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| author | Steve French <sfrench@us.ibm.com> | 2007-08-22 22:12:07 +0000 |
|---|---|---|
| committer | Steve French <sfrench@us.ibm.com> | 2007-08-22 22:12:07 +0000 |
| commit | 8064ab4da104900505f33535d230ce0da5d18341 (patch) | |
| tree | ca74f036c75ffae39d1256de7a041f9df4882da1 /fs/cifs/inode.c | |
| parent | cb00e99c0abd844b884c64c6b54aa3b7d345ebb1 (diff) | |
| download | lwn-8064ab4da104900505f33535d230ce0da5d18341.tar.gz lwn-8064ab4da104900505f33535d230ce0da5d18341.zip | |
[CIFS] cifs truncate missing a fix for private map COW race
vmtruncate had added the same fix to handle the case of private pages
being Copy on writed while truncate_inode_pages is going on
Signed-off-by: Steve French <sfrench@us.ibm.com>
Diffstat (limited to 'fs/cifs/inode.c')
| -rw-r--r-- | fs/cifs/inode.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c index dd4167762a8e..97ccc513730f 100644 --- a/fs/cifs/inode.c +++ b/fs/cifs/inode.c @@ -1377,8 +1377,17 @@ static int cifs_vmtruncate(struct inode *inode, loff_t offset) } i_size_write(inode, offset); spin_unlock(&inode->i_lock); + /* + * unmap_mapping_range is called twice, first simply for efficiency + * so that truncate_inode_pages does fewer single-page unmaps. However + * after this first call, and before truncate_inode_pages finishes, + * it is possible for private pages to be COWed, which remain after + * truncate_inode_pages finishes, hence the second unmap_mapping_range + * call must be made for correctness. + */ unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); truncate_inode_pages(mapping, offset); + unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); goto out_truncate; do_expand: |