From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
In commit dc617f29dbe5 we tried to prevent userspace programs from
writing to active swap devices. However, it turns out that userspace
hibernation requires the ability to write the hibernation image to a
swap device, so revert the write path checks.
Fixes: dc617f29dbe5 ("vfs: don't allow writes to swap files")
Reported-by: Domenico Andreoli <domenico.andreoli@xxxxxxxxx>
Reported-by: Marian Klein <mkleinsoft@xxxxxxxxx>
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/block_dev.c | 3 ---
mm/filemap.c | 3 ---
mm/memory.c | 4 ----
mm/mmap.c | 8 ++------
4 files changed, 2 insertions(+), 16 deletions(-)
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 69bf2fb6f7cd..08b088dac1f0 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -2001,9 +2001,6 @@ 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/mm/filemap.c b/mm/filemap.c
index 1784478270e1..d1b8cd15b2bf 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2920,9 +2920,6 @@ 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 0bccc622e482..e908490f7034 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2357,10 +2357,6 @@ 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 d681a20eb4ea..77d086139e13 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1461,12 +1461,8 @@ unsigned long do_mmap(struct file *file, unsigned long addr,
case MAP_SHARED_VALIDATE:
if (flags & ~flags_mask)
return -EOPNOTSUPP;
- if (prot & PROT_WRITE) {
- if (!(file->f_mode & FMODE_WRITE))
- return -EACCES;
- if (IS_SWAPFILE(file->f_mapping->host))
- return -ETXTBSY;
- }
+ if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))
+ return -EACCES;
/*
* Make sure we don't allow writing to an append-only
