Messages in this thread Patch in this message |  | | From | OGAWA Hirofumi <> | Subject | mnt_want_write_file() has problem? | Date | Mon, 03 Aug 2009 06:36:27 +0900 |
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Hi,
While I'm reading some code, I suspected that mnt_want_write_file() may have wrong assumption. I think mnt_want_write_file() is assuming it increments ->mnt_writers if (file->f_mode & FMODE_WRITE). But, if it's special_file(), it is false?
Sorry, I'm still not checking all of those though. E.g. I'm thinking the below.
static inline int __get_file_write_access(struct inode *inode, struct vfsmount *mnt) { [...] if (!special_file(inode->i_mode)) { /* * Balanced in __fput() */ error = mnt_want_write(mnt); if (error) put_write_access(inode); } return error; }
Thanks. -- OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> ---
fs/namespace.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff -puN fs/namespace.c~mnt_want_write-wrong-assume fs/namespace.c --- linux-2.6/fs/namespace.c~mnt_want_write-wrong-assume 2009-08-03 04:33:35.000000000 +0900 +++ linux-2.6-hirofumi/fs/namespace.c 2009-08-03 04:31:34.000000000 +0900 @@ -316,7 +316,8 @@ EXPORT_SYMBOL_GPL(mnt_clone_write); */ int mnt_want_write_file(struct file *file) { - if (!(file->f_mode & FMODE_WRITE)) + struct inode *inode = file->f_dentry->d_inode; + if (!(file->f_mode & FMODE_WRITE) || special_file(inode->i_mode)) return mnt_want_write(file->f_path.mnt); else return mnt_clone_write(file->f_path.mnt); _
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