tree 775c6493db0b4a15cd9e33d86f8981b3e27332df
parent 19008f6dfa16d23afcd09dceaa598bb6da8de4b1
author Theodore Ts'o <tytso@mit.edu> 1409596329 -0400
committer Theodore Ts'o <tytso@mit.edu> 1409596329 -0400

ext4: fix ZERO_RANGE bug hidden by flag aliasing

We accidently aliased EXT4_EX_NOCACHE and EXT4_GET_CONVERT_UNWRITTEN
falgs, which apparently was hiding a bug that was unmasked when this
flag aliasing issue was addressed (see the subsequent commit).  The
reproduction case was:

   fsx -N 10000 -l 500000 -r 4096 -t 4096 -w 4096 -Z -R -W /vdb/junk

... which would cause fsx to report corruption in the data file.

The fix we have is a bit of an overkill, but I'd much rather be
conservative for now, and we can optimize ZERO_RANGE_FL handling
later.  The fact that we need to zap the extent_status cache for the
inode is unfortunate, but correctness is far more important than
performance.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: Namjae Jeon <namjae.jeon@samsung.com>