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authorPádraig Brady <P@draigBrady.com>2014-04-04 13:35:56 +0100
committerPádraig Brady <P@draigBrady.com>2014-04-05 01:56:07 +0100
commitb85eb8d6835e7665bf6151db070261b123c22f95 (patch)
tree1d0fc5d1ed45ab2f5bcc115c11e00258e5c20e1f /tests
parent217618e8bf10a09270291b9825f3181ed2f83dbf (diff)
downloadcoreutils-b85eb8d6835e7665bf6151db070261b123c22f95.tar.xz
shred: overwrite inode storage used by some file systems
* doc/coreutils.texi (shred invocation): Mention some reasons why clearing slack space might be useful. * src/shred.c (do_wipefd): Add initial writes for each pass for small regular files in case the storage for those is in the inode, and thus a larger write up to a block size would bypass that. Move the direct I/O control to... (dopass): ... here so we can avoid enabling it for these small initial writes. It's better to retry direct I/O for each pass anyway to handle the case where direct I/O is disabled for only the last portion of a file when the size is not a multiple of the block size. Note we don't avoid the sync for the initial write as it will be small but more importantly could be on a different part of the disk and so worth doing independently to ensure the write is not discarded. * tests/misc/shred-exact.sh: Check some more direct I/O cases. * NEWS: Mention the improvements. The inode storage issue was mentioned by Paul Eggert.
Diffstat (limited to 'tests')
-rwxr-xr-xtests/misc/shred-exact.sh6
1 files changed, 5 insertions, 1 deletions
diff --git a/tests/misc/shred-exact.sh b/tests/misc/shred-exact.sh
index 5f2848e1d..5434229c4 100755
--- a/tests/misc/shred-exact.sh
+++ b/tests/misc/shred-exact.sh
@@ -40,6 +40,10 @@ done
# (i.e. we want to test failed writes not at the start).
truncate -s1MiB file.slop || framework_failure_
truncate -s+1 file.slop || framework_failure_
-shred --exact -n1 file.slop || fail=1
+shred --exact -n2 file.slop || fail=1
+
+# make sure direct I/O is handled appropriately at start of file
+truncate -s1 file.slop || framework_failure_
+shred --exact -n2 file.slop || fail=1
Exit $fail