Hi, When reading a file that ends exactly on a page boundary, reading an entire file and relying on read() = 0 to indicate the EOF (such as is done by cat and grep) causes readpage() to be invoked on the filesystem for a page immediately beyond EOF. Is it worth making generic_file_aio_read() note that the EOF has been reached and return 0 immediately, rather than trying to read over the EOF? The problem with doing that might be that filesystems such as NFS2/3 might occasionally miss the fact that a file has been extended on the server. The call chain I see on my testbox is this: [<ffffffffa0348382>] ? nfs_readpage+0x138/0x16a [nfs] [<ffffffff8026fa15>] ? generic_file_aio_read+0x399/0x55a [<ffffffff80294199>] ? do_sync_read+0xce/0x113 [<ffffffff80243cb8>] ? autoremove_wake_function+0x0/0x2e [<ffffffff80355fe5>] ? file_has_perm+0x82/0x8b [<ffffffff80294cd1>] ? vfs_read+0xaa/0x153 [<ffffffff80294e36>] ? sys_read+0x45/0x6e [<ffffffff8020adeb>] ? system_call_fastpath+0x16/0x1b nfs_readpage() is asked to read page 0x6400 from a 100MB file - which doesn't exist, and so calls nfs_return_empty_page(). David -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
