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Commit cf17fea6 authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Theodore Ts'o
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ext4: Properly update i_disksize. 



With delayed allocation we use i_data_sem to update i_disksize.  We need
to update i_disksize only if the new size specified is greater than the
current value and we need to make sure we don't race with other
i_disksize update.  With delayed allocation we will switch to the
write_begin function for non-delayed allocation if we are low on free
blocks.  This means the write_begin function for non-delayed allocation
also needs to use the same locking.

We also need to check and update i_disksize even if the new size is less
that inode.i_size because of delayed allocation.

Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent ae4d5372

fs/ext4/ext4.h

+11 −0
Original line number Diff line number Diff line
@@ -1218,6 +1218,17 @@ do { \ 
#define EXT4_FREEBLOCKS_WATERMARK 0

#endif



static inline void ext4_update_i_disksize(struct inode *inode, loff_t newsize)

{

	/*

	 * XXX: replace with spinlock if seen contended -bzzz

	 */

	down_write(&EXT4_I(inode)->i_data_sem);

	if (newsize > EXT4_I(inode)->i_disksize)

		EXT4_I(inode)->i_disksize = newsize;

	up_write(&EXT4_I(inode)->i_data_sem);

	return ;

}



/*

 * Inodes and files operations

fs/ext4/extents.c

+5 −4
Original line number Diff line number Diff line
@@ -2878,10 +2878,11 @@ static void ext4_falloc_update_inode(struct inode *inode, 
	 * Update only when preallocation was requested beyond

	 * the file size.

	 */

	if (!(mode & FALLOC_FL_KEEP_SIZE) &&

				new_size > i_size_read(inode)) {

	if (!(mode & FALLOC_FL_KEEP_SIZE)) {

		if (new_size > i_size_read(inode))

			i_size_write(inode, new_size);

		EXT4_I(inode)->i_disksize = new_size;

		if (new_size > EXT4_I(inode)->i_disksize)

			ext4_update_i_disksize(inode, new_size);

	}



}

fs/ext4/inode.c

+30 −24
Original line number Diff line number Diff line
@@ -1434,16 +1434,18 @@ static int ext4_ordered_write_end(struct file *file, 
	ret = ext4_jbd2_file_inode(handle, inode);



	if (ret == 0) {

		/*

		 * generic_write_end() will run mark_inode_dirty() if i_size

		 * changes.  So let's piggyback the i_disksize mark_inode_dirty

		 * into that.

		 */

		loff_t new_i_size;



		new_i_size = pos + copied;

		if (new_i_size > EXT4_I(inode)->i_disksize)

			EXT4_I(inode)->i_disksize = new_i_size;

		if (new_i_size > EXT4_I(inode)->i_disksize) {

			ext4_update_i_disksize(inode, new_i_size);

			/* We need to mark inode dirty even if

			 * new_i_size is less that inode->i_size

			 * bu greater than i_disksize.(hint delalloc)

			 */

			ext4_mark_inode_dirty(handle, inode);

		}



		ret2 = generic_write_end(file, mapping, pos, len, copied,

							page, fsdata);

		copied = ret2;
@@ -1468,8 +1470,14 @@ static int ext4_writeback_write_end(struct file *file, 
	loff_t new_i_size;



	new_i_size = pos + copied;

	if (new_i_size > EXT4_I(inode)->i_disksize)

		EXT4_I(inode)->i_disksize = new_i_size;

	if (new_i_size > EXT4_I(inode)->i_disksize) {

		ext4_update_i_disksize(inode, new_i_size);

		/* We need to mark inode dirty even if

		 * new_i_size is less that inode->i_size

		 * bu greater than i_disksize.(hint delalloc)

		 */

		ext4_mark_inode_dirty(handle, inode);

	}



	ret2 = generic_write_end(file, mapping, pos, len, copied,

							page, fsdata);
@@ -1494,6 +1502,7 @@ static int ext4_journalled_write_end(struct file *file, 
	int ret = 0, ret2;

	int partial = 0;

	unsigned from, to;

	loff_t new_i_size;



	from = pos & (PAGE_CACHE_SIZE - 1);

	to = from + len;
@@ -1508,11 +1517,12 @@ static int ext4_journalled_write_end(struct file *file, 
				to, &partial, write_end_fn);

	if (!partial)

		SetPageUptodate(page);

	if (pos+copied > inode->i_size)

	new_i_size = pos + copied;

	if (new_i_size > inode->i_size)

		i_size_write(inode, pos+copied);

	EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;

	if (inode->i_size > EXT4_I(inode)->i_disksize) {

		EXT4_I(inode)->i_disksize = inode->i_size;

	if (new_i_size > EXT4_I(inode)->i_disksize) {

		ext4_update_i_disksize(inode, new_i_size);

		ret2 = ext4_mark_inode_dirty(handle, inode);

		if (!ret)

			ret = ret2;
@@ -2227,19 +2237,10 @@ static int ext4_da_get_block_write(struct inode *inode, sector_t iblock, 
		if (disksize > i_size_read(inode))

			disksize = i_size_read(inode);

		if (disksize > EXT4_I(inode)->i_disksize) {

			/*

			 * XXX: replace with spinlock if seen contended -bzzz

			 */

			down_write(&EXT4_I(inode)->i_data_sem);

			if (disksize > EXT4_I(inode)->i_disksize)

				EXT4_I(inode)->i_disksize = disksize;

			up_write(&EXT4_I(inode)->i_data_sem);



			if (EXT4_I(inode)->i_disksize == disksize) {

			ext4_update_i_disksize(inode, disksize);

			ret = ext4_mark_inode_dirty(handle, inode);

			return ret;

		}

		}

		ret = 0;

	}

	return ret;
@@ -2654,6 +2655,11 @@ static int ext4_da_write_end(struct file *file, 
				EXT4_I(inode)->i_disksize = new_i_size;

			}

			up_write(&EXT4_I(inode)->i_data_sem);

			/* We need to mark inode dirty even if

			 * new_i_size is less that inode->i_size

			 * bu greater than i_disksize.(hint delalloc)

			 */

			ext4_mark_inode_dirty(handle, inode);

		}

	}

	ret2 = generic_write_end(file, mapping, pos, len, copied,