staging/lustre/mdt: duplicate link names in directory
When creating a hard link to a file, the MDT/MDD/OSD code does not verify whether the target link name already exists in the directory. The ZFS ZAP code checks for duplicate entries. The add_dirent_to_buf() function in ldiskfs only checks entries for duplicates while it is traversing the leaf block looking for free space. Even if it scanned the whole leaf block, this would not work for non-htree directories since there is no guarantee that the name is being inserted into the same leaf block. To fix this, link should check target object doesn't exist as other creat operations. Add sanity.sh test_31o with multiple threads racing to link a new name into the directory, while ensuring that there is a free entry in the leaf block that is large enough to hold the duplicate name. This needs to be racy, because otherwise the client VFS will see the existing name and not send the RPC to the MDS, hiding the bug. Add DLDLMRES/PLDLMRES macros for printing the whole lock resource name (including the name hash) in LDLM_DEBUG() messages in a format similar to DFID/PFID so they can be found in debug logs more easily. The patch pickes client side change of the original patch, which only contains the DLM printk part. Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-2901 Lustre-change: http://review.whamcloud.com/6591Signed-off-by: Andreas Dilger <andreas.dilger@intel.com> Signed-off-by: Lai Siyao <lai.siyao@intel.com> Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com> Reviewed-by: Mike Pershin <mike.pershin@intel.com> Signed-off-by: Peng Tao <tao.peng@emc.com> Signed-off-by: Andreas Dilger <andreas.dilger@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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