Attempting to unshare extents beyond EOF will trigger the need zeroing case, which in turn triggers a warning. Therefore, let's skip the unshare process if blocks are beyond EOF. This patch passed the xfstests using './check -g quick', without causing any additional failure Reported-and-tested-by: syzbot+296b1c84b9cbf306e5a0@xxxxxxxxxxxxxxxxxxxxxxxxx Closes: https://syzkaller.appspot.com/bug?extid=296b1c84b9cbf306e5a0 Fixes: 32a38a499104 ("iomap: use write_begin to read pages to unshare") Inspired-by: Dave Chinner <david@xxxxxxxxxxxxx> Signed-off-by: Julian Sun <sunjunchao2870@xxxxxxxxx> --- fs/xfs/xfs_iomap.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index 72c981e3dc92..81a0514b8652 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -976,6 +976,7 @@ xfs_buffered_write_iomap_begin( int error = 0; unsigned int lockmode = XFS_ILOCK_EXCL; u64 seq; + xfs_fileoff_t eof_fsb; if (xfs_is_shutdown(mp)) return -EIO; @@ -1016,6 +1017,13 @@ xfs_buffered_write_iomap_begin( if (eof) imap.br_startoff = end_fsb; /* fake hole until the end */ + /* Don't try to unshare any blocks beyond EOF. */ + eof_fsb = XFS_B_TO_FSB(mp, XFS_ISIZE(ip)); + if (flags & IOMAP_UNSHARE && end_fsb > eof_fsb) { + xfs_trim_extent(&imap, offset_fsb, eof_fsb - offset_fsb); + end_fsb = eof_fsb; + } + /* We never need to allocate blocks for zeroing or unsharing a hole. */ if ((flags & (IOMAP_UNSHARE | IOMAP_ZERO)) && imap.br_startoff > offset_fsb) { @@ -1030,7 +1038,6 @@ xfs_buffered_write_iomap_begin( */ if ((flags & IOMAP_ZERO) && imap.br_startoff <= offset_fsb && isnullstartblock(imap.br_startblock)) { - xfs_fileoff_t eof_fsb = XFS_B_TO_FSB(mp, XFS_ISIZE(ip)); if (offset_fsb >= eof_fsb) goto convert_delay; -- 2.39.2
