This is related to another question I recently asked about storing a non-bare repository in Dropbox for easy movement between computers, so it may be helpful to read that question for background.
The gist is that the fileMode keeps reporting a diff for some number of files. I can't find a way to reproduce it consistently, but it happens frequently. What I've noticed is that the file, which has 644 permissions on both machines often reports a diff from 755 on one of the machines. This makes me think that Git believes the executable bit is set, but I can't figure out whether I can actually see how Git has that bit set.
To see what git actually thinks about your files in commits and the index, use git ls-tree <tree> and git ls-files -s <path> respectively.
By the way, it seems that git only looks at the executable bit, and assumes 644 for everything else. Look at create_ce_mode in cache.h if you want to try debugging this weird issue.
来源：https://stackoverflow.com/questions/3821263/show-the-permission-of-a-indexed-file-in-git