Messages in this thread Patch in this message | | | Subject | [PATCH 19/20] elevate writer count for custom 'struct file' | From | Dave Hansen <> | Date | Tue, 27 Jun 2006 15:14:56 -0700 |
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Some filesystems forego the vfs and may_open() and create their own 'struct file's. Any of these users which set the write flag on the file will cause an extra mnt_drop_write() on __fput(), thus dropping the reference count too low.
These users tend to have artifical in-kernel vfsmounts which aren't really exposed to userspace and can't be remounted, but this patch is included for completeness and so that the warnings don't trip over these cases.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com> ---
lxc-dave/fs/hugetlbfs/inode.c | 2 ++ lxc-dave/mm/shmem.c | 2 ++ lxc-dave/mm/tiny-shmem.c | 2 ++ lxc-dave/net/socket.c | 3 +++ 4 files changed, 9 insertions(+)
diff -puN fs/hugetlbfs/inode.c~fix-__fput-rev2 fs/hugetlbfs/inode.c --- lxc/fs/hugetlbfs/inode.c~fix-__fput-rev2 2006-06-27 10:40:35.000000000 -0700 +++ lxc-dave/fs/hugetlbfs/inode.c 2006-06-27 10:40:35.000000000 -0700 @@ -790,6 +790,8 @@ struct file *hugetlb_zero_setup(size_t s file->f_mapping = inode->i_mapping; file->f_op = &hugetlbfs_file_operations; file->f_mode = FMODE_WRITE | FMODE_READ; + error = mnt_want_write(hugetlbfs_vfsmount); + WARN_ON(error); return file; out_inode: diff -puN mm/shmem.c~fix-__fput-rev2 mm/shmem.c --- lxc/mm/shmem.c~fix-__fput-rev2 2006-06-27 10:40:35.000000000 -0700 +++ lxc-dave/mm/shmem.c 2006-06-27 10:40:35.000000000 -0700 @@ -2326,6 +2326,8 @@ struct file *shmem_file_setup(char *name file->f_mapping = inode->i_mapping; file->f_op = &shmem_file_operations; file->f_mode = FMODE_WRITE | FMODE_READ; + error = mnt_want_write(shm_mnt); + WARN_ON(error); return file; close_file: diff -puN mm/tiny-shmem.c~fix-__fput-rev2 mm/tiny-shmem.c --- lxc/mm/tiny-shmem.c~fix-__fput-rev2 2006-06-27 10:40:35.000000000 -0700 +++ lxc-dave/mm/tiny-shmem.c 2006-06-27 10:40:35.000000000 -0700 @@ -88,6 +88,8 @@ struct file *shmem_file_setup(char *name file->f_mapping = inode->i_mapping; file->f_op = &ramfs_file_operations; file->f_mode = FMODE_WRITE | FMODE_READ; + error = mnt_want_write(shm_mnt); + WARN_ON(error); /* notify everyone as to the change of file size */ error = do_truncate(dentry, size, 0, file); diff -puN net/socket.c~fix-__fput-rev2 net/socket.c --- lxc/net/socket.c~fix-__fput-rev2 2006-06-27 10:40:35.000000000 -0700 +++ lxc-dave/net/socket.c 2006-06-27 10:40:35.000000000 -0700 @@ -396,6 +396,7 @@ static int sock_attach_fd(struct socket { struct qstr this; char name[32]; + int error; this.len = sprintf(name, "[%lu]", SOCK_INODE(sock)->i_ino); this.name = name; @@ -416,6 +417,8 @@ static int sock_attach_fd(struct socket file->f_flags = O_RDWR; file->f_pos = 0; file->private_data = sock; + error = mnt_want_write(sock_mnt); + WARN_ON(error); return 0; } _ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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