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authorMasatake YAMATO <yamato@redhat.com>2008-02-04 22:29:31 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-05 09:44:19 -0800
commitb5beb1caff4ce063e6e2dc13f23b80eeef4e9782 (patch)
treef3fcf8baafa1e9891edd7f16ffafd768c41c29d6 /mm/fadvise.c
parente6f3602d2c58815775b2a293cec6650622236169 (diff)
downloadlinux-b5beb1caff4ce063e6e2dc13f23b80eeef4e9782.tar.gz
check ADVICE of fadvise64_64 even if get_xip_page is given
I've written some test programs in ltp project. During writing I met an problem which I cannot solve in user land. So I wrote a patch for linux kernel. Please, include this patch if acceptable. The test program tests the 4th parameter of fadvise64_64: long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice); My test case calls fadvise64_64 with invalid advice value and checks errno is set to EINVAL. About the advice parameter man page says: ... Permissible values for advice include: POSIX_FADV_NORMAL ... POSIX_FADV_SEQUENTIAL ... POSIX_FADV_RANDOM ... POSIX_FADV_NOREUSE ... POSIX_FADV_WILLNEED ... POSIX_FADV_DONTNEED ... ERRORS ... EINVAL An invalid value was specified for advice. However, I got a bug report that the system call invocations in my test case returned 0 unexpectedly. I've inspected the kernel code: asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice) { struct file *file = fget(fd); struct address_space *mapping; struct backing_dev_info *bdi; loff_t endbyte; /* inclusive */ pgoff_t start_index; pgoff_t end_index; unsigned long nrpages; int ret = 0; if (!file) return -EBADF; if (S_ISFIFO(file->f_path.dentry->d_inode->i_mode)) { ret = -ESPIPE; goto out; } mapping = file->f_mapping; if (!mapping || len < 0) { ret = -EINVAL; goto out; } if (mapping->a_ops->get_xip_page) /* no bad return value, but ignore advice */ goto out; ... out: fput(file); return ret; } I found the advice parameter is just ignored in the case mapping->a_ops->get_xip_page is given. This behavior is different from what is written on the man page. Is this o.k.? get_xip_page is given if CONFIG_EXT2_FS_XIP is true. Anyway I cannot find the easy way to detect get_xip_page field is given or CONFIG_EXT2_FS_XIP is true from the user space. I propose the following patch which checks the advice parameter even if get_xip_page is given. Signed-off-by: Masatake YAMATO <yamato@redhat.com> Acked-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/fadvise.c')
-rw-r--r--mm/fadvise.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/mm/fadvise.c b/mm/fadvise.c
index 0df4c899e97..3c0f1e99f5e 100644
--- a/mm/fadvise.c
+++ b/mm/fadvise.c
@@ -49,9 +49,21 @@ asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
goto out;
}
- if (mapping->a_ops->get_xip_page)
- /* no bad return value, but ignore advice */
+ if (mapping->a_ops->get_xip_page) {
+ switch (advice) {
+ case POSIX_FADV_NORMAL:
+ case POSIX_FADV_RANDOM:
+ case POSIX_FADV_SEQUENTIAL:
+ case POSIX_FADV_WILLNEED:
+ case POSIX_FADV_NOREUSE:
+ case POSIX_FADV_DONTNEED:
+ /* no bad return value, but ignore advice */
+ break;
+ default:
+ ret = -EINVAL;
+ }
goto out;
+ }
/* Careful about overflows. Len == 0 means "as much as possible" */
endbyte = offset + len;