afs: prevent double cell registration (5214b729) · Commits · 戴 / test

kafs doesn't check if the cell already exists - so if you do an echo "add newcell.org 1.2.3.4" >/proc/fs/afs/cells it will try to create this cell again. kobject will also complain about a double registration. To prevent such problems, return -EEXIST in that case. Signed-off-by:

Sven Schnelle <svens@stackframe.org> Signed-off-by:

David Howells <dhowells@redhat.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

fs/afs/cell.c

+13 −2

Original line number	Diff line number	Diff line
		@@ -127,14 +127,20 @@ struct afs_cell afs_cell_create(const char name, char *vllist)

		_enter("%s,%s", name, vllist);

		down_write(&afs_cells_sem);
		read_lock(&afs_cells_lock);
		list_for_each_entry(cell, &afs_cells, link) {
		if (strcasecmp(cell->name, name) == 0)
		goto duplicate_name;
		}
		read_unlock(&afs_cells_lock);

		cell = afs_cell_alloc(name, vllist);
		if (IS_ERR(cell)) {
		_leave(" = %ld", PTR_ERR(cell));
		return cell;
		}

		down_write(&afs_cells_sem);

		/* add a proc directory for this cell */
		ret = afs_proc_cell_setup(cell);
		if (ret < 0)
		@@ -167,6 +173,11 @@ error:
		kfree(cell);
		_leave(" = %d", ret);
		return ERR_PTR(ret);

		duplicate_name:
		read_unlock(&afs_cells_lock);
		up_write(&afs_cells_sem);
		return ERR_PTR(-EEXIST);
		}

		/*

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