While handling punch-hole fallocate, it's useless to truncate page cache before removing the range from extent tree (or block map in indirect case) because page cache can be re-populated (by read-ahead or read(2) or mmap-ed read) immediately after truncating page cache, but before updating extent tree (or block map). In that case the user will see stale data even after fallocate is completed.
Signed-off-by: Maxim Patlasov <[email protected]> --- fs/ext4/inode.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 0d424d7..6b71116 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3564,14 +3564,6 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length) } - first_block_offset = round_up(offset, sb->s_blocksize); - last_block_offset = round_down((offset + length), sb->s_blocksize) - 1; - - /* Now release the pages and zero block aligned part of pages*/ - if (last_block_offset > first_block_offset) - truncate_pagecache_range(inode, first_block_offset, - last_block_offset); - /* Wait all existing dio workers, newcomers will block on i_mutex */ ext4_inode_block_unlocked_dio(inode); inode_dio_wait(inode); @@ -3621,6 +3613,15 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length) up_write(&EXT4_I(inode)->i_data_sem); if (IS_SYNC(inode)) ext4_handle_sync(handle); + + first_block_offset = round_up(offset, sb->s_blocksize); + last_block_offset = round_down((offset + length), sb->s_blocksize) - 1; + + /* Now release the pages and zero block aligned part of pages */ + if (last_block_offset > first_block_offset) + truncate_pagecache_range(inode, first_block_offset, + last_block_offset); + inode->i_mtime = inode->i_ctime = ext4_current_time(inode); ext4_mark_inode_dirty(handle, inode); out_stop: -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
