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Subject[ 28/47] target: Fix bug in handling of FILEIO + block_device resize ops
3.3-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Nicholas Bellinger <nab@linux-iscsi.org>

commit cd9323fd68aee3c1c6b5b21e5746c9d1b586fb58 upstream.

This patch fixes a bug in the handling of FILEIO w/ underlying block_device
resize operations where the original fd_dev->fd_dev_size was incorrectly being
used in fd_get_blocks() for READ_CAPACITY response payloads.

This patch avoids using fd_dev->fd_dev_size for FILEIO devices with
an underlying block_device, and instead changes fd_get_blocks() to
get the sector count directly from i_size_read() as recommended by hch.

Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/target/target_core_file.c | 22 ++++++++++++++++------
1 file changed, 16 insertions(+), 6 deletions(-)

--- a/drivers/target/target_core_file.c
+++ b/drivers/target/target_core_file.c
@@ -169,6 +169,7 @@ static struct se_device *fd_create_virtd
inode = file->f_mapping->host;
if (S_ISBLK(inode->i_mode)) {
struct request_queue *q;
+ unsigned long long dev_size;
/*
* Setup the local scope queue_limits from struct request_queue->limits
* to pass into transport_add_device_to_core_hba() as struct se_dev_limits.
@@ -183,13 +184,12 @@ static struct se_device *fd_create_virtd
* one (1) logical sector from underlying struct block_device
*/
fd_dev->fd_block_size = bdev_logical_block_size(inode->i_bdev);
- fd_dev->fd_dev_size = (i_size_read(file->f_mapping->host) -
+ dev_size = (i_size_read(file->f_mapping->host) -
fd_dev->fd_block_size);

pr_debug("FILEIO: Using size: %llu bytes from struct"
" block_device blocks: %llu logical_block_size: %d\n",
- fd_dev->fd_dev_size,
- div_u64(fd_dev->fd_dev_size, fd_dev->fd_block_size),
+ dev_size, div_u64(dev_size, fd_dev->fd_block_size),
fd_dev->fd_block_size);
} else {
if (!(fd_dev->fbd_flags & FBDF_HAS_SIZE)) {
@@ -605,10 +605,20 @@ static u32 fd_get_device_type(struct se_
static sector_t fd_get_blocks(struct se_device *dev)
{
struct fd_dev *fd_dev = dev->dev_ptr;
- unsigned long long blocks_long = div_u64(fd_dev->fd_dev_size,
- dev->se_sub_dev->se_dev_attrib.block_size);
+ struct file *f = fd_dev->fd_file;
+ struct inode *i = f->f_mapping->host;
+ unsigned long long dev_size;
+ /*
+ * When using a file that references an underlying struct block_device,
+ * ensure dev_size is always based on the current inode size in order
+ * to handle underlying block_device resize operations.
+ */
+ if (S_ISBLK(i->i_mode))
+ dev_size = (i_size_read(i) - fd_dev->fd_block_size);
+ else
+ dev_size = fd_dev->fd_dev_size;

- return blocks_long;
+ return div_u64(dev_size, dev->se_sub_dev->se_dev_attrib.block_size);
}

static struct se_subsystem_api fileio_template = {



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