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-rw-r--r--fs/dax.c21
-rw-r--r--fs/ext2/file.c4
-rw-r--r--fs/ext4/file.c16
-rw-r--r--fs/ext4/inode.c21
-rw-r--r--include/linux/fs.h6
5 files changed, 42 insertions, 26 deletions
diff --git a/fs/dax.c b/fs/dax.c
index 6f65f00e58ec..4bb5b7cd5dfd 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -309,14 +309,11 @@ static int dax_insert_mapping(struct inode *inode, struct buffer_head *bh,
out:
i_mmap_unlock_read(mapping);
- if (bh->b_end_io)
- bh->b_end_io(bh, 1);
-
return error;
}
static int do_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
- get_block_t get_block)
+ get_block_t get_block, dax_iodone_t complete_unwritten)
{
struct file *file = vma->vm_file;
struct address_space *mapping = file->f_mapping;
@@ -417,7 +414,19 @@ static int do_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
page_cache_release(page);
}
+ /*
+ * If we successfully insert the new mapping over an unwritten extent,
+ * we need to ensure we convert the unwritten extent. If there is an
+ * error inserting the mapping, the filesystem needs to leave it as
+ * unwritten to prevent exposure of the stale underlying data to
+ * userspace, but we still need to call the completion function so
+ * the private resources on the mapping buffer can be released. We
+ * indicate what the callback should do via the uptodate variable, same
+ * as for normal BH based IO completions.
+ */
error = dax_insert_mapping(inode, &bh, vma, vmf);
+ if (buffer_unwritten(&bh))
+ complete_unwritten(&bh, !error);
out:
if (error == -ENOMEM)
@@ -445,7 +454,7 @@ static int do_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
* fault handler for DAX files.
*/
int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
- get_block_t get_block)
+ get_block_t get_block, dax_iodone_t complete_unwritten)
{
int result;
struct super_block *sb = file_inode(vma->vm_file)->i_sb;
@@ -454,7 +463,7 @@ int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
sb_start_pagefault(sb);
file_update_time(vma->vm_file);
}
- result = do_dax_fault(vma, vmf, get_block);
+ result = do_dax_fault(vma, vmf, get_block, complete_unwritten);
if (vmf->flags & FAULT_FLAG_WRITE)
sb_end_pagefault(sb);
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
index 3a0a6c6406d0..3b57c9f83c9b 100644
--- a/fs/ext2/file.c
+++ b/fs/ext2/file.c
@@ -28,12 +28,12 @@
#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);
+ return dax_fault(vma, vmf, ext2_get_block, NULL);
}
static int ext2_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
{
- return dax_mkwrite(vma, vmf, ext2_get_block);
+ return dax_mkwrite(vma, vmf, ext2_get_block, NULL);
}
static const struct vm_operations_struct ext2_dax_vm_ops = {
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 0613c256c344..f713cfcc43a2 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -192,15 +192,27 @@ 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 > 16GB. 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)
{
- return dax_fault(vma, vmf, ext4_get_block);
+ return dax_fault(vma, vmf, ext4_get_block, ext4_end_io_unwritten);
/* 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);
+ return dax_mkwrite(vma, vmf, ext4_get_block, ext4_end_io_unwritten);
}
static const struct vm_operations_struct ext4_dax_vm_ops = {
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 55b187c3bac1..7c38ed3494cb 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -656,18 +656,6 @@ has_zeroout:
return retval;
}
-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 > 16GB. 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);
-}
-
/* Maximum number of blocks we map for direct IO at once. */
#define DIO_MAX_BLOCKS 4096
@@ -705,10 +693,15 @@ static int _ext4_get_block(struct inode *inode, sector_t iblock,
map_bh(bh, inode->i_sb, map.m_pblk);
bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags;
- if (IS_DAX(inode) && buffer_unwritten(bh) && !io_end) {
+ if (IS_DAX(inode) && buffer_unwritten(bh)) {
+ /*
+ * dgc: I suspect unwritten conversion on ext4+DAX is
+ * fundamentally broken here when there are concurrent
+ * read/write in progress on this inode.
+ */
+ WARN_ON_ONCE(io_end);
bh->b_assoc_map = inode->i_mapping;
bh->b_private = (void *)(unsigned long)iblock;
- bh->b_end_io = ext4_end_io_unwritten;
}
if (io_end && io_end->flag & EXT4_IO_END_UNWRITTEN)
set_buffer_defer_completion(bh);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 35ec87e490b1..c9b4cca9e08d 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -70,6 +70,7 @@ typedef int (get_block_t)(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create);
typedef void (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
ssize_t bytes, void *private);
+typedef void (dax_iodone_t)(struct buffer_head *bh_map, int uptodate);
#define MAY_EXEC 0x00000001
#define MAY_WRITE 0x00000002
@@ -2627,9 +2628,10 @@ ssize_t dax_do_io(struct kiocb *, struct inode *, struct iov_iter *, loff_t,
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);
-int dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t);
+int dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t,
+ dax_iodone_t);
int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *);
-#define dax_mkwrite(vma, vmf, gb) dax_fault(vma, vmf, gb)
+#define dax_mkwrite(vma, vmf, gb, iod) dax_fault(vma, vmf, gb, iod)
#ifdef CONFIG_BLOCK
typedef void (dio_submit_t)(int rw, struct bio *bio, struct inode *inode,