Skip to main content

Browse the archive

https://github.com/torvalds/linux
23 October 2021, 00:29:24 UTC
Revision 914ee295af418e936ec20a08c1663eaabe4cd07a authored by Xin Zhong on 09 December 2010, 09:30:14 UTC, committed by Chris Mason on 10 December 2010, 21:29:10 UTC 
Btrfs: pwrite blocked when writing from the mmaped buffer of the same page
 
This problem is found in meego testing:
http://bugs.meego.com/show_bug.cgi?id=6672
A file in btrfs is mmaped and the mmaped buffer is passed to pwrite to write to the same page
of the same file. In btrfs_file_aio_write(), the pages is locked by prepare_pages(). So when
btrfs_copy_from_user() is called, page fault happens and the same page needs to be locked again
in filemap_fault(). The fix is to move iov_iter_fault_in_readable() before prepage_pages() to make page
fault happen before pages are locked. And also disable page fault in critical region in
btrfs_copy_from_user().

Reviewed-by: Yan, Zheng<zheng.z.yan@intel.com>
Signed-off-by: Zhong, Xin <xin.zhong@intel.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
1 parent f106e82
Raw File
Tip revision: 914ee295af418e936ec20a08c1663eaabe4cd07a authored by Xin Zhong on 09 December 2010, 09:30:14 UTC
Btrfs: pwrite blocked when writing from the mmaped buffer of the same page
Tip revision: 914ee29
Makefile 

obj-$(CONFIG_BTRFS_FS) := btrfs.o

btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
	   file-item.o inode-item.o inode-map.o disk-io.o \
	   transaction.o inode.o file.o tree-defrag.o \
	   extent_map.o sysfs.o struct-funcs.o xattr.o ordered-data.o \
	   extent_io.o volumes.o async-thread.o ioctl.o locking.o orphan.o \
	   export.o tree-log.o acl.o free-space-cache.o zlib.o \
	   compression.o delayed-ref.o relocation.o
back to top