diff options
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 22 |
1 files changed, 7 insertions, 15 deletions
diff --git a/fs/namei.c b/fs/namei.c index aeaca8f45..35ebbd4f4 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -124,24 +124,16 @@ int permission(struct inode * inode,int mask) * put_write_access() releases this write permission. * This is used for regular files. * We cannot support write (and maybe mmap read-write shared) accesses and - * MAP_DENYWRITE mmappings simultaneously. + * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode + * can have the following values: + * 0: no writers, no VM_DENYWRITE mappings + * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist + * > 0: (i_writecount) users are writing to the file. */ int get_write_access(struct inode * inode) { - struct task_struct * p; - - if ((inode->i_count > 1) && S_ISREG(inode->i_mode)) /* shortcut */ - for_each_task(p) { - struct vm_area_struct * mpnt; - if (!p->mm) - continue; - for(mpnt = p->mm->mmap; mpnt; mpnt = mpnt->vm_next) { - if (inode != mpnt->vm_inode) - continue; - if (mpnt->vm_flags & VM_DENYWRITE) - return -ETXTBSY; - } - } + if (inode->i_writecount < 0) + return -ETXTBSY; inode->i_writecount++; return 0; } |