diff options
| -rw-r--r-- | fs/block_dev.c | 3 | ||||
| -rw-r--r-- | include/linux/fs.h | 11 | ||||
| -rw-r--r-- | mm/filemap.c | 3 | ||||
| -rw-r--r-- | mm/memory.c | 4 | ||||
| -rw-r--r-- | mm/mmap.c | 8 | ||||
| -rw-r--r-- | mm/swapfile.c | 41 |
6 files changed, 52 insertions, 18 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c index 677cb364d33f..9c073dbdc1b0 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1972,6 +1972,9 @@ ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) if (bdev_read_only(I_BDEV(bd_inode))) return -EPERM; + if (IS_SWAPFILE(bd_inode)) + return -ETXTBSY; + if (!iov_iter_count(from)) return 0; diff --git a/include/linux/fs.h b/include/linux/fs.h index 104a727f8a67..ae6648145d18 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3565,4 +3565,15 @@ static inline void simple_fill_fsxattr(struct fsxattr *fa, __u32 xflags) fa->fsx_xflags = xflags; } +/* + * Flush file data before changing attributes. Caller must hold any locks + * required to prevent further writes to this file until we're done setting + * flags. + */ +static inline int inode_drain_writes(struct inode *inode) +{ + inode_dio_wait(inode); + return filemap_write_and_wait(inode->i_mapping); +} + #endif /* _LINUX_FS_H */ diff --git a/mm/filemap.c b/mm/filemap.c index d0cf700bf201..40667c2f3383 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2988,6 +2988,9 @@ inline ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from) loff_t count; int ret; + if (IS_SWAPFILE(inode)) + return -ETXTBSY; + if (!iov_iter_count(from)) return 0; diff --git a/mm/memory.c b/mm/memory.c index e2bb51b6242e..b1dff75640b7 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2196,6 +2196,10 @@ static vm_fault_t do_page_mkwrite(struct vm_fault *vmf) vmf->flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; + if (vmf->vma->vm_file && + IS_SWAPFILE(vmf->vma->vm_file->f_mapping->host)) + return VM_FAULT_SIGBUS; + ret = vmf->vma->vm_ops->page_mkwrite(vmf); /* Restore original flags so that caller is not surprised */ vmf->flags = old_flags; diff --git a/mm/mmap.c b/mm/mmap.c index 7e8c3e8ae75f..6bc21fca20bc 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1483,8 +1483,12 @@ unsigned long do_mmap(struct file *file, unsigned long addr, case MAP_SHARED_VALIDATE: if (flags & ~flags_mask) return -EOPNOTSUPP; - if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) - return -EACCES; + if (prot & PROT_WRITE) { + if (!(file->f_mode & FMODE_WRITE)) + return -EACCES; + if (IS_SWAPFILE(file->f_mapping->host)) + return -ETXTBSY; + } /* * Make sure we don't allow writing to an append-only diff --git a/mm/swapfile.c b/mm/swapfile.c index 0789a762ce2f..dab43523afdd 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -2368,9 +2368,8 @@ EXPORT_SYMBOL_GPL(add_swap_extent); * requirements, they are simply tossed out - we will never use those blocks * for swapping. * - * For S_ISREG swapfiles we set S_SWAPFILE across the life of the swapon. This - * prevents root from shooting her foot off by ftruncating an in-use swapfile, - * which will scribble on the fs. + * For all swap devices we set S_SWAPFILE across the life of the swapon. This + * prevents users from writing to the swap device, which will corrupt memory. * * The amount of disk space which a single swap extent represents varies. * Typically it is in the 1-4 megabyte range. So we can have hundreds of @@ -2661,13 +2660,14 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) inode = mapping->host; if (S_ISBLK(inode->i_mode)) { struct block_device *bdev = I_BDEV(inode); + set_blocksize(bdev, old_block_size); blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL); - } else { - inode_lock(inode); - inode->i_flags &= ~S_SWAPFILE; - inode_unlock(inode); } + + inode_lock(inode); + inode->i_flags &= ~S_SWAPFILE; + inode_unlock(inode); filp_close(swap_file, NULL); /* @@ -2890,11 +2890,11 @@ static int claim_swapfile(struct swap_info_struct *p, struct inode *inode) p->flags |= SWP_BLKDEV; } else if (S_ISREG(inode->i_mode)) { p->bdev = inode->i_sb->s_bdev; - inode_lock(inode); - if (IS_SWAPFILE(inode)) - return -EBUSY; - } else - return -EINVAL; + } + + inode_lock(inode); + if (IS_SWAPFILE(inode)) + return -EBUSY; return 0; } @@ -3275,6 +3275,17 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) if (error) goto bad_swap; + /* + * Flush any pending IO and dirty mappings before we start using this + * swap device. + */ + inode->i_flags |= S_SWAPFILE; + error = inode_drain_writes(inode); + if (error) { + inode->i_flags &= ~S_SWAPFILE; + goto bad_swap; + } + mutex_lock(&swapon_mutex); prio = -1; if (swap_flags & SWAP_FLAG_PREFER) @@ -3295,8 +3306,6 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) atomic_inc(&proc_poll_event); wake_up_interruptible(&proc_poll_wait); - if (S_ISREG(inode->i_mode)) - inode->i_flags |= S_SWAPFILE; error = 0; goto out; bad_swap: @@ -3318,7 +3327,7 @@ bad_swap: if (inced_nr_rotate_swap) atomic_dec(&nr_rotate_swap); if (swap_file) { - if (inode && S_ISREG(inode->i_mode)) { + if (inode) { inode_unlock(inode); inode = NULL; } @@ -3331,7 +3340,7 @@ out: } if (name) putname(name); - if (inode && S_ISREG(inode->i_mode)) + if (inode) inode_unlock(inode); if (!error) enable_swap_slots_cache(); |