I looked more closely at the assumption that ext4_write_begin() holds i_mutex. This is guaranteed by Documentation/filesystems/Locking, which notes that write_begin() and write_end() functions hold i_mutex: PageLocked(page) i_mutex write_begin: locks the page yes write_end: yes, unlocks yes So the bug is that ext4_symlink() calls __page_symlink(); __page_symlink() calls pagecache_write_begin() which calls write_begin(), without taking i_mutex. So we can fix this by taking i_mutex in ext4_symlink(), but I think it would be better to take the i_mutex in __page_symlink(), since it would then address a violation of the locking rules for all file systems. Al, do you agree? - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
