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authorJan Kara <jack@suse.com>2015-12-07 15:10:44 -0500
committerTheodore Ts'o <tytso@mit.edu>2015-12-07 15:10:44 -0500
commitba5843f51d468644b094674c0317c9ab95632caa (patch)
treee2ab7e39a4eff12af5bc9f2b14dafc0f08731727 /fs/ext4/file.c
parentc86d8db33a922da808a5560aa15ed663a9569b37 (diff)
ext4: use pre-zeroed blocks for DAX page faults
Make DAX fault path use pre-zeroed blocks to avoid races with extent conversion and zeroing when two page faults to the same block happen. Signed-off-by: Jan Kara <jack@suse.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/file.c')
-rw-r--r--fs/ext4/file.c20
1 files changed, 3 insertions, 17 deletions
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 0d24ebcd7c9e..749b222e6498 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -193,18 +193,6 @@ out:
}
#ifdef CONFIG_FS_DAX
-static void ext4_end_io_unwritten(struct buffer_head *bh, int uptodate)
-{
- struct inode *inode = bh->b_assoc_map->host;
- /* XXX: breaks on 32-bit > 16TB. Is that even supported? */
- loff_t offset = (loff_t)(uintptr_t)bh->b_private << inode->i_blkbits;
- int err;
- if (!uptodate)
- return;
- WARN_ON(!buffer_unwritten(bh));
- err = ext4_convert_unwritten_extents(NULL, inode, offset, bh->b_size);
-}
-
static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
int result;
@@ -225,8 +213,7 @@ static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
if (IS_ERR(handle))
result = VM_FAULT_SIGBUS;
else
- result = __dax_fault(vma, vmf, ext4_get_block_dax,
- ext4_end_io_unwritten);
+ result = __dax_fault(vma, vmf, ext4_dax_mmap_get_block, NULL);
if (write) {
if (!IS_ERR(handle))
@@ -262,7 +249,7 @@ static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
result = VM_FAULT_SIGBUS;
else
result = __dax_pmd_fault(vma, addr, pmd, flags,
- ext4_get_block_dax, ext4_end_io_unwritten);
+ ext4_dax_mmap_get_block, NULL);
if (write) {
if (!IS_ERR(handle))
@@ -283,8 +270,7 @@ static int ext4_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
sb_start_pagefault(inode->i_sb);
file_update_time(vma->vm_file);
down_read(&EXT4_I(inode)->i_mmap_sem);
- err = __dax_mkwrite(vma, vmf, ext4_get_block_dax,
- ext4_end_io_unwritten);
+ err = __dax_mkwrite(vma, vmf, ext4_dax_mmap_get_block, NULL);
up_read(&EXT4_I(inode)->i_mmap_sem);
sb_end_pagefault(inode->i_sb);