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authorDan Williams <dan.j.williams@intel.com>2018-06-08 15:16:40 -0700
committerDan Williams <dan.j.williams@intel.com>2018-06-08 15:16:40 -0700
commitb56845794e1e93121acb74ca325db965035d5545 (patch)
tree3435f4e8de92d5a63fdc15953391cf057ee46642 /fs
parent808c340be17dc77131fcdf9ad1eb34452d650da1 (diff)
parentcc4a90ac816e00775fbc2a9c018bf2af606abd06 (diff)
downloadlinux-b56845794e1e93121acb74ca325db965035d5545.tar.bz2
Merge branch 'for-4.18/dax' into libnvdimm-for-next
Diffstat (limited to 'fs')
-rw-r--r--fs/Kconfig1
-rw-r--r--fs/dax.c115
-rw-r--r--fs/xfs/xfs_file.c72
-rw-r--r--fs/xfs/xfs_inode.h16
-rw-r--r--fs/xfs/xfs_ioctl.c8
-rw-r--r--fs/xfs/xfs_iops.c16
-rw-r--r--fs/xfs/xfs_pnfs.c15
-rw-r--r--fs/xfs/xfs_pnfs.h5
8 files changed, 205 insertions, 43 deletions
diff --git a/fs/Kconfig b/fs/Kconfig
index bc821a86d965..1e050e012eb9 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -38,6 +38,7 @@ config FS_DAX
bool "Direct Access (DAX) support"
depends on MMU
depends on !(ARM || MIPS || SPARC)
+ select DEV_PAGEMAP_OPS if (ZONE_DEVICE && !FS_DAX_LIMITED)
select FS_IOMAP
select DAX
help
diff --git a/fs/dax.c b/fs/dax.c
index aaec72ded1b6..31e9f51ac917 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -351,6 +351,19 @@ static void dax_disassociate_entry(void *entry, struct address_space *mapping,
}
}
+static struct page *dax_busy_page(void *entry)
+{
+ unsigned long pfn;
+
+ for_each_mapped_pfn(entry, pfn) {
+ struct page *page = pfn_to_page(pfn);
+
+ if (page_ref_count(page) > 1)
+ return page;
+ }
+ return NULL;
+}
+
/*
* Find radix tree entry at given index. If it points to an exceptional entry,
* return it with the radix tree entry locked. If the radix tree doesn't
@@ -492,6 +505,90 @@ restart:
return entry;
}
+/**
+ * dax_layout_busy_page - find first pinned page in @mapping
+ * @mapping: address space to scan for a page with ref count > 1
+ *
+ * DAX requires ZONE_DEVICE mapped pages. These pages are never
+ * 'onlined' to the page allocator so they are considered idle when
+ * page->count == 1. A filesystem uses this interface to determine if
+ * any page in the mapping is busy, i.e. for DMA, or other
+ * get_user_pages() usages.
+ *
+ * It is expected that the filesystem is holding locks to block the
+ * establishment of new mappings in this address_space. I.e. it expects
+ * to be able to run unmap_mapping_range() and subsequently not race
+ * mapping_mapped() becoming true.
+ */
+struct page *dax_layout_busy_page(struct address_space *mapping)
+{
+ pgoff_t indices[PAGEVEC_SIZE];
+ struct page *page = NULL;
+ struct pagevec pvec;
+ pgoff_t index, end;
+ unsigned i;
+
+ /*
+ * In the 'limited' case get_user_pages() for dax is disabled.
+ */
+ if (IS_ENABLED(CONFIG_FS_DAX_LIMITED))
+ return NULL;
+
+ if (!dax_mapping(mapping) || !mapping_mapped(mapping))
+ return NULL;
+
+ pagevec_init(&pvec);
+ index = 0;
+ end = -1;
+
+ /*
+ * If we race get_user_pages_fast() here either we'll see the
+ * elevated page count in the pagevec_lookup and wait, or
+ * get_user_pages_fast() will see that the page it took a reference
+ * against is no longer mapped in the page tables and bail to the
+ * get_user_pages() slow path. The slow path is protected by
+ * pte_lock() and pmd_lock(). New references are not taken without
+ * holding those locks, and unmap_mapping_range() will not zero the
+ * pte or pmd without holding the respective lock, so we are
+ * guaranteed to either see new references or prevent new
+ * references from being established.
+ */
+ unmap_mapping_range(mapping, 0, 0, 1);
+
+ while (index < end && pagevec_lookup_entries(&pvec, mapping, index,
+ min(end - index, (pgoff_t)PAGEVEC_SIZE),
+ indices)) {
+ for (i = 0; i < pagevec_count(&pvec); i++) {
+ struct page *pvec_ent = pvec.pages[i];
+ void *entry;
+
+ index = indices[i];
+ if (index >= end)
+ break;
+
+ if (!radix_tree_exceptional_entry(pvec_ent))
+ continue;
+
+ xa_lock_irq(&mapping->i_pages);
+ entry = get_unlocked_mapping_entry(mapping, index, NULL);
+ if (entry)
+ page = dax_busy_page(entry);
+ put_unlocked_mapping_entry(mapping, index, entry);
+ xa_unlock_irq(&mapping->i_pages);
+ if (page)
+ break;
+ }
+ pagevec_remove_exceptionals(&pvec);
+ pagevec_release(&pvec);
+ index++;
+
+ if (page)
+ break;
+ }
+ return page;
+}
+EXPORT_SYMBOL_GPL(dax_layout_busy_page);
+
static int __dax_invalidate_mapping_entry(struct address_space *mapping,
pgoff_t index, bool trunc)
{
@@ -912,7 +1009,6 @@ static int dax_load_hole(struct address_space *mapping, void *entry,
unsigned long vaddr = vmf->address;
int ret = VM_FAULT_NOPAGE;
struct page *zero_page;
- void *entry2;
pfn_t pfn;
zero_page = ZERO_PAGE(0);
@@ -922,13 +1018,8 @@ static int dax_load_hole(struct address_space *mapping, void *entry,
}
pfn = page_to_pfn_t(zero_page);
- entry2 = dax_insert_mapping_entry(mapping, vmf, entry, pfn,
- RADIX_DAX_ZERO_PAGE, false);
- if (IS_ERR(entry2)) {
- ret = VM_FAULT_SIGBUS;
- goto out;
- }
-
+ dax_insert_mapping_entry(mapping, vmf, entry, pfn, RADIX_DAX_ZERO_PAGE,
+ false);
vm_insert_mixed(vmf->vma, vaddr, pfn);
out:
trace_dax_load_hole(inode, vmf, ret);
@@ -1240,10 +1331,6 @@ static int dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
entry = dax_insert_mapping_entry(mapping, vmf, entry, pfn,
0, write && !sync);
- if (IS_ERR(entry)) {
- error = PTR_ERR(entry);
- goto error_finish_iomap;
- }
/*
* If we are doing synchronous page fault and inode needs fsync,
@@ -1327,8 +1414,6 @@ static int dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap,
pfn = page_to_pfn_t(zero_page);
ret = dax_insert_mapping_entry(mapping, vmf, entry, pfn,
RADIX_DAX_PMD | RADIX_DAX_ZERO_PAGE, false);
- if (IS_ERR(ret))
- goto fallback;
ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd);
if (!pmd_none(*(vmf->pmd))) {
@@ -1450,8 +1535,6 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
entry = dax_insert_mapping_entry(mapping, vmf, entry, pfn,
RADIX_DAX_PMD, write && !sync);
- if (IS_ERR(entry))
- goto finish_iomap;
/*
* If we are doing synchronous page fault and inode needs fsync,
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index e70fb8ccecea..19b0c3e0e232 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -312,7 +312,7 @@ restart:
if (error <= 0)
return error;
- error = xfs_break_layouts(inode, iolock);
+ error = xfs_break_layouts(inode, iolock, BREAK_WRITE);
if (error)
return error;
@@ -718,6 +718,69 @@ buffered:
return ret;
}
+static void
+xfs_wait_dax_page(
+ struct inode *inode,
+ bool *did_unlock)
+{
+ struct xfs_inode *ip = XFS_I(inode);
+
+ *did_unlock = true;
+ xfs_iunlock(ip, XFS_MMAPLOCK_EXCL);
+ schedule();
+ xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
+}
+
+static int
+xfs_break_dax_layouts(
+ struct inode *inode,
+ uint iolock,
+ bool *did_unlock)
+{
+ struct page *page;
+
+ ASSERT(xfs_isilocked(XFS_I(inode), XFS_MMAPLOCK_EXCL));
+
+ page = dax_layout_busy_page(inode->i_mapping);
+ if (!page)
+ return 0;
+
+ return ___wait_var_event(&page->_refcount,
+ atomic_read(&page->_refcount) == 1, TASK_INTERRUPTIBLE,
+ 0, 0, xfs_wait_dax_page(inode, did_unlock));
+}
+
+int
+xfs_break_layouts(
+ struct inode *inode,
+ uint *iolock,
+ enum layout_break_reason reason)
+{
+ bool retry;
+ int error;
+
+ ASSERT(xfs_isilocked(XFS_I(inode), XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL));
+
+ do {
+ retry = false;
+ switch (reason) {
+ case BREAK_UNMAP:
+ error = xfs_break_dax_layouts(inode, *iolock, &retry);
+ if (error || retry)
+ break;
+ /* fall through */
+ case BREAK_WRITE:
+ error = xfs_break_leased_layouts(inode, iolock, &retry);
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ error = -EINVAL;
+ }
+ } while (error == 0 && retry);
+
+ return error;
+}
+
#define XFS_FALLOC_FL_SUPPORTED \
(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \
FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE | \
@@ -734,7 +797,7 @@ xfs_file_fallocate(
struct xfs_inode *ip = XFS_I(inode);
long error;
enum xfs_prealloc_flags flags = 0;
- uint iolock = XFS_IOLOCK_EXCL;
+ uint iolock = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
loff_t new_size = 0;
bool do_file_insert = false;
@@ -744,13 +807,10 @@ xfs_file_fallocate(
return -EOPNOTSUPP;
xfs_ilock(ip, iolock);
- error = xfs_break_layouts(inode, &iolock);
+ error = xfs_break_layouts(inode, &iolock, BREAK_UNMAP);
if (error)
goto out_unlock;
- xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
- iolock |= XFS_MMAPLOCK_EXCL;
-
if (mode & FALLOC_FL_PUNCH_HOLE) {
error = xfs_free_file_space(ip, offset, len);
if (error)
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 1eebc53df7d7..e5b849815ce1 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -379,6 +379,20 @@ static inline void xfs_ifunlock(struct xfs_inode *ip)
>> XFS_ILOCK_SHIFT)
/*
+ * Layouts are broken in the BREAK_WRITE case to ensure that
+ * layout-holders do not collide with local writes. Additionally,
+ * layouts are broken in the BREAK_UNMAP case to make sure the
+ * layout-holder has a consistent view of the file's extent map. While
+ * BREAK_WRITE breaks can be satisfied by recalling FL_LAYOUT leases,
+ * BREAK_UNMAP breaks additionally require waiting for busy dax-pages to
+ * go idle.
+ */
+enum layout_break_reason {
+ BREAK_WRITE,
+ BREAK_UNMAP,
+};
+
+/*
* For multiple groups support: if S_ISGID bit is set in the parent
* directory, group of new file is set to that of the parent, and
* new subdirectory gets S_ISGID bit from parent.
@@ -443,6 +457,8 @@ enum xfs_prealloc_flags {
int xfs_update_prealloc_flags(struct xfs_inode *ip,
enum xfs_prealloc_flags flags);
+int xfs_break_layouts(struct inode *inode, uint *iolock,
+ enum layout_break_reason reason);
/* from xfs_iops.c */
extern void xfs_setup_inode(struct xfs_inode *ip);
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 89fb1eb80aae..91e73d663099 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -39,7 +39,6 @@
#include "xfs_icache.h"
#include "xfs_symlink.h"
#include "xfs_trans.h"
-#include "xfs_pnfs.h"
#include "xfs_acl.h"
#include "xfs_btree.h"
#include <linux/fsmap.h>
@@ -614,7 +613,7 @@ xfs_ioc_space(
struct xfs_inode *ip = XFS_I(inode);
struct iattr iattr;
enum xfs_prealloc_flags flags = 0;
- uint iolock = XFS_IOLOCK_EXCL;
+ uint iolock = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
int error;
/*
@@ -644,13 +643,10 @@ xfs_ioc_space(
return error;
xfs_ilock(ip, iolock);
- error = xfs_break_layouts(inode, &iolock);
+ error = xfs_break_layouts(inode, &iolock, BREAK_UNMAP);
if (error)
goto out_unlock;
- xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
- iolock |= XFS_MMAPLOCK_EXCL;
-
switch (bf->l_whence) {
case 0: /*SEEK_SET*/
break;
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index a3ed3c811dfa..ce0c1f9466a8 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -37,7 +37,6 @@
#include "xfs_da_btree.h"
#include "xfs_dir2.h"
#include "xfs_trans_space.h"
-#include "xfs_pnfs.h"
#include "xfs_iomap.h"
#include <linux/capability.h>
@@ -1030,14 +1029,19 @@ xfs_vn_setattr(
int error;
if (iattr->ia_valid & ATTR_SIZE) {
- struct xfs_inode *ip = XFS_I(d_inode(dentry));
- uint iolock = XFS_IOLOCK_EXCL;
+ struct inode *inode = d_inode(dentry);
+ struct xfs_inode *ip = XFS_I(inode);
+ uint iolock;
- error = xfs_break_layouts(d_inode(dentry), &iolock);
- if (error)
+ xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
+ iolock = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
+
+ error = xfs_break_layouts(inode, &iolock, BREAK_UNMAP);
+ if (error) {
+ xfs_iunlock(ip, XFS_MMAPLOCK_EXCL);
return error;
+ }
- xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
error = xfs_vn_setattr_size(dentry, iattr);
xfs_iunlock(ip, XFS_MMAPLOCK_EXCL);
} else {
diff --git a/fs/xfs/xfs_pnfs.c b/fs/xfs/xfs_pnfs.c
index aa6c5c193f45..f44c3599527d 100644
--- a/fs/xfs/xfs_pnfs.c
+++ b/fs/xfs/xfs_pnfs.c
@@ -31,19 +31,20 @@
* rules in the page fault path we don't bother.
*/
int
-xfs_break_layouts(
+xfs_break_leased_layouts(
struct inode *inode,
- uint *iolock)
+ uint *iolock,
+ bool *did_unlock)
{
struct xfs_inode *ip = XFS_I(inode);
int error;
- ASSERT(xfs_isilocked(ip, XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL));
-
while ((error = break_layout(inode, false) == -EWOULDBLOCK)) {
xfs_iunlock(ip, *iolock);
+ *did_unlock = true;
error = break_layout(inode, true);
- *iolock = XFS_IOLOCK_EXCL;
+ *iolock &= ~XFS_IOLOCK_SHARED;
+ *iolock |= XFS_IOLOCK_EXCL;
xfs_ilock(ip, *iolock);
}
@@ -120,8 +121,8 @@ xfs_fs_map_blocks(
* Lock out any other I/O before we flush and invalidate the pagecache,
* and then hand out a layout to the remote system. This is very
* similar to direct I/O, except that the synchronization is much more
- * complicated. See the comment near xfs_break_layouts for a detailed
- * explanation.
+ * complicated. See the comment near xfs_break_leased_layouts
+ * for a detailed explanation.
*/
xfs_ilock(ip, XFS_IOLOCK_EXCL);
diff --git a/fs/xfs/xfs_pnfs.h b/fs/xfs/xfs_pnfs.h
index bf45951e28fe..940c6c2ad88c 100644
--- a/fs/xfs/xfs_pnfs.h
+++ b/fs/xfs/xfs_pnfs.h
@@ -9,10 +9,11 @@ int xfs_fs_map_blocks(struct inode *inode, loff_t offset, u64 length,
int xfs_fs_commit_blocks(struct inode *inode, struct iomap *maps, int nr_maps,
struct iattr *iattr);
-int xfs_break_layouts(struct inode *inode, uint *iolock);
+int xfs_break_leased_layouts(struct inode *inode, uint *iolock,
+ bool *did_unlock);
#else
static inline int
-xfs_break_layouts(struct inode *inode, uint *iolock)
+xfs_break_leased_layouts(struct inode *inode, uint *iolock, bool *did_unlock)
{
return 0;
}