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Diffstat (limited to 'fs/dax.c')
-rw-r--r--fs/dax.c86
1 files changed, 62 insertions, 24 deletions
diff --git a/fs/dax.c b/fs/dax.c
index ed1619ec6537..c3e21ccfc358 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -98,9 +98,9 @@ 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)
+static ssize_t dax_io(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;
@@ -109,7 +109,7 @@ static ssize_t dax_io(int rw, struct inode *inode, struct iov_iter *iter,
void *addr;
bool hole = false;
- if (rw != WRITE)
+ if (iov_iter_rw(iter) != WRITE)
end = min(end, i_size_read(inode));
while (pos < end) {
@@ -124,7 +124,7 @@ static ssize_t dax_io(int rw, struct inode *inode, struct iov_iter *iter,
bh->b_size = PAGE_ALIGN(end - pos);
bh->b_state = 0;
retval = get_block(inode, block, bh,
- rw == WRITE);
+ iov_iter_rw(iter) == WRITE);
if (retval)
break;
if (!buffer_size_valid(bh))
@@ -137,7 +137,7 @@ static ssize_t dax_io(int rw, struct inode *inode, struct iov_iter *iter,
bh->b_size -= done;
}
- hole = (rw != WRITE) && !buffer_written(bh);
+ hole = iov_iter_rw(iter) != WRITE && !buffer_written(bh);
if (hole) {
addr = NULL;
size = bh->b_size - first;
@@ -154,8 +154,8 @@ static ssize_t dax_io(int rw, struct inode *inode, struct iov_iter *iter,
max = min(pos + size, end);
}
- if (rw == WRITE)
- len = copy_from_iter(addr, max - pos, iter);
+ if (iov_iter_rw(iter) == WRITE)
+ len = copy_from_iter_nocache(addr, max - pos, iter);
else if (!hole)
len = copy_to_iter(addr, max - pos, iter);
else
@@ -173,7 +173,6 @@ static ssize_t dax_io(int rw, struct inode *inode, struct iov_iter *iter,
/**
* 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
@@ -189,9 +188,9 @@ static ssize_t dax_io(int rw, struct inode *inode, struct iov_iter *iter,
* 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)
+ssize_t dax_do_io(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;
@@ -199,7 +198,7 @@ ssize_t dax_do_io(int rw, struct kiocb *iocb, struct inode *inode,
memset(&bh, 0, sizeof(bh));
- if ((flags & DIO_LOCKING) && (rw == READ)) {
+ if ((flags & DIO_LOCKING) && iov_iter_rw(iter) == READ) {
struct address_space *mapping = inode->i_mapping;
mutex_lock(&inode->i_mutex);
retval = filemap_write_and_wait_range(mapping, pos, end - 1);
@@ -210,17 +209,19 @@ ssize_t dax_do_io(int rw, struct kiocb *iocb, struct inode *inode,
}
/* Protects against truncate */
- atomic_inc(&inode->i_dio_count);
+ if (!(flags & DIO_SKIP_DIO_COUNT))
+ inode_dio_begin(inode);
- retval = dax_io(rw, inode, iter, pos, end, get_block, &bh);
+ retval = dax_io(inode, iter, pos, end, get_block, &bh);
- if ((flags & DIO_LOCKING) && (rw == READ))
+ if ((flags & DIO_LOCKING) && iov_iter_rw(iter) == READ)
mutex_unlock(&inode->i_mutex);
if ((retval > 0) && end_io)
end_io(iocb, pos, retval, bh.b_private);
- inode_dio_done(inode);
+ if (!(flags & DIO_SKIP_DIO_COUNT))
+ inode_dio_end(inode);
out:
return retval;
}
@@ -310,14 +311,21 @@ 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)
+/**
+ * __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. __dax_fault() assumes the caller has done all
+ * the necessary locking for the page fault to proceed successfully.
+ */
+int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
+ get_block_t get_block, dax_iodone_t complete_unwritten)
{
struct file *file = vma->vm_file;
struct address_space *mapping = file->f_mapping;
@@ -418,7 +426,19 @@ 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)
@@ -435,6 +455,7 @@ static int do_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
}
goto out;
}
+EXPORT_SYMBOL(__dax_fault);
/**
* dax_fault - handle a page fault on a DAX file
@@ -446,7 +467,7 @@ 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;
@@ -455,7 +476,7 @@ 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 = __dax_fault(vma, vmf, get_block, complete_unwritten);
if (vmf->flags & FAULT_FLAG_WRITE)
sb_end_pagefault(sb);
@@ -464,6 +485,23 @@ int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
EXPORT_SYMBOL_GPL(dax_fault);
/**
+ * dax_pfn_mkwrite - handle first write to DAX page
+ * @vma: The virtual memory area where the fault occurred
+ * @vmf: The description of the fault
+ *
+ */
+int dax_pfn_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ struct super_block *sb = file_inode(vma->vm_file)->i_sb;
+
+ sb_start_pagefault(sb);
+ file_update_time(vma->vm_file);
+ sb_end_pagefault(sb);
+ return VM_FAULT_NOPAGE;
+}
+EXPORT_SYMBOL_GPL(dax_pfn_mkwrite);
+
+/**
* 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
generated by cgit v1.2.3 (git 2.51.0) at 2025-09-25 09:02:36 +0000