diff options
| author | Ned Bass <[email protected]> | 2013-01-14 13:59:14 -0800 |
|---|---|---|
| committer | Brian Behlendorf <[email protected]> | 2013-01-16 16:28:54 -0800 |
| commit | f1a05fa11484d67161606fd1ecf50bf2abc25ced (patch) | |
| tree | 674f566861abf0ab8005ca1d6eebfaeddc0ac54f /config/kernel-dentry-operations.m4 | |
| parent | 94a9bb4709111f5fadb434cce1af6ccb6534e241 (diff) | |
Fix false ENOENT on snapshot control dentries
Lookups in the snapshot control directory for an existing snapshot
fail with ENOENT if an earlier lookup failed before the snapshot was
created. This is because the earlier lookup causes a negative dentry
to be cached which is never invalidated.
The bug can be reproduced as follows (the second ls should succeed):
$ ls /tank/.zfs/snapshot/s
ls: cannot access /tank/.zfs/snapshot/s: No such file or directory
$ zfs snap tank@s
$ ls /tank/.zfs/snapshot/s
ls: cannot access /tank/.zfs/snapshot/s: No such file or directory
To remedy this, always invalidate cached dentries in the snapshot
control directory. Since these entries never exist on disk there is
no significant performance penalty for the extra lookups.
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #1192
Diffstat (limited to 'config/kernel-dentry-operations.m4')
| -rw-r--r-- | config/kernel-dentry-operations.m4 | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/config/kernel-dentry-operations.m4 b/config/kernel-dentry-operations.m4 new file mode 100644 index 000000000..5685b7d6f --- /dev/null +++ b/config/kernel-dentry-operations.m4 @@ -0,0 +1,64 @@ +dnl # +dnl # 3.6 API change +dnl # +AC_DEFUN([ZFS_AC_KERNEL_D_REVALIDATE_NAMEIDATA], [ + AC_MSG_CHECKING([whether dops->d_revalidate() takes struct nameidata]) + ZFS_LINUX_TRY_COMPILE([ + #include <linux/dcache.h> + ],[ + int (*revalidate) (struct dentry *, struct nameidata *) = NULL; + struct dentry_operations dops __attribute__ ((unused)) = { + .d_revalidate = revalidate, + }; + ],[ + AC_MSG_RESULT(yes) + AC_DEFINE(HAVE_D_REVALIDATE_NAMEIDATA, 1, + [dops->d_revalidate() operation takes nameidata]) + ],[ + AC_MSG_RESULT(no) + ]) +]) + +dnl # +dnl # 2.6.30 API change +dnl # The 'struct dentry_operations' was constified in the dentry structure. +dnl # +AC_DEFUN([ZFS_AC_KERNEL_CONST_DENTRY_OPERATIONS], [ + AC_MSG_CHECKING([whether dentry uses const struct dentry_operations]) + ZFS_LINUX_TRY_COMPILE([ + #include <linux/dcache.h> + + const struct dentry_operations test_d_op = { + .d_revalidate = NULL, + }; + ],[ + struct dentry d __attribute__ ((unused)); + + d.d_op = &test_d_op; + ],[ + AC_MSG_RESULT(yes) + AC_DEFINE(HAVE_CONST_DENTRY_OPERATIONS, 1, + [dentry uses const struct dentry_operations]) + ],[ + AC_MSG_RESULT(no) + ]) +]) + +dnl # +dnl # 2.6.38 API change +dnl # Added d_set_d_op() helper function. +dnl # +AC_DEFUN([ZFS_AC_KERNEL_D_SET_D_OP], + [AC_MSG_CHECKING([whether d_set_d_op() is available]) + ZFS_LINUX_TRY_COMPILE_SYMBOL([ + #include <linux/dcache.h> + ], [ + d_set_d_op(NULL, NULL); + ], [d_set_d_op], [fs/dcache.c], [ + AC_MSG_RESULT(yes) + AC_DEFINE(HAVE_D_SET_D_OP, 1, + [d_set_d_op() is available]) + ], [ + AC_MSG_RESULT(no) + ]) +]) |