -ENODATA)
- /* Hole? No need to truncate */
- return 0;
- else
- return err;
- }
- memset(xip_mem + offset, 0, length);
- return 0;
-}
-EXPORT_SYMBOL_GPL(xip_truncate_page);
--
2.0.1
--
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 11/22] Replace XIP documentation with DAX documentation
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
` (9 preceding siblings ...)
2014-08-01 13:27 ` [PATCH v9 10/22] Replace xip_truncate_page with dax_truncate_page Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 12/22] Remove get_xip_mem Matthew Wilcox
` (10 subsequent siblings)
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Matthew Wilcox
From: Matthew Wilcox <willy@linux.intel.com>
Based on the original XIP documentation, this documents the current
state of affairs, and includes instructions on how users can enable DAX
if their devices and kernel support it.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
---
Documentation/filesystems/dax.txt | 89 +++++++++++++++++++++++++++++++++++++++
Documentation/filesystems/xip.txt | 71 -------------------------------
2 files changed, 89 insertions(+), 71 deletions(-)
create mode 100644 Documentation/filesystems/dax.txt
delete mode 100644 Documentation/filesystems/xip.txt
diff --git a/Documentation/filesystems/dax.txt b/Documentation/filesystems/dax.txt
new file mode 100644
index 0000000..6441766
--- /dev/null
+++ b/Documentation/filesystems/dax.txt
@@ -0,0 +1,89 @@
+Direct Access for files
+-----------------------
+
+Motivation
+----------
+
+The page cache is usually used to buffer reads and writes to files.
+It is also used to provide the pages which are mapped into userspace
+by a call to mmap.
+
+For block devices that are memory-like, the page cache pages would be
+unnecessary copies of the original storage. The DAX code removes the
+extra copy by performing reads and writes directly to the storage device.
+For file mappings, the storage device is mapped directly into userspace.
+
+
+Usage
+-----
+
+If you have a block device which supports DAX, you can make a filesystem
+on it as usual. When mounting it, use the -o dax option manually
+or add 'dax' to the options in /etc/fstab.
+
+
+Implementation Tips for Block Driver Writers
+--------------------------------------------
+
+To support DAX in your block driver, implement the 'direct_access'
+block device operation. It is used to translate the sector number
+(expressed in units of 512-byte sectors) to a page frame number (pfn)
+that identifies the physical page for the memory. It also returns a
+kernel virtual address that can be used to access the memory.
+
+The direct_access method takes a 'size' parameter that indicates the
+number of bytes being requested. The function should return the number
+of bytes that it can provide, although it must not exceed the number of
+bytes requested. It may also return a negative errno if an error occurs.
+
+In order to support this method, the storage must be byte-accessible by
+the CPU at all times. If your device uses paging techniques to expose
+a large amount of memory through a smaller window, then you cannot
+implement direct_access. Equally, if your device can occasionally
+stall the CPU for an extended period, you should also not attempt to
+implement direct_access.
+
+These block devices may be used for inspiration:
+- axonram: Axon DDR2 device driver
+- brd: RAM backed block device driver
+- dcssblk: s390 dcss block device driver
+
+
+Implementation Tips for Filesystem Writers
+------------------------------------------
+
+Filesystem support consists of
+- adding support to mark inodes as being DAX by setting the S_DAX flag in
+ i_flags
+- implementing the direct_IO address space operation, and calling
+ dax_do_io() instead of blockdev_direct_IO() if S_DAX is set
+- implementing an mmap file operation for DAX files which sets the
+ VM_MIXEDMAP flag on the VMA, and setting the vm_ops to include handlers
+ for fault and page_mkwrite (which should probably call dax_fault() and
+ dax_mkwrite(), passing the appropriate get_block() callback)
+- calling dax_truncate_page() instead of block_truncate_page() for DAX files
+- ensuring that there is sufficient locking between reads, writes,
+ truncates and page faults
+
+The get_block() callback passed to the DAX functions may return
+uninitialised extents. If it does, it must ensure that simultaneous
+calls to get_block() (for example by a page-fault racing with a read()
+or a write()) work correctly.
+
+These filesystems may be used for inspiration:
+- ext2: the second extended filesystem, see Documentation/filesystems/ext2.txt
+
+
+Shortcomings
+------------
+
+Even if the kernel or its modules are stored on a filesystem that supports
+DAX on a block device that supports DAX, they will still be copied into RAM.
+
+Calling get_user_pages() on a range of user memory that has been mmaped
+from a DAX file will fail as there are no 'struct page' to describe
+those pages. This problem is being worked on. That means that O_DIRECT
+reads/writes to those memory ranges from a non-DAX file will fail (note
+that O_DIRECT reads/writes _of a DAX file_ do work, it is the memory
+that is being accessed that is key here). Other things that will not
+work include RDMA, sendfile() and splice().
diff --git a/Documentation/filesystems/xip.txt b/Documentation/filesystems/xip.txt
deleted file mode 100644
index b62eabf..0000000
--- a/Documentation/filesystems/xip.txt
+++ /dev/null
@@ -1,71 +0,0 @@
-Execute-in-place for file mappings
-----------------------------------
-
-Motivation
-----------
-File mappings are performed by mapping page cache pages to userspace. In
-addition, read&write type file operations also transfer data from/to the page
-cache.
-
-For memory backed storage devices that use the block device interface, the page
-cache pages are in fact copies of the original storage. Various approaches
-exist to work around the need for an extra copy. The ramdisk driver for example
-does read the data into the page cache, keeps a reference, and discards the
-original data behind later on.
-
-Execute-in-place solves this issue the other way around: instead of keeping
-data in the page cache, the need to have a page cache copy is eliminated
-completely. With execute-in-place, read&write type operations are performed
-directly from/to the memory backed storage device. For file mappings, the
-storage device itself is mapped directly into userspace.
-
-This implementation was initially written for shared memory segments between
-different virtual machines on s390 hardware to allow multiple machines to
-share the same binaries and libraries.
-
-Implementation
---------------
-Execute-in-place is implemented in three steps: block device operation,
-address space operation, and file operations.
-
-A block device operation named direct_access is used to translate the
-block device sector number to a page frame number (pfn) that identifies
-the physical page for the memory. It also returns a kernel virtual
-address that can be used to access the memory.
-
-The direct_access method takes a 'size' parameter that indicates the
-number of bytes being requested. The function should return the number
-of bytes that it can provide, although it must not exceed the number of
-bytes requested. It may also return a negative errno if an error occurs.
-
-The block device operation is optional, these block devices support it as of
-today:
-- dcssblk: s390 dcss block device driver
-
-An address space operation named get_xip_mem is used to retrieve references
-to a page frame number and a kernel address. To obtain these values a reference
-to an address_space is provided. This function assigns values to the kmem and
-pfn parameters. The third argument indicates whether the function should allocate
-blocks if needed.
-
-This address space operation is mutually exclusive with readpage&writepage that
-do page cache read/write operations.
-The following filesystems support it as of today:
-- ext2: the second extended filesystem, see Documentation/filesystems/ext2.txt
-
-A set of file operations that do utilize get_xip_page can be found in
-mm/filemap_xip.c . The following file operation implementations are provided:
-- aio_read/aio_write
-- readv/writev
-- sendfile
-
-The generic file operations do_sync_read/do_sync_write can be used to implement
-classic synchronous IO calls.
-
-Shortcomings
-------------
-This implementation is limited to storage devices that are cpu addressable at
-all times (no highmem or such). It works well on rom/ram, but enhancements are
-needed to make it work with flash in read+write mode.
-Putting the Linux kernel and/or its modules on a xip filesystem does not mean
-they are not copied.
--
2.0.1
--
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 12/22] Remove get_xip_mem
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
` (10 preceding siblings ...)
2014-08-01 13:27 ` [PATCH v9 11/22] Replace XIP documentation with DAX documentation Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 13/22] ext2: Remove ext2_xip_verify_sb() Matthew Wilcox
` (9 subsequent siblings)
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Matthew Wilcox, willy
All callers of get_xip_mem() are now gone. Remove checks for it,
initialisers of it, documentation of it and the only implementation of it.
Also remove mm/filemap_xip.c as it is now empty.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
---
Documentation/filesystems/Locking | 3 ---
fs/exofs/inode.c | 1 -
fs/ext2/inode.c | 1 -
fs/ext2/xip.c | 45 ---------------------------------------
fs/ext2/xip.h | 3 ---
fs/open.c | 5 +----
include/linux/fs.h | 2 --
mm/Makefile | 1 -
mm/fadvise.c | 6 ++++--
mm/filemap_xip.c | 23 --------------------
mm/madvise.c | 2 +-
11 files changed, 6 insertions(+), 86 deletions(-)
delete mode 100644 mm/filemap_xip.c
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index b18dd17..958cf45 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -197,8 +197,6 @@ prototypes:
int (*releasepage) (struct page *, int);
void (*freepage)(struct page *);
int (*direct_IO)(int, struct kiocb *, struct iov_iter *iter, loff_t offset);
- int (*get_xip_mem)(struct address_space *, pgoff_t, int, void **,
- unsigned long *);
int (*migratepage)(struct address_space *, struct page *, struct page *);
int (*launder_page)(struct page *);
int (*is_partially_uptodate)(struct page *, unsigned long, unsigned long);
@@ -223,7 +221,6 @@ invalidatepage: yes
releasepage: yes
freepage: yes
direct_IO:
-get_xip_mem: maybe
migratepage: yes (both)
launder_page: yes
is_partially_uptodate: yes
diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index 3f9cafd..c408a53 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -985,7 +985,6 @@ const struct address_space_operations exofs_aops = {
.direct_IO = exofs_direct_IO,
/* With these NULL has special meaning or default is not exported */
- .get_xip_mem = NULL,
.migratepage = NULL,
.launder_page = NULL,
.is_partially_uptodate = NULL,
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 5ac0a34..59d6c7d 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -894,7 +894,6 @@ const struct address_space_operations ext2_aops = {
const struct address_space_operations ext2_aops_xip = {
.bmap = ext2_bmap,
- .get_xip_mem = ext2_get_xip_mem,
.direct_IO = ext2_direct_IO,
};
diff --git a/fs/ext2/xip.c b/fs/ext2/xip.c
index 8cfca3a..132d4da 100644
--- a/fs/ext2/xip.c
+++ b/fs/ext2/xip.c
@@ -13,35 +13,6 @@
#include "ext2.h"
#include "xip.h"
-static inline long __inode_direct_access(struct inode *inode, sector_t block,
- void **kaddr, unsigned long *pfn, long size)
-{
- struct block_device *bdev = inode->i_sb->s_bdev;
- sector_t sector = block * (PAGE_SIZE / 512);
- return bdev_direct_access(bdev, sector, kaddr, pfn, size);
-}
-
-static inline int
-__ext2_get_block(struct inode *inode, pgoff_t pgoff, int create,
- sector_t *result)
-{
- struct buffer_head tmp;
- int rc;
-
- memset(&tmp, 0, sizeof(struct buffer_head));
- tmp.b_size = 1 << inode->i_blkbits;
- rc = ext2_get_block(inode, pgoff, &tmp, create);
- *result = tmp.b_blocknr;
-
- /* did we get a sparse block (hole in the file)? */
- if (!tmp.b_blocknr && !rc) {
- BUG_ON(create);
- rc = -ENODATA;
- }
-
- return rc;
-}
-
void ext2_xip_verify_sb(struct super_block *sb)
{
struct ext2_sb_info *sbi = EXT2_SB(sb);
@@ -54,19 +25,3 @@ void ext2_xip_verify_sb(struct super_block *sb)
"not supported by bdev");
}
}
-
-int ext2_get_xip_mem(struct address_space *mapping, pgoff_t pgoff, int create,
- void **kmem, unsigned long *pfn)
-{
- long rc;
- sector_t block;
-
- /* first, retrieve the sector number */
- rc = __ext2_get_block(mapping->host, pgoff, create, &block);
- if (rc)
- return rc;
-
- /* retrieve address of the target data */
- rc = __inode_direct_access(mapping->host, block, kmem, pfn, PAGE_SIZE);
- return (rc < 0) ? rc : 0;
-}
diff --git a/fs/ext2/xip.h b/fs/ext2/xip.h
index b2592f2..e7b9f0a 100644
--- a/fs/ext2/xip.h
+++ b/fs/ext2/xip.h
@@ -12,10 +12,7 @@ static inline int ext2_use_xip (struct super_block *sb)
struct ext2_sb_info *sbi = EXT2_SB(sb);
return (sbi->s_mount_opt & EXT2_MOUNT_XIP);
}
-int ext2_get_xip_mem(struct address_space *, pgoff_t, int,
- void **, unsigned long *);
#else
#define ext2_xip_verify_sb(sb) do { } while (0)
#define ext2_use_xip(sb) 0
-#define ext2_get_xip_mem NULL
#endif
diff --git a/fs/open.c b/fs/open.c
index 36662d0..1a9f0d6 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -656,11 +656,8 @@ int open_check_o_direct(struct file *f)
{
/* NB: we're sure to have correct a_ops only after f_op->open */
if (f->f_flags & O_DIRECT) {
- if (!f->f_mapping->a_ops ||
- ((!f->f_mapping->a_ops->direct_IO) &&
- (!f->f_mapping->a_ops->get_xip_mem))) {
+ if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO)
return -EINVAL;
- }
}
return 0;
}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 0cdb57b..67edd2c 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -349,8 +349,6 @@ struct address_space_operations {
int (*releasepage) (struct page *, gfp_t);
void (*freepage)(struct page *);
ssize_t (*direct_IO)(int, struct kiocb *, struct iov_iter *iter, loff_t offset);
- int (*get_xip_mem)(struct address_space *, pgoff_t, int,
- void **, unsigned long *);
/*
* migrate the contents of a page to the specified target. If
* migrate_mode is MIGRATE_ASYNC, it must not block.
diff --git a/mm/Makefile b/mm/Makefile
index 4064f3e..34d1598 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -47,7 +47,6 @@ obj-$(CONFIG_SLUB) += slub.o
obj-$(CONFIG_KMEMCHECK) += kmemcheck.o
obj-$(CONFIG_FAILSLAB) += failslab.o
obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o
-obj-$(CONFIG_FS_XIP) += filemap_xip.o
obj-$(CONFIG_MIGRATION) += migrate.o
obj-$(CONFIG_QUICKLIST) += quicklist.o
obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o
diff --git a/mm/fadvise.c b/mm/fadvise.c
index 3bcfd81..1f1925f 100644
--- a/mm/fadvise.c
+++ b/mm/fadvise.c
@@ -28,6 +28,7 @@
SYSCALL_DEFINE4(fadvise64_64, int, fd, loff_t, offset, loff_t, len, int, advice)
{
struct fd f = fdget(fd);
+ struct inode *inode;
struct address_space *mapping;
struct backing_dev_info *bdi;
loff_t endbyte; /* inclusive */
@@ -39,7 +40,8 @@ SYSCALL_DEFINE4(fadvise64_64, int, fd, loff_t, offset, loff_t, len, int, advice)
if (!f.file)
return -EBADF;
- if (S_ISFIFO(file_inode(f.file)->i_mode)) {
+ inode = file_inode(f.file);
+ if (S_ISFIFO(inode->i_mode)) {
ret = -ESPIPE;
goto out;
}
@@ -50,7 +52,7 @@ SYSCALL_DEFINE4(fadvise64_64, int, fd, loff_t, offset, loff_t, len, int, advice)
goto out;
}
- if (mapping->a_ops->get_xip_mem) {
+ if (IS_DAX(inode)) {
switch (advice) {
case POSIX_FADV_NORMAL:
case POSIX_FADV_RANDOM:
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
deleted file mode 100644
index 6316578..0000000
--- a/mm/filemap_xip.c
+++ /dev/null
@@ -1,23 +0,0 @@
-/*
- * linux/mm/filemap_xip.c
- *
- * Copyright (C) 2005 IBM Corporation
- * Author: Carsten Otte <cotte@de.ibm.com>
- *
- * derived from linux/mm/filemap.c - Copyright (C) Linus Torvalds
- *
- */
-
-#include <linux/fs.h>
-#include <linux/pagemap.h>
-#include <linux/export.h>
-#include <linux/uio.h>
-#include <linux/rmap.h>
-#include <linux/mmu_notifier.h>
-#include <linux/sched.h>
-#include <linux/seqlock.h>
-#include <linux/mutex.h>
-#include <linux/gfp.h>
-#include <asm/tlbflush.h>
-#include <asm/io.h>
-
diff --git a/mm/madvise.c b/mm/madvise.c
index a402f8f..dee5dff 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -236,7 +236,7 @@ static long madvise_willneed(struct vm_area_struct *vma,
if (!file)
return -EBADF;
- if (file->f_mapping->a_ops->get_xip_mem) {
+ if (IS_DAX(file_inode(file))) {
/* no bad return value, but ignore advice */
return 0;
}
--
2.0.1
--
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 13/22] ext2: Remove ext2_xip_verify_sb()
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
` (11 preceding siblings ...)
2014-08-01 13:27 ` [PATCH v9 12/22] Remove get_xip_mem Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 14/22] ext2: Remove ext2_use_xip Matthew Wilcox
` (8 subsequent siblings)
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Matthew Wilcox, willy
Jan Kara pointed out that calling ext2_xip_verify_sb() in ext2_remount()
doesn't make sense, since changing the XIP option on remount isn't
allowed. It also doesn't make sense to re-check whether blocksize is
supported since it can't change between mounts.
Replace the call to ext2_xip_verify_sb() in ext2_fill_super() with the
equivalent check and delete the definition.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
---
fs/ext2/super.c | 33 ++++++++++++---------------------
fs/ext2/xip.c | 12 ------------
fs/ext2/xip.h | 2 --
3 files changed, 12 insertions(+), 35 deletions(-)
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 3750031..3ac6555 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -868,9 +868,6 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
MS_POSIXACL : 0);
- ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
- EXT2_MOUNT_XIP if not */
-
if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
(EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
@@ -900,11 +897,17 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
- if (ext2_use_xip(sb) && blocksize != PAGE_SIZE) {
- if (!silent)
+ if (sbi->s_mount_opt & EXT2_MOUNT_XIP) {
+ if (blocksize != PAGE_SIZE) {
ext2_msg(sb, KERN_ERR,
- "error: unsupported blocksize for xip");
- goto failed_mount;
+ "error: unsupported blocksize for xip");
+ goto failed_mount;
+ }
+ if (!sb->s_bdev->bd_disk->fops->direct_access) {
+ ext2_msg(sb, KERN_ERR,
+ "error: device does not support xip");
+ goto failed_mount;
+ }
}
/* If the blocksize doesn't match, re-read the thing.. */
@@ -1249,7 +1252,6 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
{
struct ext2_sb_info * sbi = EXT2_SB(sb);
struct ext2_super_block * es;
- unsigned long old_mount_opt = sbi->s_mount_opt;
struct ext2_mount_options old_opts;
unsigned long old_sb_flags;
int err;
@@ -1274,22 +1276,11 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
- ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
- EXT2_MOUNT_XIP if not */
-
- if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
- ext2_msg(sb, KERN_WARNING,
- "warning: unsupported blocksize for xip");
- err = -EINVAL;
- goto restore_opts;
- }
-
es = sbi->s_es;
- if ((sbi->s_mount_opt ^ old_mount_opt) & EXT2_MOUNT_XIP) {
+ if ((sbi->s_mount_opt ^ old_opts.s_mount_opt) & EXT2_MOUNT_XIP) {
ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
"xip flag with busy inodes while remounting");
- sbi->s_mount_opt &= ~EXT2_MOUNT_XIP;
- sbi->s_mount_opt |= old_mount_opt & EXT2_MOUNT_XIP;
+ sbi->s_mount_opt ^= EXT2_MOUNT_XIP;
}
if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
spin_unlock(&sbi->s_lock);
diff --git a/fs/ext2/xip.c b/fs/ext2/xip.c
index 132d4da..66ca113 100644
--- a/fs/ext2/xip.c
+++ b/fs/ext2/xip.c
@@ -13,15 +13,3 @@
#include "ext2.h"
#include "xip.h"
-void ext2_xip_verify_sb(struct super_block *sb)
-{
- struct ext2_sb_info *sbi = EXT2_SB(sb);
-
- if ((sbi->s_mount_opt & EXT2_MOUNT_XIP) &&
- !sb->s_bdev->bd_disk->fops->direct_access) {
- sbi->s_mount_opt &= (~EXT2_MOUNT_XIP);
- ext2_msg(sb, KERN_WARNING,
- "warning: ignoring xip option - "
- "not supported by bdev");
- }
-}
diff --git a/fs/ext2/xip.h b/fs/ext2/xip.h
index e7b9f0a..87eeb04 100644
--- a/fs/ext2/xip.h
+++ b/fs/ext2/xip.h
@@ -6,13 +6,11 @@
*/
#ifdef CONFIG_EXT2_FS_XIP
-extern void ext2_xip_verify_sb (struct super_block *);
static inline int ext2_use_xip (struct super_block *sb)
{
struct ext2_sb_info *sbi = EXT2_SB(sb);
return (sbi->s_mount_opt & EXT2_MOUNT_XIP);
}
#else
-#define ext2_xip_verify_sb(sb) do { } while (0)
#define ext2_use_xip(sb) 0
#endif
--
2.0.1
--
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 14/22] ext2: Remove ext2_use_xip
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
` (12 preceding siblings ...)
2014-08-01 13:27 ` [PATCH v9 13/22] ext2: Remove ext2_xip_verify_sb() Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 15/22] ext2: Remove xip.c and xip.h Matthew Wilcox
` (7 subsequent siblings)
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Matthew Wilcox, willy
Replace ext2_use_xip() with test_opt(XIP) which expands to the same code
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
---
fs/ext2/ext2.h | 4 ++++
fs/ext2/inode.c | 2 +-
fs/ext2/namei.c | 4 ++--
3 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
index d9a17d0..5ecf570 100644
--- a/fs/ext2/ext2.h
+++ b/fs/ext2/ext2.h
@@ -380,7 +380,11 @@ struct ext2_inode {
#define EXT2_MOUNT_NO_UID32 0x000200 /* Disable 32-bit UIDs */
#define EXT2_MOUNT_XATTR_USER 0x004000 /* Extended user attributes */
#define EXT2_MOUNT_POSIX_ACL 0x008000 /* POSIX Access Control Lists */
+#ifdef CONFIG_FS_XIP
#define EXT2_MOUNT_XIP 0x010000 /* Execute in place */
+#else
+#define EXT2_MOUNT_XIP 0
+#endif
#define EXT2_MOUNT_USRQUOTA 0x020000 /* user quota */
#define EXT2_MOUNT_GRPQUOTA 0x040000 /* group quota */
#define EXT2_MOUNT_RESERVATION 0x080000 /* Preallocation */
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 59d6c7d..cba3833 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -1394,7 +1394,7 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
if (S_ISREG(inode->i_mode)) {
inode->i_op = &ext2_file_inode_operations;
- if (ext2_use_xip(inode->i_sb)) {
+ if (test_opt(inode->i_sb, XIP)) {
inode->i_mapping->a_ops = &ext2_aops_xip;
inode->i_fop = &ext2_xip_file_operations;
} else if (test_opt(inode->i_sb, NOBH)) {
diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c
index c268d0a..846c356 100644
--- a/fs/ext2/namei.c
+++ b/fs/ext2/namei.c
@@ -105,7 +105,7 @@ static int ext2_create (struct inode * dir, struct dentry * dentry, umode_t mode
return PTR_ERR(inode);
inode->i_op = &ext2_file_inode_operations;
- if (ext2_use_xip(inode->i_sb)) {
+ if (test_opt(inode->i_sb, XIP)) {
inode->i_mapping->a_ops = &ext2_aops_xip;
inode->i_fop = &ext2_xip_file_operations;
} else if (test_opt(inode->i_sb, NOBH)) {
@@ -126,7 +126,7 @@ static int ext2_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
return PTR_ERR(inode);
inode->i_op = &ext2_file_inode_operations;
- if (ext2_use_xip(inode->i_sb)) {
+ if (test_opt(inode->i_sb, XIP)) {
inode->i_mapping->a_ops = &ext2_aops_xip;
inode->i_fop = &ext2_xip_file_operations;
} else if (test_opt(inode->i_sb, NOBH)) {
--
2.0.1
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 15/22] ext2: Remove xip.c and xip.h
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
` (13 preceding siblings ...)
2014-08-01 13:27 ` [PATCH v9 14/22] ext2: Remove ext2_use_xip Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 16/22] Remove CONFIG_EXT2_FS_XIP and rename CONFIG_FS_XIP to CONFIG_FS_DAX Matthew Wilcox
` (6 subsequent siblings)
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Matthew Wilcox, willy
These files are now empty, so delete them
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
---
fs/ext2/Makefile | 1 -
fs/ext2/inode.c | 1 -
fs/ext2/namei.c | 1 -
fs/ext2/super.c | 1 -
fs/ext2/xip.c | 15 ---------------
fs/ext2/xip.h | 16 ----------------
6 files changed, 35 deletions(-)
delete mode 100644 fs/ext2/xip.c
delete mode 100644 fs/ext2/xip.h
diff --git a/fs/ext2/Makefile b/fs/ext2/Makefile
index f42af45..445b0e9 100644
--- a/fs/ext2/Makefile
+++ b/fs/ext2/Makefile
@@ -10,4 +10,3 @@ ext2-y := balloc.o dir.o file.o ialloc.o inode.o \
ext2-$(CONFIG_EXT2_FS_XATTR) += xattr.o xattr_user.o xattr_trusted.o
ext2-$(CONFIG_EXT2_FS_POSIX_ACL) += acl.o
ext2-$(CONFIG_EXT2_FS_SECURITY) += xattr_security.o
-ext2-$(CONFIG_EXT2_FS_XIP) += xip.o
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index cba3833..154cbcf 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -34,7 +34,6 @@
#include <linux/aio.h>
#include "ext2.h"
#include "acl.h"
-#include "xip.h"
#include "xattr.h"
static int __ext2_write_inode(struct inode *inode, int do_sync);
diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c
index 846c356..7ca803f 100644
--- a/fs/ext2/namei.c
+++ b/fs/ext2/namei.c
@@ -35,7 +35,6 @@
#include "ext2.h"
#include "xattr.h"
#include "acl.h"
-#include "xip.h"
static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
{
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 3ac6555..747e293 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -35,7 +35,6 @@
#include "ext2.h"
#include "xattr.h"
#include "acl.h"
-#include "xip.h"
static void ext2_sync_super(struct super_block *sb,
struct ext2_super_block *es, int wait);
diff --git a/fs/ext2/xip.c b/fs/ext2/xip.c
deleted file mode 100644
index 66ca113..0000000
--- a/fs/ext2/xip.c
+++ /dev/null
@@ -1,15 +0,0 @@
-/*
- * linux/fs/ext2/xip.c
- *
- * Copyright (C) 2005 IBM Corporation
- * Author: Carsten Otte (cotte@de.ibm.com)
- */
-
-#include <linux/mm.h>
-#include <linux/fs.h>
-#include <linux/genhd.h>
-#include <linux/buffer_head.h>
-#include <linux/blkdev.h>
-#include "ext2.h"
-#include "xip.h"
-
diff --git a/fs/ext2/xip.h b/fs/ext2/xip.h
deleted file mode 100644
index 87eeb04..0000000
--- a/fs/ext2/xip.h
+++ /dev/null
@@ -1,16 +0,0 @@
-/*
- * linux/fs/ext2/xip.h
- *
- * Copyright (C) 2005 IBM Corporation
- * Author: Carsten Otte (cotte@de.ibm.com)
- */
-
-#ifdef CONFIG_EXT2_FS_XIP
-static inline int ext2_use_xip (struct super_block *sb)
-{
- struct ext2_sb_info *sbi = EXT2_SB(sb);
- return (sbi->s_mount_opt & EXT2_MOUNT_XIP);
-}
-#else
-#define ext2_use_xip(sb) 0
-#endif
--
2.0.1
--
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 16/22] Remove CONFIG_EXT2_FS_XIP and rename CONFIG_FS_XIP to CONFIG_FS_DAX
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
` (14 preceding siblings ...)
2014-08-01 13:27 ` [PATCH v9 15/22] ext2: Remove xip.c and xip.h Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 17/22] ext2: Remove ext2_aops_xip Matthew Wilcox
` (5 subsequent siblings)
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Matthew Wilcox, willy
The fewer Kconfig options we have the better. Use the generic
CONFIG_FS_DAX to enable XIP support in ext2 as well as in the core.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
---
fs/Kconfig | 21 ++++++++++++++-------
fs/Makefile | 2 +-
fs/ext2/Kconfig | 11 -----------
fs/ext2/ext2.h | 2 +-
fs/ext2/file.c | 4 ++--
fs/ext2/super.c | 4 ++--
include/linux/fs.h | 4 ++--
7 files changed, 22 insertions(+), 26 deletions(-)
diff --git a/fs/Kconfig b/fs/Kconfig
index 312393f..a9eb53d 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -13,13 +13,6 @@ if BLOCK
source "fs/ext2/Kconfig"
source "fs/ext3/Kconfig"
source "fs/ext4/Kconfig"
-
-config FS_XIP
-# execute in place
- bool
- depends on EXT2_FS_XIP
- default y
-
source "fs/jbd/Kconfig"
source "fs/jbd2/Kconfig"
@@ -40,6 +33,20 @@ source "fs/ocfs2/Kconfig"
source "fs/btrfs/Kconfig"
source "fs/nilfs2/Kconfig"
+config FS_DAX
+ bool "Direct Access support"
+ depends on MMU
+ help
+ Direct Access (DAX) can be used on memory-backed block devices.
+ If the block device supports DAX and the filesystem supports DAX,
+ then you can avoid using the pagecache to buffer I/Os. Turning
+ on this option will compile in support for DAX; you will need to
+ mount the filesystem using the -o xip option.
+
+ If you do not have a block device that is capable of using this,
+ or if unsure, say N. Saying Y will increase the size of the kernel
+ by about 2kB.
+
endif # BLOCK
# Posix ACL utility routines
diff --git a/fs/Makefile b/fs/Makefile
index 03f65091..11d8e1b 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -28,7 +28,7 @@ obj-$(CONFIG_SIGNALFD) += signalfd.o
obj-$(CONFIG_TIMERFD) += timerfd.o
obj-$(CONFIG_EVENTFD) += eventfd.o
obj-$(CONFIG_AIO) += aio.o
-obj-$(CONFIG_FS_XIP) += dax.o
+obj-$(CONFIG_FS_DAX) += dax.o
obj-$(CONFIG_FILE_LOCKING) += locks.o
obj-$(CONFIG_COMPAT) += compat.o compat_ioctl.o
obj-$(CONFIG_BINFMT_AOUT) += binfmt_aout.o
diff --git a/fs/ext2/Kconfig b/fs/ext2/Kconfig
index 14a6780..c634874e 100644
--- a/fs/ext2/Kconfig
+++ b/fs/ext2/Kconfig
@@ -42,14 +42,3 @@ config EXT2_FS_SECURITY
If you are not using a security module that requires using
extended attributes for file security labels, say N.
-
-config EXT2_FS_XIP
- bool "Ext2 execute in place support"
- depends on EXT2_FS && MMU
- help
- Execute in place can be used on memory-backed block devices. If you
- enable this option, you can select to mount block devices which are
- capable of this feature without using the page cache.
-
- If you do not use a block device that is capable of using this,
- or if unsure, say N.
diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
index 5ecf570..b30c3bd 100644
--- a/fs/ext2/ext2.h
+++ b/fs/ext2/ext2.h
@@ -380,7 +380,7 @@ struct ext2_inode {
#define EXT2_MOUNT_NO_UID32 0x000200 /* Disable 32-bit UIDs */
#define EXT2_MOUNT_XATTR_USER 0x004000 /* Extended user attributes */
#define EXT2_MOUNT_POSIX_ACL 0x008000 /* POSIX Access Control Lists */
-#ifdef CONFIG_FS_XIP
+#ifdef CONFIG_FS_DAX
#define EXT2_MOUNT_XIP 0x010000 /* Execute in place */
#else
#define EXT2_MOUNT_XIP 0
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
index da8dc64..46b333d 100644
--- a/fs/ext2/file.c
+++ b/fs/ext2/file.c
@@ -25,7 +25,7 @@
#include "xattr.h"
#include "acl.h"
-#ifdef CONFIG_EXT2_FS_XIP
+#ifdef CONFIG_FS_DAX
static int ext2_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
return dax_fault(vma, vmf, ext2_get_block);
@@ -109,7 +109,7 @@ const struct file_operations ext2_file_operations = {
.splice_write = iter_file_splice_write,
};
-#ifdef CONFIG_EXT2_FS_XIP
+#ifdef CONFIG_FS_DAX
const struct file_operations ext2_xip_file_operations = {
.llseek = generic_file_llseek,
.read = new_sync_read,
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 747e293..2b58c48 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -287,7 +287,7 @@ static int ext2_show_options(struct seq_file *seq, struct dentry *root)
seq_puts(seq, ",grpquota");
#endif
-#if defined(CONFIG_EXT2_FS_XIP)
+#ifdef CONFIG_FS_DAX
if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
seq_puts(seq, ",xip");
#endif
@@ -549,7 +549,7 @@ static int parse_options(char *options, struct super_block *sb)
break;
#endif
case Opt_xip:
-#ifdef CONFIG_EXT2_FS_XIP
+#ifdef CONFIG_FS_DAX
set_opt (sbi->s_mount_opt, XIP);
#else
ext2_msg(sb, KERN_INFO, "xip option not supported");
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 67edd2c..79b0cbe 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1616,7 +1616,7 @@ struct super_operations {
#define IS_IMA(inode) ((inode)->i_flags & S_IMA)
#define IS_AUTOMOUNT(inode) ((inode)->i_flags & S_AUTOMOUNT)
#define IS_NOSEC(inode) ((inode)->i_flags & S_NOSEC)
-#ifdef CONFIG_FS_XIP
+#ifdef CONFIG_FS_DAX
#define IS_DAX(inode) ((inode)->i_flags & S_DAX)
#else
#define IS_DAX(inode) 0
@@ -2461,7 +2461,7 @@ extern loff_t fixed_size_llseek(struct file *file, loff_t offset,
extern int generic_file_open(struct inode * inode, struct file * filp);
extern int nonseekable_open(struct inode * inode, struct file * filp);
-#ifdef CONFIG_FS_XIP
+#ifdef CONFIG_FS_DAX
int dax_clear_blocks(struct inode *, sector_t block, long size);
int dax_truncate_page(struct inode *, loff_t from, get_block_t);
ssize_t dax_do_io(int rw, struct kiocb *, struct inode *, struct iov_iter *,
--
2.0.1
--
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 17/22] ext2: Remove ext2_aops_xip
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
` (15 preceding siblings ...)
2014-08-01 13:27 ` [PATCH v9 16/22] Remove CONFIG_EXT2_FS_XIP and rename CONFIG_FS_XIP to CONFIG_FS_DAX Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 18/22] Get rid of most mentions of XIP in ext2 Matthew Wilcox
` (4 subsequent siblings)
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Matthew Wilcox, willy
We shouldn't need a special address_space_operations any more
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
---
fs/ext2/ext2.h | 1 -
fs/ext2/inode.c | 7 +------
fs/ext2/namei.c | 4 ++--
3 files changed, 3 insertions(+), 9 deletions(-)
diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
index b30c3bd..b8b1c11 100644
--- a/fs/ext2/ext2.h
+++ b/fs/ext2/ext2.h
@@ -793,7 +793,6 @@ extern const struct file_operations ext2_xip_file_operations;
/* inode.c */
extern const struct address_space_operations ext2_aops;
-extern const struct address_space_operations ext2_aops_xip;
extern const struct address_space_operations ext2_nobh_aops;
/* namei.c */
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 154cbcf..034fd42 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -891,11 +891,6 @@ const struct address_space_operations ext2_aops = {
.error_remove_page = generic_error_remove_page,
};
-const struct address_space_operations ext2_aops_xip = {
- .bmap = ext2_bmap,
- .direct_IO = ext2_direct_IO,
-};
-
const struct address_space_operations ext2_nobh_aops = {
.readpage = ext2_readpage,
.readpages = ext2_readpages,
@@ -1394,7 +1389,7 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
if (S_ISREG(inode->i_mode)) {
inode->i_op = &ext2_file_inode_operations;
if (test_opt(inode->i_sb, XIP)) {
- inode->i_mapping->a_ops = &ext2_aops_xip;
+ inode->i_mapping->a_ops = &ext2_aops;
inode->i_fop = &ext2_xip_file_operations;
} else if (test_opt(inode->i_sb, NOBH)) {
inode->i_mapping->a_ops = &ext2_nobh_aops;
diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c
index 7ca803f..0db888c 100644
--- a/fs/ext2/namei.c
+++ b/fs/ext2/namei.c
@@ -105,7 +105,7 @@ static int ext2_create (struct inode * dir, struct dentry * dentry, umode_t mode
inode->i_op = &ext2_file_inode_operations;
if (test_opt(inode->i_sb, XIP)) {
- inode->i_mapping->a_ops = &ext2_aops_xip;
+ inode->i_mapping->a_ops = &ext2_aops;
inode->i_fop = &ext2_xip_file_operations;
} else if (test_opt(inode->i_sb, NOBH)) {
inode->i_mapping->a_ops = &ext2_nobh_aops;
@@ -126,7 +126,7 @@ static int ext2_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
inode->i_op = &ext2_file_inode_operations;
if (test_opt(inode->i_sb, XIP)) {
- inode->i_mapping->a_ops = &ext2_aops_xip;
+ inode->i_mapping->a_ops = &ext2_aops;
inode->i_fop = &ext2_xip_file_operations;
} else if (test_opt(inode->i_sb, NOBH)) {
inode->i_mapping->a_ops = &ext2_nobh_aops;
--
2.0.1
--
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 18/22] Get rid of most mentions of XIP in ext2
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
` (16 preceding siblings ...)
2014-08-01 13:27 ` [PATCH v9 17/22] ext2: Remove ext2_aops_xip Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 19/22] xip: Add xip_zero_page_range Matthew Wilcox
` (3 subsequent siblings)
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Matthew Wilcox, willy
To help people transition, accept the 'xip' mount option (and report it
in /proc/mounts), but print a message encouraging people to switch over
to the 'dax' option.
---
fs/ext2/ext2.h | 13 +++++++------
fs/ext2/file.c | 2 +-
fs/ext2/inode.c | 6 +++---
fs/ext2/namei.c | 8 ++++----
fs/ext2/super.c | 25 ++++++++++++++++---------
5 files changed, 31 insertions(+), 23 deletions(-)
diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
index b8b1c11..46133a0 100644
--- a/fs/ext2/ext2.h
+++ b/fs/ext2/ext2.h
@@ -380,14 +380,15 @@ struct ext2_inode {
#define EXT2_MOUNT_NO_UID32 0x000200 /* Disable 32-bit UIDs */
#define EXT2_MOUNT_XATTR_USER 0x004000 /* Extended user attributes */
#define EXT2_MOUNT_POSIX_ACL 0x008000 /* POSIX Access Control Lists */
-#ifdef CONFIG_FS_DAX
-#define EXT2_MOUNT_XIP 0x010000 /* Execute in place */
-#else
-#define EXT2_MOUNT_XIP 0
-#endif
+#define EXT2_MOUNT_XIP 0x010000 /* Obsolete, use DAX */
#define EXT2_MOUNT_USRQUOTA 0x020000 /* user quota */
#define EXT2_MOUNT_GRPQUOTA 0x040000 /* group quota */
#define EXT2_MOUNT_RESERVATION 0x080000 /* Preallocation */
+#ifdef CONFIG_FS_DAX
+#define EXT2_MOUNT_DAX 0x100000 /* Direct Access */
+#else
+#define EXT2_MOUNT_DAX 0
+#endif
#define clear_opt(o, opt) o &= ~EXT2_MOUNT_##opt
@@ -789,7 +790,7 @@ extern int ext2_fsync(struct file *file, loff_t start, loff_t end,
int datasync);
extern const struct inode_operations ext2_file_inode_operations;
extern const struct file_operations ext2_file_operations;
-extern const struct file_operations ext2_xip_file_operations;
+extern const struct file_operations ext2_dax_file_operations;
/* inode.c */
extern const struct address_space_operations ext2_aops;
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
index 46b333d..5b8cab5 100644
--- a/fs/ext2/file.c
+++ b/fs/ext2/file.c
@@ -110,7 +110,7 @@ const struct file_operations ext2_file_operations = {
};
#ifdef CONFIG_FS_DAX
-const struct file_operations ext2_xip_file_operations = {
+const struct file_operations ext2_dax_file_operations = {
.llseek = generic_file_llseek,
.read = new_sync_read,
.write = new_sync_write,
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 034fd42..6434bc0 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -1286,7 +1286,7 @@ void ext2_set_inode_flags(struct inode *inode)
inode->i_flags |= S_NOATIME;
if (flags & EXT2_DIRSYNC_FL)
inode->i_flags |= S_DIRSYNC;
- if (test_opt(inode->i_sb, XIP))
+ if (test_opt(inode->i_sb, DAX))
inode->i_flags |= S_DAX;
}
@@ -1388,9 +1388,9 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
if (S_ISREG(inode->i_mode)) {
inode->i_op = &ext2_file_inode_operations;
- if (test_opt(inode->i_sb, XIP)) {
+ if (test_opt(inode->i_sb, DAX)) {
inode->i_mapping->a_ops = &ext2_aops;
- inode->i_fop = &ext2_xip_file_operations;
+ inode->i_fop = &ext2_dax_file_operations;
} else if (test_opt(inode->i_sb, NOBH)) {
inode->i_mapping->a_ops = &ext2_nobh_aops;
inode->i_fop = &ext2_file_operations;
diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c
index 0db888c..148f6e3 100644
--- a/fs/ext2/namei.c
+++ b/fs/ext2/namei.c
@@ -104,9 +104,9 @@ static int ext2_create (struct inode * dir, struct dentry * dentry, umode_t mode
return PTR_ERR(inode);
inode->i_op = &ext2_file_inode_operations;
- if (test_opt(inode->i_sb, XIP)) {
+ if (test_opt(inode->i_sb, DAX)) {
inode->i_mapping->a_ops = &ext2_aops;
- inode->i_fop = &ext2_xip_file_operations;
+ inode->i_fop = &ext2_dax_file_operations;
} else if (test_opt(inode->i_sb, NOBH)) {
inode->i_mapping->a_ops = &ext2_nobh_aops;
inode->i_fop = &ext2_file_operations;
@@ -125,9 +125,9 @@ static int ext2_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
return PTR_ERR(inode);
inode->i_op = &ext2_file_inode_operations;
- if (test_opt(inode->i_sb, XIP)) {
+ if (test_opt(inode->i_sb, DAX)) {
inode->i_mapping->a_ops = &ext2_aops;
- inode->i_fop = &ext2_xip_file_operations;
+ inode->i_fop = &ext2_dax_file_operations;
} else if (test_opt(inode->i_sb, NOBH)) {
inode->i_mapping->a_ops = &ext2_nobh_aops;
inode->i_fop = &ext2_file_operations;
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 2b58c48..29633627 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -290,6 +290,8 @@ static int ext2_show_options(struct seq_file *seq, struct dentry *root)
#ifdef CONFIG_FS_DAX
if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
seq_puts(seq, ",xip");
+ if (sbi->s_mount_opt & EXT2_MOUNT_DAX)
+ seq_puts(seq, ",dax");
#endif
if (!test_opt(sb, RESERVATION))
@@ -393,7 +395,7 @@ enum {
Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
- Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
+ Opt_acl, Opt_noacl, Opt_xip, Opt_dax, Opt_ignore, Opt_err, Opt_quota,
Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
};
@@ -422,6 +424,7 @@ static const match_table_t tokens = {
{Opt_acl, "acl"},
{Opt_noacl, "noacl"},
{Opt_xip, "xip"},
+ {Opt_dax, "dax"},
{Opt_grpquota, "grpquota"},
{Opt_ignore, "noquota"},
{Opt_quota, "quota"},
@@ -549,10 +552,14 @@ static int parse_options(char *options, struct super_block *sb)
break;
#endif
case Opt_xip:
+ ext2_msg(sb, KERN_INFO, "use dax instead of xip");
+ set_opt(sbi->s_mount_opt, XIP);
+ /* Fall through */
+ case Opt_dax:
#ifdef CONFIG_FS_DAX
- set_opt (sbi->s_mount_opt, XIP);
+ set_opt(sbi->s_mount_opt, DAX);
#else
- ext2_msg(sb, KERN_INFO, "xip option not supported");
+ ext2_msg(sb, KERN_INFO, "dax option not supported");
#endif
break;
@@ -896,15 +903,15 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
- if (sbi->s_mount_opt & EXT2_MOUNT_XIP) {
+ if (sbi->s_mount_opt & EXT2_MOUNT_DAX) {
if (blocksize != PAGE_SIZE) {
ext2_msg(sb, KERN_ERR,
- "error: unsupported blocksize for xip");
+ "error: unsupported blocksize for dax");
goto failed_mount;
}
if (!sb->s_bdev->bd_disk->fops->direct_access) {
ext2_msg(sb, KERN_ERR,
- "error: device does not support xip");
+ "error: device does not support dax");
goto failed_mount;
}
}
@@ -1276,10 +1283,10 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
es = sbi->s_es;
- if ((sbi->s_mount_opt ^ old_opts.s_mount_opt) & EXT2_MOUNT_XIP) {
+ if ((sbi->s_mount_opt ^ old_opts.s_mount_opt) & EXT2_MOUNT_DAX) {
ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
- "xip flag with busy inodes while remounting");
- sbi->s_mount_opt ^= EXT2_MOUNT_XIP;
+ "dax flag with busy inodes while remounting");
+ sbi->s_mount_opt ^= EXT2_MOUNT_DAX;
}
if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
spin_unlock(&sbi->s_lock);
--
2.0.1
--
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 19/22] xip: Add xip_zero_page_range
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
` (17 preceding siblings ...)
2014-08-01 13:27 ` [PATCH v9 18/22] Get rid of most mentions of XIP in ext2 Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 20/22] ext4: Avoid lock inversion between i_mmap_mutex and transaction start Matthew Wilcox
` (2 subsequent siblings)
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Matthew Wilcox, willy, Ross Zwisler
This new function allows us to support hole-punch for XIP files by zeroing
a partial page, as opposed to the xip_truncate_page() function which can
only truncate to the end of the page. Reimplement xip_truncate_page() as
a macro that calls xip_zero_page_range().
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
[ported to 3.13-rc2]
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
---
Documentation/filesystems/dax.txt | 1 +
fs/dax.c | 20 ++++++++++++++------
include/linux/fs.h | 9 ++++++++-
3 files changed, 23 insertions(+), 7 deletions(-)
diff --git a/Documentation/filesystems/dax.txt b/Documentation/filesystems/dax.txt
index 6441766..1fd3a6f 100644
--- a/Documentation/filesystems/dax.txt
+++ b/Documentation/filesystems/dax.txt
@@ -62,6 +62,7 @@ Filesystem support consists of
for fault and page_mkwrite (which should probably call dax_fault() and
dax_mkwrite(), passing the appropriate get_block() callback)
- calling dax_truncate_page() instead of block_truncate_page() for DAX files
+- calling dax_zero_page_range() instead of zero_user() for DAX files
- ensuring that there is sufficient locking between reads, writes,
truncates and page faults
diff --git a/fs/dax.c b/fs/dax.c
index 15654ce..c6c15c3 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -424,13 +424,16 @@ int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
EXPORT_SYMBOL_GPL(dax_fault);
/**
- * dax_truncate_page - handle a partial page being truncated in a DAX file
+ * dax_zero_page_range - zero a range within a page of a DAX file
* @inode: The file being truncated
* @from: The file offset that is being truncated to
+ * @length: The number of bytes to zero
* @get_block: The filesystem method used to translate file offsets to blocks
*
- * Similar to block_truncate_page(), this function can be called by a
- * filesystem when it is truncating an DAX file to handle the partial page.
+ * This function can be called by a filesystem when it is zeroing part of a
+ * page in a DAX file. This is intended for hole-punch operations. If
+ * you are truncating a file, the helper function dax_truncate_page() may be
+ * more convenient.
*
* We work in terms of PAGE_CACHE_SIZE here for commonality with
* block_truncate_page(), but we could go down to PAGE_SIZE if the filesystem
@@ -438,12 +441,12 @@ EXPORT_SYMBOL_GPL(dax_fault);
* block size is smaller than PAGE_SIZE, we have to zero the rest of the page
* since the file might be mmaped.
*/
-int dax_truncate_page(struct inode *inode, loff_t from, get_block_t get_block)
+int dax_zero_page_range(struct inode *inode, loff_t from, unsigned length,
+ get_block_t get_block)
{
struct buffer_head bh;
pgoff_t index = from >> PAGE_CACHE_SHIFT;
unsigned offset = from & (PAGE_CACHE_SIZE-1);
- unsigned length = PAGE_CACHE_ALIGN(from) - from;
int err;
/* Block boundary? Nothing to do */
@@ -460,9 +463,14 @@ int dax_truncate_page(struct inode *inode, loff_t from, get_block_t get_block)
err = dax_get_addr(&bh, &addr, inode->i_blkbits);
if (err < 0)
return err;
+ /*
+ * ext4 sometimes asks to zero past the end of a block. It
+ * really just wants to zero to the end of the block.
+ */
+ length = min_t(unsigned, length, PAGE_CACHE_SIZE - offset);
memset(addr + offset, 0, length);
}
return 0;
}
-EXPORT_SYMBOL_GPL(dax_truncate_page);
+EXPORT_SYMBOL_GPL(dax_zero_page_range);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 79b0cbe..8da9a0e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2463,6 +2463,7 @@ extern int nonseekable_open(struct inode * inode, struct file * filp);
#ifdef CONFIG_FS_DAX
int dax_clear_blocks(struct inode *, sector_t block, long size);
+int dax_zero_page_range(struct inode *, loff_t from, unsigned len, get_block_t);
int dax_truncate_page(struct inode *, loff_t from, get_block_t);
ssize_t dax_do_io(int rw, struct kiocb *, struct inode *, struct iov_iter *,
loff_t, get_block_t, dio_iodone_t, int flags);
@@ -2474,7 +2475,8 @@ static inline int dax_clear_blocks(struct inode *i, sector_t blk, long sz)
return 0;
}
-static inline int dax_truncate_page(struct inode *i, loff_t frm, get_block_t gb)
+static inline int dax_zero_page_range(struct inode *inode, loff_t from,
+ unsigned len, get_block_t gb)
{
return 0;
}
@@ -2487,6 +2489,11 @@ static inline ssize_t dax_do_io(int rw, struct kiocb *iocb, struct inode *inode,
}
#endif
+/* Can't be a function because PAGE_CACHE_SIZE is defined in pagemap.h */
+#define dax_truncate_page(inode, from, get_block) \
+ dax_zero_page_range(inode, from, PAGE_CACHE_SIZE, get_block)
+
+
#ifdef CONFIG_BLOCK
typedef void (dio_submit_t)(int rw, struct bio *bio, struct inode *inode,
loff_t file_offset);
--
2.0.1
--
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 20/22] ext4: Avoid lock inversion between i_mmap_mutex and transaction start
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
` (18 preceding siblings ...)
2014-08-01 13:27 ` [PATCH v9 19/22] xip: Add xip_zero_page_range Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 21/22] ext4: Add DAX functionality Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 22/22] brd: Rename XIP to DAX Matthew Wilcox
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Jan Kara, willy, Matthew Wilcox
From: Jan Kara <jack@suse.cz>
When DAX is enabled, it uses i_mmap_mutex as a protection against
truncate during page fault. This inevitably forces i_mmap_mutex to rank
outside of a transaction start and thus we have to avoid calling
pagecache purging operations when transaction is started.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
---
fs/ext4/inode.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 8a06473..494a864 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3631,13 +3631,19 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
if (IS_SYNC(inode))
ext4_handle_sync(handle);
- /* Now release the pages again to reduce race window */
+ inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
+ ext4_mark_inode_dirty(handle, inode);
+ ext4_journal_stop(handle);
+
+ /*
+ * Now release the pages again to reduce race window. This has to happen
+ * outside of a transaction to avoid lock inversion on i_mmap_mutex
+ * when DAX is enabled.
+ */
if (last_block_offset > first_block_offset)
truncate_pagecache_range(inode, first_block_offset,
last_block_offset);
-
- inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
- ext4_mark_inode_dirty(handle, inode);
+ goto out_dio;
out_stop:
ext4_journal_stop(handle);
out_dio:
--
2.0.1
--
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 21/22] ext4: Add DAX functionality
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
` (19 preceding siblings ...)
2014-08-01 13:27 ` [PATCH v9 20/22] ext4: Avoid lock inversion between i_mmap_mutex and transaction start Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
2014-08-01 13:27 ` [PATCH v9 22/22] brd: Rename XIP to DAX Matthew Wilcox
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Ross Zwisler, willy, Matthew Wilcox
From: Ross Zwisler <ross.zwisler@linux.intel.com>
This is a port of the DAX functionality found in the current version of
ext2.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
[heavily tweaked]
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
---
Documentation/filesystems/dax.txt | 1 +
Documentation/filesystems/ext4.txt | 2 ++
fs/ext4/ext4.h | 6 +++++
fs/ext4/file.c | 53 +++++++++++++++++++++++++++++++++-----
fs/ext4/indirect.c | 18 +++++++++----
fs/ext4/inode.c | 51 +++++++++++++++++++++++-------------
fs/ext4/namei.c | 10 +++++--
fs/ext4/super.c | 39 +++++++++++++++++++++++++++-
8 files changed, 148 insertions(+), 32 deletions(-)
diff --git a/Documentation/filesystems/dax.txt b/Documentation/filesystems/dax.txt
index 1fd3a6f..741e4cb 100644
--- a/Documentation/filesystems/dax.txt
+++ b/Documentation/filesystems/dax.txt
@@ -73,6 +73,7 @@ or a write()) work correctly.
These filesystems may be used for inspiration:
- ext2: the second extended filesystem, see Documentation/filesystems/ext2.txt
+- ext4: the fourth extended filesystem, see Documentation/filesystems/ext4.txt
Shortcomings
diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt
index 919a329..9c511c4 100644
--- a/Documentation/filesystems/ext4.txt
+++ b/Documentation/filesystems/ext4.txt
@@ -386,6 +386,8 @@ max_dir_size_kb=n This limits the size of directories so that any
i_version Enable 64-bit inode version support. This option is
off by default.
+dax Use direct access if possible
+
Data Mode
=========
There are 3 different data modes:
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 7cc5a0e..a9687b3 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -970,6 +970,11 @@ struct ext4_inode_info {
#define EXT4_MOUNT_ERRORS_MASK 0x00070
#define EXT4_MOUNT_MINIX_DF 0x00080 /* Mimics the Minix statfs */
#define EXT4_MOUNT_NOLOAD 0x00100 /* Don't use existing journal*/
+#ifdef CONFIG_FS_DAX
+#define EXT4_MOUNT_DAX 0x00200 /* Execute in place */
+#else
+#define EXT4_MOUNT_DAX 0
+#endif
#define EXT4_MOUNT_DATA_FLAGS 0x00C00 /* Mode for data writes: */
#define EXT4_MOUNT_JOURNAL_DATA 0x00400 /* Write data to journal */
#define EXT4_MOUNT_ORDERED_DATA 0x00800 /* Flush data before commit */
@@ -2557,6 +2562,7 @@ extern const struct file_operations ext4_dir_operations;
/* file.c */
extern const struct inode_operations ext4_file_inode_operations;
extern const struct file_operations ext4_file_operations;
+extern const struct file_operations ext4_dax_file_operations;
extern loff_t ext4_llseek(struct file *file, loff_t offset, int origin);
/* inline.c */
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 8695f70..9c7bde5 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -95,7 +95,7 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
struct inode *inode = file_inode(iocb->ki_filp);
struct mutex *aio_mutex = NULL;
struct blk_plug plug;
- int o_direct = file->f_flags & O_DIRECT;
+ int o_direct = io_is_direct(file);
int overwrite = 0;
size_t length = iov_iter_count(from);
ssize_t ret;
@@ -191,6 +191,27 @@ errout:
return ret;
}
+#ifdef CONFIG_FS_DAX
+static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ return dax_fault(vma, vmf, ext4_get_block);
+ /* Is this the right get_block? */
+}
+
+static int ext4_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ return dax_mkwrite(vma, vmf, ext4_get_block);
+}
+
+static const struct vm_operations_struct ext4_dax_vm_ops = {
+ .fault = ext4_dax_fault,
+ .page_mkwrite = ext4_dax_mkwrite,
+ .remap_pages = generic_file_remap_pages,
+};
+#else
+#define ext4_dax_vm_ops ext4_file_vm_ops
+#endif
+
static const struct vm_operations_struct ext4_file_vm_ops = {
.fault = filemap_fault,
.map_pages = filemap_map_pages,
@@ -200,12 +221,13 @@ static const struct vm_operations_struct ext4_file_vm_ops = {
static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
{
- struct address_space *mapping = file->f_mapping;
-
- if (!mapping->a_ops->readpage)
- return -ENOEXEC;
file_accessed(file);
- vma->vm_ops = &ext4_file_vm_ops;
+ if (IS_DAX(file_inode(file))) {
+ vma->vm_ops = &ext4_dax_vm_ops;
+ vma->vm_flags |= VM_MIXEDMAP;
+ } else {
+ vma->vm_ops = &ext4_file_vm_ops;
+ }
return 0;
}
@@ -604,6 +626,25 @@ const struct file_operations ext4_file_operations = {
.fallocate = ext4_fallocate,
};
+#ifdef CONFIG_FS_DAX
+const struct file_operations ext4_dax_file_operations = {
+ .llseek = ext4_llseek,
+ .read = new_sync_read,
+ .write = new_sync_write,
+ .read_iter = generic_file_read_iter,
+ .write_iter = ext4_file_write_iter,
+ .unlocked_ioctl = ext4_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = ext4_compat_ioctl,
+#endif
+ .mmap = ext4_file_mmap,
+ .open = ext4_file_open,
+ .release = ext4_release_file,
+ .fsync = ext4_sync_file,
+ .fallocate = ext4_fallocate,
+};
+#endif
+
const struct inode_operations ext4_file_inode_operations = {
.setattr = ext4_setattr,
.getattr = ext4_getattr,
diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index fd69da1..a07578c 100644
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -691,14 +691,22 @@ retry:
inode_dio_done(inode);
goto locked;
}
- ret = __blockdev_direct_IO(rw, iocb, inode,
- inode->i_sb->s_bdev, iter, offset,
- ext4_get_block, NULL, NULL, 0);
+ if (IS_DAX(inode))
+ ret = dax_do_io(rw, iocb, inode, iter, offset,
+ ext4_get_block, NULL, 0);
+ else
+ ret = __blockdev_direct_IO(rw, iocb, inode,
+ inode->i_sb->s_bdev, iter, offset,
+ ext4_get_block, NULL, NULL, 0);
inode_dio_done(inode);
} else {
locked:
- ret = blockdev_direct_IO(rw, iocb, inode, iter,
- offset, ext4_get_block);
+ if (IS_DAX(inode))
+ ret = dax_do_io(rw, iocb, inode, iter, offset,
+ ext4_get_block, NULL, DIO_LOCKING);
+ else
+ ret = blockdev_direct_IO(rw, iocb, inode, iter,
+ offset, ext4_get_block);
if (unlikely((rw & WRITE) && ret < 0)) {
loff_t isize = i_size_read(inode);
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 494a864..71a4ff0 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3173,13 +3173,14 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
get_block_func = ext4_get_block_write;
dio_flags = DIO_LOCKING;
}
- ret = __blockdev_direct_IO(rw, iocb, inode,
- inode->i_sb->s_bdev, iter,
- offset,
- get_block_func,
- ext4_end_io_dio,
- NULL,
- dio_flags);
+ if (IS_DAX(inode))
+ ret = dax_do_io(rw, iocb, inode, iter, offset, get_block_func,
+ ext4_end_io_dio, dio_flags);
+ else
+ ret = __blockdev_direct_IO(rw, iocb, inode,
+ inode->i_sb->s_bdev, iter, offset,
+ get_block_func,
+ ext4_end_io_dio, NULL, dio_flags);
/*
* Put our reference to io_end. This can free the io_end structure e.g.
@@ -3343,14 +3344,7 @@ void ext4_set_aops(struct inode *inode)
inode->i_mapping->a_ops = &ext4_aops;
}
-/*
- * ext4_block_zero_page_range() zeros out a mapping of length 'length'
- * starting from file offset 'from'. The range to be zero'd must
- * be contained with in one block. If the specified range exceeds
- * the end of the block it will be shortened to end of the block
- * that cooresponds to 'from'
- */
-static int ext4_block_zero_page_range(handle_t *handle,
+static int __ext4_block_zero_page_range(handle_t *handle,
struct address_space *mapping, loff_t from, loff_t length)
{
ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
@@ -3441,6 +3435,22 @@ unlock:
}
/*
+ * ext4_block_zero_page_range() zeros out a mapping of length 'length'
+ * starting from file offset 'from'. The range to be zero'd must
+ * be contained with in one block. If the specified range exceeds
+ * the end of the block it will be shortened to end of the block
+ * that cooresponds to 'from'
+ */
+static int ext4_block_zero_page_range(handle_t *handle,
+ struct address_space *mapping, loff_t from, loff_t length)
+{
+ struct inode *inode = mapping->host;
+ if (IS_DAX(inode))
+ return dax_zero_page_range(inode, from, length, ext4_get_block);
+ return __ext4_block_zero_page_range(handle, mapping, from, length);
+}
+
+/*
* ext4_block_truncate_page() zeroes out a mapping from file offset `from'
* up to the end of the block which corresponds to `from'.
* This required during truncate. We need to physically zero the tail end
@@ -3967,8 +3977,10 @@ void ext4_set_inode_flags(struct inode *inode)
new_fl |= S_NOATIME;
if (flags & EXT4_DIRSYNC_FL)
new_fl |= S_DIRSYNC;
+ if (test_opt(inode->i_sb, DAX))
+ new_fl |= S_DAX;
inode_set_flags(inode, new_fl,
- S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
+ S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|S_DAX);
}
/* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
@@ -4222,7 +4234,10 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
if (S_ISREG(inode->i_mode)) {
inode->i_op = &ext4_file_inode_operations;
- inode->i_fop = &ext4_file_operations;
+ if (test_opt(inode->i_sb, DAX))
+ inode->i_fop = &ext4_dax_file_operations;
+ else
+ inode->i_fop = &ext4_file_operations;
ext4_set_aops(inode);
} else if (S_ISDIR(inode->i_mode)) {
inode->i_op = &ext4_dir_inode_operations;
@@ -4692,7 +4707,7 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
* Truncate pagecache after we've waited for commit
* in data=journal mode to make pages freeable.
*/
- truncate_pagecache(inode, inode->i_size);
+ truncate_pagecache(inode, inode->i_size);
}
/*
* We want to call ext4_truncate() even if attr->ia_size ==
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 3520ab8..2ef6adf 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2251,7 +2251,10 @@ retry:
err = PTR_ERR(inode);
if (!IS_ERR(inode)) {
inode->i_op = &ext4_file_inode_operations;
- inode->i_fop = &ext4_file_operations;
+ if (test_opt(inode->i_sb, DAX))
+ inode->i_fop = &ext4_dax_file_operations;
+ else
+ inode->i_fop = &ext4_file_operations;
ext4_set_aops(inode);
err = ext4_add_nondir(handle, dentry, inode);
if (!err && IS_DIRSYNC(dir))
@@ -2315,7 +2318,10 @@ retry:
err = PTR_ERR(inode);
if (!IS_ERR(inode)) {
inode->i_op = &ext4_file_inode_operations;
- inode->i_fop = &ext4_file_operations;
+ if (test_opt(inode->i_sb, DAX))
+ inode->i_fop = &ext4_dax_file_operations;
+ else
+ inode->i_fop = &ext4_file_operations;
ext4_set_aops(inode);
d_tmpfile(dentry, inode);
err = ext4_orphan_add(handle, inode);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 6df7bc6..41bb01e 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1162,7 +1162,7 @@ enum {
Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota,
Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err,
- Opt_usrquota, Opt_grpquota, Opt_i_version,
+ Opt_usrquota, Opt_grpquota, Opt_i_version, Opt_dax,
Opt_stripe, Opt_delalloc, Opt_nodelalloc, Opt_mblk_io_submit,
Opt_nomblk_io_submit, Opt_block_validity, Opt_noblock_validity,
Opt_inode_readahead_blks, Opt_journal_ioprio,
@@ -1224,6 +1224,7 @@ static const match_table_t tokens = {
{Opt_barrier, "barrier"},
{Opt_nobarrier, "nobarrier"},
{Opt_i_version, "i_version"},
+ {Opt_dax, "dax"},
{Opt_stripe, "stripe=%u"},
{Opt_delalloc, "delalloc"},
{Opt_nodelalloc, "nodelalloc"},
@@ -1406,6 +1407,7 @@ static const struct mount_opts {
{Opt_min_batch_time, 0, MOPT_GTE0},
{Opt_inode_readahead_blks, 0, MOPT_GTE0},
{Opt_init_itable, 0, MOPT_GTE0},
+ {Opt_dax, EXT4_MOUNT_DAX, MOPT_SET},
{Opt_stripe, 0, MOPT_GTE0},
{Opt_resuid, 0, MOPT_GTE0},
{Opt_resgid, 0, MOPT_GTE0},
@@ -1642,6 +1644,11 @@ static int handle_mount_opt(struct super_block *sb, char *opt, int token,
}
sbi->s_jquota_fmt = m->mount_opt;
#endif
+#ifndef CONFIG_FS_DAX
+ } else if (token == Opt_dax) {
+ ext4_msg(sb, KERN_INFO, "dax option not supported");
+ return -1;
+#endif
} else {
if (!args->from)
arg = 1;
@@ -3575,6 +3582,11 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
"both data=journal and dioread_nolock");
goto failed_mount;
}
+ if (test_opt(sb, DAX)) {
+ ext4_msg(sb, KERN_ERR, "can't mount with "
+ "both data=journal and dax");
+ goto failed_mount;
+ }
if (test_opt(sb, DELALLOC))
clear_opt(sb, DELALLOC);
}
@@ -3638,6 +3650,19 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
goto failed_mount;
}
+ if (sbi->s_mount_opt & EXT4_MOUNT_DAX) {
+ if (blocksize != PAGE_SIZE) {
+ ext4_msg(sb, KERN_ERR,
+ "error: unsupported blocksize for dax");
+ goto failed_mount;
+ }
+ if (!sb->s_bdev->bd_disk->fops->direct_access) {
+ ext4_msg(sb, KERN_ERR,
+ "error: device does not support dax");
+ goto failed_mount;
+ }
+ }
+
if (sb->s_blocksize != blocksize) {
/* Validate the filesystem blocksize */
if (!sb_set_blocksize(sb, blocksize)) {
@@ -4846,6 +4871,18 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
err = -EINVAL;
goto restore_opts;
}
+ if (test_opt(sb, DAX)) {
+ ext4_msg(sb, KERN_ERR, "can't mount with "
+ "both data=journal and dax");
+ err = -EINVAL;
+ goto restore_opts;
+ }
+ }
+
+ if ((sbi->s_mount_opt ^ old_opts.s_mount_opt) & EXT4_MOUNT_DAX) {
+ ext4_msg(sb, KERN_WARNING, "warning: refusing change of "
+ "dax flag with busy inodes while remounting");
+ sbi->s_mount_opt ^= EXT4_MOUNT_DAX;
}
if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED)
--
2.0.1
--
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^ permalink raw reply related [flat|nested] 23+ messages in thread* [PATCH v9 22/22] brd: Rename XIP to DAX
2014-08-01 13:27 [PATCH v9 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
` (20 preceding siblings ...)
2014-08-01 13:27 ` [PATCH v9 21/22] ext4: Add DAX functionality Matthew Wilcox
@ 2014-08-01 13:27 ` Matthew Wilcox
21 siblings, 0 replies; 23+ messages in thread
From: Matthew Wilcox @ 2014-08-01 13:27 UTC (permalink / raw)
To: linux-fsdevel, linux-mm, linux-kernel; +Cc: Matthew Wilcox, Matthew Wilcox
From: Matthew Wilcox <willy@linux.intel.com>
Since this is relating to FS_XIP, not KERNEL_XIP, it should be called
DAX instead of XIP.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
---
drivers/block/Kconfig | 13 +++++++------
drivers/block/brd.c | 14 +++++++-------
fs/Kconfig | 4 ++--
3 files changed, 16 insertions(+), 15 deletions(-)
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index 014a1cf..1b8094d 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -393,14 +393,15 @@ config BLK_DEV_RAM_SIZE
The default value is 4096 kilobytes. Only change this if you know
what you are doing.
-config BLK_DEV_XIP
- bool "Support XIP filesystems on RAM block device"
- depends on BLK_DEV_RAM
+config BLK_DEV_RAM_DAX
+ bool "Support Direct Access (DAX) to RAM block devices"
+ depends on BLK_DEV_RAM && FS_DAX
default n
help
- Support XIP filesystems (such as ext2 with XIP support on) on
- top of block ram device. This will slightly enlarge the kernel, and
- will prevent RAM block device backing store memory from being
+ Support filesystems using DAX to access RAM block devices. This
+ avoids double-buffering data in the page cache before copying it
+ to the block device. Answering Y will slightly enlarge the kernel,
+ and will prevent RAM block device backing store memory from being
allocated from highmem (only a problem for highmem systems).
config CDROM_PKTCDVD
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index a10a0a9..3483458 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -97,13 +97,13 @@ static struct page *brd_insert_page(struct brd_device *brd, sector_t sector)
* Must use NOIO because we don't want to recurse back into the
* block or filesystem layers from page reclaim.
*
- * Cannot support XIP and highmem, because our ->direct_access
- * routine for XIP must return memory that is always addressable.
- * If XIP was reworked to use pfns and kmap throughout, this
+ * Cannot support DAX and highmem, because our ->direct_access
+ * routine for DAX must return memory that is always addressable.
+ * If DAX was reworked to use pfns and kmap throughout, this
* restriction might be able to be lifted.
*/
gfp_flags = GFP_NOIO | __GFP_ZERO;
-#ifndef CONFIG_BLK_DEV_XIP
+#ifndef CONFIG_BLK_DEV_RAM_DAX
gfp_flags |= __GFP_HIGHMEM;
#endif
page = alloc_page(gfp_flags);
@@ -369,7 +369,7 @@ static int brd_rw_page(struct block_device *bdev, sector_t sector,
return err;
}
-#ifdef CONFIG_BLK_DEV_XIP
+#ifdef CONFIG_BLK_DEV_RAM_DAX
static long brd_direct_access(struct block_device *bdev, sector_t sector,
void **kaddr, unsigned long *pfn, long size)
{
@@ -388,6 +388,8 @@ static long brd_direct_access(struct block_device *bdev, sector_t sector,
* file is mapped to the next page of physical RAM */
return min_t(long, PAGE_SIZE, size);
}
+#else
+#define brd_direct_access NULL
#endif
static int brd_ioctl(struct block_device *bdev, fmode_t mode,
@@ -428,9 +430,7 @@ static const struct block_device_operations brd_fops = {
.owner = THIS_MODULE,
.rw_page = brd_rw_page,
.ioctl = brd_ioctl,
-#ifdef CONFIG_BLK_DEV_XIP
.direct_access = brd_direct_access,
-#endif
};
/*
diff --git a/fs/Kconfig b/fs/Kconfig
index a9eb53d..117900f 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -34,7 +34,7 @@ source "fs/btrfs/Kconfig"
source "fs/nilfs2/Kconfig"
config FS_DAX
- bool "Direct Access support"
+ bool "Direct Access (DAX) support"
depends on MMU
help
Direct Access (DAX) can be used on memory-backed block devices.
@@ -45,7 +45,7 @@ config FS_DAX
If you do not have a block device that is capable of using this,
or if unsure, say N. Saying Y will increase the size of the kernel
- by about 2kB.
+ by about 5kB.
endif # BLOCK
--
2.0.1
--
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^ permalink raw reply related [flat|nested] 23+ messages in thread