When we append new block just after the end of preallocated extent, the code in inode_getblk() wrongly determined we're going to use the preallocated extent which resulted in adding block into a wrong logical offset in the file. Sequence like this manifests it:

xfs_io -f -c "pwrite 0x2cacf 0xd122" -c "truncate 0x2dd6f" \ -c "pwrite 0x27fd9 0x69a9" -c "pwrite 0x32981 0x7244" <file>

The code that determined the use of preallocated extent is actually stale because udf_do_extend_file() does not create preallocation anymore so after calling that function we are sure there's no usable preallocation. Just remove the faulty condition.

CC: stable@vger.kernel.org Fixes: 16d055656814 ("udf: Discard preallocation before extending file with a hole") Signed-off-by: Jan Kara jack@suse.cz --- fs/udf/inode.c | 24 +++++++++++------------- 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/fs/udf/inode.c b/fs/udf/inode.c index 8f55b37ddcad..6826c2aa021f 100644 --- a/fs/udf/inode.c +++ b/fs/udf/inode.c @@ -742,19 +742,17 @@ static int inode_getblk(struct inode *inode, struct udf_map_rq *map) c = 0; offset = 0; count += ret; - /* We are not covered by a preallocated extent? */ - if ((laarr[0].extLength & UDF_EXTENT_FLAG_MASK) != - EXT_NOT_RECORDED_ALLOCATED) { - /* Is there any real extent? - otherwise we overwrite - * the fake one... */ - if (count) - c = !c; - laarr[c].extLength = EXT_NOT_RECORDED_NOT_ALLOCATED | - inode->i_sb->s_blocksize; - memset(&laarr[c].extLocation, 0x00, - sizeof(struct kernel_lb_addr)); - count++; - } + /* + * Is there any real extent? - otherwise we overwrite the fake + * one... + */ + if (count) + c = !c; + laarr[c].extLength = EXT_NOT_RECORDED_NOT_ALLOCATED | + inode->i_sb->s_blocksize; + memset(&laarr[c].extLocation, 0x00, + sizeof(struct kernel_lb_addr)); + count++; endnum = c + 1; lastblock = 1; } else {