[PATCH -mm 6/9] unshare system call: allow unsharing of filesystem

From: JANAK DESAI
Date: Tue Dec 13 2005 - 17:56:06 EST



[PATCH -mm 6/9] unshare system call: allow unsharing of filesystem

If filesystem structure is being shared, allocate a new one and
copy information from the current, shared, structure.

Changes since the first submission of this patch on 12/12/05:
- Removed an unnecessary local variable (12/13/05)

Signed-off-by: Janak Desai <janak@xxxxxxxxxx>

---

fork.c | 9 ++++++---
1 files changed, 6 insertions(+), 3 deletions(-)

diff -Naurp 2.6.15-rc5-mm2+patch/kernel/fork.c 2.6.15-rc5-mm2+patch6/kernel/fork.c
--- 2.6.15-rc5-mm2+patch/kernel/fork.c 2005-12-13 18:38:26.000000000 +0000
+++ 2.6.15-rc5-mm2+patch6/kernel/fork.c 2005-12-13 19:38:03.000000000 +0000
@@ -1378,15 +1378,18 @@ static int unshare_thread(unsigned long
}

/*
- * Unsharing of fs info for tasks created with CLONE_FS is not supported yet
+ * Unshare the filesystem structure if it is being shared
*/
static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp)
{
struct fs_struct *fs = current->fs;

if ((unshare_flags & CLONE_FS) &&
- (fs && atomic_read(&fs->count) > 1))
- return -EINVAL;
+ (fs && atomic_read(&fs->count) > 1)) {
+ *new_fsp = __copy_fs_struct(current->fs);
+ if (!*new_fsp)
+ return -ENOMEM;
+ }

return 0;
}


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