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| author |   Darrick J. Wong <darrick.wong@oracle.com> | 2019-08-20 07:55:16 -0700 |
|---|---|---|
| committer | Darrick J. Wong <darrick.wong@oracle.com> | 2019-08-20 07:55:16 -0700 |
| commit | dc617f29dbe5ef0c8ced65ce62c464af1daaab3d (patch) | |
| tree | 3596eb0d334f04f87088c735748bba8e66a71cad /mm/swapfile.c | |
| parent | mm: set S_SWAPFILE on blockdev swap devices (diff) | |
| download | linux-dev-dc617f29dbe5ef0c8ced65ce62c464af1daaab3d.tar.xz linux-dev-dc617f29dbe5ef0c8ced65ce62c464af1daaab3d.zip | |
vfs: don't allow writes to swap files
Don't let userspace write to an active swap file because the kernel
effectively has a long term lease on the storage and things could get
seriously corrupted if we let this happen.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'mm/swapfile.c')
| -rw-r--r-- | mm/swapfile.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c index a53b7c49b40e..dab43523afdd 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -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) @@ -3295,7 +3306,6 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) atomic_inc(&proc_poll_event); wake_up_interruptible(&proc_poll_wait); - inode->i_flags |= S_SWAPFILE; error = 0; goto out; bad_swap: |