diff options
author | Darrick J. Wong <darrick.wong@oracle.com> | 2019-08-20 17:55:16 +0300 |
---|---|---|
committer | Darrick J. Wong <darrick.wong@oracle.com> | 2019-08-20 17:55:16 +0300 |
commit | 1638045c36772b47a0765f7dca07cb90267e4942 (patch) | |
tree | 712132e4734b88a780b7b0941ae57f326f7e24b2 /mm | |
parent | 609488bc979f99f805f34e9a32c1e3b71179d10b (diff) | |
download | linux-1638045c36772b47a0765f7dca07cb90267e4942.tar.xz |
mm: set S_SWAPFILE on blockdev swap devices
Set S_SWAPFILE on block device inodes so that they have the same
protections as a swap flie.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/swapfile.c | 31 |
1 files changed, 15 insertions, 16 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c index 0789a762ce2f..a53b7c49b40e 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; } @@ -3295,8 +3295,7 @@ 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; + inode->i_flags |= S_SWAPFILE; error = 0; goto out; bad_swap: @@ -3318,7 +3317,7 @@ 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 +3330,7 @@ out: } if (name) putname(name); - if (inode && S_ISREG(inode->i_mode)) + if (inode) inode_unlock(inode); if (!error) enable_swap_slots_cache(); |