zfs/module
Richard Sharpe a99c845fdc Fix casesensitivity=insensitive deadlock
When casesensitivity=insensitive is set for the
file system, we can deadlock in a rename if the user uses different case
for each path. For example rename("A/some-file.txt", "a/some-file.txt").

The simple test for this is:

1. mkdir some-dir in a ZFS file system
2. touch some-dir/some-file.txt
3. mv Some-dir/some-file.txt some-dir/some-other-file.txt

This last request deadlocks trying to relock the i_mutex on the inode for
the parent directory.

The solution is to use d_add_ci in zpl_lookup if we are on a file system
that has the casesensitivity=insensitive attribute set.

This patch checks if we are working on a case insensitive file system and if
so, allocates storage for the case insensitive name and passes it to
zfs_lookup and then calls d_add_ci instead of d_splice_alias.

The performance impact seems to be minimal even though we have introduced a
kmalloc and kfree in the lookup path.

The problem was found when running Microsoft's FSCT against Samba on top of
ZFS On Linux.

Signed-off-by: Richard Sharpe <realrichardsharpe@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #4136
2016-03-22 17:54:07 -07:00
..
avl Support parallel build trees (VPATH builds) 2015-07-17 13:42:51 -07:00
nvpair Support parallel build trees (VPATH builds) 2015-07-17 13:42:51 -07:00
unicode Support parallel build trees (VPATH builds) 2015-07-17 13:42:51 -07:00
zcommon Fix uioskip crash when skip to end 2015-09-29 15:27:14 -07:00
zfs Fix casesensitivity=insensitive deadlock 2016-03-22 17:54:07 -07:00
zpios Linux 4.2 compat: misc_deregister() 2015-09-01 09:33:18 -07:00
.gitignore gitignore: anchor entries at their respective directory 2013-04-02 10:50:17 -07:00
Makefile.in Prevent rm modules.* when make install 2015-12-23 17:29:34 -08:00